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From: Jan Kiszka <jan.kiszka@web.de>
To: Paolo Bonzini <pbonzini@redhat.com>,
	Gleb Natapov <gleb@kernel.org>,
	Marcelo Tosatti <mtosatti@redhat.com>
Cc: kvm <kvm@vger.kernel.org>
Subject: [PATCH 03/12] KVM: VMX: Fix DR6 update on #DB exception
Date: Sat,  4 Jan 2014 18:47:17 +0100	[thread overview]
Message-ID: <b3f12dbcd55e805595b668da8996ab307b090e23.1388857646.git.jan.kiszka@web.de> (raw)
In-Reply-To: <cover.1388857646.git.jan.kiszka@web.de>
In-Reply-To: <cover.1388857646.git.jan.kiszka@web.de>

From: Jan Kiszka <jan.kiszka@siemens.com>

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>
---
 arch/x86/kvm/vmx.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 55cb4b6..2a95ce0 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -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;
 		}
-- 
1.8.1.1.298.ge7eed54


  parent reply	other threads:[~2014-01-04 17:47 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-01-04 17:47 [PATCH 00/12] KVM: x86: Fixes for debug registers, IA32_APIC_BASE, and nVMX Jan Kiszka
2014-01-04 17:47 ` [PATCH 01/12] KVM: x86: Sync DR7 on KVM_SET_DEBUGREGS Jan Kiszka
2014-01-04 17:47 ` [PATCH 02/12] KVM: SVM: Fix reading of DR6 Jan Kiszka
2014-01-04 17:47 ` Jan Kiszka [this message]
2014-01-04 17:47 ` [PATCH 04/12] KVM: x86: Validate guest writes to MSR_IA32_APICBASE Jan Kiszka
2014-01-16 14:07   ` Paolo Bonzini
2014-01-16 14:19     ` Jan Kiszka
2014-01-04 17:47 ` [PATCH 05/12] KVM: nVMX: Leave VMX mode on clearing of feature control MSR Jan Kiszka
2014-01-04 17:47 ` [PATCH 06/12] KVM: nVMX: Pass vmexit parameters to nested_vmx_vmexit Jan Kiszka
2014-01-04 17:47 ` [PATCH 07/12] KVM: nVMX: Add tracepoints for nested_vmexit and nested_vmexit_inject Jan Kiszka
2014-01-04 17:47 ` [PATCH 08/12] KVM: nVMX: Clean up handling of VMX-related MSRs Jan Kiszka
2014-01-04 17:47 ` [PATCH 09/12] KVM: nVMX: Fix nested_run_pending on activity state HLT Jan Kiszka
2014-01-04 17:47 ` [PATCH 10/12] KVM: nVMX: Update guest activity state field on L2 exits Jan Kiszka
2014-01-05 20:01   ` Paolo Bonzini
2014-01-05 20:16     ` Jan Kiszka
2014-01-04 17:47 ` [PATCH 11/12] KVM: nVMX: Rework interception of IRQs and NMIs Jan Kiszka
2014-01-16 15:08   ` Paolo Bonzini
2014-01-04 17:47 ` [PATCH 12/12] KVM: nVMX: Fully emulate preemption timer Jan Kiszka
2014-01-16 15:08 ` [PATCH 00/12] KVM: x86: Fixes for debug registers, IA32_APIC_BASE, and nVMX Paolo Bonzini
2014-01-16 15:12   ` Jan Kiszka
2014-01-16 15:20     ` Paolo Bonzini
2014-01-16 15:38       ` Jan Kiszka
2014-01-21 15:32   ` Jan Kiszka

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