Re: [PATCH 0/6] Make set_dev_pasid op supportting domain replacement

Vasant Hegde
2024-08-16T05:20:03Z

Yi,

On 8/16/2024 6:49 AM, Yi Liu wrote:
> On 2024/8/16 01:49, Vasant Hegde wrote:
>> Hi All,
>>
>> On 6/28/2024 2:25 PM, Yi Liu wrote:
>>> This splits the preparation works of the iommu and the Intel iommu driver
>>> out from the iommufd pasid attach/replace series. [1]
>>>
>>> To support domain replacement, the definition of the set_dev_pasid op
>>> needs to be enhanced. Meanwhile, the existing set_dev_pasid callbacks
>>> should be extended as well to suit the new definition.
>>
>> IIUC this will remove PASID from old SVA domain and attaches to new SVA domain.
>> (basically attaching same dev/PASID to different process). Is that the correct?
>
> In brief, yes. But it's not only for SVA domain. Remember that SIOVr1
> extends the usage of PASID. At least on Intel side, a PASID may be
> attached to paging domains.

Right. I missed SIOV case.

>
>> So the expectation is replace existing PASID from PASID table only if old_domain
>> is passed. Otherwise sev_dev_pasid() should throw an error right?
>>
>
> yes. If no old_domain passed in, then it is just a normal attachment. As
> you are working on AMD iommu, it would be great if you can have a patch to
> make the AMD set_dev_pasid() op suit this expectation. Then it can be
> incorporated in this series. :)'

Sure. It should be simple. I will try to get the patch next week.

-Vasant