From: Yosry Ahmed Date: Tue, 3 Mar 2026 00:34:05 +0000 (+0000) Subject: KVM: nSVM: Clear EVENTINJ fields in vmcb12 on nested #VMEXIT X-Git-Tag: v7.1-rc1~118^2~4^2~43 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=69b721a86d0dcb026f6db7d111dcde7550442d2e;p=thirdparty%2Fkernel%2Flinux.git KVM: nSVM: Clear EVENTINJ fields in vmcb12 on nested #VMEXIT 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 already 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 in 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 Link: https://patch.msgid.link/20260303003421.2185681-12-yosry@kernel.org [sean: massage changelog formatting] Signed-off-by: Sean Christopherson --- diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index ac7d7f82c82bd..90c8bc641bf32 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -1035,6 +1035,8 @@ 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; } @@ -1178,9 +1180,9 @@ 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,