Re: [PATCH v2 2/7] s390x/mmu: Move DAT protection handling out of mmu_translate_asce()

[Thomas Huth <thuth@redhat.com>]

On 25/09/2019 14.52, David Hildenbrand wrote:
> We'll reuse the ilen and tec definitions in mmu_translate
> soon also for all other DAT exceptions we inject. Move it to the caller,
> where we can later pair it up with other protection checks, like IEP.
> 
> Signed-off-by: David Hildenbrand <david@redhat.com>
> ---
>  target/s390x/mmu_helper.c | 39 ++++++++++++++++-----------------------
>  1 file changed, 16 insertions(+), 23 deletions(-)
> 
> diff --git a/target/s390x/mmu_helper.c b/target/s390x/mmu_helper.c
> index 6a7ad33c4d..847fb240fb 100644
> --- a/target/s390x/mmu_helper.c
> +++ b/target/s390x/mmu_helper.c
> @@ -48,20 +48,6 @@ static void trigger_access_exception(CPUS390XState *env, uint32_t type,
>      }
>  }
>  
> -static void trigger_prot_fault(CPUS390XState *env, target_ulong vaddr,
> -                               uint64_t asc, int rw, bool exc)
> -{
> -    uint64_t tec;
> -
> -    tec = vaddr | (rw == MMU_DATA_STORE ? FS_WRITE : FS_READ) | 4 | asc >> 46;
> -
> -    if (!exc) {
> -        return;
> -    }
> -
> -    trigger_access_exception(env, PGM_PROTECTION, ILEN_AUTO, tec);
> -}
> -
>  static void trigger_page_fault(CPUS390XState *env, target_ulong vaddr,
>                                 uint32_t type, uint64_t asc, int rw, bool exc)
>  {
> @@ -229,7 +215,6 @@ static int mmu_translate_asce(CPUS390XState *env, target_ulong vaddr,
>                                int *flags, int rw, bool exc)
>  {
>      int level;
> -    int r;
>  
>      if (asce & ASCE_REAL_SPACE) {
>          /* direct mapping */
> @@ -277,14 +262,8 @@ static int mmu_translate_asce(CPUS390XState *env, target_ulong vaddr,
>          break;
>      }
>  
> -    r = mmu_translate_region(env, vaddr, asc, asce, level, raddr, flags, rw,
> -                             exc);
> -    if (!r && rw == MMU_DATA_STORE && !(*flags & PAGE_WRITE)) {
> -        trigger_prot_fault(env, vaddr, asc, rw, exc);
> -        return -1;
> -    }
> -
> -    return r;
> +    return mmu_translate_region(env, vaddr, asc, asce, level, raddr, flags, rw,
> +                                exc);
>  }
>  
>  static void mmu_handle_skey(target_ulong addr, int rw, int *flags)
> @@ -369,6 +348,10 @@ static void mmu_handle_skey(target_ulong addr, int rw, int *flags)
>  int mmu_translate(CPUS390XState *env, target_ulong vaddr, int rw, uint64_t asc,
>                    target_ulong *raddr, int *flags, bool exc)
>  {
> +    /* Code accesses have an undefined ilc, let's use 2 bytes. */
> +    const int ilen = (rw == MMU_INST_FETCH) ? 2 : ILEN_AUTO;
> +    uint64_t tec = (vaddr & TARGET_PAGE_MASK) | (asc >> 46) |
> +                   (rw == MMU_DATA_STORE ? FS_WRITE : FS_READ);
>      uint64_t asce;
>      int r;
>  
> @@ -421,6 +404,16 @@ int mmu_translate(CPUS390XState *env, target_ulong vaddr, int rw, uint64_t asc,
>          return r;
>      }
>  
> +    /* check for DAT protection */
> +    if (unlikely(rw == MMU_DATA_STORE && !(*flags & PAGE_WRITE))) {
> +        if (exc) {
> +            /* DAT sets bit 61 only */
> +            tec |= 0x4;
> +            trigger_access_exception(env, PGM_PROTECTION, ilen, tec);
> +        }
> +        return -1;
> +    }
> +
>  nodat:
>      /* Convert real address -> absolute address */
>      *raddr = mmu_real2abs(env, *raddr);
> 

Reviewed-by: Thomas Huth <thuth@redhat.com>