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

[Andreas Hartmann <andihartmann@freenet.de>]

Andreas Hartmann wrote:
> Alex Williamson wrote:
[...]
>> Are you able to setup a serial console on this system?  Enabling sysrq
>> and getting a dump of task states (t) via serial is often the best way
>> to determine the problem. 
> 
> I'll try it.

I did it now like this:

minicom on the client.

Magic SysKeyRequest via minicom:

Ctrl-A shift-f [Syskey, like m or t, ...]


On the sender:
As kerneloption: console=tty0 console=ttyS0,115200n8

Before, you have to enable syskeyrequest via
sysctl -w kernel.sysrq=1

After doing all of this, you can test w/ m or t. The output will appear
on tty9 (via Alt-F10 on openSUSE).


But what was the result after starting the VM? -> Machine is definitely
completely dead. It doesn't react on anything any more.


Remarkable:
After hard reset, the USB keyboard doesn't work any more in Linux (but
in Grub 2), because the driver gets a timeout accessing the USB 3 hw
(other USB chips are working fine). It is necessary to switch of the
machine completely and remove the mains. After ~ 30s, it can be
repowered and all is working fine again (after repairing the broken FS
the VM resides on the host).


Any more hints are welcome :-)


Thanks,
kind regards,
Andreas