Re: [PATCH v2 1/5] iommu/vt-d: Separate page request queue from SVM

[Baolu Lu]

On 9/14/24 8:52 AM, Tian, Kevin wrote:
> > From: Joel Granados via B4 Relay
> > <devnull+j.granados.samsung.com@xxxxxxxxxx>
> >
> > From: Joel Granados<j.granados@xxxxxxxxxxx>
> >
> > IO page faults are no longer dependent on CONFIG_INTEL_IOMMU_SVM.
> > Move
> > all Page Request Queue (PRQ) functions that handle prq events to a new
> > file in drivers/iommu/intel/prq.c. The page_req_des struct is now
> > declared in drivers/iommu/intel/prq.c.
> >
> > No functional changes are intended. This is a preparation patch to
> > enable the use of IO page faults outside the SVM/PASID use cases.
> Do we want to guard it under a new config option e.g.
> CONFIG_INTEL_IOMMU_IOPF? it's unnecessary to allocate resources
> for the majority usages which don't require IOPF.
>
> Baolu?

The OS builder doesn't know if Linux will run on a platform with PRI-
capable devices. They'll probably always enable this option if we
provide it.

This option could be useful for embedded systems, but I'm not sure if
any embedded systems have VT-d hardware, which is mainly for high-end
PCs or cloud servers.

So, maybe we could leave it as is for now and add it later if we see a
real use case.

Thanks,
baolu