Re: [PATCH] content: Reserve ID 52 for Snapdragon device

[Stefan Hajnoczi <stefanha@redhat.com>]

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On Thu, Aug 27, 2026 at 03:24:18PM +0200, Jan Kiszka wrote:
> On 26.08.26 20:44, Stefan Hajnoczi wrote:
> > On Wed, Aug 26, 2026 at 05:31:54PM +0200, Jan Kiszka wrote:
> >> On 26.08.26 13:55, Peter Hilber wrote:
> >>> Reserve a device ID for the Snapdragon device.  A Virtio Snapdragon
> >>> device exposes functionality across Snapdragon SoC subsystems through a
> >>> common Virtio-based protocol.
> >>>
> >>
> >> Virtio is supposed to provide generic hardware models, not so much a
> >> channel to expose concrete, physical chip IP over it. This looks very
> >> weird to me.
> > 
> > Device IDs assignments don't have to result in standardized devices. See
> > "5 Device Types" in VIRTIO 1.4 where there is a table of currently
> > reserved Device IDs.
> > 
> > While I'm in favor of defining generic device interfaces with many
> > possible implementations like virtio-net, virtio-blk, etc, I think a
> > SoC-specific control device is unlikely to fit into that category and
> > it's acceptable to allocate the Device ID with the understanding that
> > there will never be standardization of the device.
> 
> Would still list this ID by that vendor branding in the spec.
> 
> For me the question is if reservations for devices that will never be
> acceptable should be in scope for virtio. IIRC, the currently available
> ID range for virtio over PCI is 63, of which 50 (including invalid 0)
> are officially reserved already. If we see an inflation of such
> vendor-specific reservations, we might be force to hunt for another PCI
> device ID range earlier.

Interesting, maybe Michael Tsirkin knows what options are available for
extending the PCI Device ID range.

Stefan

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