When L2 is running without LBR virtualization, we should ensure that L1's LBR msrs continue to update as usual.
Signed-off-by: Maxim Levitsky mlevitsk@redhat.com --- arch/x86/kvm/svm/nested.c | 11 +++++ arch/x86/kvm/svm/svm.c | 98 +++++++++++++++++++++++++++++++-------- arch/x86/kvm/svm/svm.h | 2 + 3 files changed, 92 insertions(+), 19 deletions(-)
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index 4df59d9795b6..c6f09b591696 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -502,6 +502,9 @@ static void nested_vmcb02_prepare_save(struct vcpu_svm *svm, struct vmcb *vmcb12 svm->vcpu.arch.dr6 = vmcb12->save.dr6 | DR6_ACTIVE_LOW; vmcb_mark_dirty(svm->vmcb, VMCB_DR); } + + if (unlikely(svm->vmcb01.ptr->control.virt_ext & LBR_CTL_ENABLE_MASK)) + svm_copy_lbrs(svm->vmcb01.ptr, svm->vmcb); }
static void nested_vmcb02_prepare_control(struct vcpu_svm *svm) @@ -550,6 +553,9 @@ static void nested_vmcb02_prepare_control(struct vcpu_svm *svm) svm->vmcb->control.event_inj = svm->nested.ctl.event_inj; svm->vmcb->control.event_inj_err = svm->nested.ctl.event_inj_err;
+ svm->vmcb->control.virt_ext = svm->vmcb01.ptr->control.virt_ext & + LBR_CTL_ENABLE_MASK; + nested_svm_transition_tlb_flush(vcpu);
/* Enter Guest-Mode */ @@ -808,6 +814,11 @@ int nested_svm_vmexit(struct vcpu_svm *svm)
svm_switch_vmcb(svm, &svm->vmcb01);
+ if (unlikely(svm->vmcb->control.virt_ext & LBR_CTL_ENABLE_MASK)) { + svm_copy_lbrs(svm->nested.vmcb02.ptr, svm->vmcb); + svm_update_lbrv(vcpu); + } + /* * On vmexit the GIF is set to false and * no event can be injected in L1. diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index b08c5d826208..981cc9765b95 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -792,6 +792,17 @@ static void init_msrpm_offsets(void) } }
+void svm_copy_lbrs(struct vmcb *from_vmcb, struct vmcb *to_vmcb) +{ + to_vmcb->save.dbgctl = from_vmcb->save.dbgctl; + to_vmcb->save.br_from = from_vmcb->save.br_from; + to_vmcb->save.br_to = from_vmcb->save.br_to; + to_vmcb->save.last_excp_from = from_vmcb->save.last_excp_from; + to_vmcb->save.last_excp_to = from_vmcb->save.last_excp_to; + + vmcb_mark_dirty(to_vmcb, VMCB_LBR); +} + static void svm_enable_lbrv(struct kvm_vcpu *vcpu) { struct vcpu_svm *svm = to_svm(vcpu); @@ -801,6 +812,10 @@ static void svm_enable_lbrv(struct kvm_vcpu *vcpu) set_msr_interception(vcpu, svm->msrpm, MSR_IA32_LASTBRANCHTOIP, 1, 1); set_msr_interception(vcpu, svm->msrpm, MSR_IA32_LASTINTFROMIP, 1, 1); set_msr_interception(vcpu, svm->msrpm, MSR_IA32_LASTINTTOIP, 1, 1); + + /* Move the LBR msrs to the vmcb02 so that the guest can see them. */ + if (is_guest_mode(vcpu)) + svm_copy_lbrs(svm->vmcb01.ptr, svm->vmcb); }
static void svm_disable_lbrv(struct kvm_vcpu *vcpu) @@ -812,6 +827,63 @@ static void svm_disable_lbrv(struct kvm_vcpu *vcpu) set_msr_interception(vcpu, svm->msrpm, MSR_IA32_LASTBRANCHTOIP, 0, 0); set_msr_interception(vcpu, svm->msrpm, MSR_IA32_LASTINTFROMIP, 0, 0); set_msr_interception(vcpu, svm->msrpm, MSR_IA32_LASTINTTOIP, 0, 0); + + /* + * Move the LBR msrs back to the vmcb01 to avoid copying them + * on nested guest entries. + */ + if (is_guest_mode(vcpu)) + svm_copy_lbrs(svm->vmcb, svm->vmcb01.ptr); +} + +static int svm_get_lbr_msr(struct vcpu_svm *svm, u32 index) +{ + /* + * If the LBR virtualization is disabled, the LBR msrs are always + * kept in the vmcb01 to avoid copying them on nested guest entries. + * + * If nested, and the LBR virtualization is enabled/disabled, the msrs + * are moved between the vmcb01 and vmcb02 as needed. + */ + struct vmcb *vmcb = + (svm->vmcb->control.virt_ext & LBR_CTL_ENABLE_MASK) ? + svm->vmcb : svm->vmcb01.ptr; + + switch (index) { + case MSR_IA32_DEBUGCTLMSR: + return vmcb->save.dbgctl; + case MSR_IA32_LASTBRANCHFROMIP: + return vmcb->save.br_from; + case MSR_IA32_LASTBRANCHTOIP: + return vmcb->save.br_to; + case MSR_IA32_LASTINTFROMIP: + return vmcb->save.last_excp_from; + case MSR_IA32_LASTINTTOIP: + return vmcb->save.last_excp_to; + default: + KVM_BUG(false, svm->vcpu.kvm, + "%s: Unknown MSR 0x%x", __func__, index); + return 0; + } +} + +void svm_update_lbrv(struct kvm_vcpu *vcpu) +{ + struct vcpu_svm *svm = to_svm(vcpu); + + bool enable_lbrv = svm_get_lbr_msr(svm, MSR_IA32_DEBUGCTLMSR) & + DEBUGCTLMSR_LBR; + + bool current_enable_lbrv = !!(svm->vmcb->control.virt_ext & + LBR_CTL_ENABLE_MASK); + + if (enable_lbrv == current_enable_lbrv) + return; + + if (enable_lbrv) + svm_enable_lbrv(vcpu); + else + svm_disable_lbrv(vcpu); }
void disable_nmi_singlestep(struct vcpu_svm *svm) @@ -2704,25 +2776,12 @@ static int svm_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) case MSR_TSC_AUX: msr_info->data = svm->tsc_aux; break; - /* - * Nobody will change the following 5 values in the VMCB so we can - * safely return them on rdmsr. They will always be 0 until LBRV is - * implemented. - */ case MSR_IA32_DEBUGCTLMSR: - msr_info->data = svm->vmcb->save.dbgctl; - break; case MSR_IA32_LASTBRANCHFROMIP: - msr_info->data = svm->vmcb->save.br_from; - break; case MSR_IA32_LASTBRANCHTOIP: - msr_info->data = svm->vmcb->save.br_to; - break; case MSR_IA32_LASTINTFROMIP: - msr_info->data = svm->vmcb->save.last_excp_from; - break; case MSR_IA32_LASTINTTOIP: - msr_info->data = svm->vmcb->save.last_excp_to; + msr_info->data = svm_get_lbr_msr(svm, msr_info->index); break; case MSR_VM_HSAVE_PA: msr_info->data = svm->nested.hsave_msr; @@ -2940,12 +2999,13 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr) if (data & DEBUGCTL_RESERVED_BITS) return 1;
- svm->vmcb->save.dbgctl = data; - vmcb_mark_dirty(svm->vmcb, VMCB_LBR); - if (data & (1ULL<<0)) - svm_enable_lbrv(vcpu); + if (svm->vmcb->control.virt_ext & LBR_CTL_ENABLE_MASK) + svm->vmcb->save.dbgctl = data; else - svm_disable_lbrv(vcpu); + svm->vmcb01.ptr->save.dbgctl = data; + + svm_update_lbrv(vcpu); + break; case MSR_VM_HSAVE_PA: /* diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h index 524d943f3efc..0c351e9c4d6d 100644 --- a/arch/x86/kvm/svm/svm.h +++ b/arch/x86/kvm/svm/svm.h @@ -417,6 +417,8 @@ u32 svm_msrpm_offset(u32 msr); u32 *svm_vcpu_alloc_msrpm(void); void svm_vcpu_init_msrpm(struct kvm_vcpu *vcpu, u32 *msrpm); void svm_vcpu_free_msrpm(u32 *msrpm); +void svm_copy_lbrs(struct vmcb *from_vmcb, struct vmcb *to_vmcb); +void svm_update_lbrv(struct kvm_vcpu *vcpu);
int svm_set_efer(struct kvm_vcpu *vcpu, u64 efer); void svm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0);