Re: [RFC] [Draft Design v2] ACPI/IORT Support in Xen.

[Julien Grall <julien.grall@linaro.org>]

Hi Manish,

On 16/11/17 11:46, Manish Jaggi wrote:
> 
> 
> On 11/16/2017 5:07 PM, Julien Grall wrote:
>>
>>
>> On 16/11/17 07:39, Manish Jaggi wrote:
>>> On 11/14/2017 6:53 PM, Julien Grall wrote:
>>>>> 3. IORT for Dom0
>>>>> -----------------
>>>>> IORT for Dom0 is based on host iort. Few nodes could be removed or 
>>>>> modified.
>>>>>   For instance
>>>>> - Host SMMU nodes should not be present as Xen should only touch it.
>>>>> - platform nodes (named components) may be controlled by xen 
>>>>> command line.
>>>>
>>>> I am not sure where does this example come from? As I said, there 
>>>> are no plan to support Platform Device passthrough with ACPI. A 
>>>> better example here would removing PMCG.
>>>>
>>> It came from review comments on my previous IORT SMMU hiding patch. 
>>> Andre suggested that Platform Nodes are needed.
>>>
>>> After some brainstorming with Julien we found two problems:
>>> 1) This only covers RC nodes, but not "named components" (platform
>>> devices), which we will need. ...
>>>
>>> From: 
>>> https://www.mail-archive.com/xen-devel@lists.xen.org/msg123434.html
>>
>> I think you misunderstood my comment here... What I call "device 
>> passthrough" is giving access to a device to a domain other than the 
>> Hardware Domain
>>
>> There are no plan for supporting platform device-passthrough on ACPI 
>> and I don't understand why you would like to control that using the 
>> command line.
>>
>> What Andre was saying is your series was not covering the "named 
>> components" for the Hardware Domain.
> 
> The section 3 is IORT for Dom0, where I mentioned that  some platform 
> devices can be hidden from dom0.
> So your comment on Platform device Passthrough might not be valid then 
> as it is for domU's only.
> 
> Regarding the visibility of a platform device for dom0, I took cue from 
> your comment below

Where did I ever mention the command line solution? Please stop trying 
to put words in my mouth.

There are other reason than passthrough to hide device from the Hardware 
Domain.

> 
> This has two benefits:
> 
> ...
> 3) We could decide in a finer grain which devices (e.g platform 
> device)Dom0 can see.
> From: https://www.mail-archive.com/xen-devel@lists.xen.org/msg124534.html
> 
>>
>> Cheers,
>>
> 

-- 
Julien Grall

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
https://lists.xen.org/xen-devel