Re: [Qemu-devel] [PATCH] Enable 8-byte wide MMIO for 16550 serial devices

[Paolo Bonzini]

On 31/10/2017 16:24, Mike Nawrocki wrote:
> 
> diff --git a/hw/char/serial.c b/hw/char/serial.c
> index 376bd2f240..c16c19a406 100644
> --- a/hw/char/serial.c
> +++ b/hw/char/serial.c
> @@ -1005,7 +1005,7 @@ static void serial_mm_write(void *opaque, hwaddr addr,
>                              uint64_t value, unsigned size)
>  {
>      SerialState *s = opaque;
> -    value &= ~0u >> (32 - (size * 8));
> +    value &= ~((uint64_t)0) >> (64 - (size * 8));
>      serial_ioport_write(s, addr >> s->it_shift, value, 1);
>  }

Couldn't this be simply "value &= 255"?  Otherwise looks good.

Paolo

> @@ -1014,16 +1014,22 @@ static const MemoryRegionOps serial_mm_ops[3] = {
>          .read = serial_mm_read,
>          .write = serial_mm_write,
>          .endianness = DEVICE_NATIVE_ENDIAN,
> +        .valid.max_access_size = 8,
> +        .impl.max_access_size = 8,
>      },
>      [DEVICE_LITTLE_ENDIAN] = {
>          .read = serial_mm_read,
>          .write = serial_mm_write,
>          .endianness = DEVICE_LITTLE_ENDIAN,
> +        .valid.max_access_size = 8,
> +        .impl.max_access_size = 8,
>      },
>      [DEVICE_BIG_ENDIAN] = {
>          .read = serial_mm_read,
>          .write = serial_mm_write,
>          .endianness = DEVICE_BIG_ENDIAN,
> +        .valid.max_access_size = 8,
> +        .impl.max_access_size = 8,