From: Gleb Natapov <gleb@redhat.com>
Date: Wed, 8 May 2013 15:38:44 +0000 (+0300)
Subject: KVM: VMX: fix halt emulation while emulating invalid guest sate
X-Git-Tag: v3.9.3~101
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=f7f76899aa82aae0441f451711f3adff1df580dd;p=people%2Fms%2Flinux.git

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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 6667042714cc..0af18077012e 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -5197,6 +5197,12 @@ 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())