Re: [PATCH v10 00/26] guest dedicated crypto adapters

[Tony Krowiak]

On 09/24/2018 07:49 AM, Cornelia Huck wrote:
> On Wed, 12 Sep 2018 15:42:50 -0400
> Tony Krowiak <akrowiak@xxxxxxxxxxxxxxxxxx> wrote:
>
> > Abstract:
> > ========
> >
> > On s390, we have cryptographic coprocessor cards, which are modeled on
> > Linux as devices on the AP bus. Each card can be partitioned into domains
> > which can be thought of as a set of hardware registers for processing
> > crypto commands. Crypto commands are sent to a specific domain within a
> > card is via a queue which is identified as a (card,domain) tuple. We model
> > this something like the following (assuming we have access to cards 3 and
> > 4 and domains 1 and 2):
> >
> > AP -> card3 -> queue (3,1)
> >              -> queue (3,2)
> >     -> card4 -> queue (4,1)
> >              -> queue (4,2)
> >
> > If we want to virtualize this, we can use a feature provided by the
> > hardware. We basically attach a satellite control block to our main
> > hardware virtualization control block and the hardware takes care of
> > most of the rest.
> >
> > For this control block, we don't specify explicit tuples, but a list of
> > cards and a list of domains. The guest will get access to the cross
> > product.
> >
> > Because of this, we need to take care that the lists provided to
> > different guests don't overlap; i.e., we need to enforce sane
> > configurations. Otherwise, one guest may get access to things like
> > secret keys for another guest.
> >
> > The idea of this patch set is to introduce a new device, the matrix
> > device. This matrix device hangs off a different root and acts as the
> > parent node for mdev devices.
> >
> > If you now want to give the tuples (4,1) and (4,2), you need to do the
> > following:
> >
> > - Make sure the queues (4,1) and (4,2) belong to vfio_ap (see patches
> >    #5 and #6)
> > - Create the mediated device.
> > - Assign card 4 and domains 1 and 2 to the mediated device
> > - Optionally activate the mediated device.
> >
> > QEMU will now simply consume the mediated device and things should work.
> >
> > For a complete description of the architecture and concepts underlying
> > the design, see the Documentation/s390/vfio-ap.txt file included with this
> > patch set.
>
> I did not spot anything major, and if v11 addresses the issues raised
> by various reviewers I don't see why it should not be merged (interface
> looks sane). I skipped looking at the vsie stuff, though ;)

I think David has that covered.

>