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

From: Kuppuswamy Sathyanarayanan
Date: Thu Aug 15 2019 - 13:35:20 EST


On Wed, Aug 14, 2019 at 11:56:59PM -0500, Bjorn Helgaas wrote:
> 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.
Ok. I will fix it in next version.
>
> Bjorn

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Sathyanarayanan Kuppuswamy
Linux kernel developer