This is a note to let you know that I've just added the patch titled KVM: x86: fix user triggerable warning in kvm_apic_accept_events() to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: kvm-x86-fix-user-triggerable-warning-in-kvm_apic_accept_events.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 28bf28887976d8881a3a59491896c718fade7355 Mon Sep 17 00:00:00 2001 From: David Hildenbrand <david@xxxxxxxxxx> Date: Thu, 23 Mar 2017 11:46:03 +0100 Subject: KVM: x86: fix user triggerable warning in kvm_apic_accept_events() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: David Hildenbrand <david@xxxxxxxxxx> commit 28bf28887976d8881a3a59491896c718fade7355 upstream. If we already entered/are about to enter SMM, don't allow switching to INIT/SIPI_RECEIVED, otherwise the next call to kvm_apic_accept_events() will report a warning. Same applies if we are already in MP state INIT_RECEIVED and SMM is requested to be turned on. Refuse to set the VCPU events in this case. Fixes: cd7764fe9f73 ("KVM: x86: latch INITs while in system management mode") Reported-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx> Signed-off-by: David Hildenbrand <david@xxxxxxxxxx> Signed-off-by: Radim Krčmář <rkrcmar@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/x86/kvm/x86.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -2960,6 +2960,12 @@ static int kvm_vcpu_ioctl_x86_set_vcpu_e | KVM_VCPUEVENT_VALID_SMM)) return -EINVAL; + /* INITs are latched while in SMM */ + if (events->flags & KVM_VCPUEVENT_VALID_SMM && + (events->smi.smm || events->smi.pending) && + vcpu->arch.mp_state == KVM_MP_STATE_INIT_RECEIVED) + return -EINVAL; + process_nmi(vcpu); vcpu->arch.exception.pending = events->exception.injected; vcpu->arch.exception.nr = events->exception.nr; @@ -6993,6 +6999,12 @@ int kvm_arch_vcpu_ioctl_set_mpstate(stru mp_state->mp_state != KVM_MP_STATE_RUNNABLE) return -EINVAL; + /* INITs are latched while in SMM */ + if ((is_smm(vcpu) || vcpu->arch.smi_pending) && + (mp_state->mp_state == KVM_MP_STATE_SIPI_RECEIVED || + mp_state->mp_state == KVM_MP_STATE_INIT_RECEIVED)) + return -EINVAL; + if (mp_state->mp_state == KVM_MP_STATE_SIPI_RECEIVED) { vcpu->arch.mp_state = KVM_MP_STATE_INIT_RECEIVED; set_bit(KVM_APIC_SIPI, &vcpu->arch.apic->pending_events); Patches currently in stable-queue which might be from david@xxxxxxxxxx are queue-4.4/kvm-x86-fix-user-triggerable-warning-in-kvm_apic_accept_events.patch