From 284036c644a1dc71890503c849b22c3126308067 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 13 Jul 2021 09:33:16 -0700 Subject: [PATCH] KVM: nVMX: Remove obsolete MSR bitmap refresh at nested transitions Drop unnecessary MSR bitmap updates during nested transitions, as L1's APIC_BASE MSR is not modified by the standard VM-Enter/VM-Exit flows, and L2's MSR bitmap is managed separately. In the unlikely event that L1 is pathological and loads APIC_BASE via the VM-Exit load list, KVM will handle updating the bitmap in its normal WRMSR flows. Signed-off-by: Sean Christopherson Message-Id: <20210713163324.627647-39-seanjc@google.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/vmx/nested.c | 6 ------ arch/x86/kvm/vmx/vmx.c | 2 +- arch/x86/kvm/vmx/vmx.h | 1 - 3 files changed, 1 insertion(+), 8 deletions(-) diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index a77cfc8..0d0dd65 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -4305,9 +4305,6 @@ static void load_vmcs12_host_state(struct kvm_vcpu *vcpu, kvm_set_dr(vcpu, 7, 0x400); vmcs_write64(GUEST_IA32_DEBUGCTL, 0); - if (cpu_has_vmx_msr_bitmap()) - vmx_update_msr_bitmap(vcpu); - if (nested_vmx_load_msr(vcpu, vmcs12->vm_exit_msr_load_addr, vmcs12->vm_exit_msr_load_count)) nested_vmx_abort(vcpu, VMX_ABORT_LOAD_HOST_MSR_FAIL); @@ -4386,9 +4383,6 @@ static void nested_vmx_restore_host_state(struct kvm_vcpu *vcpu) kvm_mmu_reset_context(vcpu); - if (cpu_has_vmx_msr_bitmap()) - vmx_update_msr_bitmap(vcpu); - /* * This nasty bit of open coding is a compromise between blindly * loading L1's MSRs using the exit load lists (incorrect emulation diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index af7aa9b..6e79f1b 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -3865,7 +3865,7 @@ static void vmx_update_msr_bitmap_x2apic(struct kvm_vcpu *vcpu, u8 mode) } } -void vmx_update_msr_bitmap(struct kvm_vcpu *vcpu) +static void vmx_update_msr_bitmap(struct kvm_vcpu *vcpu) { struct vcpu_vmx *vmx = to_vmx(vcpu); u8 mode = vmx_msr_bitmap_mode(vcpu); diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h index fd076bd..a408a90 100644 --- a/arch/x86/kvm/vmx/vmx.h +++ b/arch/x86/kvm/vmx/vmx.h @@ -376,7 +376,6 @@ u64 construct_eptp(struct kvm_vcpu *vcpu, hpa_t root_hpa, int root_level); bool vmx_guest_inject_ac(struct kvm_vcpu *vcpu); void vmx_update_exception_bitmap(struct kvm_vcpu *vcpu); -void vmx_update_msr_bitmap(struct kvm_vcpu *vcpu); bool vmx_nmi_blocked(struct kvm_vcpu *vcpu); bool vmx_interrupt_blocked(struct kvm_vcpu *vcpu); bool vmx_get_nmi_mask(struct kvm_vcpu *vcpu); -- 2.7.4