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Date:   Mon, 8 Jun 2020 09:29:01 -0400
From:   "Michael S. Tsirkin" <mst@redhat.com>
To:     Jason Wang <jasowang@redhat.com>
Cc:     kvm@vger.kernel.org, virtualization@lists.linux-foundation.org,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
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        zhangweining@ruijie.com.cn, eli@mellanox.com
Subject: Re: [PATCH 5/6] vdpa: introduce virtio pci driver
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On Mon, Jun 08, 2020 at 06:07:36PM +0800, Jason Wang wrote:
> 
> On 2020/6/8 下午5:54, Michael S. Tsirkin wrote:
> > On Mon, Jun 08, 2020 at 05:46:52PM +0800, Jason Wang wrote:
> > > On 2020/6/8 下午5:45, Michael S. Tsirkin wrote:
> > > > On Mon, Jun 08, 2020 at 05:43:58PM +0800, Jason Wang wrote:
> > > > > > > Looking at
> > > > > > > pci_match_one_device() it checks both subvendor and subdevice there.
> > > > > > > 
> > > > > > > Thanks
> > > > > > But IIUC there is no guarantee that driver with a specific subvendor
> > > > > > matches in presence of a generic one.
> > > > > > So either IFC or virtio pci can win, whichever binds first.
> > > > > I'm not sure I get there. But I try manually bind IFCVF to qemu's
> > > > > virtio-net-pci, and it fails.
> > > > > 
> > > > > Thanks
> > > > Right but the reverse can happen: virtio-net can bind to IFCVF first.
> > > 
> > > That's kind of expected. The PF is expected to be bound to virtio-pci to
> > > create VF via sysfs.
> > > 
> > > Thanks
> > > 
> > > 
> > > 
> > Once VFs are created, don't we want IFCVF to bind rather than
> > virtio-pci?
> 
> 
> Yes, but for PF we need virtio-pci.
> 
> Thanks
> 

(Ab)using the driver_data field for this is an option.
What do you think?

-- 
MST