Re: [PATCH 1/2] s390x: pv: Remove sclp boundary checks

[Halil Pasic <pasic@linux.ibm.com>]

On Wed, 21 Oct 2020 09:43:44 -0400
Janosch Frank <frankja@linux.ibm.com> wrote:

> The SCLP boundary cross check is done by the Ultravisor for a
> protected guest, hence we don't need to do it. As QEMU doesn't get a
> valid SCCB address in protected mode this is even problematic and can
> lead to QEMU reporting a false boundary cross error.
> 
> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
> Reported-by: Marc Hartmayer <mhartmay@linux.ibm.com>
> Fixes: db13387ca0 ("s390/sclp: rework sclp boundary checks")
> Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
> Tested-by: Marc Hartmayer <mhartmay@linux.ibm.com>

Acked-by: Halil Pasic <pasic@linux.ibm.com>

> ---
>  hw/s390x/sclp.c | 5 -----
>  1 file changed, 5 deletions(-)
> 
> diff --git a/hw/s390x/sclp.c b/hw/s390x/sclp.c
> index 00f1e4648d..0cf2290826 100644
> --- a/hw/s390x/sclp.c
> +++ b/hw/s390x/sclp.c
> @@ -285,11 +285,6 @@ int sclp_service_call_protected(CPUS390XState *env, uint64_t sccb,
>          goto out_write;
>      }
>  
> -    if (!sccb_verify_boundary(sccb, be16_to_cpu(work_sccb->h.length), code)) {
> -        work_sccb->h.response_code = cpu_to_be16(SCLP_RC_SCCB_BOUNDARY_VIOLATION);
> -        goto out_write;
> -    }
> -
>      sclp_c->execute(sclp, work_sccb, code);
>  out_write:
>      s390_cpu_pv_mem_write(env_archcpu(env), 0, work_sccb,