Re: [Qemu-devel] [PATCH RFC v2 7/9] s390x/pci: fence off instructions for non-pci

[Thomas Huth]

On 18.07.2017 16:24, Cornelia Huck wrote:
> If a guest running on a machine without zpci issues a pci instruction,
> throw them an exception.
> 
> Signed-off-by: Cornelia Huck <address@hidden>
> ---
>  target/s390x/kvm.c | 54 
> +++++++++++++++++++++++++++++++++++++++++-------------
>  1 file changed, 41 insertions(+), 13 deletions(-)
[...]
>  static int kvm_mpcifc_service_call(S390CPU *cpu, struct kvm_run *run)
> @@ -1269,10 +1293,14 @@ static int kvm_mpcifc_service_call(S390CPU *cpu, 
> struct kvm_run *run)
>      uint64_t fiba;
>      uint8_t ar;
>  
> -    cpu_synchronize_state(CPU(cpu));
> -    fiba = get_base_disp_rxy(cpu, run, &ar);
> +    if (s390_has_feat(S390_FEAT_ZPCI)) {
> +        cpu_synchronize_state(CPU(cpu));
> +        fiba = get_base_disp_rxy(cpu, run, &ar);
>  
> -    return mpcifc_service_call(cpu, r1, fiba, ar);
> +        return mpcifc_service_call(cpu, r1, fiba, ar);
> +    } else {
> +        return -1;
> +    }
>  }

I think I'd rather write these cases with early exits à la

    if (!s390_has_feat(S390_FEAT_ZPCI)) {
        return -1;
    }

so you could get along with less change and less indentation ... but
since this is rather a matter of taste, anyway:

Reviewed-by: Thomas Huth <address@hidden>