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

["Chen, Tiejun" <tiejun.chen@xxxxxxxxx>]

> -----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
tchen0@tchen0-linux:~/workspace$

Thanks
Tiejun

> 
> ---
> 
> diff --git a/hw/acpi/pcihp.c b/hw/acpi/pcihp.c index 3b143b3..6f8e26d 100644
> --- a/hw/acpi/pcihp.c
> +++ b/hw/acpi/pcihp.c
> @@ -305,6 +305,7 @@ void acpi_pcihp_init(AcpiPciHpState *s, PCIBus
> *root_bus,
>      s->root= root_bus;
>      s->legacy_piix = !bridges_enabled;
> 
> +    fprintf(stderr, "acpi_pcihp_init\n");
>      if (s->legacy_piix) {
>          unsigned *bus_bsel = g_malloc(sizeof *bus_bsel);
> 
> @@ -313,6 +314,7 @@ void acpi_pcihp_init(AcpiPciHpState *s, PCIBus
> *root_bus,
>          *bus_bsel = ACPI_PCIHP_BSEL_DEFAULT;
>          object_property_add_uint32_ptr(OBJECT(root_bus),
> ACPI_PCIHP_PROP_BSEL,
>                                         bus_bsel, NULL);
> +     fprintf(stderr, "Legacy PCI hotplug\n");
>      }
> 
>      memory_region_init_io(&s->io, NULL, &acpi_pcihp_io_ops, s, diff --git
> a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c index 9fac589..a1211dd 100644
> --- a/hw/i386/acpi-build.c
> +++ b/hw/i386/acpi-build.c
> @@ -736,6 +736,7 @@ static void *acpi_set_bsel(PCIBus *bus, void *opaque)
>      unsigned *bsel_alloc = opaque;
>      unsigned *bus_bsel;
> 
> +    fprintf(stderr, "acpi_set_bsel bus: %s, hotpluggable: %d\n",
> + bus->qbus.name, bus->qbus.allow_hotplug);
>      if (bus->qbus.allow_hotplug) {
>          bus_bsel = g_malloc(sizeof *bus_bsel);


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