Re: [PATCH v2 6/8] iommu/vt-d: Implement set_dev_pasid domain op

[Baolu Lu <baolu.lu@linux.intel.com>]

On 3/28/23 11:40 PM, Jacob Pan wrote:
> Hi Kevin,
> 
> On Tue, 28 Mar 2023 07:47:45 +0000, "Tian, Kevin" <kevin.tian@intel.com>
> wrote:
> 
>>> From: Jacob Pan <jacob.jun.pan@linux.intel.com>
>>> Sent: Tuesday, March 28, 2023 7:22 AM
>>>
>>> Devices that use ENQCMDS to submit work on buffers mapped by DMA API
>>> must attach a PASID to the default domain of the device. In preparation
>>> for this use case, this patch implements set_dev_pasid() for the
>>> default_domain_ops. Besides PASID attachment, device will also be
>>> attached to the domain as the result of this call if the device has not
>>> been attached before.
>>>    
>>
>> I didn't get the last point. PASID attach should only have the scope
>> for the pasid. RID of the device might be attached to another domain
>> which shouldn't be changed by this call.
> I meant if the RID context has not been set up before attaching this PASID,
> this call will also set up the context, PASID dir etc. In the end, we
> eliminated ordering requirement of attaching device, RID_PASID first, then
> other PASIDs.

This occurs in default domain deferred attaching case.

> How about:
> "If the device context has not been set up prior to this call, this will
> set up the device context in addition to PASID attachment."

Best regards,
baolu