Re: [XEN][RFC PATCH V2 05/17] hvm: Modify hvm_op

[Julien Grall <julien.grall@citrix.com>]

On 09/10/2012 02:23 PM, Jan Beulich wrote:
>>>> On 10.09.12 at 15:02, Julien Grall<julien.grall@citrix.com>  wrote:
>>>>          
>> On 08/24/2012 04:38 PM, Jan Beulich wrote:
>>      
>>>>>> On 23.08.12 at 12:52, Julien Grall<julien.grall@citrix.com>   wrote:
>>>>>>
>>>>>>              
>>>> On 08/23/2012 08:27 AM, Jan Beulich wrote:
>>>>
>>>>          
>>>>>> switch ( a.index )
>>>>>> {
>>>>>> -            case HVM_PARAM_IOREQ_PFN:
>>>>>>
>>>>>>
>>>>>>              
>>>>> Removing sub-ops which a domain can issue for itself (which for this and
>>>>> another one below appears to be the case) is not allowed.
>>>>>
>>>>>
>>>>>            
>>>> I removed these 3 sub-ops because it will not work with
>>>> QEMU disaggregation. Shared pages and event channel
>>>> for IO request are private for each device model.
>>>>
>>>>          
>>> Then they need to be made inaccessible for that specific setup, not
>>> removed altogether.
>>>
>>>
>>>        
>> What do you mean by specific feature ?
>> With this patch series, you are able to handle one or more
>> QEMU.
>> Keep a compatibility with the old IO emulation is hard.
>>      
> Did you read my original reply? Code backing operations that a
> guest can issue itself (i.e. without qemu or another host side
> component involved) just can't be removed, as you/we have
> no control over which guest(s) may be making use of that
> functionality.
>    

Ah ok misundertanding of my part. I don't really understand
in which case a domain needs to retrieve its ioreq page.
How can I made it inaccessible ? Just rc = -EINVAL ?

-- 
Julien Grall