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-rw-r--r--arch/x86/include/asm/kvm_host.h1
-rw-r--r--arch/x86/kvm/cpuid.c3
-rw-r--r--arch/x86/kvm/hyperv.c19
-rw-r--r--arch/x86/kvm/hyperv.h27
-rw-r--r--arch/x86/kvm/x86.c4
5 files changed, 53 insertions, 1 deletions
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index aa4eb8cfcd7e..c70690b2c82d 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1088,6 +1088,7 @@ struct kvm_hv {
u64 hv_reenlightenment_control;
u64 hv_tsc_emulation_control;
u64 hv_tsc_emulation_status;
+ u64 hv_invtsc_control;
/* How many vCPUs have VP index != vCPU index */
atomic_t num_mismatched_vp_indexes;
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index ff342c9da172..c3f084185daf 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -1488,6 +1488,9 @@ bool kvm_cpuid(struct kvm_vcpu *vcpu, u32 *eax, u32 *ebx,
if (!__kvm_get_msr(vcpu, MSR_IA32_TSX_CTRL, &data, true) &&
(data & TSX_CTRL_CPUID_CLEAR))
*ebx &= ~(F(RTM) | F(HLE));
+ } else if (function == 0x80000007) {
+ if (kvm_hv_invtsc_suppressed(vcpu))
+ *edx &= ~SF(CONSTANT_TSC);
}
} else {
*eax = *ebx = *ecx = *edx = 0;
diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index e8296942a868..80d082ecd5c5 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -999,6 +999,7 @@ static bool kvm_hv_msr_partition_wide(u32 msr)
case HV_X64_MSR_REENLIGHTENMENT_CONTROL:
case HV_X64_MSR_TSC_EMULATION_CONTROL:
case HV_X64_MSR_TSC_EMULATION_STATUS:
+ case HV_X64_MSR_TSC_INVARIANT_CONTROL:
case HV_X64_MSR_SYNDBG_OPTIONS:
case HV_X64_MSR_SYNDBG_CONTROL ... HV_X64_MSR_SYNDBG_PENDING_BUFFER:
r = true;
@@ -1283,6 +1284,9 @@ static bool hv_check_msr_access(struct kvm_vcpu_hv *hv_vcpu, u32 msr)
case HV_X64_MSR_TSC_EMULATION_STATUS:
return hv_vcpu->cpuid_cache.features_eax &
HV_ACCESS_REENLIGHTENMENT;
+ case HV_X64_MSR_TSC_INVARIANT_CONTROL:
+ return hv_vcpu->cpuid_cache.features_eax &
+ HV_ACCESS_TSC_INVARIANT;
case HV_X64_MSR_CRASH_P0 ... HV_X64_MSR_CRASH_P4:
case HV_X64_MSR_CRASH_CTL:
return hv_vcpu->cpuid_cache.features_edx &
@@ -1410,6 +1414,17 @@ static int kvm_hv_set_msr_pw(struct kvm_vcpu *vcpu, u32 msr, u64 data,
if (!host)
return 1;
break;
+ case HV_X64_MSR_TSC_INVARIANT_CONTROL:
+ /* Only bit 0 is supported */
+ if (data & ~HV_EXPOSE_INVARIANT_TSC)
+ return 1;
+
+ /* The feature can't be disabled from the guest */
+ if (!host && hv->hv_invtsc_control && !data)
+ return 1;
+
+ hv->hv_invtsc_control = data;
+ break;
case HV_X64_MSR_SYNDBG_OPTIONS:
case HV_X64_MSR_SYNDBG_CONTROL ... HV_X64_MSR_SYNDBG_PENDING_BUFFER:
return syndbg_set_msr(vcpu, msr, data, host);
@@ -1585,6 +1600,9 @@ static int kvm_hv_get_msr_pw(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata,
case HV_X64_MSR_TSC_EMULATION_STATUS:
data = hv->hv_tsc_emulation_status;
break;
+ case HV_X64_MSR_TSC_INVARIANT_CONTROL:
+ data = hv->hv_invtsc_control;
+ break;
case HV_X64_MSR_SYNDBG_OPTIONS:
case HV_X64_MSR_SYNDBG_CONTROL ... HV_X64_MSR_SYNDBG_PENDING_BUFFER:
return syndbg_get_msr(vcpu, msr, pdata, host);
@@ -2733,6 +2751,7 @@ int kvm_get_hv_cpuid(struct kvm_vcpu *vcpu, struct kvm_cpuid2 *cpuid,
ent->eax |= HV_MSR_REFERENCE_TSC_AVAILABLE;
ent->eax |= HV_ACCESS_FREQUENCY_MSRS;
ent->eax |= HV_ACCESS_REENLIGHTENMENT;
+ ent->eax |= HV_ACCESS_TSC_INVARIANT;
ent->ebx |= HV_POST_MESSAGES;
ent->ebx |= HV_SIGNAL_EVENTS;
diff --git a/arch/x86/kvm/hyperv.h b/arch/x86/kvm/hyperv.h
index 9f96414a31c5..f83b8db72b11 100644
--- a/arch/x86/kvm/hyperv.h
+++ b/arch/x86/kvm/hyperv.h
@@ -136,6 +136,33 @@ static inline bool kvm_hv_has_stimer_pending(struct kvm_vcpu *vcpu)
HV_SYNIC_STIMER_COUNT);
}
+/*
+ * With HV_ACCESS_TSC_INVARIANT feature, invariant TSC (CPUID.80000007H:EDX[8])
+ * is only observed after HV_X64_MSR_TSC_INVARIANT_CONTROL was written to.
+ */
+static inline bool kvm_hv_invtsc_suppressed(struct kvm_vcpu *vcpu)
+{
+ struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu);
+
+ /*
+ * If Hyper-V's invariant TSC control is not exposed to the guest,
+ * the invariant TSC CPUID flag is not suppressed, Windows guests were
+ * observed to be able to handle it correctly. Going forward, VMMs are
+ * encouraged to enable Hyper-V's invariant TSC control when invariant
+ * TSC CPUID flag is set to make KVM's behavior match genuine Hyper-V.
+ */
+ if (!hv_vcpu ||
+ !(hv_vcpu->cpuid_cache.features_eax & HV_ACCESS_TSC_INVARIANT))
+ return false;
+
+ /*
+ * If Hyper-V's invariant TSC control is exposed to the guest, KVM is
+ * responsible for suppressing the invariant TSC CPUID flag if the
+ * Hyper-V control is not enabled.
+ */
+ return !(to_kvm_hv(vcpu->kvm)->hv_invtsc_control & HV_EXPOSE_INVARIANT_TSC);
+}
+
void kvm_hv_process_stimers(struct kvm_vcpu *vcpu);
void kvm_hv_setup_tsc_page(struct kvm *kvm,
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 5c3ce39cdccb..39b8dd37bc40 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1480,7 +1480,7 @@ static const u32 emulated_msrs_all[] = {
HV_X64_MSR_STIMER0_CONFIG,
HV_X64_MSR_VP_ASSIST_PAGE,
HV_X64_MSR_REENLIGHTENMENT_CONTROL, HV_X64_MSR_TSC_EMULATION_CONTROL,
- HV_X64_MSR_TSC_EMULATION_STATUS,
+ HV_X64_MSR_TSC_EMULATION_STATUS, HV_X64_MSR_TSC_INVARIANT_CONTROL,
HV_X64_MSR_SYNDBG_OPTIONS,
HV_X64_MSR_SYNDBG_CONTROL, HV_X64_MSR_SYNDBG_STATUS,
HV_X64_MSR_SYNDBG_SEND_BUFFER, HV_X64_MSR_SYNDBG_RECV_BUFFER,
@@ -3821,6 +3821,7 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
case HV_X64_MSR_REENLIGHTENMENT_CONTROL:
case HV_X64_MSR_TSC_EMULATION_CONTROL:
case HV_X64_MSR_TSC_EMULATION_STATUS:
+ case HV_X64_MSR_TSC_INVARIANT_CONTROL:
return kvm_hv_set_msr_common(vcpu, msr, data,
msr_info->host_initiated);
case MSR_IA32_BBL_CR_CTL3:
@@ -4191,6 +4192,7 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
case HV_X64_MSR_REENLIGHTENMENT_CONTROL:
case HV_X64_MSR_TSC_EMULATION_CONTROL:
case HV_X64_MSR_TSC_EMULATION_STATUS:
+ case HV_X64_MSR_TSC_INVARIANT_CONTROL:
return kvm_hv_get_msr_common(vcpu,
msr_info->index, &msr_info->data,
msr_info->host_initiated);
generated by cgit v1.2.3 (git 2.25.1) at 2025-03-16 12:53:55 +0000