From: Sean Christopherson <[email protected]> When switching between vmcs01 and vmcs02, there is no need to update state tracking for values that aren't tied to any particular VMCS as the per-vCPU values are already up-to-date (vmx_switch_vmcs() can only be called when the vCPU is loaded).
Avoiding the update eliminates a RDMSR, and potentially a RDPKRU and posted-interrupt updated (cmpxchg64() and more). Signed-off-by: Sean Christopherson <[email protected]> Signed-off-by: Paolo Bonzini <[email protected]> --- arch/x86/kvm/vmx/nested.c | 2 +- arch/x86/kvm/vmx/vmx.c | 18 +++++++++++++----- arch/x86/kvm/vmx/vmx.h | 1 + 3 files changed, 15 insertions(+), 6 deletions(-) diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index f4415756ddd5..9478d8947595 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -279,7 +279,7 @@ static void vmx_switch_vmcs(struct kvm_vcpu *vcpu, struct loaded_vmcs *vmcs) cpu = get_cpu(); prev = vmx->loaded_vmcs; vmx->loaded_vmcs = vmcs; - vmx_vcpu_load(vcpu, cpu); + vmx_vcpu_load_vmcs(vcpu, cpu); vmx_sync_vmcs_host_state(vmx, prev); put_cpu(); diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 09632b8239de..7a2d9a4b828c 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -1234,11 +1234,7 @@ static void vmx_vcpu_pi_load(struct kvm_vcpu *vcpu, int cpu) pi_set_on(pi_desc); } -/* - * Switches to specified vcpu, until a matching vcpu_put(), but assumes - * vcpu mutex is already taken. - */ -void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu) +void vmx_vcpu_load_vmcs(struct kvm_vcpu *vcpu, int cpu) { struct vcpu_vmx *vmx = to_vmx(vcpu); bool already_loaded = vmx->loaded_vmcs->cpu == cpu; @@ -1299,8 +1295,20 @@ void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu) if (kvm_has_tsc_control && vmx->current_tsc_ratio != vcpu->arch.tsc_scaling_ratio) decache_tsc_multiplier(vmx); +} + +/* + * Switches to specified vcpu, until a matching vcpu_put(), but assumes + * vcpu mutex is already taken. + */ +void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu) +{ + struct vcpu_vmx *vmx = to_vmx(vcpu); + + vmx_vcpu_load_vmcs(vcpu, cpu); vmx_vcpu_pi_load(vcpu, cpu); + vmx->host_pkru = read_pkru(); vmx->host_debugctlmsr = get_debugctlmsr(); } diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h index 581f4039b346..36a2056fafd4 100644 --- a/arch/x86/kvm/vmx/vmx.h +++ b/arch/x86/kvm/vmx/vmx.h @@ -302,6 +302,7 @@ struct kvm_vmx { }; bool nested_vmx_allowed(struct kvm_vcpu *vcpu); +void vmx_vcpu_load_vmcs(struct kvm_vcpu *vcpu, int cpu); void vmx_vcpu_load(struct kvm_vcpu *vcpu, int cpu); int allocate_vpid(void); void free_vpid(int vpid); -- 1.8.3.1
