Re: [Qemu-devel] [RFC v7 03/16] softmmu: Simplify helper_*_st_name, wrap MMIO code

["Alex Bennée" <alex.bennee@linaro.org>]

Alvise Rigo <a.rigo@virtualopensystems.com> writes:

> Attempting to simplify the helper_*_st_name, wrap the MMIO code into an
> inline function.
>
> Based on this work, Alex proposed the following patch series
> https://lists.gnu.org/archive/html/qemu-devel/2016-01/msg01136.html
> that reduces code duplication of the softmmu_helpers.
>
> Suggested-by: Jani Kokkonen <jani.kokkonen@huawei.com>
> Suggested-by: Claudio Fontana <claudio.fontana@huawei.com>
> Signed-off-by: Alvise Rigo <a.rigo@virtualopensystems.com>
> ---
>  softmmu_template.h | 66 ++++++++++++++++++++++++++++++++++++------------------
>  1 file changed, 44 insertions(+), 22 deletions(-)
>
> diff --git a/softmmu_template.h b/softmmu_template.h
> index 7029a03..3d388ec 100644
> --- a/softmmu_template.h
> +++ b/softmmu_template.h
> @@ -396,6 +396,26 @@ static inline void glue(helper_le_st_name, _do_unl_access)(CPUArchState *env,
>      }
>  }
>
> +static inline void glue(helper_le_st_name, _do_mmio_access)(CPUArchState *env,
> +                                                            DATA_TYPE val,
> +                                                            target_ulong addr,
> +                                                            TCGMemOpIdx oi,
> +                                                            unsigned mmu_idx,
> +                                                            int index,
> +                                                            uintptr_t retaddr)
> +{
> +    CPUIOTLBEntry *iotlbentry = &env->iotlb[mmu_idx][index];
> +
> +    if ((addr & (DATA_SIZE - 1)) != 0) {
> +        glue(helper_le_st_name, _do_unl_access)(env, val, addr, mmu_idx,
> +                                                oi, retaddr);
> +    }
> +    /* ??? Note that the io helpers always read data in the target
> +       byte ordering.  We should push the LE/BE request down into io.  */
> +    val = TGT_LE(val);
> +    glue(io_write, SUFFIX)(env, iotlbentry, val, addr, retaddr);
> +}
> +
>  void helper_le_st_name(CPUArchState *env, target_ulong addr, DATA_TYPE val,
>                         TCGMemOpIdx oi, uintptr_t retaddr)
>  {
> @@ -423,17 +443,8 @@ void helper_le_st_name(CPUArchState *env, target_ulong addr, DATA_TYPE val,
>
>      /* Handle an IO access.  */
>      if (unlikely(tlb_addr & ~TARGET_PAGE_MASK)) {
> -        CPUIOTLBEntry *iotlbentry;
> -        if ((addr & (DATA_SIZE - 1)) != 0) {
> -            glue(helper_le_st_name, _do_unl_access)(env, val, addr, mmu_idx,
> -                                                    oi, retaddr);
> -        }
> -        iotlbentry = &env->iotlb[mmu_idx][index];
> -
> -        /* ??? Note that the io helpers always read data in the target
> -           byte ordering.  We should push the LE/BE request down into io.  */
> -        val = TGT_LE(val);
> -        glue(io_write, SUFFIX)(env, iotlbentry, val, addr, retaddr);
> +        glue(helper_le_st_name, _do_mmio_access)(env, val, addr, oi,
> +                                                 mmu_idx, index, retaddr);
>          return;
>      }
>
> @@ -488,6 +499,26 @@ static inline void glue(helper_be_st_name, _do_unl_access)(CPUArchState *env,
>      }
>  }
>
> +static inline void glue(helper_be_st_name, _do_mmio_access)(CPUArchState *env,
> +                                                            DATA_TYPE val,
> +                                                            target_ulong addr,
> +                                                            TCGMemOpIdx oi,
> +                                                            unsigned mmu_idx,
> +                                                            int index,
> +                                                            uintptr_t retaddr)
> +{
> +    CPUIOTLBEntry *iotlbentry = &env->iotlb[mmu_idx][index];
> +
> +    if ((addr & (DATA_SIZE - 1)) != 0) {
> +        glue(helper_be_st_name, _do_unl_access)(env, val, addr, mmu_idx,
> +                                                oi, retaddr);
> +    }
> +    /* ??? Note that the io helpers always read data in the target
> +       byte ordering.  We should push the LE/BE request down into io.  */
> +    val = TGT_BE(val);
> +    glue(io_write, SUFFIX)(env, iotlbentry, val, addr, retaddr);
> +}
> +

As before I still thing there is millage in having a common helper
between LE/BE which the compiler can sort out. Having said that there is
less argument for this function as it is a bit smalled and you would
need a bit more faffing about.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>

>  void helper_be_st_name(CPUArchState *env, target_ulong addr, DATA_TYPE val,
>                         TCGMemOpIdx oi, uintptr_t retaddr)
>  {
> @@ -515,17 +546,8 @@ void helper_be_st_name(CPUArchState *env, target_ulong addr, DATA_TYPE val,
>
>      /* Handle an IO access.  */
>      if (unlikely(tlb_addr & ~TARGET_PAGE_MASK)) {
> -        CPUIOTLBEntry *iotlbentry;
> -        if ((addr & (DATA_SIZE - 1)) != 0) {
> -            glue(helper_be_st_name, _do_unl_access)(env, val, addr, mmu_idx,
> -                                                    oi, retaddr);
> -        }
> -        iotlbentry = &env->iotlb[mmu_idx][index];
> -
> -        /* ??? Note that the io helpers always read data in the target
> -           byte ordering.  We should push the LE/BE request down into io.  */
> -        val = TGT_BE(val);
> -        glue(io_write, SUFFIX)(env, iotlbentry, val, addr, retaddr);
> +        glue(helper_be_st_name, _do_mmio_access)(env, val, addr, oi,
> +                                                 mmu_idx, index, retaddr);
>          return;
>      }


--
Alex Bennée