Re: [Qemu-devel] [PATCH-for-4.2 v1 2/6] s390x/tcg: Rework MMU selection for instruction fetches

[David Hildenbrand <david@redhat.com>]

On 12.08.19 13:27, David Hildenbrand wrote:
> Instructions are always fetched from primary address space, except when
> in home address mode. Perform the selection directly in cpu_mmu_index().
> 
> get_mem_index() is only used to perform data access, instructions are
> fetched via cpu_lduw_code(), which translates to cpu_mmu_index(env, true).
> 
> We don't care about restricting the access permissions of the TLB
> entries anymore, as we no longer enter PRIMARY entries into the
> SECONDARY MMU. Cleanup related code a bit.
> 
> Signed-off-by: David Hildenbrand <david@redhat.com>
> ---
>  target/s390x/cpu.h        |  7 +++++++
>  target/s390x/mmu_helper.c | 35 ++++++++++++++---------------------
>  2 files changed, 21 insertions(+), 21 deletions(-)
> 
> diff --git a/target/s390x/cpu.h b/target/s390x/cpu.h
> index a606547b4d..c34992bb2e 100644
> --- a/target/s390x/cpu.h
> +++ b/target/s390x/cpu.h
> @@ -332,6 +332,13 @@ static inline int cpu_mmu_index(CPUS390XState *env, bool ifetch)
>          return MMU_REAL_IDX;
>      }
>  
> +    if (ifetch) {
> +        if ((env->psw.mask & PSW_MASK_ASC) == PSW_ASC_HOME) {
> +            return MMU_HOME_IDX;
> +        }
> +        return MMU_PRIMARY_IDX;
> +    }
> +
>      switch (env->psw.mask & PSW_MASK_ASC) {
>      case PSW_ASC_PRIMARY:
>          return MMU_PRIMARY_IDX;
> diff --git a/target/s390x/mmu_helper.c b/target/s390x/mmu_helper.c
> index 6e9c4d6151..2c9bb3acc0 100644
> --- a/target/s390x/mmu_helper.c
> +++ b/target/s390x/mmu_helper.c
> @@ -349,6 +349,7 @@ int mmu_translate(CPUS390XState *env, target_ulong vaddr, int rw, uint64_t asc,
>  {
>      static S390SKeysState *ss;
>      static S390SKeysClass *skeyclass;
> +    uint64_t asce;
>      int r = -1;

I can now stop initializing r.

>      uint8_t key;
>  
> @@ -381,35 +382,21 @@ int mmu_translate(CPUS390XState *env, target_ulong vaddr, int rw, uint64_t asc,
>      if (!(env->psw.mask & PSW_MASK_DAT)) {
>          *raddr = vaddr;
>          r = 0;

and this can go as well.

> -        goto out;
> +        goto nodat;
>      }
>  


-- 

Thanks,

David / dhildenb