diff options
| author | Wanpeng Li <wanpeng.li@hotmail.com> | 2017-11-29 12:31:20 +0300 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2017-12-14 11:26:47 +0300 |
| commit | 74c55931c71352317ae0f5736ee9e4ca07ba4238 (patch) | |
| tree | 74f88584fdc28674e27d3a0785c1167f9e476370 | |
| parent | 276c796cfef5bdaf9aae055f520b8857eaa3fa19 (diff) | |
| download | linux-74c55931c71352317ae0f5736ee9e4ca07ba4238.tar.xz | |
KVM: VMX: Cache IA32_DEBUGCTL in memory
MSR_IA32_DEBUGCTLMSR is zeroed on VMEXIT, so it is saved/restored each
time during world switch. This patch caches the host IA32_DEBUGCTL MSR
and saves/restores the host IA32_DEBUGCTL msr when guest/host switches
to avoid to save/restore each time during world switch. This saves
about 100 clock cycles per vmexit.
Suggested-by: Jim Mattson <jmattson@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Jim Mattson <jmattson@google.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
| -rw-r--r-- | arch/x86/kvm/vmx.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 3b5f70285414..4e7da90b4426 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -650,6 +650,8 @@ struct vcpu_vmx { u32 host_pkru; + unsigned long host_debugctlmsr; + /* * Only bits masked by msr_ia32_feature_control_valid_bits can be set in * msr_ia32_feature_control. FEATURE_CONTROL_LOCKED is always included @@ -2318,6 +2320,7 @@ static void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu) vmx_vcpu_pi_load(vcpu, cpu); vmx->host_pkru = read_pkru(); + vmx->host_debugctlmsr = get_debugctlmsr(); } static void vmx_vcpu_pi_put(struct kvm_vcpu *vcpu) @@ -9261,7 +9264,7 @@ static void vmx_arm_hv_timer(struct kvm_vcpu *vcpu) static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu) { struct vcpu_vmx *vmx = to_vmx(vcpu); - unsigned long debugctlmsr, cr3, cr4; + unsigned long cr3, cr4; /* Record the guest's net vcpu time for enforced NMI injections. */ if (unlikely(!enable_vnmi && @@ -9314,7 +9317,6 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu) __write_pkru(vcpu->arch.pkru); atomic_switch_perf_msrs(vmx); - debugctlmsr = get_debugctlmsr(); vmx_arm_hv_timer(vcpu); @@ -9425,8 +9427,8 @@ static void __noclone vmx_vcpu_run(struct kvm_vcpu *vcpu) ); /* MSR_IA32_DEBUGCTLMSR is zeroed on vmexit. Restore it if needed */ - if (debugctlmsr) - update_debugctlmsr(debugctlmsr); + if (vmx->host_debugctlmsr) + update_debugctlmsr(vmx->host_debugctlmsr); #ifndef CONFIG_X86_64 /* |