scftorture: Count single_rpc offline failures in statistics outputgrafted

scf_torture_stats_print() aggregates each invoker thread's counters
into a local scf_statistics structure before printing, but the
n_single_rpc_ofl field is missing from the aggregation loop.  As a
result, the "single_rpc_ofl" value printed in the statistics line is
always zero, even when smp_call_function_single() invocations for the
RPC test have failed due to offline CPUs and been counted by the
invoker threads.

Add the missing accumulation so that the printed value reflects the
actual counts.

Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

14 files changed, 4166 insertions, 0 deletions

diff --git a/arch/x86/hyperv/.gitignore b/arch/x86/hyperv/.gitignore
new file mode 100644
index 000000000..333615d99
--- /dev/null
+++ b/arch/x86/hyperv/.gitignore
@@ -0,0 +1 @@
+mshv-asm-offsets.h
diff --git a/arch/x86/hyperv/Makefile b/arch/x86/hyperv/Makefile
new file mode 100644
index 000000000..56292102a
--- /dev/null
+++ b/arch/x86/hyperv/Makefile
@@ -0,0 +1,22 @@
+# SPDX-License-Identifier: GPL-2.0-only
+obj-y			:= hv_init.o mmu.o nested.o irqdomain.o ivm.o
+obj-$(CONFIG_X86_64)	+= hv_apic.o
+obj-$(CONFIG_HYPERV_VTL_MODE)	+= hv_vtl.o mshv_vtl_asm.o
+
+$(obj)/mshv_vtl_asm.o: $(obj)/mshv-asm-offsets.h
+
+$(obj)/mshv-asm-offsets.h: $(obj)/mshv-asm-offsets.s FORCE
+	$(call filechk,offsets,__MSHV_ASM_OFFSETS_H__)
+
+ifdef CONFIG_X86_64
+obj-$(CONFIG_PARAVIRT_SPINLOCKS)	+= hv_spinlock.o
+
+ ifdef CONFIG_MSHV_ROOT
+  CFLAGS_REMOVE_hv_trampoline.o += -pg
+  CFLAGS_hv_trampoline.o        += -fno-stack-protector
+  obj-$(CONFIG_CRASH_DUMP)      += hv_crash.o hv_trampoline.o
+ endif
+endif
+
+targets += mshv-asm-offsets.s
+clean-files += mshv-asm-offsets.h
diff --git a/arch/x86/hyperv/hv_apic.c b/arch/x86/hyperv/hv_apic.c
new file mode 100644
index 000000000..a8de503de
--- /dev/null
+++ b/arch/x86/hyperv/hv_apic.c
@@ -0,0 +1,341 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Hyper-V specific APIC code.
+ *
+ * Copyright (C) 2018, Microsoft, Inc.
+ *
+ * Author : K. Y. Srinivasan <kys@microsoft.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
+ * NON INFRINGEMENT.  See the GNU General Public License for more
+ * details.
+ *
+ */
+
+#include <linux/types.h>
+#include <linux/vmalloc.h>
+#include <linux/mm.h>
+#include <linux/clockchips.h>
+#include <linux/slab.h>
+#include <linux/cpuhotplug.h>
+#include <asm/hypervisor.h>
+#include <asm/mshyperv.h>
+#include <asm/apic.h>
+#include <asm/msr.h>
+
+#include <asm/trace/hyperv.h>
+
+static struct apic orig_apic;
+
+static u64 hv_apic_icr_read(void)
+{
+	u64 reg_val;
+
+	rdmsrq(HV_X64_MSR_ICR, reg_val);
+	return reg_val;
+}
+
+static void hv_apic_icr_write(u32 low, u32 id)
+{
+	u64 reg_val;
+
+	reg_val = SET_XAPIC_DEST_FIELD(id);
+	reg_val = reg_val << 32;
+	reg_val |= low;
+
+	wrmsrq(HV_X64_MSR_ICR, reg_val);
+}
+
+void hv_enable_coco_interrupt(unsigned int cpu, unsigned int vector, bool set)
+{
+	apic_update_vector(cpu, vector, set);
+}
+
+static u32 hv_apic_read(u32 reg)
+{
+	u32 reg_val, hi;
+
+	switch (reg) {
+	case APIC_EOI:
+		rdmsr(HV_X64_MSR_EOI, reg_val, hi);
+		(void)hi;
+		return reg_val;
+	case APIC_TASKPRI:
+		rdmsr(HV_X64_MSR_TPR, reg_val, hi);
+		(void)hi;
+		return reg_val;
+
+	default:
+		return native_apic_mem_read(reg);
+	}
+}
+
+static void hv_apic_write(u32 reg, u32 val)
+{
+	switch (reg) {
+	case APIC_EOI:
+		wrmsrq(HV_X64_MSR_EOI, val);
+		break;
+	case APIC_TASKPRI:
+		wrmsrq(HV_X64_MSR_TPR, val);
+		break;
+	default:
+		native_apic_mem_write(reg, val);
+	}
+}
+
+static void hv_apic_eoi_write(void)
+{
+	struct hv_vp_assist_page *hvp = hv_vp_assist_page[smp_processor_id()];
+
+	if (hvp && (xchg(&hvp->apic_assist, 0) & 0x1))
+		return;
+
+	wrmsrq(HV_X64_MSR_EOI, APIC_EOI_ACK);
+}
+
+static bool cpu_is_self(int cpu)
+{
+	return cpu == smp_processor_id();
+}
+
+/*
+ * IPI implementation on Hyper-V.
+ */
+static bool __send_ipi_mask_ex(const struct cpumask *mask, int vector,
+			       bool exclude_self)
+{
+	struct hv_send_ipi_ex *ipi_arg;
+	unsigned long flags;
+	int nr_bank = 0;
+	u64 status = HV_STATUS_INVALID_PARAMETER;
+
+	if (!(ms_hyperv.hints & HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED))
+		return false;
+
+	local_irq_save(flags);
+	ipi_arg = *this_cpu_ptr(hyperv_pcpu_input_arg);
+
+	if (unlikely(!ipi_arg))
+		goto ipi_mask_ex_done;
+
+	ipi_arg->vector = vector;
+	ipi_arg->reserved = 0;
+	ipi_arg->vp_set.valid_bank_mask = 0;
+
+	/*
+	 * Use HV_GENERIC_SET_ALL and avoid converting cpumask to VP_SET
+	 * when the IPI is sent to all currently present CPUs.
+	 */
+	if (!cpumask_equal(mask, cpu_present_mask) || exclude_self) {
+		ipi_arg->vp_set.format = HV_GENERIC_SET_SPARSE_4K;
+
+		nr_bank = cpumask_to_vpset_skip(&ipi_arg->vp_set, mask,
+						exclude_self ? cpu_is_self : NULL);
+
+		/*
+		 * 'nr_bank <= 0' means some CPUs in cpumask can't be
+		 * represented in VP_SET. Return an error and fall back to
+		 * native (architectural) method of sending IPIs.
+		 */
+		if (nr_bank <= 0)
+			goto ipi_mask_ex_done;
+	} else {
+		ipi_arg->vp_set.format = HV_GENERIC_SET_ALL;
+	}
+
+	/*
+	 * For this hypercall, Hyper-V treats the valid_bank_mask field
+	 * of ipi_arg->vp_set as part of the fixed size input header.
+	 * So the variable input header size is equal to nr_bank.
+	 */
+	status = hv_do_rep_hypercall(HVCALL_SEND_IPI_EX, 0, nr_bank,
+				     ipi_arg, NULL);
+
+ipi_mask_ex_done:
+	local_irq_restore(flags);
+	return hv_result_success(status);
+}
+
+static bool __send_ipi_mask(const struct cpumask *mask, int vector,
+			    bool exclude_self)
+{
+	int cur_cpu, vcpu, this_cpu = smp_processor_id();
+	struct hv_send_ipi ipi_arg;
+	u64 status;
+	unsigned int weight;
+
+	trace_hyperv_send_ipi_mask(mask, vector);
+
+	weight = cpumask_weight(mask);
+
+	/*
+	 * Do nothing if
+	 *   1. the mask is empty
+	 *   2. the mask only contains self when exclude_self is true
+	 */
+	if (weight == 0 ||
+	    (exclude_self && weight == 1 && cpumask_test_cpu(this_cpu, mask)))
+		return true;
+
+	/* A fully enlightened TDX VM uses GHCI rather than hv_hypercall_pg. */
+	if (!hv_hypercall_pg) {
+		if (ms_hyperv.paravisor_present || !hv_isolation_type_tdx())
+			return false;
+	}
+
+	if (vector < HV_IPI_LOW_VECTOR || vector > HV_IPI_HIGH_VECTOR)
+		return false;
+
+	/*
+	 * From the supplied CPU set we need to figure out if we can get away
+	 * with cheaper HVCALL_SEND_IPI hypercall. This is possible when the
+	 * highest VP number in the set is < 64. As VP numbers are usually in
+	 * ascending order and match Linux CPU ids, here is an optimization:
+	 * we check the VP number for the highest bit in the supplied set first
+	 * so we can quickly find out if using HVCALL_SEND_IPI_EX hypercall is
+	 * a must. We will also check all VP numbers when walking the supplied
+	 * CPU set to remain correct in all cases.
+	 */
+	if (hv_cpu_number_to_vp_number(cpumask_last(mask)) >= 64)
+		goto do_ex_hypercall;
+
+	ipi_arg.vector = vector;
+	ipi_arg.cpu_mask = 0;
+
+	for_each_cpu(cur_cpu, mask) {
+		if (exclude_self && cur_cpu == this_cpu)
+			continue;
+		vcpu = hv_cpu_number_to_vp_number(cur_cpu);
+		if (vcpu == VP_INVAL)
+			return false;
+
+		/*
+		 * This particular version of the IPI hypercall can
+		 * only target up to 64 CPUs.
+		 */
+		if (vcpu >= 64)
+			goto do_ex_hypercall;
+
+		__set_bit(vcpu, (unsigned long *)&ipi_arg.cpu_mask);
+	}
+
+	status = hv_do_fast_hypercall16(HVCALL_SEND_IPI, ipi_arg.vector,
+					ipi_arg.cpu_mask);
+	return hv_result_success(status);
+
+do_ex_hypercall:
+	return __send_ipi_mask_ex(mask, vector, exclude_self);
+}
+
+static bool __send_ipi_one(int cpu, int vector)
+{
+	int vp = hv_cpu_number_to_vp_number(cpu);
+	u64 status;
+
+	trace_hyperv_send_ipi_one(cpu, vector);
+
+	if (vp == VP_INVAL)
+		return false;
+
+	/* A fully enlightened TDX VM uses GHCI rather than hv_hypercall_pg. */
+	if (!hv_hypercall_pg) {
+		if (ms_hyperv.paravisor_present || !hv_isolation_type_tdx())
+			return false;
+	}
+
+	if (vector < HV_IPI_LOW_VECTOR || vector > HV_IPI_HIGH_VECTOR)
+		return false;
+
+	if (vp >= 64)
+		return __send_ipi_mask_ex(cpumask_of(cpu), vector, false);
+
+	status = hv_do_fast_hypercall16(HVCALL_SEND_IPI, vector, BIT_ULL(vp));
+	return hv_result_success(status);
+}
+
+static void hv_send_ipi(int cpu, int vector)
+{
+	if (!__send_ipi_one(cpu, vector))
+		orig_apic.send_IPI(cpu, vector);
+}
+
+static void hv_send_ipi_mask(const struct cpumask *mask, int vector)
+{
+	if (!__send_ipi_mask(mask, vector, false))
+		orig_apic.send_IPI_mask(mask, vector);
+}
+
+static void hv_send_ipi_mask_allbutself(const struct cpumask *mask, int vector)
+{
+	if (!__send_ipi_mask(mask, vector, true))
+		orig_apic.send_IPI_mask_allbutself(mask, vector);
+}
+
+static void hv_send_ipi_allbutself(int vector)
+{
+	hv_send_ipi_mask_allbutself(cpu_online_mask, vector);
+}
+
+static void hv_send_ipi_all(int vector)
+{
+	if (!__send_ipi_mask(cpu_online_mask, vector, false))
+		orig_apic.send_IPI_all(vector);
+}
+
+static void hv_send_ipi_self(int vector)
+{
+	if (!__send_ipi_one(smp_processor_id(), vector))
+		orig_apic.send_IPI_self(vector);
+}
+
+void __init hv_apic_init(void)
+{
+	if (cc_platform_has(CC_ATTR_SNP_SECURE_AVIC))
+		return;
+
+	if (ms_hyperv.hints & HV_X64_CLUSTER_IPI_RECOMMENDED) {
+		pr_info("Hyper-V: Using IPI hypercalls\n");
+		/*
+		 * Set the IPI entry points.
+		 */
+		orig_apic = *apic;
+
+		apic_update_callback(send_IPI, hv_send_ipi);
+		apic_update_callback(send_IPI_mask, hv_send_ipi_mask);
+		apic_update_callback(send_IPI_mask_allbutself, hv_send_ipi_mask_allbutself);
+		apic_update_callback(send_IPI_allbutself, hv_send_ipi_allbutself);
+		apic_update_callback(send_IPI_all, hv_send_ipi_all);
+		apic_update_callback(send_IPI_self, hv_send_ipi_self);
+	}
+
+	if (ms_hyperv.hints & HV_X64_APIC_ACCESS_RECOMMENDED) {
+		pr_info("Hyper-V: Using enlightened APIC (%s mode)",
+			x2apic_enabled() ? "x2apic" : "xapic");
+		/*
+		 * When in x2apic mode, don't use the Hyper-V specific APIC
+		 * accessors since the field layout in the ICR register is
+		 * different in x2apic mode. Furthermore, the architectural
+		 * x2apic MSRs function just as well as the Hyper-V
+		 * synthetic APIC MSRs, so there's no benefit in having
+		 * separate Hyper-V accessors for x2apic mode. The only
+		 * exception is hv_apic_eoi_write, because it benefits from
+		 * lazy EOI when available, but the same accessor works for
+		 * both xapic and x2apic because the field layout is the same.
+		 */
+		apic_update_callback(eoi, hv_apic_eoi_write);
+		if (!x2apic_enabled()) {
+			apic_update_callback(read, hv_apic_read);
+			apic_update_callback(write, hv_apic_write);
+			apic_update_callback(icr_write, hv_apic_icr_write);
+			apic_update_callback(icr_read, hv_apic_icr_read);
+		}
+	}
+}
diff --git a/arch/x86/hyperv/hv_crash.c b/arch/x86/hyperv/hv_crash.c
new file mode 100644
index 000000000..5ffcc2325
--- /dev/null
+++ b/arch/x86/hyperv/hv_crash.c
@@ -0,0 +1,647 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * X86 specific Hyper-V root partition kdump/crash support module
+ *
+ * Copyright (C) 2025, Microsoft, Inc.
+ *
+ * This module implements hypervisor RAM collection into vmcore for both
+ * cases of the hypervisor crash and Linux root crash. Hyper-V implements
+ * a disable hypercall with a 32bit protected mode ABI callback. This
+ * mechanism must be used to unlock hypervisor RAM. Since the hypervisor RAM
+ * is already mapped in Linux, it is automatically collected into Linux vmcore,
+ * and can be examined by the crash command (raw RAM dump) or windbg.
+ *
+ * At a high level:
+ *
+ *  Hypervisor Crash:
+ *    Upon crash, hypervisor goes into an emergency minimal dispatch loop, a
+ *    restrictive mode with very limited hypercall and MSR support. Each cpu
+ *    then injects NMIs into root vcpus. A shared page is used to check
+ *    by Linux in the NMI handler if the hypervisor has crashed. This shared
+ *    page is setup in hv_root_crash_init during boot.
+ *
+ *  Linux Crash:
+ *    In case of Linux crash, the callback hv_crash_stop_other_cpus will send
+ *    NMIs to all cpus, then proceed to the crash_nmi_callback where it waits
+ *    for all cpus to be in NMI.
+ *
+ *  NMI Handler (upon quorum):
+ *    Eventually, in both cases, all cpus will end up in the NMI handler.
+ *    Hyper-V requires the disable hypervisor must be done from the BSP. So
+ *    the BSP NMI handler saves current context, does some fixups and makes
+ *    the hypercall to disable the hypervisor, ie, devirtualize. Hypervisor
+ *    at that point will suspend all vcpus (except the BSP), unlock all its
+ *    RAM, and return to Linux at the 32bit mode entry RIP.
+ *
+ *  Linux 32bit entry trampoline will then restore long mode and call C
+ *  function here to restore context and continue execution to crash kexec.
+ */
+
+#include <linux/delay.h>
+#include <linux/kexec.h>
+#include <linux/crash_dump.h>
+#include <linux/panic.h>
+#include <asm/apic.h>
+#include <asm/desc.h>
+#include <asm/page.h>
+#include <asm/pgalloc.h>
+#include <asm/mshyperv.h>
+#include <asm/nmi.h>
+#include <asm/idtentry.h>
+#include <asm/reboot.h>
+#include <asm/intel_pt.h>
+
+bool hv_crash_enabled;
+EXPORT_SYMBOL_GPL(hv_crash_enabled);
+
+struct hv_crash_ctxt {
+	ulong rsp;
+	ulong cr0;
+	ulong cr2;
+	ulong cr4;
+	ulong cr8;
+
+	u16 cs;
+	u16 ss;
+	u16 ds;
+	u16 es;
+	u16 fs;
+	u16 gs;
+
+	u16 gdt_fill;
+	struct desc_ptr gdtr;
+	char idt_fill[6];
+	struct desc_ptr idtr;
+
+	u64 gsbase;
+	u64 efer;
+	u64 pat;
+};
+static struct hv_crash_ctxt hv_crash_ctxt;
+
+/* Shared hypervisor page that contains crash dump area we peek into.
+ * NB: windbg looks for "hv_cda" symbol so don't change it.
+ */
+static struct hv_crashdump_area *hv_cda;
+
+static u32 trampoline_pa, devirt_arg;
+static atomic_t crash_cpus_wait;
+static void *hv_crash_ptpgs[4];
+static bool hv_has_crashed, lx_has_crashed;
+
+static void __noreturn hv_panic_timeout_reboot(void)
+{
+	#define PANIC_TIMER_STEP 100
+
+	if (panic_timeout > 0) {
+		int i;
+
+		for (i = 0; i < panic_timeout * 1000; i += PANIC_TIMER_STEP)
+			mdelay(PANIC_TIMER_STEP);
+	}
+
+	if (panic_timeout)
+		native_wrmsrq(HV_X64_MSR_RESET, 1);    /* get hyp to reboot */
+
+	for (;;)
+		cpu_relax();
+}
+
+static void hv_crash_restore_tss(void)
+{
+	load_TR_desc();
+}
+
+static void hv_crash_clear_kernpt(void)
+{
+	pgd_t *pgd;
+	p4d_t *p4d;
+
+	/* Clear entry so it's not confusing to someone looking at the core */
+	pgd = pgd_offset_k(trampoline_pa);
+	p4d = p4d_offset(pgd, trampoline_pa);
+	native_p4d_clear(p4d);
+}
+
+
+static void __noreturn hv_crash_handle(void)
+{
+	hv_crash_restore_tss();
+	hv_crash_clear_kernpt();
+
+	/* we are now fully in devirtualized normal kernel mode */
+	__crash_kexec(NULL);
+
+	hv_panic_timeout_reboot();
+}
+
+/*
+ * __naked functions do not permit function calls, not even to __always_inline
+ * functions that only contain asm() blocks themselves. So use a macro instead.
+ */
+#define hv_wrmsr(msr, val) \
+	asm volatile("wrmsr" :: "c"(msr), "a"((u32)val), "d"((u32)(val >> 32)) : "memory")
+
+/*
+ * This is the C entry point from the asm glue code after the disable hypercall.
+ * We enter here in IA32-e long mode, ie, full 64bit mode running on kernel
+ * page tables with our below 4G page identity mapped, but using a temporary
+ * GDT. ds/fs/gs/es are null. ss is not usable. bp is null. stack is not
+ * available. We restore kernel GDT, and rest of the context, and continue
+ * to kexec.
+ */
+static void __naked hv_crash_c_entry(void)
+{
+	/* first thing, restore kernel gdt */
+	asm volatile("lgdt %0" : : "m" (hv_crash_ctxt.gdtr));
+
+	asm volatile("movw %0, %%ss\n\t"
+		     "movq %1, %%rsp"
+		     :: "m"(hv_crash_ctxt.ss), "m"(hv_crash_ctxt.rsp));
+
+	asm volatile("movw %0, %%ds" : : "m"(hv_crash_ctxt.ds));
+	asm volatile("movw %0, %%es" : : "m"(hv_crash_ctxt.es));
+	asm volatile("movw %0, %%fs" : : "m"(hv_crash_ctxt.fs));
+	asm volatile("movw %0, %%gs" : : "m"(hv_crash_ctxt.gs));
+
+	hv_wrmsr(MSR_IA32_CR_PAT, hv_crash_ctxt.pat);
+	asm volatile("movq %0, %%cr0" : : "r"(hv_crash_ctxt.cr0));
+
+	asm volatile("movq %0, %%cr8" : : "r"(hv_crash_ctxt.cr8));
+	asm volatile("movq %0, %%cr4" : : "r"(hv_crash_ctxt.cr4));
+	asm volatile("movq %0, %%cr2" : : "r"(hv_crash_ctxt.cr2));
+
+	asm volatile("lidt %0" : : "m" (hv_crash_ctxt.idtr));
+	hv_wrmsr(MSR_GS_BASE, hv_crash_ctxt.gsbase);
+	hv_wrmsr(MSR_EFER, hv_crash_ctxt.efer);
+
+	/* restore the original kernel CS now via far return */
+	asm volatile("pushq %q0\n\t"
+		     "pushq %q1\n\t"
+		     "lretq"
+		     :: "r"(hv_crash_ctxt.cs), "r"(hv_crash_handle));
+}
+/* Tell objtool we are using lretq long jump in the above function intentionally */
+STACK_FRAME_NON_STANDARD(hv_crash_c_entry);
+
+static void hv_mark_tss_not_busy(void)
+{
+	struct desc_struct *desc = get_current_gdt_rw();
+	tss_desc tss;
+
+	memcpy(&tss, &desc[GDT_ENTRY_TSS], sizeof(tss_desc));
+	tss.type = 0x9;        /* available 64-bit TSS. 0xB is busy TSS */
+	write_gdt_entry(desc, GDT_ENTRY_TSS, &tss, DESC_TSS);
+}
+
+/* Save essential context */
+static void hv_hvcrash_ctxt_save(void)
+{
+	struct hv_crash_ctxt *ctxt = &hv_crash_ctxt;
+
+	ctxt->rsp = current_stack_pointer;
+
+	ctxt->cr0 = native_read_cr0();
+	ctxt->cr4 = native_read_cr4();
+
+	asm volatile("movq %%cr2, %0" : "=r"(ctxt->cr2));
+	asm volatile("movq %%cr8, %0" : "=r"(ctxt->cr8));
+
+	asm volatile("movw %%cs, %0" : "=m"(ctxt->cs));
+	asm volatile("movw %%ss, %0" : "=m"(ctxt->ss));
+	asm volatile("movw %%ds, %0" : "=m"(ctxt->ds));
+	asm volatile("movw %%es, %0" : "=m"(ctxt->es));
+	asm volatile("movw %%fs, %0" : "=m"(ctxt->fs));
+	asm volatile("movw %%gs, %0" : "=m"(ctxt->gs));
+
+	native_store_gdt(&ctxt->gdtr);
+	store_idt(&ctxt->idtr);
+
+	ctxt->gsbase = __rdmsr(MSR_GS_BASE);
+	ctxt->efer = __rdmsr(MSR_EFER);
+	ctxt->pat = __rdmsr(MSR_IA32_CR_PAT);
+}
+
+/* Add trampoline page to the kernel pagetable for transition to kernel PT */
+static void hv_crash_fixup_kernpt(void)
+{
+	pgd_t *pgd;
+	p4d_t *p4d;
+
+	pgd = pgd_offset_k(trampoline_pa);
+	p4d = p4d_offset(pgd, trampoline_pa);
+
+	/* trampoline_pa is below 4G, so no pre-existing entry to clobber */
+	p4d_populate(&init_mm, p4d, (pud_t *)hv_crash_ptpgs[1]);
+	p4d->p4d = p4d->p4d & ~(_PAGE_NX);    /* enable execute */
+}
+
+/*
+ * Notify the hyp that Linux has crashed. This will cause the hyp to quiesce
+ * and suspend all guest VPs.
+ */
+static void hv_notify_prepare_hyp(void)
+{
+	u64 status;
+	struct hv_input_notify_partition_event *input;
+	struct hv_partition_event_root_crashdump_input *cda;
+
+	input = *this_cpu_ptr(hyperv_pcpu_input_arg);
+	cda = &input->input.crashdump_input;
+	memset(input, 0, sizeof(*input));
+	input->event = HV_PARTITION_EVENT_ROOT_CRASHDUMP;
+
+	cda->crashdump_action = HV_CRASHDUMP_ENTRY;
+	status = hv_do_hypercall(HVCALL_NOTIFY_PARTITION_EVENT, input, NULL);
+	if (!hv_result_success(status))
+		return;
+
+	cda->crashdump_action = HV_CRASHDUMP_SUSPEND_ALL_VPS;
+	hv_do_hypercall(HVCALL_NOTIFY_PARTITION_EVENT, input, NULL);
+}
+
+/*
+ * Common function for all cpus before devirtualization.
+ *
+ * Hypervisor crash: all cpus get here in NMI context.
+ * Linux crash: the panicing cpu gets here at base level, all others in NMI
+ *		context. Note, panicing cpu may not be the BSP.
+ *
+ * The function is not inlined so it will show on the stack. It is named so
+ * because the crash cmd looks for certain well known function names on the
+ * stack before looking into the cpu saved note in the elf section, and
+ * that work is currently incomplete.
+ *
+ * Notes:
+ *  Hypervisor crash:
+ *    - the hypervisor is in a very restrictive mode at this point and any
+ *	vmexit it cannot handle would result in reboot. So, no mumbo jumbo,
+ *	just get to kexec as quickly as possible.
+ *
+ *  Devirtualization is supported from the BSP only at present.
+ */
+static noinline __noclone void crash_nmi_callback(struct pt_regs *regs)
+{
+	struct hv_input_disable_hyp_ex *input;
+	int msecs = 1000, ccpu = smp_processor_id();
+
+	if (ccpu == 0) {
+		/* crash_save_cpu() will be done in the kexec path */
+		cpu_emergency_stop_pt();	/* disable performance trace */
+		atomic_inc(&crash_cpus_wait);
+	} else {
+		crash_save_cpu(regs, ccpu);
+		cpu_emergency_stop_pt();	/* disable performance trace */
+		atomic_inc(&crash_cpus_wait);
+		for (;;)
+			cpu_relax();
+	}
+
+	while (atomic_read(&crash_cpus_wait) < num_online_cpus() && msecs--)
+		mdelay(1);
+
+	stop_nmi();
+	if (!hv_has_crashed)
+		hv_notify_prepare_hyp();
+
+	if (crashing_cpu == -1)
+		crashing_cpu = ccpu;		/* crash cmd uses this */
+
+	hv_hvcrash_ctxt_save();
+	hv_mark_tss_not_busy();
+	hv_crash_fixup_kernpt();
+
+	input = *this_cpu_ptr(hyperv_pcpu_input_arg);
+	memset(input, 0, sizeof(*input));
+	input->rip = trampoline_pa;
+	input->arg = devirt_arg;
+
+	(void)hv_do_hypercall(HVCALL_DISABLE_HYP_EX, input, NULL);
+
+	hv_panic_timeout_reboot();
+}
+
+
+static DEFINE_SPINLOCK(hv_crash_reboot_lk);
+
+/*
+ * Generic NMI callback handler: could be called without any crash also.
+ *   hv crash: hypervisor injects NMI's into all cpus
+ *   lx crash: panicing cpu sends NMI to all but self via crash_stop_other_cpus
+ */
+static int hv_crash_nmi_local(unsigned int cmd, struct pt_regs *regs)
+{
+	if (!hv_has_crashed && hv_cda && hv_cda->cda_valid)
+		hv_has_crashed = true;
+
+	if (!hv_has_crashed && !lx_has_crashed)
+		return NMI_DONE;	/* ignore the NMI */
+
+	if (hv_has_crashed && !kexec_crash_loaded()) {
+		if (spin_trylock(&hv_crash_reboot_lk))
+			hv_panic_timeout_reboot();
+		else
+			for (;;)
+				cpu_relax();
+	}
+
+	crash_nmi_callback(regs);
+
+	return NMI_DONE;
+}
+
+/*
+ * hv_crash_stop_other_cpus() == smp_ops.crash_stop_other_cpus
+ *
+ * On normal Linux panic, this is called twice: first from panic and then again
+ * from native_machine_crash_shutdown.
+ *
+ * In case of hyperv, 3 ways to get here:
+ *  1. hv crash (only BSP will get here):
+ *	BSP : NMI callback -> DisableHv -> hv_crash_asm32 -> hv_crash_c_entry
+ *		  -> __crash_kexec -> native_machine_crash_shutdown
+ *		  -> crash_smp_send_stop -> smp_ops.crash_stop_other_cpus
+ *  Linux panic:
+ *	2. panic cpu x: panic() -> crash_smp_send_stop
+ *				     -> smp_ops.crash_stop_other_cpus
+ *	3. BSP: native_machine_crash_shutdown -> crash_smp_send_stop
+ *
+ * NB: noclone and non standard stack because of call to crash_setup_regs().
+ */
+static void __noclone hv_crash_stop_other_cpus(void)
+{
+	static bool crash_stop_done;
+	struct pt_regs lregs;
+	int ccpu = smp_processor_id();
+
+	if (hv_has_crashed)
+		return;		/* all cpus already in NMI handler path */
+
+	if (!kexec_crash_loaded()) {
+		hv_notify_prepare_hyp();
+		hv_panic_timeout_reboot();	/* no return */
+	}
+
+	/* If the hv crashes also, we could come here again before cpus_stopped
+	 * is set in crash_smp_send_stop(). So use our own check.
+	 */
+	if (crash_stop_done)
+		return;
+	crash_stop_done = true;
+
+	/* Linux has crashed: hv is healthy, we can IPI safely */
+	lx_has_crashed = true;
+	wmb();			/* NMI handlers look at lx_has_crashed */
+
+	apic->send_IPI_allbutself(NMI_VECTOR);
+
+	if (crashing_cpu == -1)
+		crashing_cpu = ccpu;		/* crash cmd uses this */
+
+	/* crash_setup_regs() happens in kexec also, but for the kexec cpu which
+	 * is the BSP. We could be here on non-BSP cpu, collect regs if so.
+	 */
+	if (ccpu)
+		crash_setup_regs(&lregs, NULL);
+
+	crash_nmi_callback(&lregs);
+}
+STACK_FRAME_NON_STANDARD(hv_crash_stop_other_cpus);
+
+/* This GDT is accessed in IA32-e compat mode which uses 32bits addresses */
+struct hv_gdtreg_32 {
+	u16 fill;
+	u16 limit;
+	u32 address;
+} __packed;
+
+/* We need a CS with L bit to goto IA32-e long mode from 32bit compat mode */
+struct hv_crash_tramp_gdt {
+	u64 null;	/* index 0, selector 0, null selector */
+	u64 cs64;	/* index 1, selector 8, cs64 selector */
+} __packed;
+
+/* No stack, so jump via far ptr in memory to load the 64bit CS */
+struct hv_cs_jmptgt {
+	u32 address;
+	u16 csval;
+	u16 fill;
+} __packed;
+
+/* Linux use only, hypervisor doesn't look at this struct */
+struct hv_crash_tramp_data {
+	u64 tramp32_cr3;
+	u64 kernel_cr3;
+	struct hv_gdtreg_32 gdtr32;
+	struct hv_crash_tramp_gdt tramp_gdt;
+	struct hv_cs_jmptgt cs_jmptgt;
+	u64 c_entry_addr;
+} __packed;
+
+/*
+ * Setup a temporary gdt to allow the asm code to switch to the long mode.
+ * Since the asm code is relocated/copied to a below 4G page, it cannot use rip
+ * relative addressing, hence we must use trampoline_pa here. Also, save other
+ * info like jmp and C entry targets for same reasons.
+ *
+ * Returns: 0 on success, -1 on error
+ */
+static int hv_crash_setup_trampdata(u64 trampoline_va)
+{
+	int size, offs;
+	void *dest;
+	struct hv_crash_tramp_data *tramp;
+
+	/* These must match exactly the ones in the corresponding asm file */
+	BUILD_BUG_ON(offsetof(struct hv_crash_tramp_data, tramp32_cr3) != 0);
+	BUILD_BUG_ON(offsetof(struct hv_crash_tramp_data, kernel_cr3) != 8);
+	BUILD_BUG_ON(offsetof(struct hv_crash_tramp_data, gdtr32.limit) != 18);
+	BUILD_BUG_ON(offsetof(struct hv_crash_tramp_data,
+						     cs_jmptgt.address) != 40);
+	BUILD_BUG_ON(offsetof(struct hv_crash_tramp_data, c_entry_addr) != 48);
+
+	/* hv_crash_asm_end is beyond last byte by 1 */
+	size = &hv_crash_asm_end - &hv_crash_asm32;
+	if (size + sizeof(struct hv_crash_tramp_data) > PAGE_SIZE) {
+		pr_err("%s: trampoline page overflow\n", __func__);
+		return -1;
+	}
+
+	dest = (void *)trampoline_va;
+	memcpy(dest, &hv_crash_asm32, size);
+
+	dest += size;
+	dest = (void *)round_up((ulong)dest, 16);
+	tramp = (struct hv_crash_tramp_data *)dest;
+
+	/* see MAX_ASID_AVAILABLE in tlb.c: "PCID 0 is reserved for use by
+	 * non-PCID-aware users". Build cr3 with pcid 0
+	 */
+	tramp->tramp32_cr3 = __sme_pa(hv_crash_ptpgs[0]);
+
+	/* Note, when restoring X86_CR4_PCIDE, cr3[11:0] must be zero */
+	tramp->kernel_cr3 = __sme_pa(init_mm.pgd);
+
+	tramp->gdtr32.limit = sizeof(struct hv_crash_tramp_gdt);
+	tramp->gdtr32.address = trampoline_pa +
+				   (ulong)&tramp->tramp_gdt - trampoline_va;
+
+	 /* base:0 limit:0xfffff type:b dpl:0 P:1 L:1 D:0 avl:0 G:1 */
+	tramp->tramp_gdt.cs64 = 0x00af9a000000ffff;
+
+	tramp->cs_jmptgt.csval = 0x8;
+	offs = (ulong)&hv_crash_asm64 - (ulong)&hv_crash_asm32;
+	tramp->cs_jmptgt.address = trampoline_pa + offs;
+
+	tramp->c_entry_addr = (u64)&hv_crash_c_entry;
+
+	devirt_arg = trampoline_pa + (ulong)dest - trampoline_va;
+
+	return 0;
+}
+
+/*
+ * Build 32bit trampoline page table for transition from protected mode
+ * non-paging to long-mode paging. This transition needs pagetables below 4G.
+ */
+static void hv_crash_build_tramp_pt(void)
+{
+	p4d_t *p4d;
+	pud_t *pud;
+	pmd_t *pmd;
+	pte_t *pte;
+	u64 pa, addr = trampoline_pa;
+
+	p4d = hv_crash_ptpgs[0] + pgd_index(addr) * sizeof(p4d);
+	pa = virt_to_phys(hv_crash_ptpgs[1]);
+	set_p4d(p4d, __p4d(_PAGE_TABLE | pa));
+	p4d->p4d &= ~(_PAGE_NX);	/* enable execute */
+
+	pud = hv_crash_ptpgs[1] + pud_index(addr) * sizeof(pud);
+	pa = virt_to_phys(hv_crash_ptpgs[2]);
+	set_pud(pud, __pud(_PAGE_TABLE | pa));
+
+	pmd = hv_crash_ptpgs[2] + pmd_index(addr) * sizeof(pmd);
+	pa = virt_to_phys(hv_crash_ptpgs[3]);
+	set_pmd(pmd, __pmd(_PAGE_TABLE | pa));
+
+	pte = hv_crash_ptpgs[3] + pte_index(addr) * sizeof(pte);
+	set_pte(pte, pfn_pte(addr >> PAGE_SHIFT, PAGE_KERNEL_EXEC));
+}
+
+/*
+ * Setup trampoline for devirtualization:
+ *  - a page below 4G, ie 32bit addr containing asm glue code that hyp jmps to
+ *    in protected mode.
+ *  - 4 pages for a temporary page table that asm code uses to turn paging on
+ *  - a temporary gdt to use in the compat mode.
+ *
+ *  Returns: 0 on success
+ */
+static int hv_crash_trampoline_setup(void)
+{
+	int i, rc, order;
+	struct page *page;
+	u64 trampoline_va;
+	gfp_t flags32 = GFP_KERNEL | GFP_DMA32 | __GFP_ZERO;
+
+	/* page for 32bit trampoline assembly code + hv_crash_tramp_data */
+	page = alloc_page(flags32);
+	if (page == NULL) {
+		pr_err("%s: failed to alloc asm stub page\n", __func__);
+		return -1;
+	}
+
+	trampoline_va = (u64)page_to_virt(page);
+	trampoline_pa = (u32)page_to_phys(page);
+
+	order = 2;	   /* alloc 2^2 pages */
+	page = alloc_pages(flags32, order);
+	if (page == NULL) {
+		pr_err("%s: failed to alloc pt pages\n", __func__);
+		free_page(trampoline_va);
+		return -1;
+	}
+
+	for (i = 0; i < 4; i++, page++)
+		hv_crash_ptpgs[i] = page_to_virt(page);
+
+	hv_crash_build_tramp_pt();
+
+	rc = hv_crash_setup_trampdata(trampoline_va);
+	if (rc)
+		goto errout;
+
+	return 0;
+
+errout:
+	free_page(trampoline_va);
+	free_pages((ulong)hv_crash_ptpgs[0], order);
+
+	return rc;
+}
+
+/* Setup for kdump kexec to collect hypervisor RAM when running as root */
+void hv_root_crash_init(void)
+{
+	int rc;
+	struct hv_input_get_system_property *input;
+	struct hv_output_get_system_property *output;
+	unsigned long flags;
+	u64 status;
+	union hv_pfn_range cda_info;
+
+	if (pgtable_l5_enabled()) {
+		pr_err("Hyper-V: crash dump not yet supported on 5level PTs\n");
+		return;
+	}
+
+	rc = register_nmi_handler(NMI_LOCAL, hv_crash_nmi_local, NMI_FLAG_FIRST,
+				  "hv_crash_nmi");
+	if (rc) {
+		pr_err("Hyper-V: failed to register crash nmi handler\n");
+		return;
+	}
+
+	local_irq_save(flags);
+	input = *this_cpu_ptr(hyperv_pcpu_input_arg);
+	output = *this_cpu_ptr(hyperv_pcpu_output_arg);
+
+	memset(input, 0, sizeof(*input));
+	input->property_id = HV_SYSTEM_PROPERTY_CRASHDUMPAREA;
+
+	status = hv_do_hypercall(HVCALL_GET_SYSTEM_PROPERTY, input, output);
+	cda_info.as_uint64 = output->hv_cda_info.as_uint64;
+	local_irq_restore(flags);
+
+	if (!hv_result_success(status)) {
+		pr_err("Hyper-V: %s: property:%d %s\n", __func__,
+		       input->property_id, hv_result_to_string(status));
+		goto err_out;
+	}
+
+	if (cda_info.base_pfn == 0) {
+		pr_err("Hyper-V: hypervisor crash dump area pfn is 0\n");
+		goto err_out;
+	}
+
+	hv_cda = phys_to_virt(cda_info.base_pfn << HV_HYP_PAGE_SHIFT);
+
+	rc = hv_crash_trampoline_setup();
+	if (rc)
+		goto err_out;
+
+#ifdef CONFIG_SMP
+	smp_ops.crash_stop_other_cpus = hv_crash_stop_other_cpus;
+#endif
+
+	crash_kexec_post_notifiers = true;
+	hv_crash_enabled = true;
+	pr_info("Hyper-V: both linux and hypervisor kdump support enabled\n");
+
+	return;
+
+err_out:
+	unregister_nmi_handler(NMI_LOCAL, "hv_crash_nmi");
+	pr_err("Hyper-V: only linux root kdump support enabled\n");
+}
diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
new file mode 100644
index 000000000..55a8b6de2
--- /dev/null
+++ b/arch/x86/hyperv/hv_init.c
@@ -0,0 +1,745 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * X86 specific Hyper-V initialization code.
+ *
+ * Copyright (C) 2016, Microsoft, Inc.
+ *
+ * Author : K. Y. Srinivasan <kys@microsoft.com>
+ */
+
+#define pr_fmt(fmt)  "Hyper-V: " fmt
+
+#include <linux/efi.h>
+#include <linux/types.h>
+#include <linux/bitfield.h>
+#include <linux/io.h>
+#include <asm/apic.h>
+#include <asm/desc.h>
+#include <asm/e820/api.h>
+#include <asm/sev.h>
+#include <asm/hypervisor.h>
+#include <hyperv/hvhdk.h>
+#include <asm/mshyperv.h>
+#include <asm/msr.h>
+#include <asm/idtentry.h>
+#include <asm/set_memory.h>
+#include <linux/kexec.h>
+#include <linux/version.h>
+#include <linux/vmalloc.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/kernel.h>
+#include <linux/cpuhotplug.h>
+#include <linux/syscore_ops.h>
+#include <clocksource/hyperv_timer.h>
+#include <linux/highmem.h>
+#include <linux/export.h>
+
+void *hv_hypercall_pg;
+
+#ifdef CONFIG_X86_64
+static u64 __hv_hyperfail(u64 control, u64 param1, u64 param2)
+{
+	return U64_MAX;
+}
+
+DEFINE_STATIC_CALL(__hv_hypercall, __hv_hyperfail);
+
+u64 hv_std_hypercall(u64 control, u64 param1, u64 param2)
+{
+	u64 hv_status;
+
+	register u64 __r8 asm("r8") = param2;
+	asm volatile ("call " STATIC_CALL_TRAMP_STR(__hv_hypercall)
+		      : "=a" (hv_status), ASM_CALL_CONSTRAINT,
+		        "+c" (control), "+d" (param1), "+r" (__r8)
+		      : : "cc", "memory", "r9", "r10", "r11");
+
+	return hv_status;
+}
+
+typedef u64 (*hv_hypercall_f)(u64 control, u64 param1, u64 param2);
+
+static inline void hv_set_hypercall_pg(void *ptr)
+{
+	hv_hypercall_pg = ptr;
+
+	if (!ptr)
+		ptr = &__hv_hyperfail;
+	static_call_update(__hv_hypercall, (hv_hypercall_f)ptr);
+}
+#else
+static inline void hv_set_hypercall_pg(void *ptr)
+{
+	hv_hypercall_pg = ptr;
+}
+EXPORT_SYMBOL_GPL(hv_hypercall_pg);
+#endif
+
+union hv_ghcb * __percpu *hv_ghcb_pg;
+
+/* Storage to save the hypercall page temporarily for hibernation */
+static void *hv_hypercall_pg_saved;
+
+struct hv_vp_assist_page **hv_vp_assist_page;
+EXPORT_SYMBOL_GPL(hv_vp_assist_page);
+
+static int hyperv_init_ghcb(void)
+{
+	u64 ghcb_gpa;
+	void *ghcb_va;
+	void **ghcb_base;
+
+	if (!ms_hyperv.paravisor_present || !hv_isolation_type_snp())
+		return 0;
+
+	if (!hv_ghcb_pg)
+		return -EINVAL;
+
+	/*
+	 * GHCB page is allocated by paravisor. The address
+	 * returned by MSR_AMD64_SEV_ES_GHCB is above shared
+	 * memory boundary and map it here.
+	 */
+	rdmsrq(MSR_AMD64_SEV_ES_GHCB, ghcb_gpa);
+
+	/* Mask out vTOM bit and map as decrypted */
+	ghcb_gpa &= ~ms_hyperv.shared_gpa_boundary;
+	ghcb_va = memremap(ghcb_gpa, HV_HYP_PAGE_SIZE, MEMREMAP_WB | MEMREMAP_DEC);
+	if (!ghcb_va)
+		return -ENOMEM;
+
+	ghcb_base = (void **)this_cpu_ptr(hv_ghcb_pg);
+	*ghcb_base = ghcb_va;
+
+	return 0;
+}
+
+static int hv_cpu_init(unsigned int cpu)
+{
+	union hv_vp_assist_msr_contents msr = { 0 };
+	struct hv_vp_assist_page **hvp;
+	int ret;
+
+	ret = hv_common_cpu_init(cpu);
+	if (ret)
+		return ret;
+
+	if (!hv_vp_assist_page)
+		return 0;
+
+	hvp = &hv_vp_assist_page[cpu];
+	if (hv_root_partition()) {
+		/*
+		 * For root partition we get the hypervisor provided VP assist
+		 * page, instead of allocating a new page.
+		 */
+		rdmsrq(HV_X64_MSR_VP_ASSIST_PAGE, msr.as_uint64);
+		*hvp = memremap(msr.pfn << HV_X64_MSR_VP_ASSIST_PAGE_ADDRESS_SHIFT,
+				PAGE_SIZE, MEMREMAP_WB);
+	} else {
+		/*
+		 * The VP assist page is an "overlay" page (see Hyper-V TLFS's
+		 * Section 5.2.1 "GPA Overlay Pages"). Here it must be zeroed
+		 * out to make sure we always write the EOI MSR in
+		 * hv_apic_eoi_write() *after* the EOI optimization is disabled
+		 * in hv_cpu_die(), otherwise a CPU may not be stopped in the
+		 * case of CPU offlining and the VM will hang.
+		 */
+		if (!*hvp) {
+			*hvp = __vmalloc(PAGE_SIZE, GFP_KERNEL | __GFP_ZERO);
+
+			/*
+			 * Hyper-V should never specify a VM that is a Confidential
+			 * VM and also running in the root partition. Root partition
+			 * is blocked to run in Confidential VM. So only decrypt assist
+			 * page in non-root partition here.
+			 */
+			if (*hvp && !ms_hyperv.paravisor_present && hv_isolation_type_snp()) {
+				WARN_ON_ONCE(set_memory_decrypted((unsigned long)(*hvp), 1));
+				memset(*hvp, 0, PAGE_SIZE);
+			}
+		}
+
+		if (*hvp)
+			msr.pfn = vmalloc_to_pfn(*hvp);
+
+	}
+	if (!WARN_ON(!(*hvp))) {
+		msr.enable = 1;
+		wrmsrq(HV_X64_MSR_VP_ASSIST_PAGE, msr.as_uint64);
+	}
+
+	/* Allow Hyper-V stimer vector to be injected from Hypervisor. */
+	if (ms_hyperv.misc_features & HV_STIMER_DIRECT_MODE_AVAILABLE)
+		apic_update_vector(cpu, HYPERV_STIMER0_VECTOR, true);
+
+	return hyperv_init_ghcb();
+}
+
+static void (*hv_reenlightenment_cb)(void);
+
+static void hv_reenlightenment_notify(struct work_struct *dummy)
+{
+	struct hv_tsc_emulation_status emu_status;
+
+	rdmsrq(HV_X64_MSR_TSC_EMULATION_STATUS, *(u64 *)&emu_status);
+
+	/* Don't issue the callback if TSC accesses are not emulated */
+	if (hv_reenlightenment_cb && emu_status.inprogress)
+		hv_reenlightenment_cb();
+}
+static DECLARE_DELAYED_WORK(hv_reenlightenment_work, hv_reenlightenment_notify);
+
+void hyperv_stop_tsc_emulation(void)
+{
+	u64 freq;
+	struct hv_tsc_emulation_status emu_status;
+
+	rdmsrq(HV_X64_MSR_TSC_EMULATION_STATUS, *(u64 *)&emu_status);
+	emu_status.inprogress = 0;
+	wrmsrq(HV_X64_MSR_TSC_EMULATION_STATUS, *(u64 *)&emu_status);
+
+	rdmsrq(HV_X64_MSR_TSC_FREQUENCY, freq);
+	tsc_khz = div64_u64(freq, 1000);
+}
+EXPORT_SYMBOL_GPL(hyperv_stop_tsc_emulation);
+
+static inline bool hv_reenlightenment_available(void)
+{
+	/*
+	 * Check for required features and privileges to make TSC frequency
+	 * change notifications work.
+	 */
+	return ms_hyperv.features & HV_ACCESS_FREQUENCY_MSRS &&
+		ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE &&
+		ms_hyperv.features & HV_ACCESS_REENLIGHTENMENT;
+}
+
+DEFINE_IDTENTRY_SYSVEC(sysvec_hyperv_reenlightenment)
+{
+	apic_eoi();
+	inc_irq_stat(HYPERV_REENLIGHTENMENT);
+	schedule_delayed_work(&hv_reenlightenment_work, HZ/10);
+}
+
+void set_hv_tscchange_cb(void (*cb)(void))
+{
+	struct hv_reenlightenment_control re_ctrl = {
+		.vector = HYPERV_REENLIGHTENMENT_VECTOR,
+		.enabled = 1,
+	};
+	struct hv_tsc_emulation_control emu_ctrl = {.enabled = 1};
+
+	if (!hv_reenlightenment_available()) {
+		pr_warn("reenlightenment support is unavailable\n");
+		return;
+	}
+
+	if (!hv_vp_index)
+		return;
+
+	hv_reenlightenment_cb = cb;
+
+	/* Make sure callback is registered before we write to MSRs */
+	wmb();
+
+	re_ctrl.target_vp = hv_vp_index[get_cpu()];
+
+	wrmsrq(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
+	wrmsrq(HV_X64_MSR_TSC_EMULATION_CONTROL, *((u64 *)&emu_ctrl));
+
+	put_cpu();
+}
+EXPORT_SYMBOL_GPL(set_hv_tscchange_cb);
+
+void clear_hv_tscchange_cb(void)
+{
+	struct hv_reenlightenment_control re_ctrl;
+
+	if (!hv_reenlightenment_available())
+		return;
+
+	rdmsrq(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *(u64 *)&re_ctrl);
+	re_ctrl.enabled = 0;
+	wrmsrq(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *(u64 *)&re_ctrl);
+
+	hv_reenlightenment_cb = NULL;
+}
+EXPORT_SYMBOL_GPL(clear_hv_tscchange_cb);
+
+static int hv_cpu_die(unsigned int cpu)
+{
+	struct hv_reenlightenment_control re_ctrl;
+	unsigned int new_cpu;
+	void **ghcb_va;
+
+	if (hv_ghcb_pg) {
+		ghcb_va = (void **)this_cpu_ptr(hv_ghcb_pg);
+		if (*ghcb_va)
+			memunmap(*ghcb_va);
+		*ghcb_va = NULL;
+	}
+
+	if (ms_hyperv.misc_features & HV_STIMER_DIRECT_MODE_AVAILABLE)
+		apic_update_vector(cpu, HYPERV_STIMER0_VECTOR, false);
+
+	hv_common_cpu_die(cpu);
+
+	if (hv_vp_assist_page && hv_vp_assist_page[cpu]) {
+		union hv_vp_assist_msr_contents msr = { 0 };
+		if (hv_root_partition()) {
+			/*
+			 * For root partition the VP assist page is mapped to
+			 * hypervisor provided page, and thus we unmap the
+			 * page here and nullify it, so that in future we have
+			 * correct page address mapped in hv_cpu_init.
+			 */
+			memunmap(hv_vp_assist_page[cpu]);
+			hv_vp_assist_page[cpu] = NULL;
+			rdmsrq(HV_X64_MSR_VP_ASSIST_PAGE, msr.as_uint64);
+			msr.enable = 0;
+		}
+		wrmsrq(HV_X64_MSR_VP_ASSIST_PAGE, msr.as_uint64);
+	}
+
+	if (hv_reenlightenment_cb == NULL)
+		return 0;
+
+	rdmsrq(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
+	if (re_ctrl.target_vp == hv_vp_index[cpu]) {
+		/*
+		 * Reassign reenlightenment notifications to some other online
+		 * CPU or just disable the feature if there are no online CPUs
+		 * left (happens on hibernation).
+		 */
+		new_cpu = cpumask_any_but(cpu_online_mask, cpu);
+
+		if (new_cpu < nr_cpu_ids)
+			re_ctrl.target_vp = hv_vp_index[new_cpu];
+		else
+			re_ctrl.enabled = 0;
+
+		wrmsrq(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl));
+	}
+
+	return 0;
+}
+
+static int __init hv_pci_init(void)
+{
+	bool gen2vm = efi_enabled(EFI_BOOT);
+
+	/*
+	 * A Generation-2 VM doesn't support legacy PCI/PCIe, so both
+	 * raw_pci_ops and raw_pci_ext_ops are NULL, and pci_subsys_init() ->
+	 * pcibios_init() doesn't call pcibios_resource_survey() ->
+	 * e820__reserve_resources_late(); as a result, any emulated persistent
+	 * memory of E820_TYPE_PRAM (12) via the kernel parameter
+	 * memmap=nn[KMG]!ss is not added into iomem_resource and hence can't be
+	 * detected by register_e820_pmem(). Fix this by directly calling
+	 * e820__reserve_resources_late() here: e820__reserve_resources_late()
+	 * depends on e820__reserve_resources(), which has been called earlier
+	 * from setup_arch(). Note: e820__reserve_resources_late() also adds
+	 * any memory of E820_TYPE_PMEM (7) into iomem_resource, and
+	 * acpi_nfit_register_region() -> acpi_nfit_insert_resource() ->
+	 * region_intersects() returns REGION_INTERSECTS, so the memory of
+	 * E820_TYPE_PMEM won't get added twice.
+	 *
+	 * We return 0 here so that pci_arch_init() won't print the warning:
+	 * "PCI: Fatal: No config space access function found"
+	 */
+	if (gen2vm) {
+		e820__reserve_resources_late();
+		return 0;
+	}
+
+	/* For Generation-1 VM, we'll proceed in pci_arch_init().  */
+	return 1;
+}
+
+static int hv_suspend(void *data)
+{
+	union hv_x64_msr_hypercall_contents hypercall_msr;
+	int ret;
+
+	if (hv_root_partition())
+		return -EPERM;
+
+	/*
+	 * Reset the hypercall page as it is going to be invalidated
+	 * across hibernation. Setting hv_hypercall_pg to NULL ensures
+	 * that any subsequent hypercall operation fails safely instead of
+	 * crashing due to an access of an invalid page. The hypercall page
+	 * pointer is restored on resume.
+	 */
+	hv_hypercall_pg_saved = hv_hypercall_pg;
+	hv_set_hypercall_pg(NULL);
+
+	/* Disable the hypercall page in the hypervisor */
+	rdmsrq(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
+	hypercall_msr.enable = 0;
+	wrmsrq(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
+
+	ret = hv_cpu_die(0);
+	return ret;
+}
+
+static void hv_resume(void *data)
+{
+	union hv_x64_msr_hypercall_contents hypercall_msr;
+	int ret;
+
+	ret = hv_cpu_init(0);
+	WARN_ON(ret);
+
+	/* Re-enable the hypercall page */
+	rdmsrq(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
+	hypercall_msr.enable = 1;
+	hypercall_msr.guest_physical_address =
+		vmalloc_to_pfn(hv_hypercall_pg_saved);
+	wrmsrq(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
+
+	hv_set_hypercall_pg(hv_hypercall_pg_saved);
+	hv_hypercall_pg_saved = NULL;
+
+	/*
+	 * Reenlightenment notifications are disabled by hv_cpu_die(0),
+	 * reenable them here if hv_reenlightenment_cb was previously set.
+	 */
+	if (hv_reenlightenment_cb)
+		set_hv_tscchange_cb(hv_reenlightenment_cb);
+}
+
+/* Note: when the ops are called, only CPU0 is online and IRQs are disabled. */
+static const struct syscore_ops hv_syscore_ops = {
+	.suspend	= hv_suspend,
+	.resume		= hv_resume,
+};
+
+static struct syscore hv_syscore = {
+	.ops = &hv_syscore_ops,
+};
+
+static void (* __initdata old_setup_percpu_clockev)(void);
+
+static void __init hv_stimer_setup_percpu_clockev(void)
+{
+	/*
+	 * Ignore any errors in setting up stimer clockevents
+	 * as we can run with the LAPIC timer as a fallback.
+	 */
+	(void)hv_stimer_alloc(false);
+
+	/*
+	 * Still register the LAPIC timer, because the direct-mode STIMER is
+	 * not supported by old versions of Hyper-V. This also allows users
+	 * to switch to LAPIC timer via /sys, if they want to.
+	 */
+	if (old_setup_percpu_clockev)
+		old_setup_percpu_clockev();
+}
+
+/*
+ * This function is to be invoked early in the boot sequence after the
+ * hypervisor has been detected.
+ *
+ * 1. Setup the hypercall page.
+ * 2. Register Hyper-V specific clocksource.
+ * 3. Setup Hyper-V specific APIC entry points.
+ */
+void __init hyperv_init(void)
+{
+	u64 guest_id;
+	union hv_x64_msr_hypercall_contents hypercall_msr;
+	int cpuhp;
+
+	if (x86_hyper_type != X86_HYPER_MS_HYPERV)
+		return;
+
+	if (hv_common_init())
+		return;
+
+	/*
+	 * The VP assist page is useless to a TDX guest: the only use we
+	 * would have for it is lazy EOI, which can not be used with TDX.
+	 */
+	if (hv_isolation_type_tdx())
+		hv_vp_assist_page = NULL;
+	else
+		hv_vp_assist_page = kzalloc_objs(*hv_vp_assist_page, nr_cpu_ids);
+	if (!hv_vp_assist_page) {
+		ms_hyperv.hints &= ~HV_X64_ENLIGHTENED_VMCS_RECOMMENDED;
+
+		if (!hv_isolation_type_tdx())
+			goto common_free;
+	}
+
+	if (ms_hyperv.paravisor_present && hv_isolation_type_snp()) {
+		/* Negotiate GHCB Version. */
+		if (!hv_ghcb_negotiate_protocol())
+			hv_ghcb_terminate(SEV_TERM_SET_GEN,
+					  GHCB_SEV_ES_PROT_UNSUPPORTED);
+
+		hv_ghcb_pg = alloc_percpu(union hv_ghcb *);
+		if (!hv_ghcb_pg)
+			goto free_vp_assist_page;
+	}
+
+	cpuhp = cpuhp_setup_state(CPUHP_AP_HYPERV_ONLINE, "x86/hyperv_init:online",
+				  hv_cpu_init, hv_cpu_die);
+	if (cpuhp < 0)
+		goto free_ghcb_page;
+
+	/*
+	 * Setup the hypercall page and enable hypercalls.
+	 * 1. Register the guest ID
+	 * 2. Enable the hypercall and register the hypercall page
+	 *
+	 * A TDX VM with no paravisor only uses TDX GHCI rather than hv_hypercall_pg:
+	 * when the hypercall input is a page, such a VM must pass a decrypted
+	 * page to Hyper-V, e.g. hv_post_message() uses the per-CPU page
+	 * hyperv_pcpu_input_arg, which is decrypted if no paravisor is present.
+	 *
+	 * A TDX VM with the paravisor uses hv_hypercall_pg for most hypercalls,
+	 * which are handled by the paravisor and the VM must use an encrypted
+	 * input page: in such a VM, the hyperv_pcpu_input_arg is encrypted and
+	 * used in the hypercalls, e.g. see hv_mark_gpa_visibility() and
+	 * hv_arch_irq_unmask(). Such a VM uses TDX GHCI for two hypercalls:
+	 * 1. HVCALL_SIGNAL_EVENT: see vmbus_set_event() and _hv_do_fast_hypercall8().
+	 * 2. HVCALL_POST_MESSAGE: the input page must be a decrypted page, i.e.
+	 * hv_post_message() in such a VM can't use the encrypted hyperv_pcpu_input_arg;
+	 * instead, hv_post_message() uses the post_msg_page, which is decrypted
+	 * in such a VM and is only used in such a VM.
+	 */
+	guest_id = hv_generate_guest_id(LINUX_VERSION_CODE);
+	wrmsrq(HV_X64_MSR_GUEST_OS_ID, guest_id);
+
+	/* With the paravisor, the VM must also write the ID via GHCB/GHCI */
+	hv_ivm_msr_write(HV_X64_MSR_GUEST_OS_ID, guest_id);
+
+	/* A TDX VM with no paravisor only uses TDX GHCI rather than hv_hypercall_pg */
+	if (hv_isolation_type_tdx() && !ms_hyperv.paravisor_present)
+		goto skip_hypercall_pg_init;
+
+	hv_hypercall_pg = __vmalloc_node_range(PAGE_SIZE, 1, MODULES_VADDR,
+			MODULES_END, GFP_KERNEL, PAGE_KERNEL_ROX,
+			VM_FLUSH_RESET_PERMS, NUMA_NO_NODE,
+			__builtin_return_address(0));
+	if (hv_hypercall_pg == NULL)
+		goto clean_guest_os_id;
+
+	rdmsrq(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
+	hypercall_msr.enable = 1;
+
+	if (hv_root_partition()) {
+		struct page *pg;
+		void *src;
+
+		/*
+		 * For the root partition, the hypervisor will set up its
+		 * hypercall page. The hypervisor guarantees it will not show
+		 * up in the root's address space. The root can't change the
+		 * location of the hypercall page.
+		 *
+		 * Order is important here. We must enable the hypercall page
+		 * so it is populated with code, then copy the code to an
+		 * executable page.
+		 */
+		wrmsrq(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
+
+		pg = vmalloc_to_page(hv_hypercall_pg);
+		src = memremap(hypercall_msr.guest_physical_address << PAGE_SHIFT, PAGE_SIZE,
+				MEMREMAP_WB);
+		BUG_ON(!src);
+		memcpy_to_page(pg, 0, src, HV_HYP_PAGE_SIZE);
+		memunmap(src);
+
+		hv_remap_tsc_clocksource();
+		hv_sleep_notifiers_register();
+	} else {
+		hypercall_msr.guest_physical_address = vmalloc_to_pfn(hv_hypercall_pg);
+		wrmsrq(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
+	}
+
+	hv_set_hypercall_pg(hv_hypercall_pg);
+
+	if (hv_root_partition())        /* after set hypercall pg */
+		hv_root_crash_init();
+
+skip_hypercall_pg_init:
+	/*
+	 * hyperv_init() is called before LAPIC is initialized: see
+	 * apic_intr_mode_init() -> x86_platform.apic_post_init() and
+	 * apic_bsp_setup() -> setup_local_APIC(). The direct-mode STIMER
+	 * depends on LAPIC, so hv_stimer_alloc() should be called from
+	 * x86_init.timers.setup_percpu_clockev.
+	 */
+	old_setup_percpu_clockev = x86_init.timers.setup_percpu_clockev;
+	x86_init.timers.setup_percpu_clockev = hv_stimer_setup_percpu_clockev;
+
+	hv_apic_init();
+
+	x86_init.pci.arch_init = hv_pci_init;
+
+	register_syscore(&hv_syscore);
+
+	if (ms_hyperv.priv_high & HV_ACCESS_PARTITION_ID)
+		hv_get_partition_id();
+
+#ifdef CONFIG_PCI_MSI
+	/*
+	 * If we're running as root, we want to create our own PCI MSI domain.
+	 * We can't set this in hv_pci_init because that would be too late.
+	 */
+	if (hv_root_partition())
+		x86_init.irqs.create_pci_msi_domain = hv_create_pci_msi_domain;
+#endif
+
+	/* Query the VMs extended capability once, so that it can be cached. */
+	hv_query_ext_cap(0);
+
+	/* Find the VTL */
+	ms_hyperv.vtl = get_vtl();
+
+	if (ms_hyperv.vtl > 0) /* non default VTL */
+		hv_vtl_early_init();
+
+	return;
+
+clean_guest_os_id:
+	wrmsrq(HV_X64_MSR_GUEST_OS_ID, 0);
+	hv_ivm_msr_write(HV_X64_MSR_GUEST_OS_ID, 0);
+	cpuhp_remove_state(CPUHP_AP_HYPERV_ONLINE);
+free_ghcb_page:
+	free_percpu(hv_ghcb_pg);
+free_vp_assist_page:
+	kfree(hv_vp_assist_page);
+	hv_vp_assist_page = NULL;
+common_free:
+	hv_common_free();
+}
+
+/*
+ * This routine is called before kexec/kdump, it does the required cleanup.
+ */
+void hyperv_cleanup(void)
+{
+	union hv_x64_msr_hypercall_contents hypercall_msr;
+	union hv_reference_tsc_msr tsc_msr;
+
+	/* Reset our OS id */
+	wrmsrq(HV_X64_MSR_GUEST_OS_ID, 0);
+	hv_ivm_msr_write(HV_X64_MSR_GUEST_OS_ID, 0);
+
+	/*
+	 * Reset hv_hypercall_pg before resetting it in the hypervisor.
+	 * hv_set_hypercall_pg(NULL) is not used because at this point in the
+	 * panic path other CPUs have been stopped, causing static_call_update()
+	 * to hang. So resetting hv_hypercall_pg to cause hypercalls to fail
+	 * cleanly is only operative on 32-bit builds. But this is OK as it is
+	 * just a preventative measure to ease detecting a hypercall being made
+	 * after this point, which shouldn't be happening anyway.
+	 */
+	hv_hypercall_pg = NULL;
+
+	/* Reset the hypercall page */
+	hypercall_msr.as_uint64 = hv_get_msr(HV_X64_MSR_HYPERCALL);
+	hypercall_msr.enable = 0;
+	hv_set_msr(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
+
+	/* Reset the TSC page */
+	tsc_msr.as_uint64 = hv_get_msr(HV_X64_MSR_REFERENCE_TSC);
+	tsc_msr.enable = 0;
+	hv_set_msr(HV_X64_MSR_REFERENCE_TSC, tsc_msr.as_uint64);
+}
+
+void hyperv_report_panic(struct pt_regs *regs, long err, bool in_die)
+{
+	static bool panic_reported;
+	u64 guest_id;
+
+	if (in_die && !panic_on_oops)
+		return;
+
+	/*
+	 * We prefer to report panic on 'die' chain as we have proper
+	 * registers to report, but if we miss it (e.g. on BUG()) we need
+	 * to report it on 'panic'.
+	 */
+	if (panic_reported)
+		return;
+	panic_reported = true;
+
+	rdmsrq(HV_X64_MSR_GUEST_OS_ID, guest_id);
+
+	wrmsrq(HV_X64_MSR_CRASH_P0, err);
+	wrmsrq(HV_X64_MSR_CRASH_P1, guest_id);
+	wrmsrq(HV_X64_MSR_CRASH_P2, regs->ip);
+	wrmsrq(HV_X64_MSR_CRASH_P3, regs->ax);
+	wrmsrq(HV_X64_MSR_CRASH_P4, regs->sp);
+
+	/*
+	 * Let Hyper-V know there is crash data available
+	 */
+	wrmsrq(HV_X64_MSR_CRASH_CTL, HV_CRASH_CTL_CRASH_NOTIFY);
+}
+EXPORT_SYMBOL_GPL(hyperv_report_panic);
+
+bool hv_is_hyperv_initialized(void)
+{
+	union hv_x64_msr_hypercall_contents hypercall_msr;
+
+	/*
+	 * Ensure that we're really on Hyper-V, and not a KVM or Xen
+	 * emulation of Hyper-V
+	 */
+	if (x86_hyper_type != X86_HYPER_MS_HYPERV)
+		return false;
+
+	/* A TDX VM with no paravisor uses TDX GHCI call rather than hv_hypercall_pg */
+	if (hv_isolation_type_tdx() && !ms_hyperv.paravisor_present)
+		return true;
+	/*
+	 * Verify that earlier initialization succeeded by checking
+	 * that the hypercall page is setup
+	 */
+	hypercall_msr.as_uint64 = 0;
+	rdmsrq(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
+
+	return hypercall_msr.enable;
+}
+EXPORT_SYMBOL_GPL(hv_is_hyperv_initialized);
+
+int hv_apicid_to_vp_index(u32 apic_id)
+{
+	u64 control;
+	u64 status;
+	unsigned long irq_flags;
+	struct hv_get_vp_from_apic_id_in *input;
+	u32 *output, ret;
+
+	local_irq_save(irq_flags);
+
+	input = *this_cpu_ptr(hyperv_pcpu_input_arg);
+	memset(input, 0, sizeof(*input));
+	input->partition_id = HV_PARTITION_ID_SELF;
+	input->apic_ids[0] = apic_id;
+
+	output = *this_cpu_ptr(hyperv_pcpu_output_arg);
+
+	control = HV_HYPERCALL_REP_COMP_1 | HVCALL_GET_VP_INDEX_FROM_APIC_ID;
+	status = hv_do_hypercall(control, input, output);
+	ret = output[0];
+
+	local_irq_restore(irq_flags);
+
+	if (!hv_result_success(status)) {
+		pr_err("failed to get vp index from apic id %d, status %#llx\n",
+		       apic_id, status);
+		return -EINVAL;
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(hv_apicid_to_vp_index);
diff --git a/arch/x86/hyperv/hv_spinlock.c b/arch/x86/hyperv/hv_spinlock.c
new file mode 100644
index 000000000..210b494e4
--- /dev/null
+++ b/arch/x86/hyperv/hv_spinlock.c
@@ -0,0 +1,93 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Hyper-V specific spinlock code.
+ *
+ * Copyright (C) 2018, Intel, Inc.
+ *
+ * Author : Yi Sun <yi.y.sun@intel.com>
+ */
+
+#define pr_fmt(fmt) "Hyper-V: " fmt
+
+#include <linux/spinlock.h>
+
+#include <asm/mshyperv.h>
+#include <asm/apic.h>
+#include <asm/msr.h>
+
+static bool hv_pvspin __initdata = true;
+
+static void hv_qlock_kick(int cpu)
+{
+	__apic_send_IPI(cpu, X86_PLATFORM_IPI_VECTOR);
+}
+
+static void hv_qlock_wait(u8 *byte, u8 val)
+{
+	unsigned long flags;
+
+	if (in_nmi())
+		return;
+
+	/*
+	 * Reading HV_X64_MSR_GUEST_IDLE MSR tells the hypervisor that the
+	 * vCPU can be put into 'idle' state. This 'idle' state is
+	 * terminated by an IPI, usually from hv_qlock_kick(), even if
+	 * interrupts are disabled on the vCPU.
+	 *
+	 * To prevent a race against the unlock path it is required to
+	 * disable interrupts before accessing the HV_X64_MSR_GUEST_IDLE
+	 * MSR. Otherwise, if the IPI from hv_qlock_kick() arrives between
+	 * the lock value check and the rdmsrq() then the vCPU might be put
+	 * into 'idle' state by the hypervisor and kept in that state for
+	 * an unspecified amount of time.
+	 */
+	local_irq_save(flags);
+	/*
+	 * Only issue the rdmsrq() when the lock state has not changed.
+	 */
+	if (READ_ONCE(*byte) == val) {
+		unsigned long msr_val;
+
+		rdmsrq(HV_X64_MSR_GUEST_IDLE, msr_val);
+
+		(void)msr_val;
+	}
+	local_irq_restore(flags);
+}
+
+/*
+ * Hyper-V does not support this so far.
+ */
+__visible bool hv_vcpu_is_preempted(int vcpu)
+{
+	return false;
+}
+
+PV_CALLEE_SAVE_REGS_THUNK(hv_vcpu_is_preempted);
+
+void __init hv_init_spinlocks(void)
+{
+	if (!hv_pvspin || !apic ||
+	    !(ms_hyperv.hints & HV_X64_CLUSTER_IPI_RECOMMENDED) ||
+	    !(ms_hyperv.features & HV_MSR_GUEST_IDLE_AVAILABLE)) {
+		pr_info("PV spinlocks disabled\n");
+		return;
+	}
+	pr_info("PV spinlocks enabled\n");
+
+	__pv_init_lock_hash();
+	pv_ops_lock.queued_spin_lock_slowpath = __pv_queued_spin_lock_slowpath;
+	pv_ops_lock.queued_spin_unlock = PV_CALLEE_SAVE(__pv_queued_spin_unlock);
+	pv_ops_lock.wait = hv_qlock_wait;
+	pv_ops_lock.kick = hv_qlock_kick;
+	pv_ops_lock.vcpu_is_preempted = PV_CALLEE_SAVE(hv_vcpu_is_preempted);
+}
+
+static __init int hv_parse_nopvspin(char *arg)
+{
+	hv_pvspin = false;
+	return 0;
+}
+early_param("hv_nopvspin", hv_parse_nopvspin);
diff --git a/arch/x86/hyperv/hv_trampoline.S b/arch/x86/hyperv/hv_trampoline.S
new file mode 100644
index 000000000..25f02ff12
--- /dev/null
+++ b/arch/x86/hyperv/hv_trampoline.S
@@ -0,0 +1,101 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * X86 specific Hyper-V kdump/crash related code.
+ *
+ * Copyright (C) 2025, Microsoft, Inc.
+ *
+ */
+#include <linux/linkage.h>
+#include <asm/alternative.h>
+#include <asm/msr.h>
+#include <asm/processor-flags.h>
+#include <asm/nospec-branch.h>
+
+/*
+ * void noreturn hv_crash_asm32(arg1)
+ *    arg1 == edi == 32bit PA of struct hv_crash_tramp_data
+ *
+ * The hypervisor jumps here upon devirtualization in protected mode. This
+ * code gets copied to a page in the low 4G ie, 32bit space so it can run
+ * in the protected mode. Hence we cannot use any compile/link time offsets or
+ * addresses. It restores long mode via temporary gdt and page tables and
+ * eventually jumps to kernel code entry at HV_CRASHDATA_OFFS_C_entry.
+ *
+ * PreCondition (ie, Hypervisor call back ABI):
+ *  o CR0 is set to 0x0021: PE(prot mode) and NE are set, paging is disabled
+ *  o CR4 is set to 0x0
+ *  o IA32_EFER is set to 0x901 (SCE and NXE are set)
+ *  o EDI is set to the Arg passed to HVCALL_DISABLE_HYP_EX.
+ *  o CS, DS, ES, FS, GS are all initialized with a base of 0 and limit 0xFFFF
+ *  o IDTR, TR and GDTR are initialized with a base of 0 and limit of 0xFFFF
+ *  o LDTR is initialized as invalid (limit of 0)
+ *  o MSR PAT is power on default.
+ *  o Other state/registers are cleared. All TLBs flushed.
+ */
+
+#define HV_CRASHDATA_OFFS_TRAMPCR3    0x0    /*  0 */
+#define HV_CRASHDATA_OFFS_KERNCR3     0x8    /*  8 */
+#define HV_CRASHDATA_OFFS_GDTRLIMIT  0x12    /* 18 */
+#define HV_CRASHDATA_OFFS_CS_JMPTGT  0x28    /* 40 */
+#define HV_CRASHDATA_OFFS_C_entry    0x30    /* 48 */
+
+	.text
+	.code32
+
+SYM_CODE_START(hv_crash_asm32)
+	UNWIND_HINT_UNDEFINED
+	ENDBR
+	movl	$X86_CR4_PAE, %ecx
+	movl	%ecx, %cr4
+
+	movl %edi, %ebx
+	add $HV_CRASHDATA_OFFS_TRAMPCR3, %ebx
+	movl %cs:(%ebx), %eax
+	movl %eax, %cr3
+
+	/* Setup EFER for long mode now */
+	movl	$MSR_EFER, %ecx
+	rdmsr
+	btsl	$_EFER_LME, %eax
+	wrmsr
+
+	/* Turn paging on using the temp 32bit trampoline page table */
+	movl %cr0, %eax
+	orl $(X86_CR0_PG), %eax
+	movl %eax, %cr0
+
+	/* since kernel cr3 could be above 4G, we need to be in the long mode
+	 * before we can load 64bits of the kernel cr3. We use a temp gdt for
+	 * that with CS.L=1 and CS.D=0 */
+	mov %edi, %eax
+	add $HV_CRASHDATA_OFFS_GDTRLIMIT, %eax
+	lgdtl %cs:(%eax)
+
+	/* not done yet, restore CS now to switch to CS.L=1 */
+	mov %edi, %eax
+	add $HV_CRASHDATA_OFFS_CS_JMPTGT, %eax
+	ljmp %cs:*(%eax)
+SYM_CODE_END(hv_crash_asm32)
+
+	/* we now run in full 64bit IA32-e long mode, CS.L=1 and CS.D=0 */
+	.code64
+	.balign 8
+SYM_CODE_START(hv_crash_asm64)
+	UNWIND_HINT_UNDEFINED
+	ENDBR
+	/* restore kernel page tables so we can jump to kernel code */
+	mov %edi, %eax
+	add $HV_CRASHDATA_OFFS_KERNCR3, %eax
+	movq %cs:(%eax), %rbx
+	movq %rbx, %cr3
+
+	mov %edi, %eax
+	add $HV_CRASHDATA_OFFS_C_entry, %eax
+	movq %cs:(%eax), %rbx
+	ANNOTATE_RETPOLINE_SAFE
+	jmp *%rbx
+
+	int $3
+
+SYM_INNER_LABEL(hv_crash_asm_end, SYM_L_GLOBAL)
+SYM_CODE_END(hv_crash_asm64)
diff --git a/arch/x86/hyperv/hv_vtl.c b/arch/x86/hyperv/hv_vtl.c
new file mode 100644
index 000000000..07fac3d68
--- /dev/null
+++ b/arch/x86/hyperv/hv_vtl.c
@@ -0,0 +1,313 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2023, Microsoft Corporation.
+ *
+ * Author:
+ *   Saurabh Sengar <ssengar@microsoft.com>
+ */
+
+#include <linux/acpi.h>
+
+#include <asm/acpi.h>
+#include <asm/apic.h>
+#include <asm/boot.h>
+#include <asm/desc.h>
+#include <asm/fpu/api.h>
+#include <asm/fpu/types.h>
+#include <asm/i8259.h>
+#include <asm/mshyperv.h>
+#include <asm/msr.h>
+#include <asm/realmode.h>
+#include <asm/reboot.h>
+#include <asm/smap.h>
+#include <linux/export.h>
+#include <../kernel/smpboot.h>
+#include "../../kernel/fpu/legacy.h"
+
+extern struct boot_params boot_params;
+static struct real_mode_header hv_vtl_real_mode_header;
+
+static bool __init hv_vtl_msi_ext_dest_id(void)
+{
+	return true;
+}
+
+/*
+ * The `native_machine_emergency_restart` function from `reboot.c` writes
+ * to the physical address 0x472 to indicate the type of reboot for the
+ * firmware. We cannot have that in VSM as the memory composition might
+ * be more generic, and such write effectively corrupts the memory thus
+ * making diagnostics harder at the very least.
+ */
+static void  __noreturn hv_vtl_emergency_restart(void)
+{
+	/*
+	 * Cause a triple fault and the immediate reset. Here the code does not run
+	 * on the top of any firmware, whereby cannot reach out to its services.
+	 * The inifinite loop is for the improbable case that the triple fault does
+	 * not work and have to preserve the state intact for debugging.
+	 */
+	for (;;) {
+		idt_invalidate();
+		__asm__ __volatile__("int3");
+	}
+}
+
+/*
+ * The only way to restart in the VTL mode is to triple fault as the kernel runs
+ * as firmware.
+ */
+static void  __noreturn hv_vtl_restart(char __maybe_unused *cmd)
+{
+	hv_vtl_emergency_restart();
+}
+
+static inline bool within_page(u64 addr, u64 start)
+{
+	return addr >= start && addr < (start + PAGE_SIZE);
+}
+
+static bool hv_vtl_is_private_mmio_tdx(u64 addr)
+{
+	u64 mb_addr = acpi_get_mp_wakeup_mailbox_paddr();
+
+	return mb_addr && within_page(addr, mb_addr);
+}
+
+void __init hv_vtl_init_platform(void)
+{
+	/*
+	 * This function is a no-op if the VTL mode is not enabled.
+	 * If it is, this function runs if and only the kernel boots in
+	 * VTL2 which the x86 hv initialization path makes sure of.
+	 */
+	pr_info("Linux runs in Hyper-V Virtual Trust Level %d\n", ms_hyperv.vtl);
+
+	/* There is no paravisor present if we are here. */
+	if (hv_isolation_type_tdx()) {
+		x86_init.resources.realmode_limit = SZ_4G;
+		x86_platform.hyper.is_private_mmio = hv_vtl_is_private_mmio_tdx;
+
+	} else {
+		x86_platform.realmode_reserve = x86_init_noop;
+		x86_platform.realmode_init = x86_init_noop;
+		real_mode_header = &hv_vtl_real_mode_header;
+	}
+	x86_init.irqs.pre_vector_init = x86_init_noop;
+	x86_init.timers.timer_init = x86_init_noop;
+	x86_init.resources.probe_roms = x86_init_noop;
+
+	/* Avoid searching for BIOS MP tables */
+	x86_init.mpparse.find_mptable = x86_init_noop;
+	x86_init.mpparse.early_parse_smp_cfg = x86_init_noop;
+
+	x86_platform.get_wallclock = get_rtc_noop;
+	x86_platform.set_wallclock = set_rtc_noop;
+	x86_platform.get_nmi_reason = hv_get_nmi_reason;
+
+	x86_platform.legacy.i8042 = X86_LEGACY_I8042_PLATFORM_ABSENT;
+	x86_platform.legacy.rtc = 0;
+	x86_platform.legacy.warm_reset = 0;
+	x86_platform.legacy.reserve_bios_regions = 0;
+	x86_platform.legacy.devices.pnpbios = 0;
+
+	x86_init.hyper.msi_ext_dest_id = hv_vtl_msi_ext_dest_id;
+}
+
+static inline u64 hv_vtl_system_desc_base(struct ldttss_desc *desc)
+{
+	return ((u64)desc->base3 << 32) | ((u64)desc->base2 << 24) |
+		(desc->base1 << 16) | desc->base0;
+}
+
+static inline u32 hv_vtl_system_desc_limit(struct ldttss_desc *desc)
+{
+	return ((u32)desc->limit1 << 16) | (u32)desc->limit0;
+}
+
+typedef void (*secondary_startup_64_fn)(void*, void*);
+static void hv_vtl_ap_entry(void)
+{
+	((secondary_startup_64_fn)secondary_startup_64)(&boot_params, &boot_params);
+}
+
+static int hv_vtl_bringup_vcpu(u32 target_vp_index, int cpu, u64 eip_ignored)
+{
+	u64 status, rsp, rip;
+	int ret = 0;
+	struct hv_enable_vp_vtl *input;
+	unsigned long irq_flags;
+
+	struct desc_ptr gdt_ptr;
+	struct desc_ptr idt_ptr;
+
+	struct ldttss_desc *tss;
+	struct ldttss_desc *ldt;
+	struct desc_struct *gdt;
+
+	struct task_struct *idle = idle_thread_get(cpu);
+	if (IS_ERR(idle))
+		return PTR_ERR(idle);
+
+	rsp = (unsigned long)idle->thread.sp;
+	rip = (u64)&hv_vtl_ap_entry;
+
+	native_store_gdt(&gdt_ptr);
+	store_idt(&idt_ptr);
+
+	gdt = (struct desc_struct *)((void *)(gdt_ptr.address));
+	tss = (struct ldttss_desc *)(gdt + GDT_ENTRY_TSS);
+	ldt = (struct ldttss_desc *)(gdt + GDT_ENTRY_LDT);
+
+	local_irq_save(irq_flags);
+
+	input = *this_cpu_ptr(hyperv_pcpu_input_arg);
+	memset(input, 0, sizeof(*input));
+
+	input->partition_id = HV_PARTITION_ID_SELF;
+	input->vp_index = target_vp_index;
+	input->target_vtl.target_vtl = HV_VTL_MGMT;
+
+	/*
+	 * The x86_64 Linux kernel follows the 16-bit -> 32-bit -> 64-bit
+	 * mode transition sequence after waking up an AP with SIPI whose
+	 * vector points to the 16-bit AP startup trampoline code. Here in
+	 * VTL2, we can't perform that sequence as the AP has to start in
+	 * the 64-bit mode.
+	 *
+	 * To make this happen, we tell the hypervisor to load a valid 64-bit
+	 * context (most of which is just magic numbers from the CPU manual)
+	 * so that AP jumps right to the 64-bit entry of the kernel, and the
+	 * control registers are loaded with values that let the AP fetch the
+	 * code and data and carry on with work it gets assigned.
+	 */
+
+	input->vp_context.rip = rip;
+	input->vp_context.rsp = rsp;
+	input->vp_context.rflags = 0x0000000000000002;
+	input->vp_context.efer = native_rdmsrq(MSR_EFER);
+	input->vp_context.cr0 = native_read_cr0();
+	input->vp_context.cr3 = __native_read_cr3();
+	input->vp_context.cr4 = native_read_cr4();
+	input->vp_context.msr_cr_pat = native_rdmsrq(MSR_IA32_CR_PAT);
+	input->vp_context.idtr.limit = idt_ptr.size;
+	input->vp_context.idtr.base = idt_ptr.address;
+	input->vp_context.gdtr.limit = gdt_ptr.size;
+	input->vp_context.gdtr.base = gdt_ptr.address;
+
+	/* Non-system desc (64bit), long, code, present */
+	input->vp_context.cs.selector = __KERNEL_CS;
+	input->vp_context.cs.base = 0;
+	input->vp_context.cs.limit = 0xffffffff;
+	input->vp_context.cs.attributes = 0xa09b;
+	/* Non-system desc (64bit), data, present, granularity, default */
+	input->vp_context.ss.selector = __KERNEL_DS;
+	input->vp_context.ss.base = 0;
+	input->vp_context.ss.limit = 0xffffffff;
+	input->vp_context.ss.attributes = 0xc093;
+
+	/* System desc (128bit), present, LDT */
+	input->vp_context.ldtr.selector = GDT_ENTRY_LDT * 8;
+	input->vp_context.ldtr.base = hv_vtl_system_desc_base(ldt);
+	input->vp_context.ldtr.limit = hv_vtl_system_desc_limit(ldt);
+	input->vp_context.ldtr.attributes = 0x82;
+
+	/* System desc (128bit), present, TSS, 0x8b - busy, 0x89 -- default */
+	input->vp_context.tr.selector = GDT_ENTRY_TSS * 8;
+	input->vp_context.tr.base = hv_vtl_system_desc_base(tss);
+	input->vp_context.tr.limit = hv_vtl_system_desc_limit(tss);
+	input->vp_context.tr.attributes = 0x8b;
+
+	status = hv_do_hypercall(HVCALL_ENABLE_VP_VTL, input, NULL);
+
+	if (!hv_result_success(status) &&
+	    hv_result(status) != HV_STATUS_VTL_ALREADY_ENABLED) {
+		pr_err("HVCALL_ENABLE_VP_VTL failed for VP : %d ! [Err: %#llx\n]",
+		       target_vp_index, status);
+		ret = -EINVAL;
+		goto free_lock;
+	}
+
+	status = hv_do_hypercall(HVCALL_START_VP, input, NULL);
+
+	if (!hv_result_success(status)) {
+		pr_err("HVCALL_START_VP failed for VP : %d ! [Err: %#llx]\n",
+		       target_vp_index, status);
+		ret = -EINVAL;
+	}
+
+free_lock:
+	local_irq_restore(irq_flags);
+
+	return ret;
+}
+
+static int hv_vtl_wakeup_secondary_cpu(u32 apicid, unsigned long start_eip, unsigned int cpu)
+{
+	int vp_index;
+
+	pr_debug("Bringing up CPU with APIC ID %d in VTL2...\n", apicid);
+	vp_index = hv_apicid_to_vp_index(apicid);
+
+	if (vp_index < 0) {
+		pr_err("Couldn't find CPU with APIC ID %d\n", apicid);
+		return -EINVAL;
+	}
+	if (vp_index > ms_hyperv.max_vp_index) {
+		pr_err("Invalid CPU id %d for APIC ID %d\n", vp_index, apicid);
+		return -EINVAL;
+	}
+
+	return hv_vtl_bringup_vcpu(vp_index, cpu, start_eip);
+}
+
+int __init hv_vtl_early_init(void)
+{
+	machine_ops.emergency_restart = hv_vtl_emergency_restart;
+	machine_ops.restart = hv_vtl_restart;
+
+	/*
+	 * `boot_cpu_has` returns the runtime feature support,
+	 * and here is the earliest it can be used.
+	 */
+	if (cpu_feature_enabled(X86_FEATURE_XSAVE))
+		panic("XSAVE has to be disabled as it is not supported by this module.\n"
+			  "Please add 'noxsave' to the kernel command line.\n");
+
+	/*
+	 * TDX confidential VMs do not trust the hypervisor and cannot use it to
+	 * boot secondary CPUs. Instead, they will be booted using the wakeup
+	 * mailbox if detected during boot. See setup_arch().
+	 *
+	 * There is no paravisor present if we are here.
+	 */
+	if (!hv_isolation_type_tdx())
+		apic_update_callback(wakeup_secondary_cpu_64, hv_vtl_wakeup_secondary_cpu);
+
+	return 0;
+}
+
+DEFINE_STATIC_CALL_NULL(__mshv_vtl_return_hypercall, void (*)(void));
+
+void mshv_vtl_return_call_init(u64 vtl_return_offset)
+{
+	static_call_update(__mshv_vtl_return_hypercall,
+			   (void *)((u8 *)hv_hypercall_pg + vtl_return_offset));
+}
+EXPORT_SYMBOL(mshv_vtl_return_call_init);
+
+void mshv_vtl_return_call(struct mshv_vtl_cpu_context *vtl0)
+{
+	struct hv_vp_assist_page *hvp;
+
+	hvp = hv_vp_assist_page[smp_processor_id()];
+	hvp->vtl_ret_x64rax = vtl0->rax;
+	hvp->vtl_ret_x64rcx = vtl0->rcx;
+
+	kernel_fpu_begin_mask(0);
+	fxrstor(&vtl0->fx_state);
+	__mshv_vtl_return_call(vtl0);
+	fxsave(&vtl0->fx_state);
+	kernel_fpu_end();
+}
+EXPORT_SYMBOL(mshv_vtl_return_call);
diff --git a/arch/x86/hyperv/irqdomain.c b/arch/x86/hyperv/irqdomain.c
new file mode 100644
index 000000000..b3ad50a87
--- /dev/null
+++ b/arch/x86/hyperv/irqdomain.c
@@ -0,0 +1,428 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Irqdomain for Linux to run as the root partition on Microsoft Hypervisor.
+ *
+ * Authors:
+ *  Sunil Muthuswamy <sunilmut@microsoft.com>
+ *  Wei Liu <wei.liu@kernel.org>
+ */
+
+#include <linux/pci.h>
+#include <linux/irq.h>
+#include <linux/export.h>
+#include <linux/irqchip/irq-msi-lib.h>
+#include <asm/mshyperv.h>
+
+static int hv_map_interrupt(union hv_device_id hv_devid, bool level,
+		int cpu, int vector, struct hv_interrupt_entry *ret_entry)
+{
+	struct hv_input_map_device_interrupt *input;
+	struct hv_output_map_device_interrupt *output;
+	struct hv_device_interrupt_descriptor *intr_desc;
+	unsigned long flags;
+	u64 status;
+	int nr_bank, var_size;
+
+	local_irq_save(flags);
+
+	input = *this_cpu_ptr(hyperv_pcpu_input_arg);
+	output = *this_cpu_ptr(hyperv_pcpu_output_arg);
+
+	intr_desc = &input->interrupt_descriptor;
+	memset(input, 0, sizeof(*input));
+	input->partition_id = hv_current_partition_id;
+	input->device_id = hv_devid.as_uint64;
+	intr_desc->interrupt_type = HV_X64_INTERRUPT_TYPE_FIXED;
+	intr_desc->vector_count = 1;
+	intr_desc->target.vector = vector;
+
+	if (level)
+		intr_desc->trigger_mode = HV_INTERRUPT_TRIGGER_MODE_LEVEL;
+	else
+		intr_desc->trigger_mode = HV_INTERRUPT_TRIGGER_MODE_EDGE;
+
+	intr_desc->target.vp_set.valid_bank_mask = 0;
+	intr_desc->target.vp_set.format = HV_GENERIC_SET_SPARSE_4K;
+	nr_bank = cpumask_to_vpset(&intr_desc->target.vp_set, cpumask_of(cpu));
+	if (nr_bank < 0) {
+		local_irq_restore(flags);
+		pr_err("%s: unable to generate VP set\n", __func__);
+		return -EINVAL;
+	}
+	intr_desc->target.flags = HV_DEVICE_INTERRUPT_TARGET_PROCESSOR_SET;
+
+	/*
+	 * var-sized hypercall, var-size starts after vp_mask (thus
+	 * vp_set.format does not count, but vp_set.valid_bank_mask
+	 * does).
+	 */
+	var_size = nr_bank + 1;
+
+	status = hv_do_rep_hypercall(HVCALL_MAP_DEVICE_INTERRUPT, 0, var_size,
+			input, output);
+	*ret_entry = output->interrupt_entry;
+
+	local_irq_restore(flags);
+
+	if (!hv_result_success(status))
+		hv_status_err(status, "\n");
+
+	return hv_result_to_errno(status);
+}
+
+static int hv_unmap_interrupt(u64 id, struct hv_interrupt_entry *irq_entry)
+{
+	unsigned long flags;
+	struct hv_input_unmap_device_interrupt *input;
+	u64 status;
+
+	local_irq_save(flags);
+	input = *this_cpu_ptr(hyperv_pcpu_input_arg);
+
+	memset(input, 0, sizeof(*input));
+	input->partition_id = hv_current_partition_id;
+	input->device_id = id;
+	input->interrupt_entry = *irq_entry;
+
+	status = hv_do_hypercall(HVCALL_UNMAP_DEVICE_INTERRUPT, input, NULL);
+	local_irq_restore(flags);
+
+	if (!hv_result_success(status))
+		hv_status_err(status, "\n");
+
+	return hv_result_to_errno(status);
+}
+
+#ifdef CONFIG_PCI_MSI
+struct rid_data {
+	struct pci_dev *bridge;
+	u32 rid;
+};
+
+static int get_rid_cb(struct pci_dev *pdev, u16 alias, void *data)
+{
+	struct rid_data *rd = data;
+	u8 bus = PCI_BUS_NUM(rd->rid);
+
+	if (pdev->bus->number != bus || PCI_BUS_NUM(alias) != bus) {
+		rd->bridge = pdev;
+		rd->rid = alias;
+	}
+
+	return 0;
+}
+
+static union hv_device_id hv_build_devid_type_pci(struct pci_dev *pdev)
+{
+	int pos;
+	union hv_device_id hv_devid;
+	struct rid_data data = {
+		.bridge = NULL,
+		.rid = PCI_DEVID(pdev->bus->number, pdev->devfn)
+	};
+
+	pci_for_each_dma_alias(pdev, get_rid_cb, &data);
+
+	hv_devid.as_uint64 = 0;
+	hv_devid.device_type = HV_DEVICE_TYPE_PCI;
+	hv_devid.pci.segment = pci_domain_nr(pdev->bus);
+
+	hv_devid.pci.bdf.bus = PCI_BUS_NUM(data.rid);
+	hv_devid.pci.bdf.device = PCI_SLOT(data.rid);
+	hv_devid.pci.bdf.function = PCI_FUNC(data.rid);
+	hv_devid.pci.source_shadow = HV_SOURCE_SHADOW_NONE;
+
+	if (data.bridge == NULL)
+		goto out;
+
+	/*
+	 * Microsoft Hypervisor requires a bus range when the bridge is
+	 * running in PCI-X mode.
+	 *
+	 * To distinguish conventional vs PCI-X bridge, we can check
+	 * the bridge's PCI-X Secondary Status Register, Secondary Bus
+	 * Mode and Frequency bits. See PCI Express to PCI/PCI-X Bridge
+	 * Specification Revision 1.0 5.2.2.1.3.
+	 *
+	 * Value zero means it is in conventional mode, otherwise it is
+	 * in PCI-X mode.
+	 */
+
+	pos = pci_find_capability(data.bridge, PCI_CAP_ID_PCIX);
+	if (pos) {
+		u16 status;
+
+		pci_read_config_word(data.bridge, pos + PCI_X_BRIDGE_SSTATUS,
+				     &status);
+
+		if (status & PCI_X_SSTATUS_FREQ) {
+			/* Non-zero, PCI-X mode */
+			u8 sec_bus, sub_bus;
+
+			hv_devid.pci.source_shadow =
+					     HV_SOURCE_SHADOW_BRIDGE_BUS_RANGE;
+
+			pci_read_config_byte(data.bridge, PCI_SECONDARY_BUS,
+					     &sec_bus);
+			hv_devid.pci.shadow_bus_range.secondary_bus = sec_bus;
+			pci_read_config_byte(data.bridge, PCI_SUBORDINATE_BUS,
+					     &sub_bus);
+			hv_devid.pci.shadow_bus_range.subordinate_bus = sub_bus;
+		}
+	}
+
+out:
+	return hv_devid;
+}
+
+/*
+ * hv_map_msi_interrupt() - Map the MSI IRQ in the hypervisor.
+ * @data:      Describes the IRQ
+ * @out_entry: Hypervisor (MSI) interrupt entry (can be NULL)
+ *
+ * Map the IRQ in the hypervisor by issuing a MAP_DEVICE_INTERRUPT hypercall.
+ *
+ * Return: 0 on success, -errno on failure
+ */
+int hv_map_msi_interrupt(struct irq_data *data,
+			 struct hv_interrupt_entry *out_entry)
+{
+	struct irq_cfg *cfg = irqd_cfg(data);
+	struct hv_interrupt_entry dummy;
+	union hv_device_id hv_devid;
+	struct msi_desc *msidesc;
+	struct pci_dev *pdev;
+	int cpu;
+
+	msidesc = irq_data_get_msi_desc(data);
+	pdev = msi_desc_to_pci_dev(msidesc);
+	hv_devid = hv_build_devid_type_pci(pdev);
+	cpu = cpumask_first(irq_data_get_effective_affinity_mask(data));
+
+	return hv_map_interrupt(hv_devid, false, cpu, cfg->vector,
+				out_entry ? out_entry : &dummy);
+}
+EXPORT_SYMBOL_GPL(hv_map_msi_interrupt);
+
+static void entry_to_msi_msg(struct hv_interrupt_entry *entry,
+			     struct msi_msg *msg)
+{
+	/* High address is always 0 */
+	msg->address_hi = 0;
+	msg->address_lo = entry->msi_entry.address.as_uint32;
+	msg->data = entry->msi_entry.data.as_uint32;
+}
+
+static int hv_unmap_msi_interrupt(struct pci_dev *pdev,
+				  struct hv_interrupt_entry *irq_entry);
+
+static void hv_irq_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
+{
+	struct hv_interrupt_entry *stored_entry;
+	struct irq_cfg *cfg = irqd_cfg(data);
+	struct msi_desc *msidesc;
+	struct pci_dev *pdev;
+	int ret;
+
+	msidesc = irq_data_get_msi_desc(data);
+	pdev = msi_desc_to_pci_dev(msidesc);
+
+	if (!cfg) {
+		pr_debug("%s: cfg is NULL", __func__);
+		return;
+	}
+
+	if (data->chip_data) {
+		/*
+		 * This interrupt is already mapped. Let's unmap first.
+		 *
+		 * We don't use retarget interrupt hypercalls here because
+		 * Microsoft Hypervisor doesn't allow root to change the vector
+		 * or specify VPs outside of the set that is initially used
+		 * during mapping.
+		 */
+		stored_entry = data->chip_data;
+		data->chip_data = NULL;
+
+		ret = hv_unmap_msi_interrupt(pdev, stored_entry);
+
+		kfree(stored_entry);
+
+		if (ret)
+			return;
+	}
+
+	stored_entry = kzalloc_obj(*stored_entry, GFP_ATOMIC);
+	if (!stored_entry)
+		return;
+
+	ret = hv_map_msi_interrupt(data, stored_entry);
+	if (ret) {
+		kfree(stored_entry);
+		return;
+	}
+
+	data->chip_data = stored_entry;
+	entry_to_msi_msg(data->chip_data, msg);
+}
+
+static int hv_unmap_msi_interrupt(struct pci_dev *pdev,
+				  struct hv_interrupt_entry *irq_entry)
+{
+	union hv_device_id hv_devid;
+
+	hv_devid = hv_build_devid_type_pci(pdev);
+	return hv_unmap_interrupt(hv_devid.as_uint64, irq_entry);
+}
+
+/* NB: during map, hv_interrupt_entry is saved via data->chip_data */
+static void hv_teardown_msi_irq(struct pci_dev *pdev, struct irq_data *irqd)
+{
+	struct hv_interrupt_entry irq_entry;
+	struct msi_msg msg;
+
+	if (!irqd->chip_data) {
+		pr_debug("%s: no chip data\n!", __func__);
+		return;
+	}
+
+	irq_entry = *(struct hv_interrupt_entry *)irqd->chip_data;
+	entry_to_msi_msg(&irq_entry, &msg);
+
+	kfree(irqd->chip_data);
+	irqd->chip_data = NULL;
+
+	(void)hv_unmap_msi_interrupt(pdev, &irq_entry);
+}
+
+/*
+ * IRQ Chip for MSI PCI/PCI-X/PCI-Express Devices,
+ * which implement the MSI or MSI-X Capability Structure.
+ */
+static struct irq_chip hv_pci_msi_controller = {
+	.name			= "HV-PCI-MSI",
+	.irq_ack		= irq_chip_ack_parent,
+	.irq_compose_msi_msg	= hv_irq_compose_msi_msg,
+	.irq_set_affinity	= irq_chip_set_affinity_parent,
+};
+
+static bool hv_init_dev_msi_info(struct device *dev, struct irq_domain *domain,
+				 struct irq_domain *real_parent,
+				 struct msi_domain_info *info)
+{
+	struct irq_chip *chip = info->chip;
+
+	if (!msi_lib_init_dev_msi_info(dev, domain, real_parent, info))
+		return false;
+
+	chip->flags |= IRQCHIP_SKIP_SET_WAKE | IRQCHIP_MOVE_DEFERRED;
+
+	info->ops->msi_prepare = pci_msi_prepare;
+
+	return true;
+}
+
+#define HV_MSI_FLAGS_SUPPORTED	(MSI_GENERIC_FLAGS_MASK | MSI_FLAG_PCI_MSIX)
+#define HV_MSI_FLAGS_REQUIRED	(MSI_FLAG_USE_DEF_DOM_OPS |	\
+				 MSI_FLAG_USE_DEF_CHIP_OPS)
+
+static struct msi_parent_ops hv_msi_parent_ops = {
+	.supported_flags	= HV_MSI_FLAGS_SUPPORTED,
+	.required_flags		= HV_MSI_FLAGS_REQUIRED,
+	.bus_select_token	= DOMAIN_BUS_NEXUS,
+	.bus_select_mask	= MATCH_PCI_MSI,
+	.chip_flags		= MSI_CHIP_FLAG_SET_ACK,
+	.prefix			= "HV-",
+	.init_dev_msi_info	= hv_init_dev_msi_info,
+};
+
+/* Allocate nr_irqs IRQs for the given irq domain */
+static int hv_msi_domain_alloc(struct irq_domain *d, unsigned int virq,
+			       unsigned int nr_irqs, void *arg)
+{
+	/*
+	 * TODO: The allocation bits of hv_irq_compose_msi_msg(), i.e.
+	 *	 everything except entry_to_msi_msg() should be in here.
+	 */
+	int ret;
+
+	ret = irq_domain_alloc_irqs_parent(d, virq, nr_irqs, arg);
+	if (ret)
+		return ret;
+
+	for (int i = 0; i < nr_irqs; ++i) {
+		irq_domain_set_info(d, virq + i, 0, &hv_pci_msi_controller,
+				    NULL, handle_edge_irq, NULL, "edge");
+	}
+
+	return 0;
+}
+
+static void hv_msi_domain_free(struct irq_domain *d, unsigned int virq,
+			       unsigned int nr_irqs)
+{
+	for (int i = 0; i < nr_irqs; ++i) {
+		struct irq_data *irqd = irq_domain_get_irq_data(d, virq);
+		struct msi_desc *desc;
+
+		desc = irq_data_get_msi_desc(irqd);
+		if (!desc || !desc->irq || WARN_ON_ONCE(!dev_is_pci(desc->dev)))
+			continue;
+
+		hv_teardown_msi_irq(to_pci_dev(desc->dev), irqd);
+	}
+
+	irq_domain_free_irqs_top(d, virq, nr_irqs);
+}
+
+static const struct irq_domain_ops hv_msi_domain_ops = {
+	.select	= msi_lib_irq_domain_select,
+	.alloc	= hv_msi_domain_alloc,
+	.free	= hv_msi_domain_free,
+};
+
+struct irq_domain * __init hv_create_pci_msi_domain(void)
+{
+	struct irq_domain *d = NULL;
+
+	struct irq_domain_info info = {
+		.fwnode		= irq_domain_alloc_named_fwnode("HV-PCI-MSI"),
+		.ops		= &hv_msi_domain_ops,
+		.parent		= x86_vector_domain,
+	};
+
+	if (info.fwnode)
+		d = msi_create_parent_irq_domain(&info, &hv_msi_parent_ops);
+
+	/* No point in going further if we can't get an irq domain */
+	BUG_ON(!d);
+
+	return d;
+}
+
+#endif /* CONFIG_PCI_MSI */
+
+int hv_unmap_ioapic_interrupt(int ioapic_id, struct hv_interrupt_entry *entry)
+{
+	union hv_device_id hv_devid;
+
+	hv_devid.as_uint64 = 0;
+	hv_devid.device_type = HV_DEVICE_TYPE_IOAPIC;
+	hv_devid.ioapic.ioapic_id = (u8)ioapic_id;
+
+	return hv_unmap_interrupt(hv_devid.as_uint64, entry);
+}
+EXPORT_SYMBOL_GPL(hv_unmap_ioapic_interrupt);
+
+int hv_map_ioapic_interrupt(int ioapic_id, bool level, int cpu, int vector,
+		struct hv_interrupt_entry *entry)
+{
+	union hv_device_id hv_devid;
+
+	hv_devid.as_uint64 = 0;
+	hv_devid.device_type = HV_DEVICE_TYPE_IOAPIC;
+	hv_devid.ioapic.ioapic_id = (u8)ioapic_id;
+
+	return hv_map_interrupt(hv_devid, level, cpu, vector, entry);
+}
+EXPORT_SYMBOL_GPL(hv_map_ioapic_interrupt);
diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c
new file mode 100644
index 000000000..2ce4dfe53
--- /dev/null
+++ b/arch/x86/hyperv/ivm.c
@@ -0,0 +1,946 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Hyper-V Isolation VM interface with paravisor and hypervisor
+ *
+ * Author:
+ *  Tianyu Lan <Tianyu.Lan@microsoft.com>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/cpu.h>
+#include <linux/export.h>
+#include <asm/svm.h>
+#include <asm/sev.h>
+#include <asm/io.h>
+#include <asm/coco.h>
+#include <asm/mem_encrypt.h>
+#include <asm/set_memory.h>
+#include <asm/mshyperv.h>
+#include <asm/hypervisor.h>
+#include <asm/mtrr.h>
+#include <asm/io_apic.h>
+#include <asm/realmode.h>
+#include <asm/e820/api.h>
+#include <asm/desc.h>
+#include <asm/msr.h>
+#include <asm/segment.h>
+#include <uapi/asm/vmx.h>
+
+#ifdef CONFIG_AMD_MEM_ENCRYPT
+
+#define GHCB_USAGE_HYPERV_CALL	1
+
+union hv_ghcb {
+	struct ghcb ghcb;
+	struct {
+		u64 hypercalldata[509];
+		u64 outputgpa;
+		union {
+			union {
+				struct {
+					u32 callcode        : 16;
+					u32 isfast          : 1;
+					u32 reserved1       : 14;
+					u32 isnested        : 1;
+					u32 countofelements : 12;
+					u32 reserved2       : 4;
+					u32 repstartindex   : 12;
+					u32 reserved3       : 4;
+				};
+				u64 asuint64;
+			} hypercallinput;
+			union {
+				struct {
+					u16 callstatus;
+					u16 reserved1;
+					u32 elementsprocessed : 12;
+					u32 reserved2         : 20;
+				};
+				u64 asunit64;
+			} hypercalloutput;
+		};
+		u64 reserved2;
+	} hypercall;
+} __packed __aligned(HV_HYP_PAGE_SIZE);
+
+/* Only used in an SNP VM with the paravisor */
+static u16 hv_ghcb_version __ro_after_init;
+
+/* Functions only used in an SNP VM with the paravisor go here. */
+u64 hv_ghcb_hypercall(u64 control, void *input, void *output, u32 input_size)
+{
+	union hv_ghcb *hv_ghcb;
+	void **ghcb_base;
+	unsigned long flags;
+	u64 status;
+
+	if (!hv_ghcb_pg)
+		return -EFAULT;
+
+	WARN_ON(in_nmi());
+
+	local_irq_save(flags);
+	ghcb_base = (void **)this_cpu_ptr(hv_ghcb_pg);
+	hv_ghcb = (union hv_ghcb *)*ghcb_base;
+	if (!hv_ghcb) {
+		local_irq_restore(flags);
+		return -EFAULT;
+	}
+
+	hv_ghcb->ghcb.protocol_version = GHCB_PROTOCOL_MAX;
+	hv_ghcb->ghcb.ghcb_usage = GHCB_USAGE_HYPERV_CALL;
+
+	hv_ghcb->hypercall.outputgpa = (u64)output;
+	hv_ghcb->hypercall.hypercallinput.asuint64 = 0;
+	hv_ghcb->hypercall.hypercallinput.callcode = control;
+
+	if (input_size)
+		memcpy(hv_ghcb->hypercall.hypercalldata, input, input_size);
+
+	VMGEXIT();
+
+	hv_ghcb->ghcb.ghcb_usage = 0xffffffff;
+	memset(hv_ghcb->ghcb.save.valid_bitmap, 0,
+	       sizeof(hv_ghcb->ghcb.save.valid_bitmap));
+
+	status = hv_ghcb->hypercall.hypercalloutput.callstatus;
+
+	local_irq_restore(flags);
+
+	return status;
+}
+
+static inline u64 rd_ghcb_msr(void)
+{
+	return native_rdmsrq(MSR_AMD64_SEV_ES_GHCB);
+}
+
+static inline void wr_ghcb_msr(u64 val)
+{
+	native_wrmsrq(MSR_AMD64_SEV_ES_GHCB, val);
+}
+
+static enum es_result hv_ghcb_hv_call(struct ghcb *ghcb, u64 exit_code,
+				   u64 exit_info_1, u64 exit_info_2)
+{
+	/* Fill in protocol and format specifiers */
+	ghcb->protocol_version = hv_ghcb_version;
+	ghcb->ghcb_usage       = GHCB_DEFAULT_USAGE;
+
+	ghcb_set_sw_exit_code(ghcb, exit_code);
+	ghcb_set_sw_exit_info_1(ghcb, exit_info_1);
+	ghcb_set_sw_exit_info_2(ghcb, exit_info_2);
+
+	VMGEXIT();
+
+	if (ghcb->save.sw_exit_info_1 & GENMASK_ULL(31, 0))
+		return ES_VMM_ERROR;
+	else
+		return ES_OK;
+}
+
+void __noreturn hv_ghcb_terminate(unsigned int set, unsigned int reason)
+{
+	u64 val = GHCB_MSR_TERM_REQ;
+
+	/* Tell the hypervisor what went wrong. */
+	val |= GHCB_SEV_TERM_REASON(set, reason);
+
+	/* Request Guest Termination from Hypervisor */
+	wr_ghcb_msr(val);
+	VMGEXIT();
+
+	while (true)
+		asm volatile("hlt\n" : : : "memory");
+}
+
+bool hv_ghcb_negotiate_protocol(void)
+{
+	u64 ghcb_gpa;
+	u64 val;
+
+	/* Save ghcb page gpa. */
+	ghcb_gpa = rd_ghcb_msr();
+
+	/* Do the GHCB protocol version negotiation */
+	wr_ghcb_msr(GHCB_MSR_SEV_INFO_REQ);
+	VMGEXIT();
+	val = rd_ghcb_msr();
+
+	if (GHCB_MSR_INFO(val) != GHCB_MSR_SEV_INFO_RESP)
+		return false;
+
+	if (GHCB_MSR_PROTO_MAX(val) < GHCB_PROTOCOL_MIN ||
+	    GHCB_MSR_PROTO_MIN(val) > GHCB_PROTOCOL_MAX)
+		return false;
+
+	hv_ghcb_version = min_t(size_t, GHCB_MSR_PROTO_MAX(val),
+			     GHCB_PROTOCOL_MAX);
+
+	/* Write ghcb page back after negotiating protocol. */
+	wr_ghcb_msr(ghcb_gpa);
+	VMGEXIT();
+
+	return true;
+}
+
+static void hv_ghcb_msr_write(u64 msr, u64 value)
+{
+	union hv_ghcb *hv_ghcb;
+	void **ghcb_base;
+	unsigned long flags;
+
+	if (!hv_ghcb_pg)
+		return;
+
+	WARN_ON(in_nmi());
+
+	local_irq_save(flags);
+	ghcb_base = (void **)this_cpu_ptr(hv_ghcb_pg);
+	hv_ghcb = (union hv_ghcb *)*ghcb_base;
+	if (!hv_ghcb) {
+		local_irq_restore(flags);
+		return;
+	}
+
+	ghcb_set_rcx(&hv_ghcb->ghcb, msr);
+	ghcb_set_rax(&hv_ghcb->ghcb, lower_32_bits(value));
+	ghcb_set_rdx(&hv_ghcb->ghcb, upper_32_bits(value));
+
+	if (hv_ghcb_hv_call(&hv_ghcb->ghcb, SVM_EXIT_MSR, 1, 0))
+		pr_warn("Fail to write msr via ghcb %llx.\n", msr);
+
+	local_irq_restore(flags);
+}
+
+static void hv_ghcb_msr_read(u64 msr, u64 *value)
+{
+	union hv_ghcb *hv_ghcb;
+	void **ghcb_base;
+	unsigned long flags;
+
+	/* Check size of union hv_ghcb here. */
+	BUILD_BUG_ON(sizeof(union hv_ghcb) != HV_HYP_PAGE_SIZE);
+
+	if (!hv_ghcb_pg)
+		return;
+
+	WARN_ON(in_nmi());
+
+	local_irq_save(flags);
+	ghcb_base = (void **)this_cpu_ptr(hv_ghcb_pg);
+	hv_ghcb = (union hv_ghcb *)*ghcb_base;
+	if (!hv_ghcb) {
+		local_irq_restore(flags);
+		return;
+	}
+
+	ghcb_set_rcx(&hv_ghcb->ghcb, msr);
+	if (hv_ghcb_hv_call(&hv_ghcb->ghcb, SVM_EXIT_MSR, 0, 0))
+		pr_warn("Fail to read msr via ghcb %llx.\n", msr);
+	else
+		*value = (u64)lower_32_bits(hv_ghcb->ghcb.save.rax)
+			| ((u64)lower_32_bits(hv_ghcb->ghcb.save.rdx) << 32);
+	local_irq_restore(flags);
+}
+
+/* Only used in a fully enlightened SNP VM, i.e. without the paravisor */
+static u8 ap_start_input_arg[PAGE_SIZE] __bss_decrypted __aligned(PAGE_SIZE);
+static u8 ap_start_stack[PAGE_SIZE] __aligned(PAGE_SIZE);
+static DEFINE_PER_CPU(struct sev_es_save_area *, hv_sev_vmsa);
+
+/* Functions only used in an SNP VM without the paravisor go here. */
+
+#define hv_populate_vmcb_seg(seg, gdtr_base)			\
+do {								\
+	if (seg.selector) {					\
+		seg.base = 0;					\
+		seg.limit = HV_AP_SEGMENT_LIMIT;		\
+		seg.attrib = *(u16 *)(gdtr_base + seg.selector + 5);	\
+		seg.attrib = (seg.attrib & 0xFF) | ((seg.attrib >> 4) & 0xF00); \
+	}							\
+} while (0)							\
+
+static int snp_set_vmsa(void *va, bool vmsa)
+{
+	u64 attrs;
+
+	/*
+	 * Running at VMPL0 allows the kernel to change the VMSA bit for a page
+	 * using the RMPADJUST instruction. However, for the instruction to
+	 * succeed it must target the permissions of a lesser privileged
+	 * (higher numbered) VMPL level, so use VMPL1 (refer to the RMPADJUST
+	 * instruction in the AMD64 APM Volume 3).
+	 */
+	attrs = 1;
+	if (vmsa)
+		attrs |= RMPADJUST_VMSA_PAGE_BIT;
+
+	return rmpadjust((unsigned long)va, RMP_PG_SIZE_4K, attrs);
+}
+
+static void snp_cleanup_vmsa(struct sev_es_save_area *vmsa)
+{
+	int err;
+
+	err = snp_set_vmsa(vmsa, false);
+	if (err)
+		pr_err("clear VMSA page failed (%u), leaking page\n", err);
+	else
+		free_page((unsigned long)vmsa);
+}
+
+int hv_snp_boot_ap(u32 apic_id, unsigned long start_ip, unsigned int cpu)
+{
+	struct sev_es_save_area *vmsa = (struct sev_es_save_area *)
+		__get_free_page(GFP_KERNEL | __GFP_ZERO);
+	struct sev_es_save_area *cur_vmsa;
+	struct desc_ptr gdtr;
+	u64 ret, retry = 5;
+	struct hv_enable_vp_vtl *start_vp_input;
+	unsigned long flags;
+	int vp_index;
+
+	if (!vmsa)
+		return -ENOMEM;
+
+	/* Find the Hyper-V VP index which might be not the same as APIC ID */
+	vp_index = hv_apicid_to_vp_index(apic_id);
+	if (vp_index < 0 || vp_index > ms_hyperv.max_vp_index)
+		return -EINVAL;
+
+	native_store_gdt(&gdtr);
+
+	vmsa->gdtr.base = gdtr.address;
+	vmsa->gdtr.limit = gdtr.size;
+
+	savesegment(es, vmsa->es.selector);
+	hv_populate_vmcb_seg(vmsa->es, vmsa->gdtr.base);
+
+	savesegment(cs, vmsa->cs.selector);
+	hv_populate_vmcb_seg(vmsa->cs, vmsa->gdtr.base);
+
+	savesegment(ss, vmsa->ss.selector);
+	hv_populate_vmcb_seg(vmsa->ss, vmsa->gdtr.base);
+
+	savesegment(ds, vmsa->ds.selector);
+	hv_populate_vmcb_seg(vmsa->ds, vmsa->gdtr.base);
+
+	vmsa->efer = native_read_msr(MSR_EFER);
+
+	vmsa->cr4 = native_read_cr4();
+	vmsa->cr3 = __native_read_cr3();
+	vmsa->cr0 = native_read_cr0();
+
+	vmsa->xcr0 = 1;
+	vmsa->g_pat = HV_AP_INIT_GPAT_DEFAULT;
+	vmsa->rip = (u64)secondary_startup_64_no_verify;
+	vmsa->rsp = (u64)&ap_start_stack[PAGE_SIZE];
+
+	/*
+	 * Set the SNP-specific fields for this VMSA:
+	 *   VMPL level
+	 *   SEV_FEATURES (matches the SEV STATUS MSR right shifted 2 bits)
+	 */
+	vmsa->vmpl = 0;
+	vmsa->sev_features = sev_status >> 2;
+
+	ret = snp_set_vmsa(vmsa, true);
+	if (ret) {
+		pr_err("RMPADJUST(%llx) failed: %llx\n", (u64)vmsa, ret);
+		free_page((u64)vmsa);
+		return ret;
+	}
+
+	local_irq_save(flags);
+	start_vp_input = (struct hv_enable_vp_vtl *)ap_start_input_arg;
+	memset(start_vp_input, 0, sizeof(*start_vp_input));
+	start_vp_input->partition_id = -1;
+	start_vp_input->vp_index = vp_index;
+	start_vp_input->target_vtl.target_vtl = ms_hyperv.vtl;
+	*(u64 *)&start_vp_input->vp_context = __pa(vmsa) | 1;
+
+	do {
+		ret = hv_do_hypercall(HVCALL_START_VP,
+				      start_vp_input, NULL);
+	} while (hv_result(ret) == HV_STATUS_TIME_OUT && retry--);
+
+	local_irq_restore(flags);
+
+	if (!hv_result_success(ret)) {
+		pr_err("HvCallStartVirtualProcessor failed: %llx\n", ret);
+		snp_cleanup_vmsa(vmsa);
+		vmsa = NULL;
+	}
+
+	cur_vmsa = per_cpu(hv_sev_vmsa, cpu);
+	/* Free up any previous VMSA page */
+	if (cur_vmsa)
+		snp_cleanup_vmsa(cur_vmsa);
+
+	/* Record the current VMSA page */
+	per_cpu(hv_sev_vmsa, cpu) = vmsa;
+
+	return ret;
+}
+
+u64 hv_snp_hypercall(u64 control, u64 param1, u64 param2)
+{
+	u64 hv_status;
+
+	register u64 __r8 asm("r8") = param2;
+	asm volatile("vmmcall"
+		     : "=a" (hv_status),
+		       "+c" (control), "+d" (param1), "+r" (__r8)
+		     : : "cc", "memory", "r9", "r10", "r11");
+
+	return hv_status;
+}
+
+#else
+static inline void hv_ghcb_msr_write(u64 msr, u64 value) {}
+static inline void hv_ghcb_msr_read(u64 msr, u64 *value) {}
+u64 hv_snp_hypercall(u64 control, u64 param1, u64 param2) { return U64_MAX; }
+#endif /* CONFIG_AMD_MEM_ENCRYPT */
+
+#ifdef CONFIG_INTEL_TDX_GUEST
+static void hv_tdx_msr_write(u64 msr, u64 val)
+{
+	struct tdx_module_args args = {
+		.r10 = TDX_HYPERCALL_STANDARD,
+		.r11 = EXIT_REASON_MSR_WRITE,
+		.r12 = msr,
+		.r13 = val,
+	};
+
+	u64 ret = __tdx_hypercall(&args);
+
+	WARN_ONCE(ret, "Failed to emulate MSR write: %lld\n", ret);
+}
+
+static void hv_tdx_msr_read(u64 msr, u64 *val)
+{
+	struct tdx_module_args args = {
+		.r10 = TDX_HYPERCALL_STANDARD,
+		.r11 = EXIT_REASON_MSR_READ,
+		.r12 = msr,
+	};
+
+	u64 ret = __tdx_hypercall(&args);
+
+	if (WARN_ONCE(ret, "Failed to emulate MSR read: %lld\n", ret))
+		*val = 0;
+	else
+		*val = args.r11;
+}
+
+u64 hv_tdx_hypercall(u64 control, u64 param1, u64 param2)
+{
+	struct tdx_module_args args = { };
+
+	args.r10 = control;
+	args.rdx = param1;
+	args.r8  = param2;
+
+	(void)__tdx_hypercall(&args);
+
+	return args.r11;
+}
+
+#else
+static inline void hv_tdx_msr_write(u64 msr, u64 value) {}
+static inline void hv_tdx_msr_read(u64 msr, u64 *value) {}
+u64 hv_tdx_hypercall(u64 control, u64 param1, u64 param2) { return U64_MAX; }
+#endif /* CONFIG_INTEL_TDX_GUEST */
+
+#if defined(CONFIG_AMD_MEM_ENCRYPT) || defined(CONFIG_INTEL_TDX_GUEST)
+void hv_ivm_msr_write(u64 msr, u64 value)
+{
+	if (!ms_hyperv.paravisor_present)
+		return;
+
+	if (hv_isolation_type_tdx())
+		hv_tdx_msr_write(msr, value);
+	else if (hv_isolation_type_snp())
+		hv_ghcb_msr_write(msr, value);
+}
+
+void hv_ivm_msr_read(u64 msr, u64 *value)
+{
+	if (!ms_hyperv.paravisor_present)
+		return;
+
+	if (hv_isolation_type_tdx())
+		hv_tdx_msr_read(msr, value);
+	else if (hv_isolation_type_snp())
+		hv_ghcb_msr_read(msr, value);
+}
+
+/*
+ * Keep track of the PFN regions which were shared with the host. The access
+ * must be revoked upon kexec/kdump (see hv_ivm_clear_host_access()).
+ */
+struct hv_enc_pfn_region {
+	struct list_head list;
+	u64 pfn;
+	int count;
+};
+
+static LIST_HEAD(hv_list_enc);
+static DEFINE_RAW_SPINLOCK(hv_list_enc_lock);
+
+static int hv_list_enc_add(const u64 *pfn_list, int count)
+{
+	struct hv_enc_pfn_region *ent;
+	unsigned long flags;
+	u64 pfn;
+	int i;
+
+	for (i = 0; i < count; i++) {
+		pfn = pfn_list[i];
+
+		raw_spin_lock_irqsave(&hv_list_enc_lock, flags);
+		/* Check if the PFN already exists in some region first */
+		list_for_each_entry(ent, &hv_list_enc, list) {
+			if ((ent->pfn <= pfn) && (ent->pfn + ent->count - 1 >= pfn))
+				/* Nothing to do - pfn is already in the list */
+				goto unlock_done;
+		}
+
+		/*
+		 * Check if the PFN is adjacent to an existing region. Growing
+		 * a region can make it adjacent to another one but merging is
+		 * not (yet) implemented for simplicity. A PFN cannot be added
+		 * to two regions to keep the logic in hv_list_enc_remove()
+		 * correct.
+		 */
+		list_for_each_entry(ent, &hv_list_enc, list) {
+			if (ent->pfn + ent->count == pfn) {
+				/* Grow existing region up */
+				ent->count++;
+				goto unlock_done;
+			} else if (pfn + 1 == ent->pfn) {
+				/* Grow existing region down */
+				ent->pfn--;
+				ent->count++;
+				goto unlock_done;
+			}
+		}
+		raw_spin_unlock_irqrestore(&hv_list_enc_lock, flags);
+
+		/* No adjacent region found -- create a new one */
+		ent = kzalloc_obj(struct hv_enc_pfn_region);
+		if (!ent)
+			return -ENOMEM;
+
+		ent->pfn = pfn;
+		ent->count = 1;
+
+		raw_spin_lock_irqsave(&hv_list_enc_lock, flags);
+		list_add(&ent->list, &hv_list_enc);
+
+unlock_done:
+		raw_spin_unlock_irqrestore(&hv_list_enc_lock, flags);
+	}
+
+	return 0;
+}
+
+static int hv_list_enc_remove(const u64 *pfn_list, int count)
+{
+	struct hv_enc_pfn_region *ent, *t;
+	struct hv_enc_pfn_region new_region;
+	unsigned long flags;
+	u64 pfn;
+	int i;
+
+	for (i = 0; i < count; i++) {
+		pfn = pfn_list[i];
+
+		raw_spin_lock_irqsave(&hv_list_enc_lock, flags);
+		list_for_each_entry_safe(ent, t, &hv_list_enc, list) {
+			if (pfn == ent->pfn + ent->count - 1) {
+				/* Removing tail pfn */
+				ent->count--;
+				if (!ent->count) {
+					list_del(&ent->list);
+					kfree(ent);
+				}
+				goto unlock_done;
+			} else if (pfn == ent->pfn) {
+				/* Removing head pfn */
+				ent->count--;
+				ent->pfn++;
+				if (!ent->count) {
+					list_del(&ent->list);
+					kfree(ent);
+				}
+				goto unlock_done;
+			} else if (pfn > ent->pfn && pfn < ent->pfn + ent->count - 1) {
+				/*
+				 * Removing a pfn in the middle. Cut off the tail
+				 * of the existing region and create a template for
+				 * the new one.
+				 */
+				new_region.pfn = pfn + 1;
+				new_region.count = ent->count - (pfn - ent->pfn + 1);
+				ent->count = pfn - ent->pfn;
+				goto unlock_split;
+			}
+
+		}
+unlock_done:
+		raw_spin_unlock_irqrestore(&hv_list_enc_lock, flags);
+		continue;
+
+unlock_split:
+		raw_spin_unlock_irqrestore(&hv_list_enc_lock, flags);
+
+		ent = kzalloc_obj(struct hv_enc_pfn_region);
+		if (!ent)
+			return -ENOMEM;
+
+		ent->pfn = new_region.pfn;
+		ent->count = new_region.count;
+
+		raw_spin_lock_irqsave(&hv_list_enc_lock, flags);
+		list_add(&ent->list, &hv_list_enc);
+		raw_spin_unlock_irqrestore(&hv_list_enc_lock, flags);
+	}
+
+	return 0;
+}
+
+/* Stop new private<->shared conversions */
+static void hv_vtom_kexec_begin(void)
+{
+	if (!IS_ENABLED(CONFIG_KEXEC_CORE))
+		return;
+
+	/*
+	 * Crash kernel reaches here with interrupts disabled: can't wait for
+	 * conversions to finish.
+	 *
+	 * If race happened, just report and proceed.
+	 */
+	if (!set_memory_enc_stop_conversion())
+		pr_warn("Failed to stop shared<->private conversions\n");
+}
+
+static void hv_vtom_kexec_finish(void)
+{
+	struct hv_gpa_range_for_visibility *input;
+	struct hv_enc_pfn_region *ent;
+	unsigned long flags;
+	u64 hv_status;
+	int cur, i;
+
+	local_irq_save(flags);
+	input = *this_cpu_ptr(hyperv_pcpu_input_arg);
+
+	if (unlikely(!input))
+		goto out;
+
+	list_for_each_entry(ent, &hv_list_enc, list) {
+		for (i = 0, cur = 0; i < ent->count; i++) {
+			input->gpa_page_list[cur] = ent->pfn + i;
+			cur++;
+
+			if (cur == HV_MAX_MODIFY_GPA_REP_COUNT || i == ent->count - 1) {
+				input->partition_id = HV_PARTITION_ID_SELF;
+				input->host_visibility = VMBUS_PAGE_NOT_VISIBLE;
+				input->reserved0 = 0;
+				input->reserved1 = 0;
+				hv_status = hv_do_rep_hypercall(
+					HVCALL_MODIFY_SPARSE_GPA_PAGE_HOST_VISIBILITY,
+					cur, 0, input, NULL);
+				WARN_ON_ONCE(!hv_result_success(hv_status));
+				cur = 0;
+			}
+		}
+
+	}
+
+out:
+	local_irq_restore(flags);
+}
+
+/*
+ * hv_mark_gpa_visibility - Set pages visible to host via hvcall.
+ *
+ * In Isolation VM, all guest memory is encrypted from host and guest
+ * needs to set memory visible to host via hvcall before sharing memory
+ * with host.
+ */
+static int hv_mark_gpa_visibility(u16 count, const u64 pfn[],
+			   enum hv_mem_host_visibility visibility)
+{
+	struct hv_gpa_range_for_visibility *input;
+	u64 hv_status;
+	unsigned long flags;
+	int ret;
+
+	/* no-op if partition isolation is not enabled */
+	if (!hv_is_isolation_supported())
+		return 0;
+
+	if (count > HV_MAX_MODIFY_GPA_REP_COUNT) {
+		pr_err("Hyper-V: GPA count:%d exceeds supported:%lu\n", count,
+			HV_MAX_MODIFY_GPA_REP_COUNT);
+		return -EINVAL;
+	}
+
+	if (visibility == VMBUS_PAGE_NOT_VISIBLE)
+		ret = hv_list_enc_remove(pfn, count);
+	else
+		ret = hv_list_enc_add(pfn, count);
+	if (ret)
+		return ret;
+
+	local_irq_save(flags);
+	input = *this_cpu_ptr(hyperv_pcpu_input_arg);
+
+	if (unlikely(!input)) {
+		local_irq_restore(flags);
+		return -EINVAL;
+	}
+
+	input->partition_id = HV_PARTITION_ID_SELF;
+	input->host_visibility = visibility;
+	input->reserved0 = 0;
+	input->reserved1 = 0;
+	memcpy((void *)input->gpa_page_list, pfn, count * sizeof(*pfn));
+	hv_status = hv_do_rep_hypercall(
+			HVCALL_MODIFY_SPARSE_GPA_PAGE_HOST_VISIBILITY, count,
+			0, input, NULL);
+	local_irq_restore(flags);
+
+	if (hv_result_success(hv_status))
+		return 0;
+
+	if (visibility == VMBUS_PAGE_NOT_VISIBLE)
+		ret = hv_list_enc_add(pfn, count);
+	else
+		ret = hv_list_enc_remove(pfn, count);
+	/*
+	 * There's no good way to recover from -ENOMEM here, the accounting is
+	 * wrong either way.
+	 */
+	WARN_ON_ONCE(ret);
+
+	return -EFAULT;
+}
+
+/*
+ * When transitioning memory between encrypted and decrypted, the caller
+ * of set_memory_encrypted() or set_memory_decrypted() is responsible for
+ * ensuring that the memory isn't in use and isn't referenced while the
+ * transition is in progress.  The transition has multiple steps, and the
+ * memory is in an inconsistent state until all steps are complete. A
+ * reference while the state is inconsistent could result in an exception
+ * that can't be cleanly fixed up.
+ *
+ * But the Linux kernel load_unaligned_zeropad() mechanism could cause a
+ * stray reference that can't be prevented by the caller, so Linux has
+ * specific code to handle this case. But when the #VC and #VE exceptions
+ * routed to a paravisor, the specific code doesn't work. To avoid this
+ * problem, mark the pages as "not present" while the transition is in
+ * progress. If load_unaligned_zeropad() causes a stray reference, a normal
+ * page fault is generated instead of #VC or #VE, and the page-fault-based
+ * handlers for load_unaligned_zeropad() resolve the reference.  When the
+ * transition is complete, hv_vtom_set_host_visibility() marks the pages
+ * as "present" again.
+ */
+static int hv_vtom_clear_present(unsigned long kbuffer, int pagecount, bool enc)
+{
+	return set_memory_np(kbuffer, pagecount);
+}
+
+/*
+ * hv_vtom_set_host_visibility - Set specified memory visible to host.
+ *
+ * In Isolation VM, all guest memory is encrypted from host and guest
+ * needs to set memory visible to host via hvcall before sharing memory
+ * with host. This function works as wrap of hv_mark_gpa_visibility()
+ * with memory base and size.
+ */
+static int hv_vtom_set_host_visibility(unsigned long kbuffer, int pagecount, bool enc)
+{
+	enum hv_mem_host_visibility visibility = enc ?
+			VMBUS_PAGE_NOT_VISIBLE : VMBUS_PAGE_VISIBLE_READ_WRITE;
+	u64 *pfn_array;
+	phys_addr_t paddr;
+	int i, pfn, err;
+	void *vaddr;
+	int ret = 0;
+
+	pfn_array = kmalloc(HV_HYP_PAGE_SIZE, GFP_KERNEL);
+	if (!pfn_array) {
+		ret = -ENOMEM;
+		goto err_set_memory_p;
+	}
+
+	for (i = 0, pfn = 0; i < pagecount; i++) {
+		/*
+		 * Use slow_virt_to_phys() because the PRESENT bit has been
+		 * temporarily cleared in the PTEs.  slow_virt_to_phys() works
+		 * without the PRESENT bit while virt_to_hvpfn() or similar
+		 * does not.
+		 */
+		vaddr = (void *)kbuffer + (i * HV_HYP_PAGE_SIZE);
+		paddr = slow_virt_to_phys(vaddr);
+		pfn_array[pfn] = paddr >> HV_HYP_PAGE_SHIFT;
+		pfn++;
+
+		if (pfn == HV_MAX_MODIFY_GPA_REP_COUNT || i == pagecount - 1) {
+			ret = hv_mark_gpa_visibility(pfn, pfn_array,
+						     visibility);
+			if (ret)
+				goto err_free_pfn_array;
+			pfn = 0;
+		}
+	}
+
+err_free_pfn_array:
+	kfree(pfn_array);
+
+err_set_memory_p:
+	/*
+	 * Set the PTE PRESENT bits again to revert what hv_vtom_clear_present()
+	 * did. Do this even if there is an error earlier in this function in
+	 * order to avoid leaving the memory range in a "broken" state. Setting
+	 * the PRESENT bits shouldn't fail, but return an error if it does.
+	 */
+	err = set_memory_p(kbuffer, pagecount);
+	if (err && !ret)
+		ret = err;
+
+	return ret;
+}
+
+static bool hv_vtom_tlb_flush_required(bool private)
+{
+	/*
+	 * Since hv_vtom_clear_present() marks the PTEs as "not present"
+	 * and flushes the TLB, they can't be in the TLB. That makes the
+	 * flush controlled by this function redundant, so return "false".
+	 */
+	return false;
+}
+
+static bool hv_vtom_cache_flush_required(void)
+{
+	return false;
+}
+
+static bool hv_is_private_mmio(u64 addr)
+{
+	/*
+	 * Hyper-V always provides a single IO-APIC in a guest VM.
+	 * When a paravisor is used, it is emulated by the paravisor
+	 * in the guest context and must be mapped private.
+	 */
+	if (addr >= HV_IOAPIC_BASE_ADDRESS &&
+	    addr < (HV_IOAPIC_BASE_ADDRESS + PAGE_SIZE))
+		return true;
+
+	/* Same with a vTPM */
+	if (addr >= VTPM_BASE_ADDRESS &&
+	    addr < (VTPM_BASE_ADDRESS + PAGE_SIZE))
+		return true;
+
+	return false;
+}
+
+void __init hv_vtom_init(void)
+{
+	enum hv_isolation_type type = hv_get_isolation_type();
+
+	switch (type) {
+	case HV_ISOLATION_TYPE_VBS:
+		fallthrough;
+	/*
+	 * By design, a VM using vTOM doesn't see the SEV setting,
+	 * so SEV initialization is bypassed and sev_status isn't set.
+	 * Set it here to indicate a vTOM VM.
+	 *
+	 * Note: if CONFIG_AMD_MEM_ENCRYPT is not set, sev_status is
+	 * defined as 0ULL, to which we can't assigned a value.
+	 */
+#ifdef CONFIG_AMD_MEM_ENCRYPT
+	case HV_ISOLATION_TYPE_SNP:
+		sev_status = MSR_AMD64_SNP_VTOM;
+		cc_vendor = CC_VENDOR_AMD;
+		break;
+#endif
+
+	case HV_ISOLATION_TYPE_TDX:
+		cc_vendor = CC_VENDOR_INTEL;
+		break;
+
+	default:
+		panic("hv_vtom_init: unsupported isolation type %d\n", type);
+	}
+
+	cc_set_mask(ms_hyperv.shared_gpa_boundary);
+	physical_mask &= ms_hyperv.shared_gpa_boundary - 1;
+
+	x86_platform.hyper.is_private_mmio = hv_is_private_mmio;
+	x86_platform.guest.enc_cache_flush_required = hv_vtom_cache_flush_required;
+	x86_platform.guest.enc_tlb_flush_required = hv_vtom_tlb_flush_required;
+	x86_platform.guest.enc_status_change_prepare = hv_vtom_clear_present;
+	x86_platform.guest.enc_status_change_finish = hv_vtom_set_host_visibility;
+	x86_platform.guest.enc_kexec_begin = hv_vtom_kexec_begin;
+	x86_platform.guest.enc_kexec_finish = hv_vtom_kexec_finish;
+
+	/* Set WB as the default cache mode. */
+	guest_force_mtrr_state(NULL, 0, MTRR_TYPE_WRBACK);
+}
+
+#endif /* defined(CONFIG_AMD_MEM_ENCRYPT) || defined(CONFIG_INTEL_TDX_GUEST) */
+
+enum hv_isolation_type hv_get_isolation_type(void)
+{
+	if (!(ms_hyperv.priv_high & HV_ISOLATION))
+		return HV_ISOLATION_TYPE_NONE;
+	return FIELD_GET(HV_ISOLATION_TYPE, ms_hyperv.isolation_config_b);
+}
+EXPORT_SYMBOL_GPL(hv_get_isolation_type);
+
+/*
+ * hv_is_isolation_supported - Check system runs in the Hyper-V
+ * isolation VM.
+ */
+bool hv_is_isolation_supported(void)
+{
+	if (!cpu_feature_enabled(X86_FEATURE_HYPERVISOR))
+		return false;
+
+	if (!hypervisor_is_type(X86_HYPER_MS_HYPERV))
+		return false;
+
+	return hv_get_isolation_type() != HV_ISOLATION_TYPE_NONE;
+}
+
+DEFINE_STATIC_KEY_FALSE(isolation_type_snp);
+
+/*
+ * hv_isolation_type_snp - Check if the system runs in an AMD SEV-SNP based
+ * isolation VM.
+ */
+bool hv_isolation_type_snp(void)
+{
+	return static_branch_unlikely(&isolation_type_snp);
+}
+
+DEFINE_STATIC_KEY_FALSE(isolation_type_tdx);
+/*
+ * hv_isolation_type_tdx - Check if the system runs in an Intel TDX based
+ * isolated VM.
+ */
+bool hv_isolation_type_tdx(void)
+{
+	return static_branch_unlikely(&isolation_type_tdx);
+}
diff --git a/arch/x86/hyperv/mmu.c b/arch/x86/hyperv/mmu.c
new file mode 100644
index 000000000..cfcb60468
--- /dev/null
+++ b/arch/x86/hyperv/mmu.c
@@ -0,0 +1,246 @@
+#define pr_fmt(fmt)  "Hyper-V: " fmt
+
+#include <linux/log2.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+#include <asm/fpu/api.h>
+#include <asm/mshyperv.h>
+#include <asm/msr.h>
+#include <asm/tlbflush.h>
+#include <asm/tlb.h>
+
+#define CREATE_TRACE_POINTS
+#include <asm/trace/hyperv.h>
+
+/* Each gva in gva_list encodes up to 4096 pages to flush */
+#define HV_TLB_FLUSH_UNIT (4096 * PAGE_SIZE)
+
+static u64 hyperv_flush_tlb_others_ex(const struct cpumask *cpus,
+				      const struct flush_tlb_info *info);
+
+/*
+ * Fills in gva_list starting from offset. Returns the number of items added.
+ */
+static inline int fill_gva_list(u64 gva_list[], int offset,
+				unsigned long start, unsigned long end)
+{
+	int gva_n = offset;
+	unsigned long cur = start, diff;
+
+	do {
+		diff = end > cur ? end - cur : 0;
+
+		gva_list[gva_n] = cur & PAGE_MASK;
+		/*
+		 * Lower 12 bits encode the number of additional
+		 * pages to flush (in addition to the 'cur' page).
+		 */
+		if (diff >= HV_TLB_FLUSH_UNIT) {
+			gva_list[gva_n] |= ~PAGE_MASK;
+			cur += HV_TLB_FLUSH_UNIT;
+		}  else if (diff) {
+			gva_list[gva_n] |= (diff - 1) >> PAGE_SHIFT;
+			cur = end;
+		}
+
+		gva_n++;
+
+	} while (cur < end);
+
+	return gva_n - offset;
+}
+
+static bool cpu_is_lazy(int cpu)
+{
+	return per_cpu(cpu_tlbstate_shared.is_lazy, cpu);
+}
+
+static void hyperv_flush_tlb_multi(const struct cpumask *cpus,
+				   const struct flush_tlb_info *info)
+{
+	int cpu, vcpu, gva_n, max_gvas;
+	struct hv_tlb_flush *flush;
+	u64 status;
+	unsigned long flags;
+	bool do_lazy = !info->freed_tables;
+
+	trace_hyperv_mmu_flush_tlb_multi(cpus, info);
+
+	if (!hv_hypercall_pg)
+		goto do_native;
+
+	local_irq_save(flags);
+
+	flush = *this_cpu_ptr(hyperv_pcpu_input_arg);
+
+	if (unlikely(!flush)) {
+		local_irq_restore(flags);
+		goto do_native;
+	}
+
+	if (info->mm) {
+		/*
+		 * AddressSpace argument must match the CR3 with PCID bits
+		 * stripped out.
+		 */
+		flush->address_space = virt_to_phys(info->mm->pgd);
+		flush->address_space &= CR3_ADDR_MASK;
+		flush->flags = 0;
+	} else {
+		flush->address_space = 0;
+		flush->flags = HV_FLUSH_ALL_VIRTUAL_ADDRESS_SPACES;
+	}
+
+	flush->processor_mask = 0;
+	if (cpumask_equal(cpus, cpu_present_mask)) {
+		flush->flags |= HV_FLUSH_ALL_PROCESSORS;
+	} else {
+		/*
+		 * From the supplied CPU set we need to figure out if we can get
+		 * away with cheaper HVCALL_FLUSH_VIRTUAL_ADDRESS_{LIST,SPACE}
+		 * hypercalls. This is possible when the highest VP number in
+		 * the set is < 64. As VP numbers are usually in ascending order
+		 * and match Linux CPU ids, here is an optimization: we check
+		 * the VP number for the highest bit in the supplied set first
+		 * so we can quickly find out if using *_EX hypercalls is a
+		 * must. We will also check all VP numbers when walking the
+		 * supplied CPU set to remain correct in all cases.
+		 */
+		cpu = cpumask_last(cpus);
+
+		if (cpu < nr_cpumask_bits && hv_cpu_number_to_vp_number(cpu) >= 64)
+			goto do_ex_hypercall;
+
+		for_each_cpu(cpu, cpus) {
+			if (do_lazy && cpu_is_lazy(cpu))
+				continue;
+			vcpu = hv_cpu_number_to_vp_number(cpu);
+			if (vcpu == VP_INVAL) {
+				local_irq_restore(flags);
+				goto do_native;
+			}
+
+			if (vcpu >= 64)
+				goto do_ex_hypercall;
+
+			__set_bit(vcpu, (unsigned long *)
+				  &flush->processor_mask);
+		}
+
+		/* nothing to flush if 'processor_mask' ends up being empty */
+		if (!flush->processor_mask) {
+			local_irq_restore(flags);
+			return;
+		}
+	}
+
+	/*
+	 * We can flush not more than max_gvas with one hypercall. Flush the
+	 * whole address space if we were asked to do more.
+	 */
+	max_gvas = (PAGE_SIZE - sizeof(*flush)) / sizeof(flush->gva_list[0]);
+
+	if (info->end == TLB_FLUSH_ALL) {
+		flush->flags |= HV_FLUSH_NON_GLOBAL_MAPPINGS_ONLY;
+		status = hv_do_hypercall(HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE,
+					 flush, NULL);
+	} else if (info->end &&
+		   ((info->end - info->start)/HV_TLB_FLUSH_UNIT) > max_gvas) {
+		status = hv_do_hypercall(HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE,
+					 flush, NULL);
+	} else {
+		gva_n = fill_gva_list(flush->gva_list, 0,
+				      info->start, info->end);
+		status = hv_do_rep_hypercall(HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST,
+					     gva_n, 0, flush, NULL);
+	}
+	goto check_status;
+
+do_ex_hypercall:
+	status = hyperv_flush_tlb_others_ex(cpus, info);
+
+check_status:
+	local_irq_restore(flags);
+
+	if (hv_result_success(status))
+		return;
+do_native:
+	native_flush_tlb_multi(cpus, info);
+}
+
+static u64 hyperv_flush_tlb_others_ex(const struct cpumask *cpus,
+				      const struct flush_tlb_info *info)
+{
+	int nr_bank = 0, max_gvas, gva_n;
+	struct hv_tlb_flush_ex *flush;
+	u64 status;
+
+	if (!(ms_hyperv.hints & HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED))
+		return HV_STATUS_INVALID_PARAMETER;
+
+	flush = *this_cpu_ptr(hyperv_pcpu_input_arg);
+
+	if (info->mm) {
+		/*
+		 * AddressSpace argument must match the CR3 with PCID bits
+		 * stripped out.
+		 */
+		flush->address_space = virt_to_phys(info->mm->pgd);
+		flush->address_space &= CR3_ADDR_MASK;
+		flush->flags = 0;
+	} else {
+		flush->address_space = 0;
+		flush->flags = HV_FLUSH_ALL_VIRTUAL_ADDRESS_SPACES;
+	}
+
+	flush->hv_vp_set.valid_bank_mask = 0;
+
+	flush->hv_vp_set.format = HV_GENERIC_SET_SPARSE_4K;
+	nr_bank = cpumask_to_vpset_skip(&flush->hv_vp_set, cpus,
+			info->freed_tables ? NULL : cpu_is_lazy);
+	if (nr_bank < 0)
+		return HV_STATUS_INVALID_PARAMETER;
+
+	/*
+	 * We can flush not more than max_gvas with one hypercall. Flush the
+	 * whole address space if we were asked to do more.
+	 *
+	 * For these hypercalls, Hyper-V treats the valid_bank_mask field
+	 * of flush->hv_vp_set as part of the fixed size input header.
+	 * So the variable input header size is equal to nr_bank.
+	 */
+	max_gvas =
+		(PAGE_SIZE - sizeof(*flush) - nr_bank *
+		 sizeof(flush->hv_vp_set.bank_contents[0])) /
+		sizeof(flush->gva_list[0]);
+
+	if (info->end == TLB_FLUSH_ALL) {
+		flush->flags |= HV_FLUSH_NON_GLOBAL_MAPPINGS_ONLY;
+		status = hv_do_rep_hypercall(
+			HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX,
+			0, nr_bank, flush, NULL);
+	} else if (info->end &&
+		   ((info->end - info->start)/HV_TLB_FLUSH_UNIT) > max_gvas) {
+		status = hv_do_rep_hypercall(
+			HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX,
+			0, nr_bank, flush, NULL);
+	} else {
+		gva_n = fill_gva_list(flush->gva_list, nr_bank,
+				      info->start, info->end);
+		status = hv_do_rep_hypercall(
+			HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST_EX,
+			gva_n, nr_bank, flush, NULL);
+	}
+
+	return status;
+}
+
+void hyperv_setup_mmu_ops(void)
+{
+	if (!(ms_hyperv.hints & HV_X64_REMOTE_TLB_FLUSH_RECOMMENDED))
+		return;
+
+	pr_info("Using hypercall for remote TLB flush\n");
+	pv_ops.mmu.flush_tlb_multi = hyperv_flush_tlb_multi;
+}
diff --git a/arch/x86/hyperv/mshv-asm-offsets.c b/arch/x86/hyperv/mshv-asm-offsets.c
new file mode 100644
index 000000000..882c1db6d
--- /dev/null
+++ b/arch/x86/hyperv/mshv-asm-offsets.c
@@ -0,0 +1,37 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Generate definitions needed by assembly language modules.
+ * This code generates raw asm output which is post-processed to extract
+ * and format the required data.
+ *
+ * Copyright (c) 2025, Microsoft Corporation.
+ *
+ * Author:
+ *   Naman Jain <namjain@microsoft.com>
+ */
+#define COMPILE_OFFSETS
+
+#include <linux/kbuild.h>
+#include <asm/mshyperv.h>
+
+static void __used common(void)
+{
+	if (IS_ENABLED(CONFIG_HYPERV_VTL_MODE)) {
+		OFFSET(MSHV_VTL_CPU_CONTEXT_rax, mshv_vtl_cpu_context, rax);
+		OFFSET(MSHV_VTL_CPU_CONTEXT_rcx, mshv_vtl_cpu_context, rcx);
+		OFFSET(MSHV_VTL_CPU_CONTEXT_rdx, mshv_vtl_cpu_context, rdx);
+		OFFSET(MSHV_VTL_CPU_CONTEXT_rbx, mshv_vtl_cpu_context, rbx);
+		OFFSET(MSHV_VTL_CPU_CONTEXT_rbp, mshv_vtl_cpu_context, rbp);
+		OFFSET(MSHV_VTL_CPU_CONTEXT_rsi, mshv_vtl_cpu_context, rsi);
+		OFFSET(MSHV_VTL_CPU_CONTEXT_rdi, mshv_vtl_cpu_context, rdi);
+		OFFSET(MSHV_VTL_CPU_CONTEXT_r8,  mshv_vtl_cpu_context, r8);
+		OFFSET(MSHV_VTL_CPU_CONTEXT_r9,  mshv_vtl_cpu_context, r9);
+		OFFSET(MSHV_VTL_CPU_CONTEXT_r10, mshv_vtl_cpu_context, r10);
+		OFFSET(MSHV_VTL_CPU_CONTEXT_r11, mshv_vtl_cpu_context, r11);
+		OFFSET(MSHV_VTL_CPU_CONTEXT_r12, mshv_vtl_cpu_context, r12);
+		OFFSET(MSHV_VTL_CPU_CONTEXT_r13, mshv_vtl_cpu_context, r13);
+		OFFSET(MSHV_VTL_CPU_CONTEXT_r14, mshv_vtl_cpu_context, r14);
+		OFFSET(MSHV_VTL_CPU_CONTEXT_r15, mshv_vtl_cpu_context, r15);
+		OFFSET(MSHV_VTL_CPU_CONTEXT_cr2, mshv_vtl_cpu_context, cr2);
+	}
+}
diff --git a/arch/x86/hyperv/mshv_vtl_asm.S b/arch/x86/hyperv/mshv_vtl_asm.S
new file mode 100644
index 000000000..f595eefad
--- /dev/null
+++ b/arch/x86/hyperv/mshv_vtl_asm.S
@@ -0,0 +1,116 @@
+/* SPDX-License-Identifier: GPL-2.0
+ *
+ * Assembly level code for mshv_vtl VTL transition
+ *
+ * Copyright (c) 2025, Microsoft Corporation.
+ *
+ * Author:
+ *   Naman Jain <namjain@microsoft.com>
+ */
+
+#include <linux/linkage.h>
+#include <linux/static_call_types.h>
+#include <asm/asm.h>
+#include <asm/asm-offsets.h>
+#include <asm/frame.h>
+#include "mshv-asm-offsets.h"
+
+	.text
+	.section .noinstr.text, "ax"
+/*
+ * void __mshv_vtl_return_call(struct mshv_vtl_cpu_context *vtl0)
+ *
+ * This function is used to context switch between different Virtual Trust Levels.
+ * It is marked as 'noinstr' to prevent against instrumentation and debugging facilities.
+ * NMIs aren't a problem because the NMI handler saves/restores CR2 specifically to guard
+ * against #PFs in NMI context clobbering the guest state.
+ */
+SYM_FUNC_START(__mshv_vtl_return_call)
+	/* Push callee save registers */
+	pushq %rbp
+	mov %rsp, %rbp
+	pushq %r12
+	pushq %r13
+	pushq %r14
+	pushq %r15
+	pushq %rbx
+
+	/* register switch to VTL0 clobbers all registers except rax/rcx */
+	mov %_ASM_ARG1, %rax
+
+	/* grab rbx/rbp/rsi/rdi/r8-r15 */
+	mov MSHV_VTL_CPU_CONTEXT_rbx(%rax), %rbx
+	mov MSHV_VTL_CPU_CONTEXT_rbp(%rax), %rbp
+	mov MSHV_VTL_CPU_CONTEXT_rsi(%rax), %rsi
+	mov MSHV_VTL_CPU_CONTEXT_rdi(%rax), %rdi
+	mov MSHV_VTL_CPU_CONTEXT_r8(%rax), %r8
+	mov MSHV_VTL_CPU_CONTEXT_r9(%rax), %r9
+	mov MSHV_VTL_CPU_CONTEXT_r10(%rax), %r10
+	mov MSHV_VTL_CPU_CONTEXT_r11(%rax), %r11
+	mov MSHV_VTL_CPU_CONTEXT_r12(%rax), %r12
+	mov MSHV_VTL_CPU_CONTEXT_r13(%rax), %r13
+	mov MSHV_VTL_CPU_CONTEXT_r14(%rax), %r14
+	mov MSHV_VTL_CPU_CONTEXT_r15(%rax), %r15
+
+	mov MSHV_VTL_CPU_CONTEXT_cr2(%rax), %rdx
+	mov %rdx, %cr2
+	mov MSHV_VTL_CPU_CONTEXT_rdx(%rax), %rdx
+
+	/* stash host registers on stack */
+	pushq %rax
+	pushq %rcx
+
+	xor %ecx, %ecx
+
+	/* make a hypercall to switch VTL */
+	call STATIC_CALL_TRAMP_STR(__mshv_vtl_return_hypercall)
+
+	/* stash guest registers on stack, restore saved host copies */
+	pushq %rax
+	pushq %rcx
+	mov 16(%rsp), %rcx
+	mov 24(%rsp), %rax
+
+	mov %rdx, MSHV_VTL_CPU_CONTEXT_rdx(%rax)
+	mov %cr2, %rdx
+	mov %rdx, MSHV_VTL_CPU_CONTEXT_cr2(%rax)
+	pop MSHV_VTL_CPU_CONTEXT_rcx(%rax)
+	pop MSHV_VTL_CPU_CONTEXT_rax(%rax)
+	add $16, %rsp
+
+	/* save rbx/rbp/rsi/rdi/r8-r15 */
+	mov %rbx, MSHV_VTL_CPU_CONTEXT_rbx(%rax)
+	mov %rbp, MSHV_VTL_CPU_CONTEXT_rbp(%rax)
+	mov %rsi, MSHV_VTL_CPU_CONTEXT_rsi(%rax)
+	mov %rdi, MSHV_VTL_CPU_CONTEXT_rdi(%rax)
+	mov %r8,  MSHV_VTL_CPU_CONTEXT_r8(%rax)
+	mov %r9,  MSHV_VTL_CPU_CONTEXT_r9(%rax)
+	mov %r10, MSHV_VTL_CPU_CONTEXT_r10(%rax)
+	mov %r11, MSHV_VTL_CPU_CONTEXT_r11(%rax)
+	mov %r12, MSHV_VTL_CPU_CONTEXT_r12(%rax)
+	mov %r13, MSHV_VTL_CPU_CONTEXT_r13(%rax)
+	mov %r14, MSHV_VTL_CPU_CONTEXT_r14(%rax)
+	mov %r15, MSHV_VTL_CPU_CONTEXT_r15(%rax)
+
+	/* pop callee-save registers r12-r15, rbx */
+	pop %rbx
+	pop %r15
+	pop %r14
+	pop %r13
+	pop %r12
+
+	pop %rbp
+	RET
+SYM_FUNC_END(__mshv_vtl_return_call)
+/*
+ * Make sure that static_call_key symbol: __SCK____mshv_vtl_return_hypercall is accessible here.
+ * Below code is inspired from __ADDRESSABLE(sym) macro. Symbol name is kept simple, to avoid
+ * naming it something like "__UNIQUE_ID_addressable___SCK____mshv_vtl_return_hypercall_662.0"
+ * which would otherwise have been generated by the macro.
+ */
+	.section	.discard.addressable,"aw"
+	.align 8
+	.type	mshv_vtl_return_sym, @object
+	.size	mshv_vtl_return_sym, 8
+mshv_vtl_return_sym:
+	.quad	__SCK____mshv_vtl_return_hypercall
diff --git a/arch/x86/hyperv/nested.c b/arch/x86/hyperv/nested.c
new file mode 100644
index 000000000..8ccbb7c4f
--- /dev/null
+++ b/arch/x86/hyperv/nested.c
@@ -0,0 +1,130 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Hyper-V nested virtualization code.
+ *
+ * Copyright (C) 2018, Microsoft, Inc.
+ *
+ * Author : Lan Tianyu <Tianyu.Lan@microsoft.com>
+ */
+#define pr_fmt(fmt)  "Hyper-V: " fmt
+
+
+#include <linux/types.h>
+#include <linux/export.h>
+#include <hyperv/hvhdk.h>
+#include <asm/mshyperv.h>
+#include <asm/tlbflush.h>
+
+#include <asm/trace/hyperv.h>
+
+int hyperv_flush_guest_mapping(u64 as)
+{
+	struct hv_guest_mapping_flush *flush;
+	u64 status;
+	unsigned long flags;
+	int ret = -ENOTSUPP;
+
+	if (!hv_hypercall_pg)
+		goto fault;
+
+	local_irq_save(flags);
+
+	flush = *this_cpu_ptr(hyperv_pcpu_input_arg);
+
+	if (unlikely(!flush)) {
+		local_irq_restore(flags);
+		goto fault;
+	}
+
+	flush->address_space = as;
+	flush->flags = 0;
+
+	status = hv_do_hypercall(HVCALL_FLUSH_GUEST_PHYSICAL_ADDRESS_SPACE,
+				 flush, NULL);
+	local_irq_restore(flags);
+
+	if (hv_result_success(status))
+		ret = 0;
+
+fault:
+	trace_hyperv_nested_flush_guest_mapping(as, ret);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(hyperv_flush_guest_mapping);
+
+int hyperv_fill_flush_guest_mapping_list(
+		struct hv_guest_mapping_flush_list *flush,
+		u64 start_gfn, u64 pages)
+{
+	u64 cur = start_gfn;
+	u64 additional_pages;
+	int gpa_n = 0;
+
+	do {
+		/*
+		 * If flush requests exceed max flush count, go back to
+		 * flush tlbs without range.
+		 */
+		if (gpa_n >= HV_MAX_FLUSH_REP_COUNT)
+			return -ENOSPC;
+
+		additional_pages = min_t(u64, pages, HV_MAX_FLUSH_PAGES) - 1;
+
+		flush->gpa_list[gpa_n].page.additional_pages = additional_pages;
+		flush->gpa_list[gpa_n].page.largepage = false;
+		flush->gpa_list[gpa_n].page.basepfn = cur;
+
+		pages -= additional_pages + 1;
+		cur += additional_pages + 1;
+		gpa_n++;
+	} while (pages > 0);
+
+	return gpa_n;
+}
+EXPORT_SYMBOL_GPL(hyperv_fill_flush_guest_mapping_list);
+
+int hyperv_flush_guest_mapping_range(u64 as,
+		hyperv_fill_flush_list_func fill_flush_list_func, void *data)
+{
+	struct hv_guest_mapping_flush_list *flush;
+	u64 status;
+	unsigned long flags;
+	int ret = -ENOTSUPP;
+	int gpa_n = 0;
+
+	if (!hv_hypercall_pg || !fill_flush_list_func)
+		goto fault;
+
+	local_irq_save(flags);
+
+	flush = *this_cpu_ptr(hyperv_pcpu_input_arg);
+
+	if (unlikely(!flush)) {
+		local_irq_restore(flags);
+		goto fault;
+	}
+
+	flush->address_space = as;
+	flush->flags = 0;
+
+	gpa_n = fill_flush_list_func(flush, data);
+	if (gpa_n < 0) {
+		local_irq_restore(flags);
+		goto fault;
+	}
+
+	status = hv_do_rep_hypercall(HVCALL_FLUSH_GUEST_PHYSICAL_ADDRESS_LIST,
+				     gpa_n, 0, flush, NULL);
+
+	local_irq_restore(flags);
+
+	if (hv_result_success(status))
+		ret = 0;
+	else
+		ret = hv_result(status);
+fault:
+	trace_hyperv_nested_flush_guest_mapping_range(as, ret);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(hyperv_flush_guest_mapping_range);