According to the APM, from the reference of the VMRUN instruction: Upon #VMEXIT, the processor performs the following actions in order to return to the host execution context: ... clear EVENTINJ field in VMCB KVM syncs EVENTINJ fields from vmcb02 to cached vmcb12 on every L2->L0 #VMEXIT. Since these fields are zeroed by the CPU on #VMEXIT, they will mostly be zeroed in vmcb12 on nested #VMEXIT by nested_svm_vmexit(). However, this is not the case when: 1. Consistency checks fail, as nested_svm_vmexit() is not called. 2. Entering guest mode fails before L2 runs (e.g. due to failed load of CR3). (2) was broken by commit 2d8a42be0e2b ("KVM: nSVM: synchronize VMCB controls updated by the processor on every vmexit"), as prior to that nested_svm_vmexit() always zeroed EVENTINJ fields. Explicitly clear the fields all nested #VMEXIT code paths. Fixes: 3d6368ef580a ("KVM: SVM: Add VMRUN handler") Fixes: 2d8a42be0e2b ("KVM: nSVM: synchronize VMCB controls updated by the processor on every vmexit") Cc: stable@vger.kernel.org Signed-off-by: Yosry Ahmed --- arch/x86/kvm/svm/nested.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index 04ccab887c5ec..f0ed352a3e901 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -1036,6 +1036,8 @@ int nested_svm_vmrun(struct kvm_vcpu *vcpu) vmcb12->control.exit_code = SVM_EXIT_ERR; vmcb12->control.exit_info_1 = 0; vmcb12->control.exit_info_2 = 0; + vmcb12->control.event_inj = 0; + vmcb12->control.event_inj_err = 0; svm_set_gif(svm, false); goto out; } @@ -1179,9 +1181,9 @@ static int nested_svm_vmexit_update_vmcb12(struct kvm_vcpu *vcpu) if (nested_vmcb12_has_lbrv(vcpu)) svm_copy_lbrs(&vmcb12->save, &vmcb02->save); + vmcb12->control.event_inj = 0; + vmcb12->control.event_inj_err = 0; vmcb12->control.int_ctl = svm->nested.ctl.int_ctl; - vmcb12->control.event_inj = svm->nested.ctl.event_inj; - vmcb12->control.event_inj_err = svm->nested.ctl.event_inj_err; trace_kvm_nested_vmexit_inject(vmcb12->control.exit_code, vmcb12->control.exit_info_1, -- 2.53.0.473.g4a7958ca14-goog