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KVM: nSVM: Use the "outer" helper for writing multiplier to MSR_AMD64_TSC_RATIO

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When emulating nested SVM transitions, use the outer helper for writing
the TSC multiplier for L2.  Using the inner helper only for one-off cases,
i.e. for paths where KVM is NOT emulating or modifying vCPU state, will
allow for multiple cleanups:

 - Explicitly disabling preemption only in the outer helper
 - Getting the multiplier from the vCPU field in the outer helper
 - Skipping the WRMSR in the outer helper if guest state isn't loaded

Opportunistically delete an extra newline.

No functional change intended.

Link: https://lore.kernel.org/r/20230729011608.1065019-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
This commit is contained in:
Sean Christopherson 2023-07-28 18:15:50 -07:00
parent 0c94e24684
commit c0dc39bd2c
3 changed files with 5 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
arch/x86/kvm/svm/nested.c
View File

@ -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->arch.tsc_scaling_ratio);
svm_write_tsc_multiplier(vcpu, vcpu->arch.tsc_scaling_ratio);
}
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->arch.tsc_scaling_ratio);
svm_write_tsc_multiplier(vcpu, vcpu->arch.tsc_scaling_ratio);
}
/* Inverse operation of nested_copy_vmcb_control_to_cache(). asid is copied too. */

5
arch/x86/kvm/svm/svm.c
View File

@ -567,7 +567,7 @@ static int svm_check_processor_compat(void)
return 0;
}
void __svm_write_tsc_multiplier(u64 multiplier)
static void __svm_write_tsc_multiplier(u64 multiplier)
{
preempt_disable();
@ -1150,12 +1150,11 @@ static void svm_write_tsc_offset(struct kvm_vcpu *vcpu, u64 offset)
vmcb_mark_dirty(svm->vmcb, VMCB_INTERCEPTS);
}
static void svm_write_tsc_multiplier(struct kvm_vcpu *vcpu, u64 multiplier)
void svm_write_tsc_multiplier(struct kvm_vcpu *vcpu, u64 multiplier)
{
__svm_write_tsc_multiplier(multiplier);
}
/* Evaluate instruction intercepts that depend on guest CPUID features. */
static void svm_recalc_instruction_intercepts(struct kvm_vcpu *vcpu,
struct vcpu_svm *svm)

2
arch/x86/kvm/svm/svm.h
View File

@ -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(u64 multiplier);
void svm_write_tsc_multiplier(struct kvm_vcpu *vcpu, u64 multiplier);
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,