Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 273 insertions, 0 deletions

diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c
new file mode 100644
index 000000000..10eb7249a
--- /dev/null
+++ b/arch/arm64/kvm/reset.c
@@ -0,0 +1,273 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2012,2013 - ARM Ltd
+ * Author: Marc Zyngier <marc.zyngier@arm.com>
+ *
+ * Derived from arch/arm/kvm/reset.c
+ * Copyright (C) 2012 - Virtual Open Systems and Columbia University
+ * Author: Christoffer Dall <c.dall@virtualopensystems.com>
+ */
+
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/kvm_host.h>
+#include <linux/kvm.h>
+#include <linux/hw_breakpoint.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/types.h>
+
+#include <kvm/arm_arch_timer.h>
+
+#include <asm/cpufeature.h>
+#include <asm/cputype.h>
+#include <asm/fpsimd.h>
+#include <asm/ptrace.h>
+#include <asm/kvm_arm.h>
+#include <asm/kvm_asm.h>
+#include <asm/kvm_emulate.h>
+#include <asm/kvm_mmu.h>
+#include <asm/kvm_nested.h>
+#include <asm/virt.h>
+
+/* Maximum phys_shift supported for any VM on this host */
+static u32 __ro_after_init kvm_ipa_limit;
+unsigned int __ro_after_init kvm_host_sve_max_vl;
+
+unsigned int __ro_after_init kvm_sve_max_vl;
+
+int __init kvm_arm_init_sve(void)
+{
+	if (system_supports_sve()) {
+		kvm_sve_max_vl = sve_max_virtualisable_vl();
+		kvm_host_sve_max_vl = sve_max_vl();
+		kvm_nvhe_sym(kvm_host_sve_max_vl) = kvm_host_sve_max_vl;
+
+		/*
+		 * The get_sve_reg()/set_sve_reg() ioctl interface will need
+		 * to be extended with multiple register slice support in
+		 * order to support vector lengths greater than
+		 * VL_ARCH_MAX:
+		 */
+		if (WARN_ON(kvm_sve_max_vl > VL_ARCH_MAX))
+			kvm_sve_max_vl = VL_ARCH_MAX;
+
+		/*
+		 * Don't even try to make use of vector lengths that
+		 * aren't available on all CPUs, for now:
+		 */
+		if (kvm_sve_max_vl < sve_max_vl())
+			pr_warn("KVM: SVE vector length for guests limited to %u bytes\n",
+				kvm_sve_max_vl);
+	}
+
+	return 0;
+}
+
+static void kvm_vcpu_enable_sve(struct kvm_vcpu *vcpu)
+{
+	vcpu->arch.sve_max_vl = kvm_sve_max_vl;
+
+	/*
+	 * Userspace can still customize the vector lengths by writing
+	 * KVM_REG_ARM64_SVE_VLS.  Allocation is deferred until
+	 * kvm_arm_vcpu_finalize(), which freezes the configuration.
+	 */
+	set_bit(KVM_ARCH_FLAG_GUEST_HAS_SVE, &vcpu->kvm->arch.flags);
+}
+
+/*
+ * Finalize vcpu's maximum SVE vector length, allocating
+ * vcpu->arch.sve_state as necessary.
+ */
+static int kvm_vcpu_finalize_sve(struct kvm_vcpu *vcpu)
+{
+	void *buf;
+	unsigned int vl;
+	size_t reg_sz;
+	int ret;
+
+	vl = vcpu->arch.sve_max_vl;
+
+	/*
+	 * Responsibility for these properties is shared between
+	 * kvm_arm_init_sve(), kvm_vcpu_enable_sve() and
+	 * set_sve_vls().  Double-check here just to be sure:
+	 */
+	if (WARN_ON(!sve_vl_valid(vl) || vl > sve_max_virtualisable_vl() ||
+		    vl > VL_ARCH_MAX))
+		return -EIO;
+
+	reg_sz = vcpu_sve_state_size(vcpu);
+	buf = kzalloc(reg_sz, GFP_KERNEL_ACCOUNT);
+	if (!buf)
+		return -ENOMEM;
+
+	ret = kvm_share_hyp(buf, buf + reg_sz);
+	if (ret) {
+		kfree(buf);
+		return ret;
+	}
+	
+	vcpu->arch.sve_state = buf;
+	vcpu_set_flag(vcpu, VCPU_SVE_FINALIZED);
+	return 0;
+}
+
+int kvm_arm_vcpu_finalize(struct kvm_vcpu *vcpu, int feature)
+{
+	switch (feature) {
+	case KVM_ARM_VCPU_SVE:
+		if (!vcpu_has_sve(vcpu))
+			return -EINVAL;
+
+		if (kvm_arm_vcpu_sve_finalized(vcpu))
+			return -EPERM;
+
+		return kvm_vcpu_finalize_sve(vcpu);
+	}
+
+	return -EINVAL;
+}
+
+bool kvm_arm_vcpu_is_finalized(struct kvm_vcpu *vcpu)
+{
+	if (vcpu_has_sve(vcpu) && !kvm_arm_vcpu_sve_finalized(vcpu))
+		return false;
+
+	return true;
+}
+
+void kvm_arm_vcpu_destroy(struct kvm_vcpu *vcpu)
+{
+	void *sve_state = vcpu->arch.sve_state;
+
+	kvm_unshare_hyp(vcpu, vcpu + 1);
+	if (sve_state)
+		kvm_unshare_hyp(sve_state, sve_state + vcpu_sve_state_size(vcpu));
+	kfree(sve_state);
+	free_page((unsigned long)vcpu->arch.ctxt.vncr_array);
+	kfree(vcpu->arch.vncr_tlb);
+	kfree(vcpu->arch.ccsidr);
+}
+
+static void kvm_vcpu_reset_sve(struct kvm_vcpu *vcpu)
+{
+	if (vcpu_has_sve(vcpu))
+		memset(vcpu->arch.sve_state, 0, vcpu_sve_state_size(vcpu));
+}
+
+/**
+ * kvm_reset_vcpu - sets core registers and sys_regs to reset value
+ * @vcpu: The VCPU pointer
+ *
+ * This function sets the registers on the virtual CPU struct to their
+ * architecturally defined reset values, except for registers whose reset is
+ * deferred until kvm_arm_vcpu_finalize().
+ *
+ * Note: This function can be called from two paths: The KVM_ARM_VCPU_INIT
+ * ioctl or as part of handling a request issued by another VCPU in the PSCI
+ * handling code.  In the first case, the VCPU will not be loaded, and in the
+ * second case the VCPU will be loaded.  Because this function operates purely
+ * on the memory-backed values of system registers, we want to do a full put if
+ * we were loaded (handling a request) and load the values back at the end of
+ * the function.  Otherwise we leave the state alone.  In both cases, we
+ * disable preemption around the vcpu reset as we would otherwise race with
+ * preempt notifiers which also call put/load.
+ */
+void kvm_reset_vcpu(struct kvm_vcpu *vcpu)
+{
+	struct vcpu_reset_state reset_state;
+	bool loaded;
+
+	spin_lock(&vcpu->arch.mp_state_lock);
+	reset_state = vcpu->arch.reset_state;
+	vcpu->arch.reset_state.reset = false;
+	spin_unlock(&vcpu->arch.mp_state_lock);
+
+	preempt_disable();
+	loaded = (vcpu->cpu != -1);
+	if (loaded)
+		kvm_arch_vcpu_put(vcpu);
+
+	if (!kvm_arm_vcpu_sve_finalized(vcpu)) {
+		if (vcpu_has_feature(vcpu, KVM_ARM_VCPU_SVE))
+			kvm_vcpu_enable_sve(vcpu);
+	} else {
+		kvm_vcpu_reset_sve(vcpu);
+	}
+
+	/* Reset core registers */
+	kvm_reset_vcpu_core(vcpu);
+
+	/* Reset system registers */
+	kvm_reset_sys_regs(vcpu);
+
+	/*
+	 * Additional reset state handling that PSCI may have imposed on us.
+	 * Must be done after all the sys_reg reset.
+	 */
+	if (reset_state.reset)
+		kvm_reset_vcpu_psci(vcpu, &reset_state);
+
+	/* Reset timer */
+	kvm_timer_vcpu_reset(vcpu);
+
+	if (loaded)
+		kvm_arch_vcpu_load(vcpu, smp_processor_id());
+	preempt_enable();
+}
+
+u32 kvm_get_pa_bits(struct kvm *kvm)
+{
+	/* Fixed limit until we can configure ID_AA64MMFR0.PARange */
+	return kvm_ipa_limit;
+}
+
+u32 get_kvm_ipa_limit(void)
+{
+	return kvm_ipa_limit;
+}
+
+int __init kvm_set_ipa_limit(void)
+{
+	unsigned int parange;
+	u64 mmfr0;
+
+	mmfr0 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1);
+	parange = cpuid_feature_extract_unsigned_field(mmfr0,
+				ID_AA64MMFR0_EL1_PARANGE_SHIFT);
+	/*
+	 * IPA size beyond 48 bits for 4K and 16K page size is only supported
+	 * when LPA2 is available. So if we have LPA2, enable it, else cap to 48
+	 * bits, in case it's reported as larger on the system.
+	 */
+	if (!kvm_lpa2_is_enabled() && PAGE_SIZE != SZ_64K)
+		parange = min(parange, (unsigned int)ID_AA64MMFR0_EL1_PARANGE_48);
+
+	/*
+	 * Check with ARMv8.5-GTG that our PAGE_SIZE is supported at
+	 * Stage-2. If not, things will stop very quickly.
+	 */
+	switch (cpuid_feature_extract_unsigned_field(mmfr0, ID_AA64MMFR0_EL1_TGRAN_2_SHIFT)) {
+	case ID_AA64MMFR0_EL1_TGRAN_2_SUPPORTED_NONE:
+		kvm_err("PAGE_SIZE not supported at Stage-2, giving up\n");
+		return -EINVAL;
+	case ID_AA64MMFR0_EL1_TGRAN_2_SUPPORTED_DEFAULT:
+		kvm_debug("PAGE_SIZE supported at Stage-2 (default)\n");
+		break;
+	case ID_AA64MMFR0_EL1_TGRAN_2_SUPPORTED_MIN ... ID_AA64MMFR0_EL1_TGRAN_2_SUPPORTED_MAX:
+		kvm_debug("PAGE_SIZE supported at Stage-2 (advertised)\n");
+		break;
+	default:
+		kvm_err("Unsupported value for TGRAN_2, giving up\n");
+		return -EINVAL;
+	}
+
+	kvm_ipa_limit = id_aa64mmfr0_parange_to_phys_shift(parange);
+	kvm_info("IPA Size Limit: %d bits%s\n", kvm_ipa_limit,
+		 ((kvm_ipa_limit < KVM_PHYS_SHIFT) ?
+		  " (Reduced IPA size, limited VM/VMM compatibility)" : ""));
+
+	return 0;
+}