diff options
Diffstat (limited to 'arch/x86/kvm/svm/svm.c')
-rw-r--r-- | arch/x86/kvm/svm/svm.c | 78 |
1 files changed, 66 insertions, 12 deletions
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 4543dd6bcab2..800f781475c0 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -1483,7 +1483,7 @@ static void svm_clear_current_vmcb(struct vmcb *vmcb) { int i; - for_each_online_cpu(i) + for_each_possible_cpu(i) cmpxchg(per_cpu_ptr(&svm_data.current_vmcb, i), vmcb, NULL); } @@ -1993,11 +1993,11 @@ static void new_asid(struct vcpu_svm *svm, struct svm_cpu_data *sd) svm->asid = sd->next_asid++; } -static void svm_set_dr6(struct vcpu_svm *svm, unsigned long value) +static void svm_set_dr6(struct kvm_vcpu *vcpu, unsigned long value) { - struct vmcb *vmcb = svm->vmcb; + struct vmcb *vmcb = to_svm(vcpu)->vmcb; - if (svm->vcpu.arch.guest_state_protected) + if (vcpu->arch.guest_state_protected) return; if (unlikely(value != vmcb->save.dr6)) { @@ -2222,6 +2222,10 @@ static int shutdown_interception(struct kvm_vcpu *vcpu) */ if (!sev_es_guest(vcpu->kvm)) { clear_page(svm->vmcb); +#ifdef CONFIG_KVM_SMM + if (is_smm(vcpu)) + kvm_smm_changed(vcpu, false); +#endif kvm_vcpu_reset(vcpu, true); } @@ -3167,6 +3171,27 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr) kvm_pr_unimpl_wrmsr(vcpu, ecx, data); break; } + + /* + * AMD changed the architectural behavior of bits 5:2. On CPUs + * without BusLockTrap, bits 5:2 control "external pins", but + * on CPUs that support BusLockDetect, bit 2 enables BusLockTrap + * and bits 5:3 are reserved-to-zero. Sadly, old KVM allowed + * the guest to set bits 5:2 despite not actually virtualizing + * Performance-Monitoring/Breakpoint external pins. Drop bits + * 5:2 for backwards compatibility. + */ + data &= ~GENMASK(5, 2); + + /* + * Suppress BTF as KVM doesn't virtualize BTF, but there's no + * way to communicate lack of support to the guest. + */ + if (data & DEBUGCTLMSR_BTF) { + kvm_pr_unimpl_wrmsr(vcpu, MSR_IA32_DEBUGCTLMSR, data); + data &= ~DEBUGCTLMSR_BTF; + } + if (data & DEBUGCTL_RESERVED_BITS) return 1; @@ -4176,6 +4201,18 @@ static noinstr void svm_vcpu_enter_exit(struct kvm_vcpu *vcpu, bool spec_ctrl_in guest_state_enter_irqoff(); + /* + * Set RFLAGS.IF prior to VMRUN, as the host's RFLAGS.IF at the time of + * VMRUN controls whether or not physical IRQs are masked (KVM always + * runs with V_INTR_MASKING_MASK). Toggle RFLAGS.IF here to avoid the + * temptation to do STI+VMRUN+CLI, as AMD CPUs bleed the STI shadow + * into guest state if delivery of an event during VMRUN triggers a + * #VMEXIT, and the guest_state transitions already tell lockdep that + * IRQs are being enabled/disabled. Note! GIF=0 for the entirety of + * this path, so IRQs aren't actually unmasked while running host code. + */ + raw_local_irq_enable(); + amd_clear_divider(); if (sev_es_guest(vcpu->kvm)) @@ -4184,12 +4221,14 @@ static noinstr void svm_vcpu_enter_exit(struct kvm_vcpu *vcpu, bool spec_ctrl_in else __svm_vcpu_run(svm, spec_ctrl_intercepted); + raw_local_irq_disable(); + guest_state_exit_irqoff(); } -static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu, - bool force_immediate_exit) +static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu, u64 run_flags) { + bool force_immediate_exit = run_flags & KVM_RUN_FORCE_IMMEDIATE_EXIT; struct vcpu_svm *svm = to_svm(vcpu); bool spec_ctrl_intercepted = msr_write_intercepted(vcpu, MSR_IA32_SPEC_CTRL); @@ -4231,17 +4270,28 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu, svm_hv_update_vp_id(svm->vmcb, vcpu); /* - * Run with all-zero DR6 unless needed, so that we can get the exact cause - * of a #DB. + * Run with all-zero DR6 unless the guest can write DR6 freely, so that + * KVM can get the exact cause of a #DB. Note, loading guest DR6 from + * KVM's snapshot is only necessary when DR accesses won't exit. */ - if (unlikely(vcpu->arch.switch_db_regs & KVM_DEBUGREG_WONT_EXIT)) - svm_set_dr6(svm, vcpu->arch.dr6); - else - svm_set_dr6(svm, DR6_ACTIVE_LOW); + if (unlikely(run_flags & KVM_RUN_LOAD_GUEST_DR6)) + svm_set_dr6(vcpu, vcpu->arch.dr6); + else if (likely(!(vcpu->arch.switch_db_regs & KVM_DEBUGREG_WONT_EXIT))) + svm_set_dr6(vcpu, DR6_ACTIVE_LOW); clgi(); kvm_load_guest_xsave_state(vcpu); + /* + * Hardware only context switches DEBUGCTL if LBR virtualization is + * enabled. Manually load DEBUGCTL if necessary (and restore it after + * VM-Exit), as running with the host's DEBUGCTL can negatively affect + * guest state and can even be fatal, e.g. due to Bus Lock Detect. + */ + if (!(svm->vmcb->control.virt_ext & LBR_CTL_ENABLE_MASK) && + vcpu->arch.host_debugctl != svm->vmcb->save.dbgctl) + update_debugctlmsr(svm->vmcb->save.dbgctl); + kvm_wait_lapic_expire(vcpu); /* @@ -4269,6 +4319,10 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu, if (unlikely(svm->vmcb->control.exit_code == SVM_EXIT_NMI)) kvm_before_interrupt(vcpu, KVM_HANDLING_NMI); + if (!(svm->vmcb->control.virt_ext & LBR_CTL_ENABLE_MASK) && + vcpu->arch.host_debugctl != svm->vmcb->save.dbgctl) + update_debugctlmsr(vcpu->arch.host_debugctl); + kvm_load_host_xsave_state(vcpu); stgi(); |