From e183d17ac362655e5ef061760245b4402b9c04f8 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 15 Aug 2023 13:36:49 -0700 Subject: [PATCH] KVM: nSVM: Use KVM-governed feature framework to track "LBRv enabled" Track "LBR virtualization exposed to L1" via a governed feature flag instead of using a dedicated bit/flag in vcpu_svm. Note, checking KVM's capabilities instead of the "lbrv" param means that the code isn't strictly equivalent, as lbrv_enabled could have been set if nested=false where as that the governed feature cannot. But that's a glorified nop as the feature/flag is consumed only by paths that are gated by nSVM being enabled. Link: https://lore.kernel.org/r/20230815203653.519297-12-seanjc@google.com Signed-off-by: Sean Christopherson --- arch/x86/kvm/governed_features.h | 1 + arch/x86/kvm/svm/nested.c | 23 +++++++++++++---------- arch/x86/kvm/svm/svm.c | 5 ++--- arch/x86/kvm/svm/svm.h | 1 - 4 files changed, 16 insertions(+), 14 deletions(-) diff --git a/arch/x86/kvm/governed_features.h b/arch/x86/kvm/governed_features.h index f01a95f..3a4c0e4 100644 --- a/arch/x86/kvm/governed_features.h +++ b/arch/x86/kvm/governed_features.h @@ -11,6 +11,7 @@ KVM_GOVERNED_X86_FEATURE(VMX) KVM_GOVERNED_X86_FEATURE(NRIPS) KVM_GOVERNED_X86_FEATURE(TSCRATEMSR) KVM_GOVERNED_X86_FEATURE(V_VMSAVE_VMLOAD) +KVM_GOVERNED_X86_FEATURE(LBRV) #undef KVM_GOVERNED_X86_FEATURE #undef KVM_GOVERNED_FEATURE diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index 24d47eb..f50f74b 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -552,6 +552,7 @@ static void nested_vmcb02_prepare_save(struct vcpu_svm *svm, struct vmcb *vmcb12 bool new_vmcb12 = false; struct vmcb *vmcb01 = svm->vmcb01.ptr; struct vmcb *vmcb02 = svm->nested.vmcb02.ptr; + struct kvm_vcpu *vcpu = &svm->vcpu; nested_vmcb02_compute_g_pat(svm); @@ -577,18 +578,18 @@ static void nested_vmcb02_prepare_save(struct vcpu_svm *svm, struct vmcb *vmcb12 vmcb_mark_dirty(vmcb02, VMCB_DT); } - kvm_set_rflags(&svm->vcpu, vmcb12->save.rflags | X86_EFLAGS_FIXED); + kvm_set_rflags(vcpu, vmcb12->save.rflags | X86_EFLAGS_FIXED); - svm_set_efer(&svm->vcpu, svm->nested.save.efer); + svm_set_efer(vcpu, svm->nested.save.efer); - svm_set_cr0(&svm->vcpu, svm->nested.save.cr0); - svm_set_cr4(&svm->vcpu, svm->nested.save.cr4); + svm_set_cr0(vcpu, svm->nested.save.cr0); + svm_set_cr4(vcpu, svm->nested.save.cr4); svm->vcpu.arch.cr2 = vmcb12->save.cr2; - kvm_rax_write(&svm->vcpu, vmcb12->save.rax); - kvm_rsp_write(&svm->vcpu, vmcb12->save.rsp); - kvm_rip_write(&svm->vcpu, vmcb12->save.rip); + kvm_rax_write(vcpu, vmcb12->save.rax); + kvm_rsp_write(vcpu, vmcb12->save.rsp); + kvm_rip_write(vcpu, vmcb12->save.rip); /* In case we don't even reach vcpu_run, the fields are not updated */ vmcb02->save.rax = vmcb12->save.rax; @@ -602,7 +603,8 @@ static void nested_vmcb02_prepare_save(struct vcpu_svm *svm, struct vmcb *vmcb12 vmcb_mark_dirty(vmcb02, VMCB_DR); } - if (unlikely(svm->lbrv_enabled && (svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK))) { + if (unlikely(guest_can_use(vcpu, X86_FEATURE_LBRV) && + (svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK))) { /* * Reserved bits of DEBUGCTL are ignored. Be consistent with * svm_set_msr's definition of reserved bits. @@ -734,7 +736,7 @@ static void nested_vmcb02_prepare_control(struct vcpu_svm *svm, vmcb02->control.virt_ext = vmcb01->control.virt_ext & LBR_CTL_ENABLE_MASK; - if (svm->lbrv_enabled) + if (guest_can_use(vcpu, X86_FEATURE_LBRV)) vmcb02->control.virt_ext |= (svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK); @@ -1065,7 +1067,8 @@ int nested_svm_vmexit(struct vcpu_svm *svm) if (!nested_exit_on_intr(svm)) kvm_make_request(KVM_REQ_EVENT, &svm->vcpu); - if (unlikely(svm->lbrv_enabled && (svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK))) { + if (unlikely(guest_can_use(vcpu, X86_FEATURE_LBRV) && + (svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK))) { svm_copy_lbrs(vmcb12, vmcb02); svm_update_lbrv(vcpu); } else if (unlikely(vmcb01->control.virt_ext & LBR_CTL_ENABLE_MASK)) { diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 78d53ea..3b8e412 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -1024,7 +1024,7 @@ void svm_update_lbrv(struct kvm_vcpu *vcpu) bool current_enable_lbrv = !!(svm->vmcb->control.virt_ext & LBR_CTL_ENABLE_MASK); - if (unlikely(is_guest_mode(vcpu) && svm->lbrv_enabled)) + if (unlikely(is_guest_mode(vcpu) && guest_can_use(vcpu, X86_FEATURE_LBRV))) if (unlikely(svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK)) enable_lbrv = true; @@ -4261,8 +4261,7 @@ static void svm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu) kvm_governed_feature_check_and_set(vcpu, X86_FEATURE_NRIPS); kvm_governed_feature_check_and_set(vcpu, X86_FEATURE_TSCRATEMSR); - - svm->lbrv_enabled = lbrv && guest_cpuid_has(vcpu, X86_FEATURE_LBRV); + kvm_governed_feature_check_and_set(vcpu, X86_FEATURE_LBRV); /* * Intercept VMLOAD if the vCPU mode is Intel in order to emulate that diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h index b475241..0e21823 100644 --- a/arch/x86/kvm/svm/svm.h +++ b/arch/x86/kvm/svm/svm.h @@ -259,7 +259,6 @@ struct vcpu_svm { bool soft_int_injected; /* optional nested SVM features that are enabled for this guest */ - bool lbrv_enabled : 1; bool pause_filter_enabled : 1; bool pause_threshold_enabled : 1; bool vgif_enabled : 1; -- 2.7.4