From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: Re: [Qemu-devel] [PATCH] qemu: Introduce VIRTIO_NET_F_STANDBY feature bit to virtio_net Date: Thu, 21 Jun 2018 21:20:13 +0300 Message-ID: <20180621211712-mutt-send-email-mst@kernel.org> References: <20180615134815.6613620e.cohuck@redhat.com> <20180619125453.2d2dfb2d.cohuck@redhat.com> <20180619233001-mutt-send-email-mst@kernel.org> <20180620115359.1a3bf6fb.cohuck@redhat.com> <20180620170904-mutt-send-email-mst@kernel.org> <20180620180619.6b4ee52d.cohuck@redhat.com> <20180620224535-mutt-send-email-mst@kernel.org> <20180621165913.7e3f4faa.cohuck@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Siwei Liu , "Samudrala, Sridhar" , Alexander Duyck , virtio-dev@lists.oasis-open.org, aaron.f.brown@intel.com, Jiri Pirko , Jakub Kicinski , Netdev , qemu-devel@nongnu.org, virtualization@lists.linux-foundation.org, konrad.wilk@oracle.com, boris.ostrovsky@oracle.com, Joao Martins , Venu Busireddy , vijay.balakrishna@oracle.com To: Cornelia Huck Return-path: Sender: List-Post: List-Help: List-Unsubscribe: List-Subscribe: Content-Disposition: inline In-Reply-To: <20180621165913.7e3f4faa.cohuck@redhat.com> List-Id: netdev.vger.kernel.org On Thu, Jun 21, 2018 at 04:59:13PM +0200, Cornelia Huck wrote: > On Wed, 20 Jun 2018 22:48:58 +0300 > "Michael S. Tsirkin" wrote: > > > On Wed, Jun 20, 2018 at 06:06:19PM +0200, Cornelia Huck wrote: > > > In any case, I'm not sure anymore why we'd want the extra uuid. > > > > It's mostly so we can have e.g. multiple devices with same MAC > > (which some people seem to want in order to then use > > then with different containers). > > > > But it is also handy for when you assign a PF, since then you > > can't set the MAC. > > > > OK, so what about the following: > > - introduce a new feature bit, VIRTIO_NET_F_STANDBY_UUID that indicates > that we have a new uuid field in the virtio-net config space > - in QEMU, add a property for virtio-net that allows to specify a uuid, > offer VIRTIO_NET_F_STANDBY_UUID if set > - when configuring, set the property to the group UUID of the vfio-pci > device > - in the guest, use the uuid from the virtio-net device's config space > if applicable; else, fall back to matching by MAC as done today > > That should work for all virtio transports. True. I'm a bit unhappy that it's virtio net specific though since down the road I expect we'll have a very similar feature for scsi (and maybe others). But we do not have a way to have fields that are portable both across devices and transports, and I think it would be a useful addition. How would this work though? Any idea? -- MST