Re: [Qemu-devel] [v2][PATCH 4/8] xen, gfx passthrough: reserve 00:02.0 for INTEL IGD

[Chen, Tiejun]

> -----Original Message-----
> From: Gerd Hoffmann [mailto:address@hidden
> Sent: Thursday, May 22, 2014 2:45 PM
> To: Chen, Tiejun
> Cc: Anthony PERARD; Daniel P. Berrange; address@hidden;
> address@hidden; address@hidden;
> address@hidden; Kay, Allen M; address@hidden;
> address@hidden; Zhang, Yang Z; address@hidden
> Subject: Re: [Qemu-devel] [v2][PATCH 4/8] xen, gfx passthrough: reserve
> 00:02.0 for INTEL IGD
> 
>   Hi,
> 
> > > Another useful thing would be to not create the xen platform device
> > > in case "-nodefaults" was specified on the command line (that switch
> > > turns off a bunch of other devices present by default: vga, nic, cdrom, 
> > > ...).
> >
> > Currently looks 'xen-platform' itself can't be created, not those devices
> existed on that.
> 
> The error message looks more like libxl tries to hot-unplug the xen platform
> device.
> 
> Attached patch (untested!) hooks up the xen platform device to the default
> device code we have in qemu.  Two effects:
> 
>   (1) As mentioned above the device will not be created in case
>       -nodefaults  is specified on the command line.

I think this is unnecessary to add this option to support GFX passthrough.

>   (2) Autocreating the device is also turned off in case xen-platform
>       is added manually via -device.
> 
> With the patch applied you should be able to move the xen-platform device to
> some other place with a simple 'qemu -device xen-platform,addr=$slot'.
> 

Yes, this patch works now. So I assume this would be merged into ML soon.

Thanks for your great help, Gerd!

Tiejun