Re: [PATCH v1 2/5] s390x/mmu: Implement ESOP-2 and access-exception-fetch/store-indication facility

[David Hildenbrand <david@redhat.com>]

On 26.09.19 12:16, 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.
> 
> We always have to indicate whether it is a fetch or a store for all access
> exceptions. This is only missing for LAP exceptions.
> 
> Signed-off-by: David Hildenbrand <david@redhat.com>
> ---
>  target/s390x/mmu_helper.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/target/s390x/mmu_helper.c b/target/s390x/mmu_helper.c
> index 54f54137ec..8abc5d31d8 100644
> --- a/target/s390x/mmu_helper.c
> +++ b/target/s390x/mmu_helper.c
> @@ -384,7 +384,9 @@ 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) {
> -                trigger_access_exception(env, PGM_PROTECTION, ILEN_AUTO, 0);
> +                /* LAP sets bit 56 */
> +                tec |= 0x80;
> +                trigger_access_exception(env, PGM_PROTECTION, ilen, tec);
>              }
>              return -EACCES;
>          }
> @@ -540,6 +542,10 @@ void s390_cpu_virt_mem_handle_exc(S390CPU *cpu, uintptr_t ra)
>  int mmu_translate_real(CPUS390XState *env, target_ulong raddr, int rw,
>                         target_ulong *addr, int *flags)
>  {
> +    /* Code accesses have an undefined ilc, let's use 2 bytes. */
> +    const int ilen = (rw == MMU_INST_FETCH) ? 2 : ILEN_AUTO;
> +    uint64_t tec = (raddr & TARGET_PAGE_MASK) |
> +                   (rw == MMU_DATA_STORE ? FS_WRITE : FS_READ);
>      const bool lowprot_enabled = env->cregs[0] & CR0_LOWPROT;
>  
>      *flags = PAGE_READ | PAGE_WRITE | PAGE_EXEC;
> @@ -547,7 +553,9 @@ 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) {
> -            trigger_access_exception(env, PGM_PROTECTION, ILEN_AUTO, 0);
> +            /* LAP sets bit 56 */
> +            tec |= 0x80;
> +            trigger_access_exception(env, PGM_PROTECTION, ilen, tec);

I'll drop the ilen change from this patch again as it is handled
properly when filling the TLB and Richard is about to rework that either
way.

-- 

Thanks,

David / dhildenb