Re: [PATCH V2 0/2] virito-pci: PASID support

[Jason Wang <jasowang@redhat.com>]

On Wed, Jan 12, 2022 at 6:44 PM Stefan Hajnoczi <stefanha@redhat.com> wrote:
>
> On Wed, Jan 12, 2022 at 01:57:53PM +0800, Jason Wang wrote:
> > Hi All:
> >
> > This series tries to add PASID support for virtio-pci to allow the
> > virtqueue to use PASID TLP prefix for PCI transactions. This will be
> > useful for future work like, queue assignment, virtqueue
> > virtualization and presenting multiple vDPA devices with a single PCI
> > device.
> >
> > Since we're short of the space for the PCI capabilities, the PCI
> > extended capability for virtio structure is introduced that allows the
> > PASID configuration structure to use.
> >
> > A prototype is implemented with emulated virtio-pci device in [1]. A
> > test driver is implemented in [2].
> >
> > Please review.
>
> I don't know the security model for PASIDs. My guess is that PASIDs can
> be bruteforced so we must trust the driver (it can assign PASIDs to
> virtqueue groups) and we must prevent untrusted applications from
> setting PASIDs on virtqueues. Is that correct?

Yes, and the kernel can choose to hide PASID even for the trusted
application by using token or other intermediate layers.

Thanks

>
> Thanks,
> Stefan