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 05/21] KVM: x86: Always write vCPU's current TSC offset/ratio in vendor hooks
Date: Fri, 28 Jul 2023 18:15:52 -0700 [thread overview]
Message-ID: <20230729011608.1065019-6-seanjc@google.com> (raw)
In-Reply-To: <20230729011608.1065019-1-seanjc@google.com>
Drop the @offset and @multiplier params from the kvm_x86_ops hooks for
propagating TSC offsets/multipliers into hardware, and instead have the
vendor implementations pull the information directly from the vCPU
structure. The respective vCPU fields _must_ be written at the same
time in order to maintain consistent state, i.e. it's not random luck
that the value passed in by all callers is grabbed from the vCPU.
Explicitly grabbing the value from the vCPU field in SVM's implementation
in particular will allow for additional cleanup without introducing even
more subtle dependencies. Specifically, SVM can skip the WRMSR if guest
state isn't loaded, i.e. svm_prepare_switch_to_guest() will load the
correct value for the vCPU prior to entering the guest.
This also reconciles KVM's handling of related values that are stored in
the vCPU, as svm_write_tsc_offset() already assumes/requires the caller
to have updated l1_tsc_offset.
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/include/asm/kvm_host.h | 4 ++--
arch/x86/kvm/svm/nested.c | 4 ++--
arch/x86/kvm/svm/svm.c | 8 ++++----
arch/x86/kvm/svm/svm.h | 2 +-
arch/x86/kvm/vmx/vmx.c | 8 ++++----
arch/x86/kvm/x86.c | 5 ++---
6 files changed, 15 insertions(+), 16 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 28bd38303d70..dad9331c5270 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1654,8 +1654,8 @@ struct kvm_x86_ops {
u64 (*get_l2_tsc_offset)(struct kvm_vcpu *vcpu);
u64 (*get_l2_tsc_multiplier)(struct kvm_vcpu *vcpu);
- void (*write_tsc_offset)(struct kvm_vcpu *vcpu, u64 offset);
- void (*write_tsc_multiplier)(struct kvm_vcpu *vcpu, u64 multiplier);
+ void (*write_tsc_offset)(struct kvm_vcpu *vcpu);
+ void (*write_tsc_multiplier)(struct kvm_vcpu *vcpu);
/*
* Retrieve somewhat arbitrary exit information. Intended to
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index 5d5a1d7832fb..3342cc4a5189 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -1103,7 +1103,7 @@ int nested_svm_vmexit(struct vcpu_svm *svm)
if (kvm_caps.has_tsc_control &&
vcpu->arch.tsc_scaling_ratio != vcpu->arch.l1_tsc_scaling_ratio) {
vcpu->arch.tsc_scaling_ratio = vcpu->arch.l1_tsc_scaling_ratio;
- svm_write_tsc_multiplier(vcpu, vcpu->arch.tsc_scaling_ratio);
+ svm_write_tsc_multiplier(vcpu);
}
svm->nested.ctl.nested_cr3 = 0;
@@ -1536,7 +1536,7 @@ void nested_svm_update_tsc_ratio_msr(struct kvm_vcpu *vcpu)
vcpu->arch.tsc_scaling_ratio =
kvm_calc_nested_tsc_multiplier(vcpu->arch.l1_tsc_scaling_ratio,
svm->tsc_ratio_msr);
- svm_write_tsc_multiplier(vcpu, vcpu->arch.tsc_scaling_ratio);
+ svm_write_tsc_multiplier(vcpu);
}
/* Inverse operation of nested_copy_vmcb_control_to_cache(). asid is copied too. */
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 9fc5e402636a..c786c8e9108f 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -1097,19 +1097,19 @@ static u64 svm_get_l2_tsc_multiplier(struct kvm_vcpu *vcpu)
return svm->tsc_ratio_msr;
}
-static void svm_write_tsc_offset(struct kvm_vcpu *vcpu, u64 offset)
+static void svm_write_tsc_offset(struct kvm_vcpu *vcpu)
{
struct vcpu_svm *svm = to_svm(vcpu);
svm->vmcb01.ptr->control.tsc_offset = vcpu->arch.l1_tsc_offset;
- svm->vmcb->control.tsc_offset = offset;
+ svm->vmcb->control.tsc_offset = vcpu->arch.tsc_offset;
vmcb_mark_dirty(svm->vmcb, VMCB_INTERCEPTS);
}
-void svm_write_tsc_multiplier(struct kvm_vcpu *vcpu, u64 multiplier)
+void svm_write_tsc_multiplier(struct kvm_vcpu *vcpu)
{
preempt_disable();
- __svm_write_tsc_multiplier(multiplier);
+ __svm_write_tsc_multiplier(vcpu->arch.tsc_scaling_ratio);
preempt_enable();
}
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 7132c0a04817..5829a1801862 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -658,7 +658,7 @@ int nested_svm_check_exception(struct vcpu_svm *svm, unsigned nr,
bool has_error_code, u32 error_code);
int nested_svm_exit_special(struct vcpu_svm *svm);
void nested_svm_update_tsc_ratio_msr(struct kvm_vcpu *vcpu);
-void svm_write_tsc_multiplier(struct kvm_vcpu *vcpu, u64 multiplier);
+void svm_write_tsc_multiplier(struct kvm_vcpu *vcpu);
void nested_copy_vmcb_control_to_cache(struct vcpu_svm *svm,
struct vmcb_control_area *control);
void nested_copy_vmcb_save_to_cache(struct vcpu_svm *svm,
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 0ecf4be2c6af..ca6194b0e35e 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -1884,14 +1884,14 @@ u64 vmx_get_l2_tsc_multiplier(struct kvm_vcpu *vcpu)
return kvm_caps.default_tsc_scaling_ratio;
}
-static void vmx_write_tsc_offset(struct kvm_vcpu *vcpu, u64 offset)
+static void vmx_write_tsc_offset(struct kvm_vcpu *vcpu)
{
- vmcs_write64(TSC_OFFSET, offset);
+ vmcs_write64(TSC_OFFSET, vcpu->arch.tsc_offset);
}
-static void vmx_write_tsc_multiplier(struct kvm_vcpu *vcpu, u64 multiplier)
+static void vmx_write_tsc_multiplier(struct kvm_vcpu *vcpu)
{
- vmcs_write64(TSC_MULTIPLIER, multiplier);
+ vmcs_write64(TSC_MULTIPLIER, vcpu->arch.tsc_scaling_ratio);
}
/*
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index a6b9bea62fb8..5a14378ed4e1 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2615,7 +2615,7 @@ static void kvm_vcpu_write_tsc_offset(struct kvm_vcpu *vcpu, u64 l1_offset)
else
vcpu->arch.tsc_offset = l1_offset;
- static_call(kvm_x86_write_tsc_offset)(vcpu, vcpu->arch.tsc_offset);
+ static_call(kvm_x86_write_tsc_offset)(vcpu);
}
static void kvm_vcpu_write_tsc_multiplier(struct kvm_vcpu *vcpu, u64 l1_multiplier)
@@ -2631,8 +2631,7 @@ static void kvm_vcpu_write_tsc_multiplier(struct kvm_vcpu *vcpu, u64 l1_multipli
vcpu->arch.tsc_scaling_ratio = l1_multiplier;
if (kvm_caps.has_tsc_control)
- static_call(kvm_x86_write_tsc_multiplier)(
- vcpu, vcpu->arch.tsc_scaling_ratio);
+ static_call(kvm_x86_write_tsc_multiplier)(vcpu);
}
static inline bool kvm_check_tsc_unstable(void)
--
2.41.0.487.g6d72f3e995-goog
next prev parent reply other threads:[~2023-07-29 1:16 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 ` Sean Christopherson [this message]
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 ` [PATCH v2 15/21] KVM: nSVM: Use KVM-governed feature framework to track "TSC scaling enabled" Sean Christopherson
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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