Proposed plan for libxl USB interface (was Re: [PATCH V4 3/7] libxl: add pvusb API)

From: Ian Jackson <Ian.Jackson@eu.citrix.com>
To: George Dunlap <george.dunlap@eu.citrix.com>
Cc: Juergen Gross <jgross@suse.com>, Wei Liu <wei.liu2@citrix.com>,
	Ian Campbell <ian.campbell@citrix.com>,
	Chunyan Liu <cyliu@suse.com>,
	"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>,
	Jim Fehlig <jfehlig@suse.com>, Simon Cao <caobosimon@gmail.com>
Subject: Proposed plan for libxl USB interface (was Re: [PATCH V4 3/7] libxl: add pvusb API)
Date: Mon, 22 Jun 2015 15:22:57 +0100	[thread overview]
Message-ID: <21896.6721.528004.191502@mariner.uk.xensource.com> (raw)
In-Reply-To: <55880DCC.6070902@eu.citrix.com>

George Dunlap writes ("Proposed plan for libxl USB interface (was Re: [Xen-devel] [PATCH V4 3/7] libxl: add pvusb API)"):
> With all that in mind, here is a proposal:

FAOD, this all sounds good.  I have one comment on this:

> 4. We work on a set of helper functions that a toolstack can use to
> translate other ways of specifying a device, much like the disk
> specification helper functions that we provide.  One of these should be
> something which is reliably stable over reboots, such as the udev
> ID_PATH specification.

We should invent, similar to the disk specification, a specification
for how to interpret a string referring to a usb device.  That can be
used by xl but also by libvirt and anyone else that wants to.

If we don't know right away how this will work, then we should come up
with a temporary arrangement which encodes bus.address in a region of
the string syntax space which we are confident we won't need in the
future for something else.

Ian.