[3.8.y.z,extended,stable] Patch "KVM: VMX: fix halt emulation while emulating invalid guest sate" has been added to staging queue

Submitted by Kamal Mostafa on May 22, 2013, 9:55 p.m.


Message ID 1369259726-25132-1-git-send-email-kamal@canonical.com
State New
Headers show

Commit Message

Kamal Mostafa May 22, 2013, 9:55 p.m.
This is a note to let you know that I have just added a patch titled

    KVM: VMX: fix halt emulation while emulating invalid guest sate

to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree 
which can be found at:


If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.8.y.z tree, see



From ea89e81bf579685a95fe16717ed9fec0e5457f34 Mon Sep 17 00:00:00 2001
From: Gleb Natapov <gleb@redhat.com>
Date: Wed, 8 May 2013 18:38:44 +0300
Subject: KVM: VMX: fix halt emulation while emulating invalid guest sate

commit 8d76c49e9ffeee839bc0b7a3278a23f99101263e upstream.

The invalid guest state emulation loop does not check halt_request
which causes 100% cpu loop while guest is in halt and in invalid
state, but more serious issue is that this leaves halt_request set, so
random instruction emulated by vm86 #GP exit can be interpreted
as halt which causes guest hang. Fix both problems by handling
halt_request in emulation loop.

Reported-by: Tomas Papan <tomas.papan@gmail.com>
Tested-by: Tomas Papan <tomas.papan@gmail.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
 arch/x86/kvm/vmx.c | 6 ++++++
 1 file changed, 6 insertions(+)


Patch hide | download patch | download mbox

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 9120ae1..1b29ec6 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -5059,6 +5059,12 @@  static int handle_invalid_guest_state(struct kvm_vcpu *vcpu)
 			return 0;

+		if (vcpu->arch.halt_request) {
+			vcpu->arch.halt_request = 0;
+			ret = kvm_emulate_halt(vcpu);
+			goto out;
+		}
 		if (signal_pending(current))
 			goto out;
 		if (need_resched())