Re: [PATCH v5 3/7] PCI/ATS: Initialize PASID in pci_ats_init()

[Bjorn Helgaas]

On Thu, Aug 01, 2019 at 05:06:00PM -0700, sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx wrote:
> From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>
> 
> Currently, PASID Capability checks are repeated across all PASID API's.
> Instead, cache the capability check result in pci_pasid_init() and use
> it in other PASID API's. Also, since PASID is a shared resource between
> PF/VF, initialize PASID features with default values in pci_pasid_init().
> 
> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>

> + * TODO: Since PASID is a shared resource between PF/VF, don't update
> + * PASID features in the same API as a per device feature.

This comment is slightly misleading (at least, it misled *me* :))
because it hints that PASID might be specific to SR-IOV.  But I don't
think that's true, so if you keep a comment like this, please reword
it along the lines of "for SR-IOV devices, the PF's PASID is shared
between the PF and all VFs" so it leaves open the possibility of
non-SR-IOV devices using PASID as well.

Bjorn