From: Sean Christopherson <seanjc@google.com>
To: Sean Christopherson <seanjc@google.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Maxim Levitsky <mlevitsk@redhat.com>
Subject: [PATCH v2 15/21] KVM: nSVM: Use KVM-governed feature framework to track "TSC scaling enabled"
Date: Fri, 28 Jul 2023 18:16:02 -0700 [thread overview]
Message-ID: <20230729011608.1065019-16-seanjc@google.com> (raw)
In-Reply-To: <20230729011608.1065019-1-seanjc@google.com>
Track "TSC scaling exposed to L1" via a governed feature flag instead of
using a dedicated bit/flag in vcpu_svm.
Note, this fixes a benign bug where KVM would mark TSC scaling as exposed
to L1 even if overall nested SVM supported is disabled, i.e. KVM would let
L1 write MSR_AMD64_TSC_RATIO even when KVM didn't advertise TSCRATEMSR
support to userspace.
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kvm/governed_features.h | 1 +
arch/x86/kvm/svm/nested.c | 2 +-
arch/x86/kvm/svm/svm.c | 10 ++++++----
arch/x86/kvm/svm/svm.h | 1 -
4 files changed, 8 insertions(+), 6 deletions(-)
diff --git a/arch/x86/kvm/governed_features.h b/arch/x86/kvm/governed_features.h
index 722b66af412c..32c0469cf952 100644
--- a/arch/x86/kvm/governed_features.h
+++ b/arch/x86/kvm/governed_features.h
@@ -9,6 +9,7 @@ KVM_GOVERNED_X86_FEATURE(GBPAGES)
KVM_GOVERNED_X86_FEATURE(XSAVES)
KVM_GOVERNED_X86_FEATURE(VMX)
KVM_GOVERNED_X86_FEATURE(NRIPS)
+KVM_GOVERNED_X86_FEATURE(TSCRATEMSR)
#undef KVM_GOVERNED_X86_FEATURE
#undef KVM_GOVERNED_FEATURE
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index 9092f3f8dccf..da65948064dc 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -695,7 +695,7 @@ static void nested_vmcb02_prepare_control(struct vcpu_svm *svm,
vmcb02->control.tsc_offset = vcpu->arch.tsc_offset;
- if (svm->tsc_scaling_enabled &&
+ if (guest_can_use(vcpu, X86_FEATURE_TSCRATEMSR) &&
svm->tsc_ratio_msr != kvm_caps.default_tsc_scaling_ratio)
nested_svm_update_tsc_ratio_msr(vcpu);
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 7c1aa532f767..2f7f7df5a591 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -2755,7 +2755,8 @@ static int svm_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
switch (msr_info->index) {
case MSR_AMD64_TSC_RATIO:
- if (!msr_info->host_initiated && !svm->tsc_scaling_enabled)
+ if (!msr_info->host_initiated &&
+ !guest_can_use(vcpu, X86_FEATURE_TSCRATEMSR))
return 1;
msr_info->data = svm->tsc_ratio_msr;
break;
@@ -2897,7 +2898,7 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr)
switch (ecx) {
case MSR_AMD64_TSC_RATIO:
- if (!svm->tsc_scaling_enabled) {
+ if (!guest_can_use(vcpu, X86_FEATURE_TSCRATEMSR)) {
if (!msr->host_initiated)
return 1;
@@ -2919,7 +2920,8 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr)
svm->tsc_ratio_msr = data;
- if (svm->tsc_scaling_enabled && is_guest_mode(vcpu))
+ if (guest_can_use(vcpu, X86_FEATURE_TSCRATEMSR) &&
+ is_guest_mode(vcpu))
nested_svm_update_tsc_ratio_msr(vcpu);
break;
@@ -4220,8 +4222,8 @@ static void svm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
kvm_governed_feature_set(vcpu, X86_FEATURE_XSAVES);
kvm_governed_feature_check_and_set(vcpu, X86_FEATURE_NRIPS);
+ kvm_governed_feature_check_and_set(vcpu, X86_FEATURE_TSCRATEMSR);
- svm->tsc_scaling_enabled = tsc_scaling && guest_cpuid_has(vcpu, X86_FEATURE_TSCRATEMSR);
svm->lbrv_enabled = lbrv && guest_cpuid_has(vcpu, X86_FEATURE_LBRV);
svm->v_vmload_vmsave_enabled = vls && guest_cpuid_has(vcpu, X86_FEATURE_V_VMSAVE_VMLOAD);
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index c06de55425d4..4e7332f77702 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -259,7 +259,6 @@ struct vcpu_svm {
bool soft_int_injected;
/* optional nested SVM features that are enabled for this guest */
- bool tsc_scaling_enabled : 1;
bool v_vmload_vmsave_enabled : 1;
bool lbrv_enabled : 1;
bool pause_filter_enabled : 1;
--
2.41.0.487.g6d72f3e995-goog
next prev parent reply other threads:[~2023-07-29 1:18 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-29 1:15 [PATCH v2 00/21] KVM: x86: Add "governed" X86_FEATURE framework Sean Christopherson
2023-07-29 1:15 ` [PATCH v2 01/21] KVM: nSVM: Check instead of asserting on nested TSC scaling support Sean Christopherson
2023-07-29 1:15 ` [PATCH v2 02/21] KVM: nSVM: Load L1's TSC multiplier based on L1 state, not L2 state Sean Christopherson
2023-07-29 1:15 ` [PATCH v2 03/21] KVM: nSVM: Use the "outer" helper for writing multiplier to MSR_AMD64_TSC_RATIO Sean Christopherson
2023-07-29 1:15 ` [PATCH v2 04/21] KVM: SVM: Clean up preemption toggling related " Sean Christopherson
2023-07-29 1:15 ` [PATCH v2 05/21] KVM: x86: Always write vCPU's current TSC offset/ratio in vendor hooks Sean Christopherson
2023-07-29 1:15 ` [PATCH v2 06/21] KVM: nSVM: Skip writes to MSR_AMD64_TSC_RATIO if guest state isn't loaded Sean Christopherson
2023-07-29 1:15 ` [PATCH v2 07/21] KVM: x86: Add a framework for enabling KVM-governed x86 features Sean Christopherson
2023-08-14 4:43 ` Zeng Guang
2023-08-14 17:20 ` Sean Christopherson
2023-07-29 1:15 ` [PATCH v2 08/21] KVM: x86/mmu: Use KVM-governed feature framework to track "GBPAGES enabled" Sean Christopherson
2023-07-29 1:15 ` [PATCH v2 09/21] KVM: VMX: Recompute "XSAVES enabled" only after CPUID update Sean Christopherson
2023-07-29 1:15 ` [PATCH v2 10/21] KVM: VMX: Check KVM CPU caps, not just VMX MSR support, for XSAVE enabling Sean Christopherson
2023-07-29 1:15 ` [PATCH v2 11/21] KVM: VMX: Rename XSAVES control to follow KVM's preferred "ENABLE_XYZ" Sean Christopherson
2023-07-29 1:15 ` [PATCH v2 12/21] KVM: x86: Use KVM-governed feature framework to track "XSAVES enabled" Sean Christopherson
2023-08-14 6:28 ` Zeng Guang
2023-07-29 1:16 ` [PATCH v2 13/21] KVM: nVMX: Use KVM-governed feature framework to track "nested VMX enabled" Sean Christopherson
2023-08-14 8:11 ` Yuan Yao
2023-07-29 1:16 ` [PATCH v2 14/21] KVM: nSVM: Use KVM-governed feature framework to track "NRIPS enabled" Sean Christopherson
2023-07-29 1:16 ` Sean Christopherson [this message]
2023-07-29 1:16 ` [PATCH v2 16/21] KVM: nSVM: Use KVM-governed feature framework to track "vVM{SAVE,LOAD} enabled" Sean Christopherson
2023-07-29 1:16 ` [PATCH v2 17/21] KVM: nSVM: Use KVM-governed feature framework to track "LBRv enabled" Sean Christopherson
2023-07-29 1:16 ` [PATCH v2 18/21] KVM: nSVM: Use KVM-governed feature framework to track "Pause Filter enabled" Sean Christopherson
2023-07-29 1:16 ` [PATCH v2 19/21] KVM: nSVM: Use KVM-governed feature framework to track "vGIF enabled" Sean Christopherson
2023-07-29 1:16 ` [PATCH v2 20/21] KVM: nSVM: Use KVM-governed feature framework to track "vNMI enabled" Sean Christopherson
2023-07-29 1:16 ` [PATCH v2 21/21] KVM: x86: Disallow guest CPUID lookups when IRQs are disabled Sean Christopherson
2023-08-04 0:40 ` [PATCH v2 00/21] KVM: x86: Add "governed" X86_FEATURE framework Sean Christopherson
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