Re: [PATCH V1 14/16] xen/ioreq: Use guest_cmpxchg64() instead of cmpxchg()

[Jan Beulich <jbeulich@xxxxxxxx>]

On 10.09.2020 22:22, Oleksandr Tyshchenko wrote:
> @@ -1325,7 +1327,7 @@ static int hvm_send_buffered_ioreq(struct 
> hvm_ioreq_server *s, ioreq_t *p)
>  
>          new.read_pointer = old.read_pointer - n * IOREQ_BUFFER_SLOT_NUM;
>          new.write_pointer = old.write_pointer - n * IOREQ_BUFFER_SLOT_NUM;
> -        cmpxchg(&pg->ptrs.full, old.full, new.full);
> +        guest_cmpxchg64(d, &pg->ptrs.full, old.full, new.full);

But the memory we're updating is shared with s->emulator, not with d,
if I'm not mistaken.

Jan