From: Yosry Ahmed <yosry@kernel.org> stable inclusion from stable-v6.6.140 commit 1709418535a8df95532999d61b03d59975280258 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/15238 CVE: CVE-2026-45987 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit 03bee264f8ebfd39e0254c98e112d033a7aa9055 upstream. After VMRUN in guest mode, nested_sync_control_from_vmcb02() syncs fields written by the CPU from vmcb02 to the cached vmcb12. This is because the cached vmcb12 is used as the authoritative copy of some of the controls, and is the payload when saving/restoring nested state. int_state is also written by the CPU, specifically bit 0 (i.e. SVM_INTERRUPT_SHADOW_MASK) for nested VMs, but it is not sync'd to cached vmcb12. This does not cause a problem if KVM_SET_NESTED_STATE preceeds KVM_SET_VCPU_EVENTS in the restore path, as an interrupt shadow would be correctly restored to vmcb02 (KVM_SET_VCPU_EVENTS overwrites what KVM_SET_NESTED_STATE restored in int_state). However, if KVM_SET_VCPU_EVENTS preceeds KVM_SET_NESTED_STATE, an interrupt shadow would be restored into vmcb01 instead of vmcb02. This would mostly be benign for L1 (delays an interrupt), but not for L2. For L2, the vCPU could hang (e.g. if a wakeup interrupt is delivered before a HLT that should have been in an interrupt shadow). Sync int_state to the cached vmcb12 in nested_sync_control_from_vmcb02() to avoid this problem. With that, KVM_SET_NESTED_STATE restores the correct interrupt shadow state, and if KVM_SET_VCPU_EVENTS follows it would overwrite it with the same value. Fixes: cc440cdad5b7 ("KVM: nSVM: implement KVM_GET_NESTED_STATE and KVM_SET_NESTED_STATE") CC: stable@vger.kernel.org Signed-off-by: Yosry Ahmed <yosry@kernel.org> Link: https://patch.msgid.link/20260225005950.3739782-3-yosry@kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Zhang Kunbo <zhangkunbo@huawei.com> --- arch/x86/kvm/svm/nested.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c index 382ff1b18161..6dcd9b4cae29 100644 --- a/arch/x86/kvm/svm/nested.c +++ b/arch/x86/kvm/svm/nested.c @@ -307,6 +307,7 @@ void sync_nested_vmcb_control(struct vcpu_svm *svm) u32 mask; svm->nested.ctl.event_inj = svm->vmcb->control.event_inj; svm->nested.ctl.event_inj_err = svm->vmcb->control.event_inj_err; + svm->nested.ctl.int_state = svm->vmcb->control.int_state; /* Only a few fields of int_ctl are written by the processor. */ mask = V_IRQ_MASK | V_TPR_MASK; -- 2.34.1