Re: [Qemu-devel] [PATCH] watch_mem_write: implement 8-byte accesses

[Philippe Mathieu-Daudé]

On 10/17/2017 09:17 AM, Paolo Bonzini wrote:
> Aligned 8-byte memory writes by a 64-bit target on a 64-bit host should
> always turn into atomic 8-byte writes on the host, however a write
> write watchpoint would end up tearing the 8-byte write into two 4-byte
> writes in access_with_adjusted_size().
> 
> Reported-by: Andrew Baumann <address@hidden>
> Signed-off-by: Paolo Bonzini <address@hidden>

Reviewed-by: Philippe Mathieu-Daudé <address@hidden>

> ---
>  exec.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/exec.c b/exec.c
> index b58bc4eff7..db5ae23118 100644
> --- a/exec.c
> +++ b/exec.c
> @@ -2503,6 +2503,9 @@ static MemTxResult watch_mem_read(void *opaque, hwaddr 
> addr, uint64_t *pdata,
>      case 4:
>          data = address_space_ldl(as, addr, attrs, &res);
>          break;
> +    case 8:
> +        data = address_space_ldq(as, addr, attrs, &res);
> +        break;
>      default: abort();
>      }
>      *pdata = data;
> @@ -2528,6 +2531,9 @@ static MemTxResult watch_mem_write(void *opaque, hwaddr 
> addr,
>      case 4:
>          address_space_stl(as, addr, val, attrs, &res);
>          break;
> +    case 8:
> +        address_space_stq(as, addr, val, attrs, &res);
> +        break;
>      default: abort();
>      }
>      return res;
> @@ -2537,6 +2543,16 @@ static const MemoryRegionOps watch_mem_ops = {
>      .read_with_attrs = watch_mem_read,
>      .write_with_attrs = watch_mem_write,
>      .endianness = DEVICE_NATIVE_ENDIAN,
> +    .valid = {
> +        .min_access_size = 1,
> +        .max_access_size = 8,
> +        .unaligned = false,
> +    },
> +    .impl = {
> +        .min_access_size = 1,
> +        .max_access_size = 8,
> +        .unaligned = false,
> +    },
>  };
>  
>  static MemTxResult flatview_write(FlatView *fv, hwaddr addr, MemTxAttrs 
> attrs,
>