From: Nadav Amit <namit@cs.technion.ac.il>
Date: Sun, 2 Nov 2014 09:54:44 +0000 (+0200)
Subject: KVM: x86: Clear DR6[0:3] on #DB during handle_dr
X-Git-Tag: v6.6-pxa1908~22013^2~85
X-Git-Url: https://git.dujemihanovic.xyz/?a=commitdiff_plain;h=7305eb5d8cf147ce4178e723c95de15e2f001429;p=linux.git

KVM: x86: Clear DR6[0:3] on #DB during handle_dr

DR6[0:3] (previous breakpoint indications) are cleared when #DB is injected
during handle_exception, just as real hardware does.  Similarily, handle_dr
should clear DR6[0:3].

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index f9d56c1945de..ad5e0806e1e1 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -5125,6 +5125,7 @@ static int handle_dr(struct kvm_vcpu *vcpu)
 			vcpu->run->exit_reason = KVM_EXIT_DEBUG;
 			return 0;
 		} else {
+			vcpu->arch.dr6 &= ~15;
 			vcpu->arch.dr6 |= DR6_BD | DR6_RTM;
 			kvm_queue_exception(vcpu, DB_VECTOR);
 			return 1;