Re: Xen PCI passthrough & OpenWRT domU

[Jean Baptiste Favre <xen-devel@jbfavre.org>]

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