linux-kernel - Re: [RFC PATCH 0/7] vfio/pci: SR-IOV support

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Wed, 5 Feb 2020 07:18:26 -0700
From:   Alex Williamson <alex.williamson@...hat.com>
To:     "Liu, Yi L" <yi.l.liu@...el.com>
Cc:     "kvm@...r.kernel.org" <kvm@...r.kernel.org>,
        "linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "dev@...k.org" <dev@...k.org>,
        "mtosatti@...hat.com" <mtosatti@...hat.com>,
        "thomas@...jalon.net" <thomas@...jalon.net>,
        "bluca@...ian.org" <bluca@...ian.org>,
        "jerinjacobk@...il.com" <jerinjacobk@...il.com>,
        "Richardson, Bruce" <bruce.richardson@...el.com>,
        "cohuck@...hat.com" <cohuck@...hat.com>
Subject: Re: [RFC PATCH 0/7] vfio/pci: SR-IOV support

On Wed, 5 Feb 2020 07:57:36 +0000
"Liu, Yi L" <yi.l.liu@...el.com> wrote:

> > From: Alex Williamson <alex.williamson@...hat.com>
> > Sent: Wednesday, February 5, 2020 7:18 AM
> > To: kvm@...r.kernel.org
> > Subject: Re: [RFC PATCH 0/7] vfio/pci: SR-IOV support
> > 
> > 
> > Promised example QEMU test case...
> > 
> > commit 3557c63bcb286c71f3f7242cad632edd9e297d26
> > Author: Alex Williamson <alex.williamson@...hat.com>
> > Date:   Tue Feb 4 13:47:41 2020 -0700
> > 
> >     vfio-pci: QEMU support for vfio-pci VF tokens
> > 
> >     Example support for using a vf_token to gain access to a device as
> >     well as using the VFIO_DEVICE_FEATURE interface to set the VF token.
> >     Note that the kernel will disregard the additional option where it's
> >     not required, such as opening the PF with no VF users, so we can
> >     always provide it.
> > 
> >     NB. It's unclear whether there's value to this QEMU support without
> >     further exposure of SR-IOV within a VM.  This is meant mostly as a
> >     test case where the real initial users will likely be DPDK drivers.
> > 
> >     Signed-off-by: Alex Williamson <alex.williamson@...hat.com>  
> 
> Just curious how UUID is used across the test. Should the QEMU
> which opens VFs add the vfio_token=UUID or the QEMU which
> opens PF add the vfio_token=UUID? or both should add vfio_token=UUID.

In this example we do both as this covers the case where there are
existing VF users, which requires the PF to also provide the vf_token.
If there are no VF users, the PF is not required to provide a vf_token
and vfio-pci will not fail the device match if a vf_token is provided
but not needed.  In fact, when a PF is probed by vfio-pci a random
vf_token is set, so it's required to use a PF driver to set a known
vf_token before any VF users can access their VFs.  Thanks,

Alex