Re: [Qemu-devel] [qemu-s390x] [PATCH-for-4.2 v1 6/9] s390x/mmu: Implement enhanced suppression-on-protection facility 2

[Thomas Huth <thuth@redhat.com>]

On 8/5/19 5:29 PM, David Hildenbrand wrote:
> We already implement ESOP-1. For ESOP-2, we only have to indicate all
> protection exceptions properly. Due to EDAT-1, we already indicate DAT
> exceptions properly. We don't trigger KCP/ALCP/IEP exceptions yet.
> 
> So all we have to do is set the TEID (TEC) to the right values
> (bit 56, 60, 61) in case of LAP.
> 
> We don't have any side-effects (e.g., no guarded-storage facility),
> therefore, bit 64 of the TEID (TEC) is always 0.
> 
> Signed-off-by: David Hildenbrand <david@redhat.com>
> ---
>  target/s390x/mmu_helper.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/target/s390x/mmu_helper.c b/target/s390x/mmu_helper.c
> index f3e988e4fd..631cc29c28 100644
> --- a/target/s390x/mmu_helper.c
> +++ b/target/s390x/mmu_helper.c
> @@ -333,6 +333,8 @@ int mmu_translate(CPUS390XState *env, target_ulong vaddr, int rw, uint64_t asc,
>          *flags |= PAGE_WRITE_INV;
>          if (is_low_address(vaddr) && rw == MMU_DATA_STORE) {
>              if (exc) {
> +                /* LAP sets bit 56 */
> +                tec |= 0x80;
>                  trigger_access_exception(env, PGM_PROTECTION, ilen, tec);
>              }
>              return -EACCES;
> @@ -520,6 +522,8 @@ int mmu_translate_real(CPUS390XState *env, target_ulong raddr, int rw,
>          /* see comment in mmu_translate() how this works */
>          *flags |= PAGE_WRITE_INV;
>          if (is_low_address(raddr) && rw == MMU_DATA_STORE) {
> +            /* LAP sets bit 56 */
> +            tec |= 0x80;
>              trigger_access_exception(env, PGM_PROTECTION, ILEN_AUTO, tec);
>              return -EACCES;
>          }

I'd suggest to merge this with the previous patch since the other bits
are only valid if bit 56 is enabled.

 Thomas