Re: [RFC PATCH V1 08/12] xen/arm: Invalidate qemu mapcache on XENMEM_decrease_reservation

[Oleksandr <olekstysh@gmail.com>]

On 06.08.20 14:50, Jan Beulich wrote:

Hi Jan

>>> On 03.08.2020 20:21, Oleksandr Tyshchenko wrote:
>>>> --- a/xen/common/memory.c
>>>> +++ b/xen/common/memory.c
>>>> @@ -1652,6 +1652,12 @@ long do_memory_op(unsigned long cmd, XEN_GUEST_HANDLE_PARAM(void) arg)
>>>>            break;
>>>>        }
>>>>    
>>>> +    /* x86 already sets the flag in hvm_memory_op() */
>>>> +#if defined(CONFIG_ARM64) && defined(CONFIG_IOREQ_SERVER)
>>>> +    if ( op == XENMEM_decrease_reservation )
>>>> +        curr_d->arch.hvm.qemu_mapcache_invalidate = true;
>>>> +#endif
>>> Doesn't the comment already indicate a route towards an approach
>>> not requiring to alter common code?
>> Given that IOREQ is now moved under common/, I think it would make sense
>> to have this set in common code as well for all the architecture.
>>
>> IOW, I would suggest to drop the #ifdef CONFIG_ARM64. In addition, we
>> may want to introduce an helper to check if a domain is using ioreq.
> Of course, with the (part of the) conditional dropped and the struct
> field moved out of the arch sub-struct, this is fine to live here.

ok.


I suspect this should *also* live in compat_memory_op(). Please confirm 
whether my understanding correct.


-- 
Regards,

Oleksandr Tyshchenko