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

["Michael S. Tsirkin" <mst@redhat.com>]

On Thu, May 22, 2014 at 10:50:10AM +0000, Chen, Tiejun wrote:
> > -----Original Message-----
> > From: Gerd Hoffmann [mailto:kraxel@redhat.com]
> > Sent: Thursday, May 22, 2014 2:45 PM
> > To: Chen, Tiejun
> > Cc: Anthony PERARD; Daniel P. Berrange; peter.maydell@linaro.org;
> > xen-devel@lists.xensource.com; mst@redhat.com;
> > stefano.stabellini@eu.citrix.com; Kay, Allen M; Kelly.Zytaruk@amd.com;
> > qemu-devel@nongnu.org; Zhang, Yang Z; anthony@codemonkey.ws
> > 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.
> >   (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=$slot'.
> > 
> 
> Gerd,
> 
> Sorry, I may misunderstand what you mean previously then have a wrong test.
> 
> So this still doesn't work actually. 
> 
> After applied your patch, 'xen-platform' is always disabled by default, right? So 00:02.0 is left naturally to be assigned to IGD as we expect like this,
> 
> tchen0@tchen0-HVM-domU:~$ lspci
> 00:00.0 Host bridge: Intel Corporation 4th Gen Core Processor DRAM Controller (rev 06)
> 00:01.0 ISA bridge: Intel Corporation 82371SB PIIX3 ISA [Natoma/Triton II]
> 00:01.1 IDE interface: Intel Corporation 82371SB PIIX3 IDE [Natoma/Triton II]
> 00:01.3 Bridge: Intel Corporation 82371AB/EB/MB PIIX4 ACPI (rev 03)
> 00:02.0 VGA compatible controller: Intel Corporation Xeon E3-1200 v3/4th Gen Core Processor Integrated Graphics Controller (rev 06)
> 00:03.0 USB controller: Intel Corporation 8 Series/C220 Series Chipset Family USB EHCI #2 (rev 04)
> 00:1f.0 ISA bridge: Intel Corporation Q87 Express LPC Controller (rev 04)
> 
> Then this is fine but if you intend to add a 'qemu -device xen-platform,addr=$slot', this doesn't work well. In my case,
> 
> gfx_passthru=1
> pci=["00:02.0@2", "00:1a.0"]
> xen_platform_pci=0
> device_model_args_hvm = ['-device', 'xen-platform,addr=0x3']
> 
> tchen0@tchen0-linux:~/workspace$ sudo xl cr domu-cfg
> Parsing config from domu-cfg
> libxl: error: libxl_qmp.c:287:qmp_handle_error_response: received an error message from QMP server: Unsupported bus. Bus doesn't have property 'acpi-pcihp-bsel' set
> libxl: error: libxl_create.c:1277:domcreate_attach_pci: libxl_device_pci_add failed: -3
> 
> Thanks
> Tiejun

Weird: this implies use_acpi_pci_hotplug got set somehow.

-- 
MST