Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull KVM updates from Paolo Bonzini:
 "ARM:

   - Support for userspace handling of synchronous external aborts
     (SEAs), allowing the VMM to potentially handle the abort in a
     non-fatal manner

   - Large rework of the VGIC's list register handling with the goal of
     supporting more active/pending IRQs than available list registers
     in hardware. In addition, the VGIC now supports EOImode==1 style
     deactivations for IRQs which may occur on a separate vCPU than the
     one that acked the IRQ

   - Support for FEAT_XNX (user / privileged execute permissions) and
     FEAT_HAF (hardware update to the Access Flag) in the software page
     table walkers and shadow MMU

   - Allow page table destruction to reschedule, fixing long
     need_resched latencies observed when destroying a large VM

   - Minor fixes to KVM and selftests

  Loongarch:

   - Get VM PMU capability from HW GCFG register

   - Add AVEC basic support

   - Use 64-bit register definition for EIOINTC

   - Add KVM timer test cases for tools/selftests

  RISC/V:

   - SBI message passing (MPXY) support for KVM guest

   - Give a new, more specific error subcode for the case when in-kernel
     AIA virtualization fails to allocate IMSIC VS-file

   - Support KVM_DIRTY_LOG_INITIALLY_SET, enabling dirty log gradually
     in small chunks

   - Fix guest page fault within HLV* instructions

   - Flush VS-stage TLB after VCPU migration for Andes cores

  s390:

   - Always allocate ESCA (Extended System Control Area), instead of
     starting with the basic SCA and converting to ESCA with the
     addition of the 65th vCPU. The price is increased number of exits
     (and worse performance) on z10 and earlier processor; ESCA was
     introduced by z114/z196 in 2010

   - VIRT_XFER_TO_GUEST_WORK support

   - Operation exception forwarding support

   - Cleanups

  x86:

   - Skip the costly "zap all SPTEs" on an MMIO generation wrap if MMIO
     SPTE caching is disabled, as there can't be any relevant SPTEs to
     zap

   - Relocate a misplaced export

   - Fix an async #PF bug where KVM would clear the completion queue
     when the guest transitioned in and out of paging mode, e.g. when
     handling an SMI and then returning to paged mode via RSM

   - Leave KVM's user-return notifier registered even when disabling
     virtualization, as long as kvm.ko is loaded. On reboot/shutdown,
     keeping the notifier registered is ok; the kernel does not use the
     MSRs and the callback will run cleanly and restore host MSRs if the
     CPU manages to return to userspace before the system goes down

   - Use the checked version of {get,put}_user()

   - Fix a long-lurking bug where KVM's lack of catch-up logic for
     periodic APIC timers can result in a hard lockup in the host

   - Revert the periodic kvmclock sync logic now that KVM doesn't use a
     clocksource that's subject to NTP corrections

   - Clean up KVM's handling of MMIO Stale Data and L1TF, and bury the
     latter behind CONFIG_CPU_MITIGATIONS

   - Context switch XCR0, XSS, and PKRU outside of the entry/exit fast
     path; the only reason they were handled in the fast path was to
     paper of a bug in the core #MC code, and that has long since been
     fixed

   - Add emulator support for AVX MOV instructions, to play nice with
     emulated devices whose guest drivers like to access PCI BARs with
     large multi-byte instructions

  x86 (AMD):

   - Fix a few missing "VMCB dirty" bugs

   - Fix the worst of KVM's lack of EFER.LMSLE emulation

   - Add AVIC support for addressing 4k vCPUs in x2AVIC mode

   - Fix incorrect handling of selective CR0 writes when checking
     intercepts during emulation of L2 instructions

   - Fix a currently-benign bug where KVM would clobber SPEC_CTRL[63:32]
     on VMRUN and #VMEXIT

   - Fix a bug where KVM corrupt the guest code stream when re-injecting
     a soft interrupt if the guest patched the underlying code after the
     VM-Exit, e.g. when Linux patches code with a temporary INT3

   - Add KVM_X86_SNP_POLICY_BITS to advertise supported SNP policy bits
     to userspace, and extend KVM "support" to all policy bits that
     don't require any actual support from KVM

  x86 (Intel):

   - Use the root role from kvm_mmu_page to construct EPTPs instead of
     the current vCPU state, partly as worthwhile cleanup, but mostly to
     pave the way for tracking per-root TLB flushes, and elide EPT
     flushes on pCPU migration if the root is clean from a previous
     flush

   - Add a few missing nested consistency checks

   - Rip out support for doing "early" consistency checks via hardware
     as the functionality hasn't been used in years and is no longer
     useful in general; replace it with an off-by-default module param
     to WARN if hardware fails a check that KVM does not perform

   - Fix a currently-benign bug where KVM would drop the guest's
     SPEC_CTRL[63:32] on VM-Enter

   - Misc cleanups

   - Overhaul the TDX code to address systemic races where KVM (acting
     on behalf of userspace) could inadvertantly trigger lock contention
     in the TDX-Module; KVM was either working around these in weird,
     ugly ways, or was simply oblivious to them (though even Yan's
     devilish selftests could only break individual VMs, not the host
     kernel)

   - Fix a bug where KVM could corrupt a vCPU's cpu_list when freeing a
     TDX vCPU, if creating said vCPU failed partway through

   - Fix a few sparse warnings (bad annotation, 0 != NULL)

   - Use struct_size() to simplify copying TDX capabilities to userspace

   - Fix a bug where TDX would effectively corrupt user-return MSR
     values if the TDX Module rejects VP.ENTER and thus doesn't clobber
     host MSRs as expected

  Selftests:

   - Fix a math goof in mmu_stress_test when running on a single-CPU
     system/VM

   - Forcefully override ARCH from x86_64 to x86 to play nice with
     specifying ARCH=x86_64 on the command line

   - Extend a bunch of nested VMX to validate nested SVM as well

   - Add support for LA57 in the core VM_MODE_xxx macro, and add a test
     to verify KVM can save/restore nested VMX state when L1 is using
     5-level paging, but L2 is not

   - Clean up the guest paging code in anticipation of sharing the core
     logic for nested EPT and nested NPT

  guest_memfd:

   - Add NUMA mempolicy support for guest_memfd, and clean up a variety
     of rough edges in guest_memfd along the way

   - Define a CLASS to automatically handle get+put when grabbing a
     guest_memfd from a memslot to make it harder to leak references

   - Enhance KVM selftests to make it easer to develop and debug
     selftests like those added for guest_memfd NUMA support, e.g. where
     test and/or KVM bugs often result in hard-to-debug SIGBUS errors

   - Misc cleanups

  Generic:

   - Use the recently-added WQ_PERCPU when creating the per-CPU
     workqueue for irqfd cleanup

   - Fix a goof in the dirty ring documentation

   - Fix choice of target for directed yield across different calls to
     kvm_vcpu_on_spin(); the function was always starting from the first
     vCPU instead of continuing the round-robin search"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (260 commits)
  KVM: arm64: at: Update AF on software walk only if VM has FEAT_HAFDBS
  KVM: arm64: at: Use correct HA bit in TCR_EL2 when regime is EL2
  KVM: arm64: Document KVM_PGTABLE_PROT_{UX,PX}
  KVM: arm64: Fix spelling mistake "Unexpeced" -> "Unexpected"
  KVM: arm64: Add break to default case in kvm_pgtable_stage2_pte_prot()
  KVM: arm64: Add endian casting to kvm_swap_s[12]_desc()
  KVM: arm64: Fix compilation when CONFIG_ARM64_USE_LSE_ATOMICS=n
  KVM: arm64: selftests: Add test for AT emulation
  KVM: arm64: nv: Expose hardware access flag management to NV guests
  KVM: arm64: nv: Implement HW access flag management in stage-2 SW PTW
  KVM: arm64: Implement HW access flag management in stage-1 SW PTW
  KVM: arm64: Propagate PTW errors up to AT emulation
  KVM: arm64: Add helper for swapping guest descriptor
  KVM: arm64: nv: Use pgtable definitions in stage-2 walk
  KVM: arm64: Handle endianness in read helper for emulated PTW
  KVM: arm64: nv: Stop passing vCPU through void ptr in S2 PTW
  KVM: arm64: Call helper for reading descriptors directly
  KVM: arm64: nv: Advertise support for FEAT_XNX
  KVM: arm64: Teach ptdump about FEAT_XNX permissions
  KVM: s390: Use generic VIRT_XFER_TO_GUEST_WORK functions
  ...

1 files changed, 156 insertions, 129 deletions

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index c9c2aa6f4705..0c6d899d53dd 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -159,9 +159,6 @@ EXPORT_SYMBOL_FOR_KVM_INTERNAL(report_ignored_msrs);
 unsigned int min_timer_period_us = 200;
 module_param(min_timer_period_us, uint, 0644);
 
-static bool __read_mostly kvmclock_periodic_sync = true;
-module_param(kvmclock_periodic_sync, bool, 0444);
-
 /* tsc tolerance in parts per million - default to 1/2 of the NTP threshold */
 static u32 __read_mostly tsc_tolerance_ppm = 250;
 module_param(tsc_tolerance_ppm, uint, 0644);
@@ -212,7 +209,7 @@ struct kvm_user_return_msrs {
 u32 __read_mostly kvm_nr_uret_msrs;
 EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_nr_uret_msrs);
 static u32 __read_mostly kvm_uret_msrs_list[KVM_MAX_NR_USER_RETURN_MSRS];
-static struct kvm_user_return_msrs __percpu *user_return_msrs;
+static DEFINE_PER_CPU(struct kvm_user_return_msrs, user_return_msrs);
 
 #define KVM_SUPPORTED_XCR0     (XFEATURE_MASK_FP | XFEATURE_MASK_SSE \
 				| XFEATURE_MASK_YMM | XFEATURE_MASK_BNDREGS \
@@ -575,24 +572,26 @@ static inline void kvm_async_pf_hash_reset(struct kvm_vcpu *vcpu)
 		vcpu->arch.apf.gfns[i] = ~0;
 }
 
+static void kvm_destroy_user_return_msrs(void)
+{
+	int cpu;
+
+	for_each_possible_cpu(cpu)
+		WARN_ON_ONCE(per_cpu(user_return_msrs, cpu).registered);
+
+	kvm_nr_uret_msrs = 0;
+}
+
 static void kvm_on_user_return(struct user_return_notifier *urn)
 {
 	unsigned slot;
 	struct kvm_user_return_msrs *msrs
 		= container_of(urn, struct kvm_user_return_msrs, urn);
 	struct kvm_user_return_msr_values *values;
-	unsigned long flags;
 
-	/*
-	 * Disabling irqs at this point since the following code could be
-	 * interrupted and executed through kvm_arch_disable_virtualization_cpu()
-	 */
-	local_irq_save(flags);
-	if (msrs->registered) {
-		msrs->registered = false;
-		user_return_notifier_unregister(urn);
-	}
-	local_irq_restore(flags);
+	msrs->registered = false;
+	user_return_notifier_unregister(urn);
+
 	for (slot = 0; slot < kvm_nr_uret_msrs; ++slot) {
 		values = &msrs->values[slot];
 		if (values->host != values->curr) {
@@ -643,7 +642,7 @@ EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_find_user_return_msr);
 
 static void kvm_user_return_msr_cpu_online(void)
 {
-	struct kvm_user_return_msrs *msrs = this_cpu_ptr(user_return_msrs);
+	struct kvm_user_return_msrs *msrs = this_cpu_ptr(&user_return_msrs);
 	u64 value;
 	int i;
 
@@ -665,7 +664,7 @@ static void kvm_user_return_register_notifier(struct kvm_user_return_msrs *msrs)
 
 int kvm_set_user_return_msr(unsigned slot, u64 value, u64 mask)
 {
-	struct kvm_user_return_msrs *msrs = this_cpu_ptr(user_return_msrs);
+	struct kvm_user_return_msrs *msrs = this_cpu_ptr(&user_return_msrs);
 	int err;
 
 	value = (value & mask) | (msrs->values[slot].host & ~mask);
@@ -681,24 +680,15 @@ int kvm_set_user_return_msr(unsigned slot, u64 value, u64 mask)
 }
 EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_set_user_return_msr);
 
-void kvm_user_return_msr_update_cache(unsigned int slot, u64 value)
-{
-	struct kvm_user_return_msrs *msrs = this_cpu_ptr(user_return_msrs);
-
-	msrs->values[slot].curr = value;
-	kvm_user_return_register_notifier(msrs);
-}
-EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_user_return_msr_update_cache);
-
 u64 kvm_get_user_return_msr(unsigned int slot)
 {
-	return this_cpu_ptr(user_return_msrs)->values[slot].curr;
+	return this_cpu_ptr(&user_return_msrs)->values[slot].curr;
 }
 EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_get_user_return_msr);
 
 static void drop_user_return_notifiers(void)
 {
-	struct kvm_user_return_msrs *msrs = this_cpu_ptr(user_return_msrs);
+	struct kvm_user_return_msrs *msrs = this_cpu_ptr(&user_return_msrs);
 
 	if (msrs->registered)
 		kvm_on_user_return(&msrs->urn);
@@ -1045,6 +1035,13 @@ bool kvm_require_dr(struct kvm_vcpu *vcpu, int dr)
 }
 EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_require_dr);
 
+static bool kvm_pv_async_pf_enabled(struct kvm_vcpu *vcpu)
+{
+	u64 mask = KVM_ASYNC_PF_ENABLED | KVM_ASYNC_PF_DELIVERY_AS_INT;
+
+	return (vcpu->arch.apf.msr_en_val & mask) == mask;
+}
+
 static inline u64 pdptr_rsvd_bits(struct kvm_vcpu *vcpu)
 {
 	return vcpu->arch.reserved_gpa_bits | rsvd_bits(5, 8) | rsvd_bits(1, 2);
@@ -1137,15 +1134,20 @@ void kvm_post_set_cr0(struct kvm_vcpu *vcpu, unsigned long old_cr0, unsigned lon
 	}
 
 	if ((cr0 ^ old_cr0) & X86_CR0_PG) {
-		kvm_clear_async_pf_completion_queue(vcpu);
-		kvm_async_pf_hash_reset(vcpu);
-
 		/*
 		 * Clearing CR0.PG is defined to flush the TLB from the guest's
 		 * perspective.
 		 */
 		if (!(cr0 & X86_CR0_PG))
 			kvm_make_request(KVM_REQ_TLB_FLUSH_GUEST, vcpu);
+		/*
+		 * Check for async #PF completion events when enabling paging,
+		 * as the vCPU may have previously encountered async #PFs (it's
+		 * entirely legal for the guest to toggle paging on/off without
+		 * waiting for the async #PF queue to drain).
+		 */
+		else if (kvm_pv_async_pf_enabled(vcpu))
+			kvm_make_request(KVM_REQ_APF_READY, vcpu);
 	}
 
 	if ((cr0 ^ old_cr0) & KVM_MMU_CR0_ROLE_BITS)
@@ -1203,20 +1205,27 @@ void kvm_lmsw(struct kvm_vcpu *vcpu, unsigned long msw)
 }
 EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_lmsw);
 
-void kvm_load_guest_xsave_state(struct kvm_vcpu *vcpu)
+static void kvm_load_xfeatures(struct kvm_vcpu *vcpu, bool load_guest)
 {
 	if (vcpu->arch.guest_state_protected)
 		return;
 
-	if (kvm_is_cr4_bit_set(vcpu, X86_CR4_OSXSAVE)) {
+	if (!kvm_is_cr4_bit_set(vcpu, X86_CR4_OSXSAVE))
+		return;
 
-		if (vcpu->arch.xcr0 != kvm_host.xcr0)
-			xsetbv(XCR_XFEATURE_ENABLED_MASK, vcpu->arch.xcr0);
+	if (vcpu->arch.xcr0 != kvm_host.xcr0)
+		xsetbv(XCR_XFEATURE_ENABLED_MASK,
+		       load_guest ? vcpu->arch.xcr0 : kvm_host.xcr0);
 
-		if (guest_cpu_cap_has(vcpu, X86_FEATURE_XSAVES) &&
-		    vcpu->arch.ia32_xss != kvm_host.xss)
-			wrmsrq(MSR_IA32_XSS, vcpu->arch.ia32_xss);
-	}
+	if (guest_cpu_cap_has(vcpu, X86_FEATURE_XSAVES) &&
+	    vcpu->arch.ia32_xss != kvm_host.xss)
+		wrmsrq(MSR_IA32_XSS, load_guest ? vcpu->arch.ia32_xss : kvm_host.xss);
+}
+
+static void kvm_load_guest_pkru(struct kvm_vcpu *vcpu)
+{
+	if (vcpu->arch.guest_state_protected)
+		return;
 
 	if (cpu_feature_enabled(X86_FEATURE_PKU) &&
 	    vcpu->arch.pkru != vcpu->arch.host_pkru &&
@@ -1224,9 +1233,8 @@ void kvm_load_guest_xsave_state(struct kvm_vcpu *vcpu)
 	     kvm_is_cr4_bit_set(vcpu, X86_CR4_PKE)))
 		wrpkru(vcpu->arch.pkru);
 }
-EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_load_guest_xsave_state);
 
-void kvm_load_host_xsave_state(struct kvm_vcpu *vcpu)
+static void kvm_load_host_pkru(struct kvm_vcpu *vcpu)
 {
 	if (vcpu->arch.guest_state_protected)
 		return;
@@ -1238,19 +1246,7 @@ void kvm_load_host_xsave_state(struct kvm_vcpu *vcpu)
 		if (vcpu->arch.pkru != vcpu->arch.host_pkru)
 			wrpkru(vcpu->arch.host_pkru);
 	}
-
-	if (kvm_is_cr4_bit_set(vcpu, X86_CR4_OSXSAVE)) {
-
-		if (vcpu->arch.xcr0 != kvm_host.xcr0)
-			xsetbv(XCR_XFEATURE_ENABLED_MASK, kvm_host.xcr0);
-
-		if (guest_cpu_cap_has(vcpu, X86_FEATURE_XSAVES) &&
-		    vcpu->arch.ia32_xss != kvm_host.xss)
-			wrmsrq(MSR_IA32_XSS, kvm_host.xss);
-	}
-
 }
-EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_load_host_xsave_state);
 
 #ifdef CONFIG_X86_64
 static inline u64 kvm_guest_supported_xfd(struct kvm_vcpu *vcpu)
@@ -3505,27 +3501,17 @@ uint64_t kvm_get_wall_clock_epoch(struct kvm *kvm)
 /*
  * kvmclock updates which are isolated to a given vcpu, such as
  * vcpu->cpu migration, should not allow system_timestamp from
- * the rest of the vcpus to remain static. Otherwise ntp frequency
- * correction applies to one vcpu's system_timestamp but not
- * the others.
+ * the rest of the vcpus to remain static.
  *
  * So in those cases, request a kvmclock update for all vcpus.
- * We need to rate-limit these requests though, as they can
- * considerably slow guests that have a large number of vcpus.
- * The time for a remote vcpu to update its kvmclock is bound
- * by the delay we use to rate-limit the updates.
+ * The worst case for a remote vcpu to update its kvmclock
+ * is then bounded by maximum nohz sleep latency.
  */
-
-#define KVMCLOCK_UPDATE_DELAY msecs_to_jiffies(100)
-
-static void kvmclock_update_fn(struct work_struct *work)
+static void kvm_gen_kvmclock_update(struct kvm_vcpu *v)
 {
 	unsigned long i;
-	struct delayed_work *dwork = to_delayed_work(work);
-	struct kvm_arch *ka = container_of(dwork, struct kvm_arch,
-					   kvmclock_update_work);
-	struct kvm *kvm = container_of(ka, struct kvm, arch);
 	struct kvm_vcpu *vcpu;
+	struct kvm *kvm = v->kvm;
 
 	kvm_for_each_vcpu(i, vcpu, kvm) {
 		kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu);
@@ -3533,29 +3519,6 @@ static void kvmclock_update_fn(struct work_struct *work)
 	}
 }
 
-static void kvm_gen_kvmclock_update(struct kvm_vcpu *v)
-{
-	struct kvm *kvm = v->kvm;
-
-	kvm_make_request(KVM_REQ_CLOCK_UPDATE, v);
-	schedule_delayed_work(&kvm->arch.kvmclock_update_work,
-					KVMCLOCK_UPDATE_DELAY);
-}
-
-#define KVMCLOCK_SYNC_PERIOD (300 * HZ)
-
-static void kvmclock_sync_fn(struct work_struct *work)
-{
-	struct delayed_work *dwork = to_delayed_work(work);
-	struct kvm_arch *ka = container_of(dwork, struct kvm_arch,
-					   kvmclock_sync_work);
-	struct kvm *kvm = container_of(ka, struct kvm, arch);
-
-	schedule_delayed_work(&kvm->arch.kvmclock_update_work, 0);
-	schedule_delayed_work(&kvm->arch.kvmclock_sync_work,
-					KVMCLOCK_SYNC_PERIOD);
-}
-
 /* These helpers are safe iff @msr is known to be an MCx bank MSR. */
 static bool is_mci_control_msr(u32 msr)
 {
@@ -3650,13 +3613,6 @@ static int set_msr_mce(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 	return 0;
 }
 
-static inline bool kvm_pv_async_pf_enabled(struct kvm_vcpu *vcpu)
-{
-	u64 mask = KVM_ASYNC_PF_ENABLED | KVM_ASYNC_PF_DELIVERY_AS_INT;
-
-	return (vcpu->arch.apf.msr_en_val & mask) == mask;
-}
-
 static int kvm_pv_enable_async_pf(struct kvm_vcpu *vcpu, u64 data)
 {
 	gpa_t gpa = data & ~0x3f;
@@ -4182,7 +4138,12 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 		if (!guest_pv_has(vcpu, KVM_FEATURE_ASYNC_PF_INT))
 			return 1;
 		if (data & 0x1) {
-			vcpu->arch.apf.pageready_pending = false;
+			/*
+			 * Pairs with the smp_mb__after_atomic() in
+			 * kvm_arch_async_page_present_queued().
+			 */
+			smp_store_mb(vcpu->arch.apf.pageready_pending, false);
+
 			kvm_check_async_pf_completion(vcpu);
 		}
 		break;
@@ -5188,7 +5149,7 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 {
 	struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
 
-	vcpu->arch.l1tf_flush_l1d = true;
+	kvm_request_l1tf_flush_l1d();
 
 	if (vcpu->scheduled_out && pmu->version && pmu->event_count) {
 		pmu->need_cleanup = true;
@@ -7239,6 +7200,19 @@ static int kvm_vm_ioctl_set_clock(struct kvm *kvm, void __user *argp)
 	return 0;
 }
 
+long kvm_arch_vcpu_unlocked_ioctl(struct file *filp, unsigned int ioctl,
+				  unsigned long arg)
+{
+	struct kvm_vcpu *vcpu = filp->private_data;
+	void __user *argp = (void __user *)arg;
+
+	if (ioctl == KVM_MEMORY_ENCRYPT_OP &&
+	    kvm_x86_ops.vcpu_mem_enc_unlocked_ioctl)
+		return kvm_x86_call(vcpu_mem_enc_unlocked_ioctl)(vcpu, argp);
+
+	return -ENOIOCTLCMD;
+}
+
 int kvm_arch_vm_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg)
 {
 	struct kvm *kvm = filp->private_data;
@@ -7998,7 +7972,7 @@ int kvm_write_guest_virt_system(struct kvm_vcpu *vcpu, gva_t addr, void *val,
 				unsigned int bytes, struct x86_exception *exception)
 {
 	/* kvm_write_guest_virt_system can pull in tons of pages. */
-	vcpu->arch.l1tf_flush_l1d = true;
+	kvm_request_l1tf_flush_l1d();
 
 	return kvm_write_guest_virt_helper(addr, val, bytes, vcpu,
 					   PFERR_WRITE_MASK, exception);
@@ -8842,6 +8816,14 @@ static void emulator_triple_fault(struct x86_emulate_ctxt *ctxt)
 	kvm_make_request(KVM_REQ_TRIPLE_FAULT, emul_to_vcpu(ctxt));
 }
 
+static int emulator_get_xcr(struct x86_emulate_ctxt *ctxt, u32 index, u64 *xcr)
+{
+	if (index != XCR_XFEATURE_ENABLED_MASK)
+		return 1;
+	*xcr = emul_to_vcpu(ctxt)->arch.xcr0;
+	return 0;
+}
+
 static int emulator_set_xcr(struct x86_emulate_ctxt *ctxt, u32 index, u64 xcr)
 {
 	return __kvm_set_xcr(emul_to_vcpu(ctxt), index, xcr);
@@ -8914,6 +8896,7 @@ static const struct x86_emulate_ops emulate_ops = {
 	.is_smm              = emulator_is_smm,
 	.leave_smm           = emulator_leave_smm,
 	.triple_fault        = emulator_triple_fault,
+	.get_xcr             = emulator_get_xcr,
 	.set_xcr             = emulator_set_xcr,
 	.get_untagged_addr   = emulator_get_untagged_addr,
 	.is_canonical_addr   = emulator_is_canonical_addr,
@@ -9109,6 +9092,18 @@ void kvm_prepare_event_vectoring_exit(struct kvm_vcpu *vcpu, gpa_t gpa)
 }
 EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_prepare_event_vectoring_exit);
 
+void kvm_prepare_unexpected_reason_exit(struct kvm_vcpu *vcpu, u64 exit_reason)
+{
+	vcpu_unimpl(vcpu, "unexpected exit reason 0x%llx\n", exit_reason);
+
+	vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
+	vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_UNEXPECTED_EXIT_REASON;
+	vcpu->run->internal.ndata = 2;
+	vcpu->run->internal.data[0] = exit_reason;
+	vcpu->run->internal.data[1] = vcpu->arch.last_vmentry_cpu;
+}
+EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_prepare_unexpected_reason_exit);
+
 static int handle_emulation_failure(struct kvm_vcpu *vcpu, int emulation_type)
 {
 	struct kvm *kvm = vcpu->kvm;
@@ -9337,6 +9332,23 @@ static bool is_vmware_backdoor_opcode(struct x86_emulate_ctxt *ctxt)
 	return false;
 }
 
+static bool is_soft_int_instruction(struct x86_emulate_ctxt *ctxt,
+				    int emulation_type)
+{
+	u8 vector = EMULTYPE_GET_SOFT_INT_VECTOR(emulation_type);
+
+	switch (ctxt->b) {
+	case 0xcc:
+		return vector == BP_VECTOR;
+	case 0xcd:
+		return vector == ctxt->src.val;
+	case 0xce:
+		return vector == OF_VECTOR;
+	default:
+		return false;
+	}
+}
+
 /*
  * Decode an instruction for emulation.  The caller is responsible for handling
  * code breakpoints.  Note, manually detecting code breakpoints is unnecessary
@@ -9394,7 +9406,7 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
 		return handle_emulation_failure(vcpu, emulation_type);
 	}
 
-	vcpu->arch.l1tf_flush_l1d = true;
+	kvm_request_l1tf_flush_l1d();
 
 	if (!(emulation_type & EMULTYPE_NO_DECODE)) {
 		kvm_clear_exception_queue(vcpu);
@@ -9447,6 +9459,10 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
 	 * injecting single-step #DBs.
 	 */
 	if (emulation_type & EMULTYPE_SKIP) {
+		if (emulation_type & EMULTYPE_SKIP_SOFT_INT &&
+		    !is_soft_int_instruction(ctxt, emulation_type))
+			return 0;
+
 		if (ctxt->mode != X86EMUL_MODE_PROT64)
 			ctxt->eip = (u32)ctxt->_eip;
 		else
@@ -10031,17 +10047,9 @@ int kvm_x86_vendor_init(struct kvm_x86_init_ops *ops)
 		return -ENOMEM;
 	}
 
-	user_return_msrs = alloc_percpu(struct kvm_user_return_msrs);
-	if (!user_return_msrs) {
-		pr_err("failed to allocate percpu kvm_user_return_msrs\n");
-		r = -ENOMEM;
-		goto out_free_x86_emulator_cache;
-	}
-	kvm_nr_uret_msrs = 0;
-
 	r = kvm_mmu_vendor_module_init();
 	if (r)
-		goto out_free_percpu;
+		goto out_free_x86_emulator_cache;
 
 	kvm_caps.supported_vm_types = BIT(KVM_X86_DEFAULT_VM);
 	kvm_caps.supported_mce_cap = MCG_CTL_P | MCG_SER_P;
@@ -10066,6 +10074,8 @@ int kvm_x86_vendor_init(struct kvm_x86_init_ops *ops)
 	if (boot_cpu_has(X86_FEATURE_ARCH_CAPABILITIES))
 		rdmsrq(MSR_IA32_ARCH_CAPABILITIES, kvm_host.arch_capabilities);
 
+	WARN_ON_ONCE(kvm_nr_uret_msrs);
+
 	r = ops->hardware_setup();
 	if (r != 0)
 		goto out_mmu_exit;
@@ -10138,9 +10148,8 @@ out_unwind_ops:
 	kvm_x86_ops.enable_virtualization_cpu = NULL;
 	kvm_x86_call(hardware_unsetup)();
 out_mmu_exit:
+	kvm_destroy_user_return_msrs();
 	kvm_mmu_vendor_module_exit();
-out_free_percpu:
-	free_percpu(user_return_msrs);
 out_free_x86_emulator_cache:
 	kmem_cache_destroy(x86_emulator_cache);
 	return r;
@@ -10168,8 +10177,8 @@ void kvm_x86_vendor_exit(void)
 	cancel_work_sync(&pvclock_gtod_work);
 #endif
 	kvm_x86_call(hardware_unsetup)();
+	kvm_destroy_user_return_msrs();
 	kvm_mmu_vendor_module_exit();
-	free_percpu(user_return_msrs);
 	kmem_cache_destroy(x86_emulator_cache);
 #ifdef CONFIG_KVM_XEN
 	static_key_deferred_flush(&kvm_xen_enabled);
@@ -11291,6 +11300,8 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 	if (vcpu->arch.guest_fpu.xfd_err)
 		wrmsrq(MSR_IA32_XFD_ERR, vcpu->arch.guest_fpu.xfd_err);
 
+	kvm_load_xfeatures(vcpu, true);
+
 	if (unlikely(vcpu->arch.switch_db_regs &&
 		     !(vcpu->arch.switch_db_regs & KVM_DEBUGREG_AUTO_SWITCH))) {
 		set_debugreg(DR7_FIXED_1, 7);
@@ -11319,6 +11330,12 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 
 	guest_timing_enter_irqoff();
 
+	/*
+	 * Swap PKRU with hardware breakpoints disabled to minimize the number
+	 * of flows where non-KVM code can run with guest state loaded.
+	 */
+	kvm_load_guest_pkru(vcpu);
+
 	for (;;) {
 		/*
 		 * Assert that vCPU vs. VM APICv state is consistent.  An APICv
@@ -11347,6 +11364,8 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 		++vcpu->stat.exits;
 	}
 
+	kvm_load_host_pkru(vcpu);
+
 	/*
 	 * Do this here before restoring debug registers on the host.  And
 	 * since we do this before handling the vmexit, a DR access vmexit
@@ -11377,6 +11396,8 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
 	vcpu->mode = OUTSIDE_GUEST_MODE;
 	smp_wmb();
 
+	kvm_load_xfeatures(vcpu, false);
+
 	/*
 	 * Sync xfd before calling handle_exit_irqoff() which may
 	 * rely on the fact that guest_fpu::xfd is up-to-date (e.g.
@@ -12734,8 +12755,6 @@ fail_mmu_destroy:
 
 void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu)
 {
-	struct kvm *kvm = vcpu->kvm;
-
 	if (mutex_lock_killable(&vcpu->mutex))
 		return;
 	vcpu_load(vcpu);
@@ -12746,10 +12765,6 @@ void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu)
 	vcpu->arch.msr_kvm_poll_control = 1;
 
 	mutex_unlock(&vcpu->mutex);
-
-	if (kvmclock_periodic_sync && vcpu->vcpu_idx == 0)
-		schedule_delayed_work(&kvm->arch.kvmclock_sync_work,
-						KVMCLOCK_SYNC_PERIOD);
 }
 
 void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu)
@@ -13088,7 +13103,21 @@ int kvm_arch_enable_virtualization_cpu(void)
 void kvm_arch_disable_virtualization_cpu(void)
 {
 	kvm_x86_call(disable_virtualization_cpu)();
-	drop_user_return_notifiers();
+
+	/*
+	 * Leave the user-return notifiers as-is when disabling virtualization
+	 * for reboot, i.e. when disabling via IPI function call, and instead
+	 * pin kvm.ko (if it's a module) to defend against use-after-free (in
+	 * the *very* unlikely scenario module unload is racing with reboot).
+	 * On a forced reboot, tasks aren't frozen before shutdown, and so KVM
+	 * could be actively modifying user-return MSR state when the IPI to
+	 * disable virtualization arrives.  Handle the extreme edge case here
+	 * instead of trying to account for it in the normal flows.
+	 */
+	if (in_task() || WARN_ON_ONCE(!kvm_rebooting))
+		drop_user_return_notifiers();
+	else
+		__module_get(THIS_MODULE);
 }
 
 bool kvm_vcpu_is_reset_bsp(struct kvm_vcpu *vcpu)
@@ -13160,9 +13189,6 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
 	kvm->arch.hv_root_tdp = INVALID_PAGE;
 #endif
 
-	INIT_DELAYED_WORK(&kvm->arch.kvmclock_update_work, kvmclock_update_fn);
-	INIT_DELAYED_WORK(&kvm->arch.kvmclock_sync_work, kvmclock_sync_fn);
-
 	kvm_apicv_init(kvm);
 	kvm_hv_init_vm(kvm);
 	kvm_xen_init_vm(kvm);
@@ -13269,9 +13295,6 @@ void kvm_arch_pre_destroy_vm(struct kvm *kvm)
 	 * is unsafe, i.e. will lead to use-after-free.  The PIT also needs to
 	 * be stopped before IRQ routing is freed.
 	 */
-	cancel_delayed_work_sync(&kvm->arch.kvmclock_sync_work);
-	cancel_delayed_work_sync(&kvm->arch.kvmclock_update_work);
-
 #ifdef CONFIG_KVM_IOAPIC
 	kvm_free_pit(kvm);
 #endif
@@ -13888,7 +13911,7 @@ void kvm_arch_async_page_present(struct kvm_vcpu *vcpu,
 	if ((work->wakeup_all || work->notpresent_injected) &&
 	    kvm_pv_async_pf_enabled(vcpu) &&
 	    !apf_put_user_ready(vcpu, work->arch.token)) {
-		vcpu->arch.apf.pageready_pending = true;
+		WRITE_ONCE(vcpu->arch.apf.pageready_pending, true);
 		kvm_apic_set_irq(vcpu, &irq, NULL);
 	}
 
@@ -13899,7 +13922,11 @@ void kvm_arch_async_page_present(struct kvm_vcpu *vcpu,
 void kvm_arch_async_page_present_queued(struct kvm_vcpu *vcpu)
 {
 	kvm_make_request(KVM_REQ_APF_READY, vcpu);
-	if (!vcpu->arch.apf.pageready_pending)
+
+	/* Pairs with smp_store_mb() in kvm_set_msr_common(). */
+	smp_mb__after_atomic();
+
+	if (!READ_ONCE(vcpu->arch.apf.pageready_pending))
 		kvm_vcpu_kick(vcpu);
 }