Commit 8246bf52 authored Jan 04, 2014 by Jan Kiszka Committed by Paolo Bonzini Jan 17, 2014

KVM: VMX: Fix DR6 update on #DB exception

According to the SDM, only bits 0-3 of DR6 "may" be cleared by "certain"
debug exception. So do update them on #DB exception in KVM, but leave
the rest alone, only setting BD and BS in addition to already set bits
in DR6. This also aligns us with kvm_vcpu_check_singlestep.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

parent 73aaf249

arch/x86/kvm/vmx.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -4869,7 +4869,8 @@ static int handle_exception(struct kvm_vcpu *vcpu)
		dr6 = vmcs_readl(EXIT_QUALIFICATION);
		if (!(vcpu->guest_debug &
		(KVM_GUESTDBG_SINGLESTEP \| KVM_GUESTDBG_USE_HW_BP))) {
		vcpu->arch.dr6 = dr6 \| DR6_FIXED_1;
		vcpu->arch.dr6 &= ~15;
		vcpu->arch.dr6 \|= dr6;
		kvm_queue_exception(vcpu, DB_VECTOR);
		return 1;
		}