Re: Hard and silent lock up since linux 3.14 with PCIe pass through (vfio)

[Alex Williamson <alex.williamson@redhat.com>]

Hi Andreas,

On Fri, 2014-10-17 at 03:04 +0200, Andreas Hartmann wrote:
> Hello Alex,
> 
> Alex Williamson wrote:
> > Hi Andreas,
> [...]
> > Sorry for the breakage.  Is it possible to run lspci on the device in a
> > loop from the host and capture whether we're failing to restore some of
> > the VC bits to their previous state? 
> 
> > Does the problem also occur if you
> > unbind from host driver,
> 
> The machine is booted w/ blacklisted ath9k. Then, the device is bound to
> vfio:
> 
> echo "168c 0030" > /sys/bus/pci/drivers/vfio-pci/new_id
> echo 0000:03:00.0 > /sys/bus/pci/devices/0000:03:00.0/driver/unbind
> echo 0000:03:00.0 > /sys/bus/pci/drivers/vfio-pci/bind
> 
> afterwards the VM is started -> hang.
> 
> W/o starting th VM, I can bind it to vfio and unbind it from vfio w/o
> any problem.
> 
> > echo 1 > reset in pci-sysfs,
> 
> echo 1 > /sys/bus/pci/devices/0000:03:00.0 works w/o any problem while
> bound to vfio. Even after unbinding from vfio and rebinding to vfio
> again ... .
> 
> > and re-bind to the
> 
> Do you mean loading ath9k in host system after unbinding from vfio? If
> yes: Works w/o any problem. It's even possible to reset it or do a
> ifconfig wlan0 up, ifconfig wlan0 down, rmmod ath9k, bind it to vfio
> again and reset it, ....
> 
> Looks like the hang only is triggered by qemu-system_x86_64 on startup
> the VM.
> 
> > host?  I'll also try to reproduce on my 990fx system, but I won't be
> > able to do that until next week due to travel.  Thanks,

Could you send me the lspci -vvvxxxx for the device and parent root
port?  Thanks,

Alex