From 8ef863e67a89c72b5af893a1214f6c35a5f456f8 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 7 May 2019 09:06:32 -0700 Subject: [PATCH] KVM: nVMX: Don't reread VMCS-agnostic state when switching VMCS 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 update (cmpxchg64() and more). Signed-off-by: Sean Christopherson Signed-off-by: Paolo Bonzini --- 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 856ac90ce10a..691f84bff051 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 26b3d96ef5a5..7ffcbb674b1c 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 0bd598c47aec..613f272cdcf8 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); -- 2.45.2