Re: [Qemu-devel] pvpanic device should not be automatically included as an internal device

[Eric Blake <eblake@redhat.com>]

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On 08/01/2013 04:23 PM, Paolo Bonzini wrote:
>> Automatic devices with no command line argument have proven to be a
>> nightmare for libvirt as well.  Although the just-released libvirt 1.1.1
>> now supports the <on_crash> element for controlling the command line
>> parameters of qemu related to how qemu will behave when the pvpanic
>> device is triggered, I would also welcome having the ability to control
>> whether the guest even has a pvpanic device exposed, just as we can
>> control whether a guest has a memballoon device exposed.
> 
> This is quite different from memballoon.
> 
> pvpanic is a single I/O port, it doesn't use up a PCI slot (thus
> causing conflicts with other devices at the same address).
> 
> Perhaps this issue is simply fixed by making the _STA method
> return 0x0B instead of 0x0F (i.e. turning off the "show in user
> interface" bit).

That may "fix" the issue of a windows guest showing the yellow ! mark,
but what if, down the road, someone writes an actual windows driver that
is aware of that port and how to make a windows BSOD write a panic
notification to the port?  How does a user go about installing such a
driver if the device is not exposed in the user interface list of devices?


-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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