Re: [Qemu-arm] [PATCH] virtio: move bi-endian target support to a single location

[Paolo Bonzini]

On 01/06/2016 04:33, David Gibson wrote:
> On Tue, May 31, 2016 at 03:15:21PM +0200, Paolo Bonzini wrote:
>>
>>
>> On 31/05/2016 15:10, Greg Kurz wrote:
>>>>>>> +#if defined(TARGET_PPC64) || defined(TARGET_ARM)
>>>>>>> +#define LEGACY_VIRTIO_IS_BIENDIAN 1
>>>>>>> +#endif  
>>>>>
>>>>> These will only be correct if something else includes cpu.h.  Instead of
>>> Unless I missed something, the TARGET_* macros come from the generated
>>> config-target.h header, which is in turn included by qemu/osdep.h and
>>> thus included by most of the code.
>>
>> You're right.  Problems _could_ happen if virtio-access.h is included in
>> a file compiled without -DNEED_CPU_H (i.e. with common-obj-y instead of
>> obj-y) but include/exec/poison.h should take care of that.
>>
>>>>> defining this, you should add
>>>>>
>>>>> #include "cpu.h"
>>>>>
>>>>> at the top of include/hw/virtio-access.h and leave the definitions in
>>>>> target-*/cpu.h.
>>>>>
>>> All this bi-endian stuff is really an old-virtio-only thing... it is
>>> only to be used by virtio_access_is_big_endian(). The fact that it
>>> broke silently with your cleanup series is yet another proof that
>>> this workaround is fragile.
>>
>> It is not fragile actually.  cpu.h doesn't exist in common-obj-y, so the
>> TARGET_IS_BIENDIAN define can be safely taken from cpu.h.
>>
>> Anyway because of poison.h your solution isn't fragile either, so
>>
>> Reviewed-by: Paolo Bonzini <address@hidden>
> 
> Should I take this through my tree?

If you don't hear from mst, go ahead.

Paolo