Ian Jackson schrieb:
> Kevin Wolf writes ("Re: [PATCH] qemu-xen: Fix PV segfault"):
>> Ian Jackson schrieb:
>>> Kevin Wolf writes ("[PATCH] qemu-xen: Fix PV segfault"):
>>>> Don't access cur_cpu with CONFIG_DM, for PV machines it is NULL.
>>> I'm not sure I understand the execution context here properly.  Is
>>> this for blktap ?  It would be better to make cur_cpu be set to some
>>> sensible value.
>> No, this is completely independent of blktap. Currently, PV machines
>> just don't have a virtual cpu in qemu - in contrary to FV machines which
>> call a complete pc_machine.init() during their initialization.
> 
> Evidently this is a configuration I haven't tested.  My PV machines
> don't use a qemu-dm at all.

AFAIK, you automatically get qemu-dm as soon as you use VNC. So this is
probably the most common use case.

While I'm at it: There's another problem with qemu-xen, I can establish
a VNC connection only if I was connected via xm console before. Maybe I
can take a look at this later this week.

> I would very much prefer an answer which didn't make any additional
> changes to vl.c (or other code shared with upstream).  If such changes
> are necessary they should be textually small.  This will make keeping
> us up to date with qemu upstream much easier.

Yes, I couldn't agree more.

Attached is a new version of the patch which creates a dummy CPU for PV
machines. Now it touches no upstream code any more.

Kevin