Re: [PATCH] KVM: VMX: Do not skip the instruction if handle_dr injects a fault

[Paolo Bonzini <pbonzini@redhat.com>]

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