Re: [Xen-devel] Xen PCI passthrough & OpenWRT domU

[Jean Baptiste Favre <xen-devel@xxxxxxxxxxx>]

Hello everybody,

Just a quick mail to inform you that I succeed to make PCI passthrough
run with OpenWRT trunk and newly released Linux kernel 2.6.37 :)

I'll now write an howto

Regards,
JB


Le 29/12/2010 14:11, Jean Baptiste Favre a écrit :
> Hello Pasi,
> 
> Le 29/12/2010 13:07, Pasi Kärkkäinen a écrit :
>> On Wed, Dec 29, 2010 at 12:04:17PM +0100, Jean Baptiste Favre wrote:
>>> Hello,
>>> I'm trying to make Openwrt running as domU with network cards PCI
>>> passthrough.
>>>
>>> First part is OK, OpenWRT runs fine as x86 PV domU, but not PCI passthrough.
>>>
>>> Dom0 runs debian Xen packages.
>>> # cat /proc/cmdline
>>> placeholder root=/dev/mapper/system-root ro console=tty0 console=hvc0
>>> console=ttyS0,115200n8 xen-pciback.permissive xen-pciback.hide=(04:00.0)
>>> pci=resource_alignment=04:00.0 quiet
>>>
>>> # lspci
>>> ...
>>> 04:00.0 Ethernet controller: Marvell Technology Group Ltd. 88E8056 PCI-E
>>> Gigabit Ethernet Controller (rev 12)
>>>
>>> # uname -a
>>> Linux remus 2.6.32-5-xen-amd64 #1 SMP Fri Dec 10 17:41:50 UTC 2010
>>> x86_64 GNU/Linux
>>>
>>> OpenWRT uses upstream kernel 2.6.32.27 (but I also tested 2.6.35.9
>>> without any changes).
>>>
>>
>> Upstream Linux 2.6.32.27 doesn't have xen-pcifront driver.
>> Upstream 2.6.35.9 doesn't have it either.
>>
>> xen-pcifront driver was merged to upcoming upstream 2.6.37 kernel.
> 
> So, I'll try with 2.6.37 :)
> 
> 
>>> domU informations:
>>> # cat /proc/cmdline
>>> root=/dev/xvda2 rw swiotlb=force console=hvc0 xencons=tty
>>>
>>> # lspci
>>> [empty]
>>>
>>
>> You should see the PCI device with lspci. 
>> I guess you don't have xen-pcifront driver in use.
> 
> That's what I think, but do not know how to check xen-pcifront use
> 
> 
>>> # dmesg | grep -i pci
>>> Allocating PCI resources starting at 10000000 (gap: 10000000:f0000000)
>>> PCI: Fatal: No config space access function found
>>> PCI: System does not support PCI
>>> PCI: System does not support PCI
>>> PCI: CLS 0 bytes, default 128
>>> XENBUS: Device with no driver: device/pci/0
>>>
>>> # dmesg | grep -i xen
>>>  Xen: 0000000000000000 - 00000000000a0000 (usable)
>>>  Xen: 00000000000a0000 - 0000000000100000 (reserved)
>>>  Xen: 0000000000100000 - 0000000010000000 (usable)
>>>   #0 [00014c6000 - 00014d4000]   XEN PAGETABLES ==> [00014c6000 -
>>> 00014d4000]
>>>   #3 [0001483000 - 00014c6000]   XEN START INFO ==> [0001483000 -
>>> 00014c6000]
>>> Booting paravirtualized kernel on Xen
>>> Xen version: 4.0.1 (preserve-AD)
>>> Xen: using vcpu_info placement
>>> Kernel command line: root=/dev/xvda2 rw swiotlb=force console=hvc0
>>> xencons=tty
>>> Xen: using vcpuop timer interface
>>> installing Xen timer for CPU 0
>>> xen_balloon: Initialising balloon driver.
>>> Switching to clocksource xen
>>> Initialising Xen virtual ethernet driver.
>>> XENBUS: Device with no driver: device/pci/0
>>> XENBUS: Device with no driver: device/console/0
>>>
>>> So, it seems that domU sees PCI device (and sky2 module is loaded), but
>>> do not recognize it.
>>> I have tried to compile PCI frontend driver, which is not by default,
>>> but not sure I succeeded. How can I check it ?
>>>
>>> Another question, are there any requirement in terms of kernel version
>>> regarding the version of Xen I use ? If yes, how can I check that too ?
>>>
>>
>> xen-pcifront driver is required in the domU kernel.
>>
>>> Sorry for long email, but I also ask it on OpenWRT devel list without
>>> answer for now.
>>
>> See: http://wiki.xensource.com/xenwiki/XenPCIpassthrough
> 
> Already saw this page. This is my reference for these tries :)
> 
> 
> Thanks a lot for answer,
> JB
> 
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> http://lists.xensource.com/xen-devel
> 


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