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

Pull KVM fixes from Paolo Bonzini:
 "Early fixes for x86.

  Instead of the (botched) revert, the lockdep/might_sleep splat has a
  real fix provided by Andrea"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  kvm: nVMX: Allow L1 to intercept software exceptions (#BP and #OF)
  kvm: take srcu lock around kvm_steal_time_set_preempted()
  kvm: fix schedule in atomic in kvm_steal_time_set_preempted()
  KVM: hyperv: fix locking of struct kvm_hv fields
  KVM: x86: Expose Intel AVX512IFMA/AVX512VBMI/SHA features to guest.
  kvm: nVMX: Correct a VMX instruction error code for VMPTRLD

Documentation/virtual/kvm/locking.txt

@@ -13,8 +13,12 @@ The acquisition orders for mutexes are as follows:
 - kvm->slots_lock is taken outside kvm->irq_lock, though acquiring
   them together is quite rare.
 
-For spinlocks, kvm_lock is taken outside kvm->mmu_lock.  Everything
-else is a leaf: no other lock is taken inside the critical sections.
+On x86, vcpu->mutex is taken outside kvm->arch.hyperv.hv_lock.
+
+For spinlocks, kvm_lock is taken outside kvm->mmu_lock.
+
+Everything else is a leaf: no other lock is taken inside the critical
+sections.
 
 2: Exception
 ------------

arch/x86/include/asm/kvm_host.h

@@ -704,6 +704,7 @@ struct kvm_apic_map {
 
 /* Hyper-V emulation context */
 struct kvm_hv {
+	struct mutex hv_lock;
 	u64 hv_guest_os_id;
 	u64 hv_hypercall;
 	u64 hv_tsc_page;

arch/x86/kvm/cpuid.c

@@ -373,16 +373,17 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
 	const u32 kvm_cpuid_7_0_ebx_x86_features =
 		F(FSGSBASE) | F(BMI1) | F(HLE) | F(AVX2) | F(SMEP) |
 		F(BMI2) | F(ERMS) | f_invpcid | F(RTM) | f_mpx | F(RDSEED) |
-		F(ADX) | F(SMAP) | F(AVX512F) | F(AVX512PF) | F(AVX512ER) |
-		F(AVX512CD) | F(CLFLUSHOPT) | F(CLWB) | F(AVX512DQ) |
-		F(AVX512BW) | F(AVX512VL);
+		F(ADX) | F(SMAP) | F(AVX512IFMA) | F(AVX512F) | F(AVX512PF) |
+		F(AVX512ER) | F(AVX512CD) | F(CLFLUSHOPT) | F(CLWB) | F(AVX512DQ) |
+		F(SHA_NI) | F(AVX512BW) | F(AVX512VL);
 
 	/* cpuid 0xD.1.eax */
 	const u32 kvm_cpuid_D_1_eax_x86_features =
 		F(XSAVEOPT) | F(XSAVEC) | F(XGETBV1) | f_xsaves;
 
 	/* cpuid 7.0.ecx*/
-	const u32 kvm_cpuid_7_0_ecx_x86_features = F(PKU) | 0 /*OSPKE*/;
+	const u32 kvm_cpuid_7_0_ecx_x86_features =
+		F(AVX512VBMI) | F(PKU) | 0 /*OSPKE*/;
 
 	/* cpuid 7.0.edx*/
 	const u32 kvm_cpuid_7_0_edx_x86_features =

arch/x86/kvm/hyperv.c

@@ -852,6 +852,10 @@ void kvm_hv_setup_tsc_page(struct kvm *kvm,
 	if (!(hv->hv_tsc_page & HV_X64_MSR_TSC_REFERENCE_ENABLE))
 		return;
 
+	mutex_lock(&kvm->arch.hyperv.hv_lock);
+	if (!(hv->hv_tsc_page & HV_X64_MSR_TSC_REFERENCE_ENABLE))
+		goto out_unlock;
+
 	gfn = hv->hv_tsc_page >> HV_X64_MSR_TSC_REFERENCE_ADDRESS_SHIFT;
 	/*
 	 * Because the TSC parameters only vary when there is a
@@ -859,7 +863,7 @@ void kvm_hv_setup_tsc_page(struct kvm *kvm,
 	 */
 	if (unlikely(kvm_read_guest(kvm, gfn_to_gpa(gfn),
 				    &tsc_seq, sizeof(tsc_seq))))
-		return;
+		goto out_unlock;
 
 	/*
 	 * While we're computing and writing the parameters, force the
@@ -868,15 +872,15 @@ void kvm_hv_setup_tsc_page(struct kvm *kvm,
 	hv->tsc_ref.tsc_sequence = 0;
 	if (kvm_write_guest(kvm, gfn_to_gpa(gfn),
 			    &hv->tsc_ref, sizeof(hv->tsc_ref.tsc_sequence)))
-		return;
+		goto out_unlock;
 
 	if (!compute_tsc_page_parameters(hv_clock, &hv->tsc_ref))
-		return;
+		goto out_unlock;
 
 	/* Ensure sequence is zero before writing the rest of the struct.  */
 	smp_wmb();
 	if (kvm_write_guest(kvm, gfn_to_gpa(gfn), &hv->tsc_ref, sizeof(hv->tsc_ref)))
-		return;
+		goto out_unlock;
 
 	/*
 	 * Now switch to the TSC page mechanism by writing the sequence.
@@ -891,6 +895,8 @@ void kvm_hv_setup_tsc_page(struct kvm *kvm,
 	hv->tsc_ref.tsc_sequence = tsc_seq;
 	kvm_write_guest(kvm, gfn_to_gpa(gfn),
 			&hv->tsc_ref, sizeof(hv->tsc_ref.tsc_sequence));
+out_unlock:
+	mutex_unlock(&kvm->arch.hyperv.hv_lock);
 }
 
 static int kvm_hv_set_msr_pw(struct kvm_vcpu *vcpu, u32 msr, u64 data,
@@ -1142,9 +1148,9 @@ int kvm_hv_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data, bool host)
 	if (kvm_hv_msr_partition_wide(msr)) {
 		int r;
 
-		mutex_lock(&vcpu->kvm->lock);
+		mutex_lock(&vcpu->kvm->arch.hyperv.hv_lock);
 		r = kvm_hv_set_msr_pw(vcpu, msr, data, host);
-		mutex_unlock(&vcpu->kvm->lock);
+		mutex_unlock(&vcpu->kvm->arch.hyperv.hv_lock);
 		return r;
 	} else
 		return kvm_hv_set_msr(vcpu, msr, data, host);
@@ -1155,9 +1161,9 @@ int kvm_hv_get_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata)
 	if (kvm_hv_msr_partition_wide(msr)) {
 		int r;
 
-		mutex_lock(&vcpu->kvm->lock);
+		mutex_lock(&vcpu->kvm->arch.hyperv.hv_lock);
 		r = kvm_hv_get_msr_pw(vcpu, msr, pdata);
-		mutex_unlock(&vcpu->kvm->lock);
+		mutex_unlock(&vcpu->kvm->arch.hyperv.hv_lock);
 		return r;
 	} else
 		return kvm_hv_get_msr(vcpu, msr, pdata);
@@ -1165,7 +1171,7 @@ int kvm_hv_get_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata)
 
 bool kvm_hv_hypercall_enabled(struct kvm *kvm)
 {
-	return kvm->arch.hyperv.hv_hypercall & HV_X64_MSR_HYPERCALL_ENABLE;
+	return READ_ONCE(kvm->arch.hyperv.hv_hypercall) & HV_X64_MSR_HYPERCALL_ENABLE;
 }
 
 static void kvm_hv_hypercall_set_result(struct kvm_vcpu *vcpu, u64 result)

arch/x86/kvm/vmx.c

@@ -1389,10 +1389,10 @@ static inline bool nested_cpu_has_posted_intr(struct vmcs12 *vmcs12)
 	return vmcs12->pin_based_vm_exec_control & PIN_BASED_POSTED_INTR;
 }
 
-static inline bool is_exception(u32 intr_info)
+static inline bool is_nmi(u32 intr_info)
 {
 	return (intr_info & (INTR_INFO_INTR_TYPE_MASK | INTR_INFO_VALID_MASK))
-		== (INTR_TYPE_HARD_EXCEPTION | INTR_INFO_VALID_MASK);
+		== (INTR_TYPE_NMI_INTR | INTR_INFO_VALID_MASK);
 }
 
 static void nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32 exit_reason,
@@ -5728,7 +5728,7 @@ static int handle_exception(struct kvm_vcpu *vcpu)
 	if (is_machine_check(intr_info))
 		return handle_machine_check(vcpu);
 
-	if ((intr_info & INTR_INFO_INTR_TYPE_MASK) == INTR_TYPE_NMI_INTR)
+	if (is_nmi(intr_info))
 		return 1;  /* already handled by vmx_vcpu_run() */
 
 	if (is_no_device(intr_info)) {
@@ -7122,7 +7122,7 @@ static int nested_vmx_check_vmptr(struct kvm_vcpu *vcpu, int exit_reason,
 
 		if (vmptr == vmx->nested.vmxon_ptr) {
 			nested_vmx_failValid(vcpu,
-					     VMXERR_VMCLEAR_VMXON_POINTER);
+					     VMXERR_VMPTRLD_VMXON_POINTER);
 			return kvm_skip_emulated_instruction(vcpu);
 		}
 		break;
@@ -8170,7 +8170,7 @@ static bool nested_vmx_exit_handled(struct kvm_vcpu *vcpu)
 
 	switch (exit_reason) {
 	case EXIT_REASON_EXCEPTION_NMI:
-		if (!is_exception(intr_info))
+		if (is_nmi(intr_info))
 			return false;
 		else if (is_page_fault(intr_info))
 			return enable_ept;
@@ -8765,8 +8765,7 @@ static void vmx_complete_atomic_exit(struct vcpu_vmx *vmx)
 		kvm_machine_check();
 
 	/* We need to handle NMIs before interrupts are enabled */
-	if ((exit_intr_info & INTR_INFO_INTR_TYPE_MASK) == INTR_TYPE_NMI_INTR &&
-	    (exit_intr_info & INTR_INFO_VALID_MASK)) {
+	if (is_nmi(exit_intr_info)) {
 		kvm_before_handle_nmi(&vmx->vcpu);
 		asm("int $2");
 		kvm_after_handle_nmi(&vmx->vcpu);

arch/x86/kvm/x86.c

@@ -2844,7 +2844,24 @@ static void kvm_steal_time_set_preempted(struct kvm_vcpu *vcpu)
 
 void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
 {
+	int idx;
+	/*
+	 * Disable page faults because we're in atomic context here.
+	 * kvm_write_guest_offset_cached() would call might_fault()
+	 * that relies on pagefault_disable() to tell if there's a
+	 * bug. NOTE: the write to guest memory may not go through if
+	 * during postcopy live migration or if there's heavy guest
+	 * paging.
+	 */
+	pagefault_disable();
+	/*
+	 * kvm_memslots() will be called by
+	 * kvm_write_guest_offset_cached() so take the srcu lock.
+	 */
+	idx = srcu_read_lock(&vcpu->kvm->srcu);
 	kvm_steal_time_set_preempted(vcpu);
+	srcu_read_unlock(&vcpu->kvm->srcu, idx);
+	pagefault_enable();
 	kvm_x86_ops->vcpu_put(vcpu);
 	kvm_put_guest_fpu(vcpu);
 	vcpu->arch.last_host_tsc = rdtsc();
@@ -7881,6 +7898,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
 
 	raw_spin_lock_init(&kvm->arch.tsc_write_lock);
 	mutex_init(&kvm->arch.apic_map_lock);
+	mutex_init(&kvm->arch.hyperv.hv_lock);
 	spin_lock_init(&kvm->arch.pvclock_gtod_sync_lock);
 
 	kvm->arch.kvmclock_offset = -ktime_get_boot_ns();