Patch "KVM: x86: fix user triggerable warning in kvm_apic_accept_events()" has been added to the 4.4-stable tree

[<gregkh@linuxfoundation.org>]

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@vger.kernel.org> know about it.


>From 28bf28887976d8881a3a59491896c718fade7355 Mon Sep 17 00:00:00 2001
From: David Hildenbrand <david@redhat.com>
Date: Thu, 23 Mar 2017 11:46:03 +0100
Subject: KVM: x86: fix user triggerable warning in kvm_apic_accept_events()
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Content-Type: text/plain; charset=UTF-8
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From: David Hildenbrand <david@redhat.com>

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@google.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 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@redhat.com are

queue-4.4/kvm-x86-fix-user-triggerable-warning-in-kvm_apic_accept_events.patch