Re: [Qemu-devel] [PATCH 3/3] memory: Fix access_with_adjusted_size(small size) on big-endian memory regions

[Eric Blake]

On 9/26/18 7:24 PM, Philippe Mathieu-Daudé wrote:
> Memory regions configured as DEVICE_BIG_ENDIAN (or DEVICE_NATIVE_ENDIAN on
> big-endian guest) behave incorrectly when the memory access 'size' is smaller
> than the implementation 'access_size'.

> Fix this by changing the access_fn() prototype to handle signed shift values,
> and modify the memory_region_shift_read|write_access() helpers to correctly
> arithmetic shift the opposite direction when the 'shift' value is negative.
>
> Signed-off-by: Philippe Mathieu-Daudé <address@hidden>
> ---
>   memory.c | 34 +++++++++++++++++++++++-----------
>   1 file changed, 23 insertions(+), 11 deletions(-)
>
> diff --git a/memory.c b/memory.c
> index 48edf7dc23..a9f0fdc440 100644
> --- a/memory.c
> +++ b/memory.c
> @@ -375,18 +375,30 @@ static void adjust_endianness(MemoryRegion *mr, uint64_t 
> *data, unsigned size)
>   }
>   
>   static inline void memory_region_shift_read_access(uint64_t *value,
> -                                                   unsigned shift,
> +                                                   signed shift,

This is more typically spelled s/signed/int/

--
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org