From 1196cb970b996be69a2fcd9756117b394f8e7526 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Fri, 20 Mar 2020 14:28:23 -0700 Subject: [PATCH] KVM: nVMX: Reload APIC access page on nested VM-Exit only if necessary Defer reloading L1's APIC page by logging the need for a reload and processing it during nested VM-Exit instead of unconditionally reloading the APIC page on nested VM-Exit. This eliminates a TLB flush on the majority of VM-Exits as the APIC page rarely needs to be reloaded. Signed-off-by: Sean Christopherson Message-Id: <20200320212833.3507-28-sean.j.christopherson@intel.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/vmx/nested.c | 9 ++++----- arch/x86/kvm/vmx/vmx.c | 10 +++++++--- arch/x86/kvm/vmx/vmx.h | 1 + 3 files changed, 12 insertions(+), 8 deletions(-) diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index deddf0f0f6e7..a7a526a21292 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -4346,11 +4346,10 @@ void nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32 exit_reason, kvm_vcpu_unmap(vcpu, &vmx->nested.pi_desc_map, true); vmx->nested.pi_desc = NULL; - /* - * We are now running in L2, mmu_notifier will force to reload the - * page's hpa for L2 vmcs. Need to reload it for L1 before entering L1. - */ - kvm_make_request(KVM_REQ_APIC_PAGE_RELOAD, vcpu); + if (vmx->nested.reload_vmcs01_apic_access_page) { + vmx->nested.reload_vmcs01_apic_access_page = false; + kvm_make_request(KVM_REQ_APIC_PAGE_RELOAD, vcpu); + } if ((exit_reason != -1) && (enable_shadow_vmcs || vmx->nested.hv_evmcs)) vmx->nested.need_vmcs12_to_shadow_sync = true; diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index d958cee52f41..4739b780c74e 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -6142,10 +6142,14 @@ void vmx_set_virtual_apic_mode(struct kvm_vcpu *vcpu) static void vmx_set_apic_access_page_addr(struct kvm_vcpu *vcpu, hpa_t hpa) { - if (!is_guest_mode(vcpu)) { - vmcs_write64(APIC_ACCESS_ADDR, hpa); - vmx_flush_tlb_current(vcpu); + /* Defer reload until vmcs01 is the current VMCS. */ + if (is_guest_mode(vcpu)) { + to_vmx(vcpu)->nested.reload_vmcs01_apic_access_page = true; + return; } + + vmcs_write64(APIC_ACCESS_ADDR, hpa); + vmx_flush_tlb_current(vcpu); } static void vmx_hwapic_isr_update(struct kvm_vcpu *vcpu, int max_isr) diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h index 4c7b0713b438..31d7252df163 100644 --- a/arch/x86/kvm/vmx/vmx.h +++ b/arch/x86/kvm/vmx/vmx.h @@ -136,6 +136,7 @@ struct nested_vmx { bool vmcs02_initialized; bool change_vmcs01_virtual_apic_mode; + bool reload_vmcs01_apic_access_page; /* * Enlightened VMCS has been enabled. It does not mean that L1 has to -- 2.25.1