Re: VGA Passthrough crashes machine

[Anthony Wright <anthony@overnetdata.com>]

On 14/12/2011 21:38, Konrad Rzeszutek Wilk wrote:
> On Thu, Dec 08, 2011 at 12:00:07PM +0000, Anthony Wright wrote:
>> I've just had my first attempt at getting VGA passthrough to work, and
>> it crashed the machine. I'm trying to understand whether this is a
>> problem with my hardware, configuration or a software problem.
>>
>> I'm running Xen 4.1.2 with Linux 3.1.2
>>
>>
>> The CPU is an Intel Core i5-650
>> http://ark.intel.com/products/43546/Intel-Core-i5-650-Processor-%284M-Cache-3_20-GHz%29
> And what is your motherboard? Does it have VT-d?
That was the important question... I'd missed the BIOS option to enable
VT-d which was disabled by default. I enabled the BIOS option and
everything worked, and it's very cool. :-)

This does beg a couple of other questions though....

Shouldn't I get a nice(ish) error message if I try to start a VGA
passthrough VM on hardware that doesn't support it rather than crashing
the machine?

Can I tell whether hardware will support VGA passthrough without trying
to start a VM that uses it?

Also when I shut down the VM I have to use 'xl destroy' as I'm testing
with Windows. After issuing the 'xl destroy' there is a long pause and
then the error:

    libxl: error: libxl_device.c:470:libxl__wait_for_device_model Device
Model not ready
    libxl: error: libxl_pci.c:892:do_pci_remove Device Model didn't
respond in time

If I pass through more than one device, I get the pause and the message
for each device.