Re: [Qemu-devel] [Xen-devel] RFC: configuring QEMU virtfs for Xen PV(H) guests

[Wei Liu <wei.liu2@citrix.com>]

On Mon, Feb 15, 2016 at 02:33:05PM +0100, Juergen Gross wrote:
> On 15/02/16 14:16, Wei Liu wrote:
> > On Mon, Feb 15, 2016 at 09:07:13AM +0000, Paul Durrant wrote:
> >>>
> > [...]
> >>> # Option 2: Invent a xen-9p device
> >>>
> >>> Another way of doing it is to expose a dummy xen-9p device, so that we
> >>> can use -fsdev XXX -device xen-9p,YYY.  This simple device should be
> >>> used to capture the parameters like mount_tag and fsdev_id, and then
> >>> chained itself to a known location.  Later Xen transport can traverse
> >>> this known location. This xen-9p device doesn't seem to fit well into
> >>> the hierarchy. The best I can think of its parent should be
> >>> TYPE_DEVICE.  In this case:
> >>>
> >>> 1. Toolstack arranges some xenstore entries.
> >>> 2. Toolstack arranges command line options for QEMU:
> >>>       -fsdev XXX -device xen-9p,XXX
> >>> 3. QEMU starts up in xen-attach mode, scans xenstore for relevant
> >>>    entries, then traverses the known location.
> >>>
> >>> Downside: Inventing a dummy device looks suboptimal to me.
> 
> Sorry, didn't notice this thread before.
> 

No need to be sorry. I posted this last Friday night. I wouldn't expect
many replies on Monady.

> For Xen pvUSB backend in qemu I need a Xen system device acting as
> parent for being able to attach/detach virtual USB busses.
> 
> I haven't had time to update my patches for some time, but the patch
> for this system device is rather easy. It could be used as a parent
> of the xen-9p devices, too.
> 
> I've attached the patch for reference.
> 

Thanks. I will have a look at your patch.

Wei.