Re: Xen pci-passthrough problem with pci-detach and pci-assignable-remove

[Sander Eikelenboom <linux@eikelenboom.it>]

Monday, January 27, 2014, 5:29:27 PM, you wrote:

> On Fri, Jan 24, 2014 at 1:36 PM, Sander Eikelenboom
> <linux@eikelenboom.it> wrote:
>>
>> Friday, January 10, 2014, 6:38:10 PM, you wrote:
>>
>>>> > Wow. You just walked in a pile of bugs didn't you? And on Friday
>>>> > nonethless.
>>>>
>>>> As usual ;-)
>>
>>> Ha!
>>> ..snip..
>>>> >> [  489.082358]  [<ffffffff81087ac6>] ? mutex_spin_on_owner+0x38/0x45
>>>> >> [  489.106272]  [<ffffffff818e5e22>] ? schedule_preempt_disabled+0x6/0x9
>>>> >> [  489.130158]  [<ffffffff818e7034>] ? __mutex_lock_slowpath+0x159/0x1b5
>>>> >> [  489.154147]  [<ffffffff818e70a6>] ? mutex_lock+0x16/0x25
>>>> >> [  489.177890]  [<ffffffff8135972d>] ? pci_reset_function+0x26/0x4e
>>>>
>>>> > Yeah, that bug my RFC patchset (the one that does the slot/bus reset) should also fix.
>>>> > I totally forgot about it !
>>>>
>>>> Got a link to that patchset ?
>>
>>> https://lkml.org/lkml/2013/12/13/315
>>
>>>> I at least could give it a spin .. you never know when fortune is on your side :-)
>>
>>> It is also at this git tree:
>>
>>> git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen.git and the
>>> branch name is "devel/xen-pciback.slot_and_bus.v0". You will likely
>>> want to merge it in your current Linus tree.
>>
>>> Thank you!
>>
>>
>> Hi Konrad,
>>
>> Just got time to test this some more, when merging this branch *except* the last commit (9599a5ad38a3bb250e996ccb2cdaab6fb68aaacd)
>> seems to help with my problem,i'm no capable of using:
>> - xl pci-detach
>> - xl pci-assignable-remove
>> - echo "BDF" > /sys/bus/pci/drivers/<devicename>/bind

> Out of curiosity, have you tried adding the -r option to pci-assignable-remove?

> xl pci-assignable-add will store the original driver to which the
> device was bound in xenstore; if you do "xl pci-assignable-remove -r"
> it will attempt to re-bind it to that driver.

> See more information here:

> http://blog.xen.org/index.php/2012/06/04/xen-4-2-preview-xl-and-pci-pass-through/

Hi George,

Yes i did, but since i seize the device at boot it was never bound to a device, so
that isn't useful in this case (it doesn't know what to rebind to).


But this problem seems fixed after applying the first 4 commits in konrad's pci reset branch at:

http://git.kernel.org/cgit/linux/kernel/git/konrad/xen.git devel/xen-pciback.slot_and_bus.v0

Applying the last commit creates more problems than it fixes at the moment (hungtasks), so that
one clearly need more polishing. 

So it's clearly a problem in the kernel and pciback specifically.

--
Sander


>  -George