From 78f2145c4d937a4770f365d6f5dc6eb825658d10 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Wed, 4 Mar 2020 17:05:44 -0500 Subject: [PATCH] KVM: nSVM: avoid loss of pending IRQ/NMI before entering L2 This patch reproduces for nSVM the change that was made for nVMX in commit b5861e5cf2fc ("KVM: nVMX: Fix loss of pending IRQ/NMI before entering L2"). While I do not have a test that breaks without it, I cannot see why it would not be necessary since all events are unblocked by VMRUN's setting of GIF back to 1. Signed-off-by: Paolo Bonzini --- arch/x86/kvm/svm.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 80f15a2483f4..c923ad1d7321 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -3576,6 +3576,10 @@ static bool nested_vmcb_checks(struct vmcb *vmcb) static void enter_svm_guest_mode(struct vcpu_svm *svm, u64 vmcb_gpa, struct vmcb *nested_vmcb, struct kvm_host_map *map) { + bool evaluate_pending_interrupts = + is_intercept(svm, INTERCEPT_VINTR) || + is_intercept(svm, INTERCEPT_IRET); + if (kvm_get_rflags(&svm->vcpu) & X86_EFLAGS_IF) svm->vcpu.arch.hflags |= HF_HIF_MASK; else @@ -3662,7 +3666,21 @@ static void enter_svm_guest_mode(struct vcpu_svm *svm, u64 vmcb_gpa, svm->nested.vmcb = vmcb_gpa; + /* + * If L1 had a pending IRQ/NMI before executing VMRUN, + * which wasn't delivered because it was disallowed (e.g. + * interrupts disabled), L0 needs to evaluate if this pending + * event should cause an exit from L2 to L1 or be delivered + * directly to L2. + * + * Usually this would be handled by the processor noticing an + * IRQ/NMI window request. However, VMRUN can unblock interrupts + * by implicitly setting GIF, so force L0 to perform pending event + * evaluation by requesting a KVM_REQ_EVENT. + */ enable_gif(svm); + if (unlikely(evaluate_pending_interrupts)) + kvm_make_request(KVM_REQ_EVENT, &svm->vcpu); mark_all_dirty(svm->vmcb); } -- 2.11.0