perf/x86/intel: Rename DMR offcore_rsp attribute to offmodule_rspgrafted

DMR introduces Offmodule Response events in place of the legacy
Offcore Response events, but it still exposes the inherited
offcore_rsp PMU attribute for programming the corresponding MSR data.

Rename the DMR PMU attribute to offmodule_rsp so the sysfs interface
matches the underlying event name and avoids user & tooling confusion.

Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://patch.msgid.link/20260917015234.981153-12-dapeng1.mi@linux.intel.com

1 files changed, 148 insertions, 0 deletions

diff --git a/arch/arm64/kvm/fpsimd.c b/arch/arm64/kvm/fpsimd.c
new file mode 100644
index 000000000..3f6b1e29c
--- /dev/null
+++ b/arch/arm64/kvm/fpsimd.c
@@ -0,0 +1,148 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * arch/arm64/kvm/fpsimd.c: Guest/host FPSIMD context coordination helpers
+ *
+ * Copyright 2018 Arm Limited
+ * Author: Dave Martin <Dave.Martin@arm.com>
+ */
+#include <linux/irqflags.h>
+#include <linux/sched.h>
+#include <linux/kvm_host.h>
+#include <asm/fpsimd.h>
+#include <asm/kvm_asm.h>
+#include <asm/kvm_hyp.h>
+#include <asm/kvm_mmu.h>
+#include <asm/sysreg.h>
+
+/*
+ * Prepare vcpu for saving the host's FPSIMD state and loading the guest's.
+ * The actual loading is done by the FPSIMD access trap taken to hyp.
+ *
+ * Here, we just set the correct metadata to indicate that the FPSIMD
+ * state in the cpu regs (if any) belongs to current on the host.
+ */
+void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu)
+{
+	BUG_ON(!current->mm);
+
+	if (!system_supports_fpsimd())
+		return;
+
+	/*
+	 * Avoid needless save/restore of the guest's common
+	 * FPSIMD/SVE/SME regs during transitions between L1/L2.
+	 *
+	 * These transitions only happens in a non-preemptible context
+	 * where the host regs have already been saved and unbound. The
+	 * live registers are either free or owned by the guest.
+	 */
+	if (vcpu_get_flag(vcpu, IN_NESTED_ERET) ||
+	    vcpu_get_flag(vcpu, IN_NESTED_EXCEPTION)) {
+		WARN_ON_ONCE(host_owns_fp_regs());
+		return;
+	}
+
+	/*
+	 * Ensure that any host FPSIMD/SVE/SME state is saved and unbound such
+	 * that the host kernel is responsible for restoring this state upon
+	 * return to userspace, and the hyp code doesn't need to save anything.
+	 *
+	 * When the host may use SME, fpsimd_save_and_flush_cpu_state() ensures
+	 * that PSTATE.{SM,ZA} == {0,0}.
+	 */
+	fpsimd_save_and_flush_cpu_state();
+	*host_data_ptr(fp_owner) = FP_STATE_FREE;
+
+	WARN_ON_ONCE(system_supports_sme() && read_sysreg_s(SYS_SVCR));
+}
+
+/*
+ * Called just before entering the guest once we are no longer preemptible
+ * and interrupts are disabled. If we have managed to run anything using
+ * FP while we were preemptible (such as off the back of an interrupt),
+ * then neither the host nor the guest own the FP hardware (and it was the
+ * responsibility of the code that used FP to save the existing state).
+ */
+void kvm_arch_vcpu_ctxflush_fp(struct kvm_vcpu *vcpu)
+{
+	if (test_thread_flag(TIF_FOREIGN_FPSTATE))
+		*host_data_ptr(fp_owner) = FP_STATE_FREE;
+}
+
+/*
+ * Called just after exiting the guest. If the guest FPSIMD state
+ * was loaded, update the host's context tracking data mark the CPU
+ * FPSIMD regs as dirty and belonging to vcpu so that they will be
+ * written back if the kernel clobbers them due to kernel-mode NEON
+ * before re-entry into the guest.
+ */
+void kvm_arch_vcpu_ctxsync_fp(struct kvm_vcpu *vcpu)
+{
+	struct cpu_fp_state fp_state;
+
+	WARN_ON_ONCE(!irqs_disabled());
+
+	if (guest_owns_fp_regs()) {
+		/*
+		 * Currently we do not support SME guests so SVCR is
+		 * always 0 and we just need a variable to point to.
+		 */
+		fp_state.st = &vcpu->arch.ctxt.fp_regs;
+		fp_state.sve_state = vcpu->arch.sve_state;
+		fp_state.sve_vl = vcpu->arch.sve_max_vl;
+		fp_state.sme_state = NULL;
+		fp_state.svcr = __ctxt_sys_reg(&vcpu->arch.ctxt, SVCR);
+		fp_state.fpmr = __ctxt_sys_reg(&vcpu->arch.ctxt, FPMR);
+		fp_state.fp_type = &vcpu->arch.fp_type;
+
+		if (vcpu_has_sve(vcpu))
+			fp_state.to_save = FP_STATE_SVE;
+		else
+			fp_state.to_save = FP_STATE_FPSIMD;
+
+		fpsimd_bind_state_to_cpu(&fp_state);
+
+		clear_thread_flag(TIF_FOREIGN_FPSTATE);
+	}
+}
+
+/*
+ * Write back the vcpu FPSIMD regs if they are dirty, and invalidate the
+ * cpu FPSIMD regs so that they can't be spuriously reused if this vcpu
+ * disappears and another task or vcpu appears that recycles the same
+ * struct fpsimd_state.
+ */
+void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu)
+{
+	unsigned long flags;
+
+	/*
+	 * See comment in kvm_arch_vcpu_load_fp(). Note that we also rely on
+	 * the guest's max VL to have been set by fpsimd_lazy_switch_to_host()
+	 * so that any intervening kernel-mode SIMD (NEON or otherwise)
+	 * operation sees the full guest state that needs saving.
+	 */
+	if (vcpu_get_flag(vcpu, IN_NESTED_ERET) ||
+	    vcpu_get_flag(vcpu, IN_NESTED_EXCEPTION)) {
+		WARN_ON_ONCE(host_owns_fp_regs());
+		return;
+	}
+
+	local_irq_save(flags);
+
+	if (guest_owns_fp_regs()) {
+		/*
+		 * Flush (save and invalidate) the fpsimd/sve state so that if
+		 * the host tries to use fpsimd/sve, it's not using stale data
+		 * from the guest.
+		 *
+		 * Flushing the state sets the TIF_FOREIGN_FPSTATE bit for the
+		 * context unconditionally, in both nVHE and VHE. This allows
+		 * the kernel to restore the fpsimd/sve state, including ZCR_EL1
+		 * when needed.
+		 */
+		fpsimd_save_and_flush_cpu_state();
+	}
+
+	local_irq_restore(flags);
+}