[Qemu-devel] Re: virtio-serial: An interface for host-guest communication

[Jamie Lokier]

Anthony Liguori wrote:
> Richard W.M. Jones wrote:
> Have you considered using a usb serial device?  Something attractive 
> about it is that a productid/vendorid can be specified which means that 
> you can use that as a method of enumerating devices.
> 
> Hot add/remove is supported automagically.

The same applies to PCI: productid/vendorid (and subids);
PCI hotplug is possible though not as native as USB.

Here's another idea: Many devices these days have a serial number or
id string.  E.g. USB storage, ATA drives, media cards, etc.  Linux
these days creates alias device nodes which include the id string in
the device name.  E.g. /dev/disks/by-id/ata-FUJITSU_MHV2100BH_NWAQT662615H

So in addition to (or instead of) /dev/vmch0, /dev/vmch1 etc.,
Linux guests could easily generate:

    /dev/vmchannel/by-role/clipboard-0
    /dev/vmchannel/by-role/gueststats-0
    /dev/vmchannel/by-role/vmmanager-0

It's not necessary to do this at the beginning.  All that is needed is
to provide enough id information that will appear in /sys/..., so that
that a udev policy for naming devices can be created at some later date.

-- Jamie