From 8d1cd5e00a27d2225d5454d5c00901ce020a57c5 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Mon, 2 May 2022 00:07:30 +0200 Subject: [PATCH] KVM: SVM: Re-inject INTn instead of retrying the insn on "failure" Re-inject INTn software interrupts instead of retrying the instruction if the CPU encountered an intercepted exception while vectoring the INTn, e.g. if KVM intercepted a #PF when utilizing shadow paging. Retrying the instruction is architecturally wrong e.g. will result in a spurious #DB if there's a code breakpoint on the INT3/O, and lack of re-injection also breaks nested virtualization, e.g. if L1 injects a software interrupt and vectoring the injected interrupt encounters an exception that is intercepted by L0 but not L1. Signed-off-by: Sean Christopherson Signed-off-by: Maciej S. Szmigiero Message-Id: <1654ad502f860948e4f2d57b8bd881d67301f785.1651440202.git.maciej.szmigiero@oracle.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/svm/nested.c | 7 +++---- arch/x86/kvm/svm/svm.c | 23 +++++++++++++++++++---- 2 files changed, 22 insertions(+), 8 deletions(-) diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index 525117a49c180..0d25dea407965 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -617,10 +617,9 @@ static inline bool is_evtinj_soft(u32 evtinj) if (!(evtinj & SVM_EVTINJ_VALID)) return false; - /* - * Intentionally return false for SOFT events, SVM doesn't yet support - * re-injecting soft interrupts. - */ + if (type == SVM_EVTINJ_TYPE_SOFT) + return true; + return type == SVM_EVTINJ_TYPE_EXEPT && kvm_exception_is_soft(vector); } diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index ec37647ca0685..6248967d4a77c 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -3438,12 +3438,22 @@ static void svm_inject_nmi(struct kvm_vcpu *vcpu) static void svm_inject_irq(struct kvm_vcpu *vcpu) { struct vcpu_svm *svm = to_svm(vcpu); + u32 type; + + if (vcpu->arch.interrupt.soft) { + if (svm_update_soft_interrupt_rip(vcpu)) + return; + + type = SVM_EVTINJ_TYPE_SOFT; + } else { + type = SVM_EVTINJ_TYPE_INTR; + } trace_kvm_inj_virq(vcpu->arch.interrupt.nr); ++vcpu->stat.irq_injections; svm->vmcb->control.event_inj = vcpu->arch.interrupt.nr | - SVM_EVTINJ_VALID | SVM_EVTINJ_TYPE_INTR; + SVM_EVTINJ_VALID | type; } void svm_complete_interrupt_delivery(struct kvm_vcpu *vcpu, int delivery_mode, @@ -3723,6 +3733,8 @@ static inline void sync_lapic_to_cr8(struct kvm_vcpu *vcpu) static void svm_complete_soft_interrupt(struct kvm_vcpu *vcpu, u8 vector, int type) { + bool is_exception = (type == SVM_EXITINTINFO_TYPE_EXEPT); + bool is_soft = (type == SVM_EXITINTINFO_TYPE_SOFT); struct vcpu_svm *svm = to_svm(vcpu); /* @@ -3734,8 +3746,7 @@ static void svm_complete_soft_interrupt(struct kvm_vcpu *vcpu, u8 vector, * the same event, i.e. if the event is a soft exception/interrupt, * otherwise next_rip is unused on VMRUN. */ - if (nrips && type == SVM_EXITINTINFO_TYPE_EXEPT && - kvm_exception_is_soft(vector) && + if (nrips && (is_soft || (is_exception && kvm_exception_is_soft(vector))) && kvm_is_linear_rip(vcpu, svm->soft_int_old_rip + svm->soft_int_csbase)) svm->vmcb->control.next_rip = svm->soft_int_next_rip; /* @@ -3746,7 +3757,7 @@ static void svm_complete_soft_interrupt(struct kvm_vcpu *vcpu, u8 vector, * hit a #NP in the guest, and the #NP encountered a #PF, the #NP will * be the reported vectored event, but RIP still needs to be unwound. */ - else if (!nrips && type == SVM_EXITINTINFO_TYPE_EXEPT && + else if (!nrips && (is_soft || is_exception) && kvm_is_linear_rip(vcpu, svm->soft_int_next_rip + svm->soft_int_csbase)) kvm_rip_write(vcpu, svm->soft_int_old_rip); } @@ -3808,9 +3819,13 @@ static void svm_complete_interrupts(struct kvm_vcpu *vcpu) case SVM_EXITINTINFO_TYPE_INTR: kvm_queue_interrupt(vcpu, vector, false); break; + case SVM_EXITINTINFO_TYPE_SOFT: + kvm_queue_interrupt(vcpu, vector, true); + break; default: break; } + } static void svm_cancel_injection(struct kvm_vcpu *vcpu) -- 2.39.5