KVM: nVMX: Fix switching of debug state

PATCH Applied Jan Kiszka 2 participants 2 messages Mar 3, 2013 – Mar 5, 2013

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x86 KVM KVM x86

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Jan Kiszka

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2013-03-03 12:05 UTC #0 lore raw

PATCH 1/1 KVM: nVMX: Fix switching of debug state

From: Jan Kiszka <[email protected]>

First of all, do not blindly overwrite GUEST_DR7 on L2 entry. The host may have guest debugging enabled. Then properly reset DR7 and DEBUG_CTL on L2->L1 switch as specified in the SDM.

Signed-off-by Jan Kiszka <[email protected]>

---
 arch/x86/kvm/vmx.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

arch/x86/kvm/vmx.c +4 -1

index c204f0d..486078d 100644
@@ -6971,7 +6971,7 @@ static void prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12)
 		vmcs12->guest_interruptibility_info);
 	vmcs_write32(GUEST_ACTIVITY_STATE, vmcs12->guest_activity_state);
 	vmcs_write32(GUEST_SYSENTER_CS, vmcs12->guest_sysenter_cs);
-	vmcs_writel(GUEST_DR7, vmcs12->guest_dr7);
+	kvm_set_dr(vcpu, 7, vmcs12->guest_dr7);
 	vmcs_writel(GUEST_RFLAGS, vmcs12->guest_rflags);
 	vmcs_writel(GUEST_PENDING_DBG_EXCEPTIONS,
 		vmcs12->guest_pending_dbg_exceptions);

@@ -7512,6 +7512,9 @@ static void load_vmcs12_host_state(struct kvm_vcpu *vcpu,
 	if (vmcs12->vm_exit_controls & VM_EXIT_LOAD_IA32_PERF_GLOBAL_CTRL)
 		vmcs_write64(GUEST_IA32_PERF_GLOBAL_CTRL,
 			vmcs12->host_ia32_perf_global_ctrl);
+
+	kvm_set_dr(vcpu, 7, 0x400);
+	vmcs_write64(GUEST_IA32_DEBUGCTL, 0);
 }
 
 /*

Signature · 1 line

1.7.3.4

Marcelo Tosatti

Applied

2013-03-05 00:45 UTC #1 lore raw

Quoted 10 lines · Jan Kiszka

From: Jan Kiszka <[email protected]>
First of all, do not blindly overwrite GUEST_DR7 on L2 entry. The host may have guest debugging enabled. Then properly reset DR7 and DEBUG_CTL on L2->L1 switch as specified in the SDM.
Signed-off-by Jan Kiszka <[email protected]>
---
 arch/x86/kvm/vmx.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

Applied, thanks.