diff mbox

KVM: VMX: Do not skip the instruction if handle_dr injects a fault

Message ID 52B1E678.6060609@siemens.com (mailing list archive)
State New, archived
Headers show

Commit Message

Jan Kiszka Dec. 18, 2013, 6:16 p.m. UTC
If kvm_get_dr or kvm_set_dr reports that it raised a fault, we must not
advance the instruction pointer. Otherwise the exception will hit the
wrong instruction.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
---
 arch/x86/kvm/vmx.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

Comments

Paolo Bonzini Dec. 20, 2013, 6:20 p.m. UTC | #1
Il 18/12/2013 19:16, Jan Kiszka ha scritto:
> If kvm_get_dr or kvm_set_dr reports that it raised a fault, we must not
> advance the instruction pointer. Otherwise the exception will hit the
> wrong instruction.
> 
> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
> ---
>  arch/x86/kvm/vmx.c | 10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index 56c654c..ee3bf54 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -5141,10 +5141,14 @@ static int handle_dr(struct kvm_vcpu *vcpu)
>  	reg = DEBUG_REG_ACCESS_REG(exit_qualification);
>  	if (exit_qualification & TYPE_MOV_FROM_DR) {
>  		unsigned long val;
> -		if (!kvm_get_dr(vcpu, dr, &val))
> -			kvm_register_write(vcpu, reg, val);
> +
> +		if (kvm_get_dr(vcpu, dr, &val))
> +			return 1;
> +		kvm_register_write(vcpu, reg, val);
>  	} else
> -		kvm_set_dr(vcpu, dr, vcpu->arch.regs[reg]);
> +		if (kvm_set_dr(vcpu, dr, vcpu->arch.regs[reg]))
> +			return 1;
> +
>  	skip_emulated_instruction(vcpu);
>  	return 1;
>  }
> 

Applied to kvm/queue, thanks.

Paolo
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diff mbox

Patch

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 56c654c..ee3bf54 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -5141,10 +5141,14 @@  static int handle_dr(struct kvm_vcpu *vcpu)
 	reg = DEBUG_REG_ACCESS_REG(exit_qualification);
 	if (exit_qualification & TYPE_MOV_FROM_DR) {
 		unsigned long val;
-		if (!kvm_get_dr(vcpu, dr, &val))
-			kvm_register_write(vcpu, reg, val);
+
+		if (kvm_get_dr(vcpu, dr, &val))
+			return 1;
+		kvm_register_write(vcpu, reg, val);
 	} else
-		kvm_set_dr(vcpu, dr, vcpu->arch.regs[reg]);
+		if (kvm_set_dr(vcpu, dr, vcpu->arch.regs[reg]))
+			return 1;
+
 	skip_emulated_instruction(vcpu);
 	return 1;
 }