Re: [PATCH v2 10/22] iommufd/viommmu: Add IOMMUFD_CMD_VCMDQ_ALLOC ioctl

Vasant Hegde
2025-04-30T10:44:17Z

On 4/30/2025 1:31 PM, Nicolin Chen wrote:
> On Wed, Apr 30, 2025 at 09:52:09AM +0530, Vasant Hegde wrote:
>>>>> Will the hardware replace the physical device ID in the event with
>>>>> the virtual device ID when injecting the event to a guest event/PPR
>>>>> queue?
>>>>> If so, yea, I think you can define them separately using the> vCMDQ
>>>> infrastructures:
>>>>> - IOMMU_VCMDQ_TYPE_AMD_VIOMMU_CMDBUF
>>>>> - IOMMU_VCMDQ_TYPE_AMD_VIOMMU_EVENTLOG
>>>>> - IOMMU_VCMDQ_TYPE_AMD_VIOMMU_PPRLOG
>>>>> (@Kevin @Jason Hmm, in this case we might want to revert the naming
>>>>> "vCMDQ" back to "vQEUEUE", once Vasant confirms.)
>>>
>>> I think I should rename IOMMUFD_OBJ_VCMDQ back to IOMMUFD_OBJ_VQUEUE
>>> since the same object fits three types of queue now in the AMD case.
>>
>> Makes sense.
>>
>> AMD architecture supports 5 buffers. In practice we have not implemented event
>> log B / PPR Log B in Linux.
>> Command buffer
>> Event Log A / B
>> PPR Log A / B
>
> I think those A/B should be dual buffers of the same type?

Yes.

>
> Anyway, I have renamed all the core "vCMDQ" back to "vQUEUE" in my
> local branch. Will send v3 in the next days.

Sure thanks.

-Vasant