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

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

On Fri, Jan 10, 2014 at 03:51:57PM +0100, Sander Eikelenboom wrote:
> Hi Konrad,
> 
> Normally i'm never reattaching pci devices to dom0, but at the moment i have 
> some use for it.
> 
> But it seems pci-detach isn't completely detaching the device from the guest.
> 
> - Say i have a guest (HVM) with domid=2 and a pci device passedthrough with 
> bdf 00:19.0, the device is hidden on boot with xen-pciback.hide=(00:19.0) in 
> grub.
> 
> - Now i do a "xl pci-assignable-list"
>   This returns nothing, which is correct since all hidden devices have 
> already been assigned to guests.
> 
> - Then i do "xl -v pci-detach 2 00:19.0"
>   Which also returns nothing ...
> 
> - Now i do a "xl pci-assignable-list" again ..
>   This returns:
>   "0000:00:19.0"
>   So the pci-detach does seem to have done *something* :-)

Or it thinks it has :-)

> 
> - But when now trying to remove the device from pciback to dom0 with "xl 
> pci-assignable-remove 00:19.0" it gives an error
>   and later it give some stacktraces ..
> 
>   xen_pciback: ****** removing device 0000:00:19.0 while still in-use! ******
>   xen_pciback: ****** driver domain may still access this device's i/o 
> resources!
>   xen_pciback: ****** shutdown driver domain before binding device
>   xen_pciback: ****** to other drivers of domains

What about /var/log/xen/qemu-dm* and the 'lspci' in the guest? Is the PCI device
removed from there?
> 
> 
> When i shut the guest down instead of using pci-detach, the "xl 
> pci-assignable-remove" works fine and i can rebind the device to it's driver 
> in dom0.
> 
> So am i misreading the wiki .. and is it not possible to detach a device from 
> a running domain or ... ?
> 
> Oh yes running xen-unstable and a 3.13-rc7 kernel

Do you see the same issue with 'xend'? 
> 
> --
> Sander
> 
> 

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