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

[Igor Mammedov <imammedo@xxxxxxxxxx>]

On Fri, 23 May 2014 01:18:33 +0000
"Chen, Tiejun" <tiejun.chen@xxxxxxxxx> wrote:

> > -----Original Message-----
> > From: Igor Mammedov [mailto:imammedo@xxxxxxxxxx]
> > Sent: Thursday, May 22, 2014 10:20 PM
> > To: Michael S. Tsirkin
> > Cc: Chen, Tiejun; peter.maydell@xxxxxxxxxx; xen-devel@xxxxxxxxxxxxxxxxxxx;
> > Daniel P. Berrange; stefano.stabellini@xxxxxxxxxxxxx; Kay, Allen M;
> > Kelly.Zytaruk@xxxxxxx; qemu-devel@xxxxxxxxxx; Zhang, Yang Z; Gerd
> > Hoffmann; anthony@xxxxxxxxxxxxx; Anthony PERARD
> > Subject: Re: [Xen-devel] [Qemu-devel] [v2][PATCH 4/8] xen, gfx passthrough:
> > reserve 00:02.0 for INTEL IGD
> > 
> > On Thu, 22 May 2014 14:25:32 +0300
> > "Michael S. Tsirkin" <mst@xxxxxxxxxx> wrote:
> > 
> > > On Thu, May 22, 2014 at 10:50:10AM +0000, Chen, Tiejun wrote:
> > > > > -----Original Message-----
> > > > > From: Gerd Hoffmann [mailto:kraxel@xxxxxxxxxx]
> > > > > Sent: Thursday, May 22, 2014 2:45 PM
> > > > > To: Chen, Tiejun
> > > > > Cc: Anthony PERARD; Daniel P. Berrange; peter.maydell@xxxxxxxxxx;
> > > > > xen-devel@xxxxxxxxxxxxxxxxxxx; mst@xxxxxxxxxx;
> > > > > stefano.stabellini@xxxxxxxxxxxxx; Kay, Allen M;
> > > > > Kelly.Zytaruk@xxxxxxx; qemu-devel@xxxxxxxxxx; Zhang, Yang Z;
> > > > > anthony@xxxxxxxxxxxxx
> > > > > 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.
> > even if it's not set, and xenfv compat prop says it isn't, root PCI bus 
> > should have
> > property present.
> > 
> > Tiejun,
> >   What is output of the following debug patch:
> 
> With your patch and the following configurations,
> 
> gfx_passthru=1
> pci=["00:02.0@2", "00:1a.0"]
> xen_platform_pci=0
> device_model_args_hvm = ['-device', 'xen-platform,addr=0x3']
> 
> Then,
> 
> 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
> tchen0@tchen0-linux:~/workspace$ cat /var/log/xen/qemu-dm-HVM.log             
>                                                                               
>            
> char device redirected to /dev/pts/40 (label serial0)
> acpi_pcihp_init
> qemu: terminating on signal 1 from pid 24621

it looks like compat property "acpi-pci-hotplug-with-bridge-support"
which is defined as 'off' for 'xenfv' machine is not applied for
some reason.

I'd suggest to investigate a reason why compat properties don't work
for xenfv machine.

> 
> Thanks
> Tiejun

-- 
Regards,
  Igor

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