From 97413d2981bb3619a9d39f0b611318664d7231f5 Mon Sep 17 00:00:00 2001 From: Vitaly Kuznetsov Date: Tue, 13 Aug 2019 15:53:31 +0200 Subject: [PATCH] x86: KVM: clear interrupt shadow on EMULTYPE_SKIP When doing x86_emulate_instruction(EMULTYPE_SKIP) interrupt shadow has to be cleared if and only if the skipping is successful. There are two immediate issues: - In SVM skip_emulated_instruction() we are not zapping interrupt shadow in case kvm_emulate_instruction(EMULTYPE_SKIP) is used to advance RIP (!nrpip_save). - In VMX handle_ept_misconfig() when running as a nested hypervisor we (static_cpu_has(X86_FEATURE_HYPERVISOR) case) forget to clear interrupt shadow. Note that we intentionally don't handle the case when the skipped instruction is supposed to prolong the interrupt shadow ("MOV/POP SS") as skip-emulation of those instructions should not happen under normal circumstances. Suggested-by: Sean Christopherson Reviewed-by: Sean Christopherson Signed-off-by: Vitaly Kuznetsov Signed-off-by: Paolo Bonzini --- arch/x86/kvm/x86.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 73825ab..90a895d 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -6546,6 +6546,7 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu, kvm_rip_write(vcpu, ctxt->_eip); if (ctxt->eflags & X86_EFLAGS_RF) kvm_set_rflags(vcpu, ctxt->eflags & ~X86_EFLAGS_RF); + kvm_x86_ops->set_interrupt_shadow(vcpu, 0); return EMULATE_DONE; } -- 2.7.4