RE: [PATCH 1/4] iommu/vt-d: Implement set device pasid op for default domain

[Tian, Kevin]

> From: Baolu Lu <baolu.lu@xxxxxxxxxxxxxxx>
> Sent: Friday, March 3, 2023 12:38 PM
> 
> On 3/3/23 11:02 AM, Tian, Kevin wrote:
> >> From: Baolu Lu <baolu.lu@xxxxxxxxxxxxxxx>
> >> Sent: Friday, March 3, 2023 10:49 AM
> >>
> >> On 3/3/23 10:36 AM, Tian, Kevin wrote:
> >>>> From: Baolu Lu <baolu.lu@xxxxxxxxxxxxxxx>
> >>>> Sent: Thursday, March 2, 2023 10:07 PM
> >>>>> +
> >>>>> +	if (!sm_supported(iommu) || !info)
> >>>>
> >>>> @info has been referenced. !info check makes no sense.
> >>>>
> >>>> Add pasid_supported(iommu).
> >>>>
> >>>> Do you need to check whether the domain is compatible for this rid
> >>>> pasid?
> >>>
> >>> what kind of compatibility is concerned here? In concept a pasid
> >>> can be attached to any domain if it has been successfully attached
> >>> to rid. Probably we can add a check here that RID2PASID must
> >>> point to the domain already.
> >>
> >> "...if it has been successfully attached to rid..."
> >>
> >> We should not have this assumption in iommu driver's callback. The
> iommu
> >> driver has no (and should not have) knowledge about the history of any
> >> domain.
> >
> > but this is an op for default domain which must have been attached
> > to RID2PASID and any compatibility check between this domain and device
> > should be passed.
> 
> This is an op for DMA, DMA-FQ and UNMANAGED domain. The IOMMU
> driver
> doesn't need to interpret the default domain concept. :-)
> 

yes if we target a general callback for all those domain types.

and probably this is the right thing to do as in the end DMA type will
be removed with Jason's cleanup