Re: [Xen-devel] Unshared IOMMU issues

[Oleksandr Tyshchenko <olekstysh@xxxxxxxxx>]

On Wed, Feb 22, 2017 at 1:39 PM, Julien Grall <julien.grall@xxxxxxx> wrote:
> On 21/02/17 10:39, Oleksandr Tyshchenko wrote:
>>
>> Hi, Julien.

Hi, Julien, all.

>
>
> Hi Oleksandr,
>
>> On Mon, Feb 20, 2017 at 10:31 AM, Julien Grall <julien.grall@xxxxxxx>
>> wrote:
>>>
>>> Hello Oleksandr,
>>>
>>> On 02/17/2017 08:20 PM, Oleksandr Tyshchenko wrote:
>>>>
>>>>
>>>> Hi, all.
>>>>
>>>> So, as I understand we have two possible solutions for the IOMMU page
>>>> table to be populated:
>>>> 1.  When the first device is being assigned. Retrieve all mappings
>>>> from stage-2 table.
>>>> 2.  When the domain is being created.
>>>>
>>>> I would prefer the second variant.
>>>
>>>
>>>
>>> I am happy with the second variant as long as IOMMU is not enabled by
>>> default when the guest will have no device assigned.
>>
>> OK.
>>
>> Just to clarify.
>> We don't need to assign devices when creating domain (at the
>> iommu_domain_init() time).
>> We just need to have some knowledge about device assignment in general
>> (will the guest have assigned devices or won't) .
>> And only in case when the guest is going to have assigned devices we
>> will populate IOMMU page table (call iommu_construct()).
>> Right?
>
>
> That's correct.

Thank you.

>
> Cheers,
>
> --
> Julien Grall



-- 
Regards,

Oleksandr Tyshchenko

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