Re: [Qemu-devel] [PATCH for-1.6 V2 0/2] pvpanic: Separate pvpanic from machine type

[Michael S. Tsirkin]

On Wed, Aug 21, 2013 at 10:18:23AM +0200, Paolo Bonzini wrote:
> Il 21/08/2013 10:03, Marcel Apfelbaum ha scritto:
> > On Wed, 2013-08-14 at 10:02 +0300, Ronen Hod wrote:
> >> How about adding a flag that tells QEMU whether to pause or reboot the 
> >> guest
> >> after the panic?
> >> We cannot assume that we always have a management layer that takes care
> >> of this.
> >> One example is Microsoft's WHQL that deliberately generates a BSOD, and 
> >> then
> >> examines the dump files.
> > After this patch the pvpanic is not part of the global devices anymore so 
> > just
> > don't enable it if you want to reboot on BSOD.
> > In my opinion "reboot after panic" equals "run without pvpanic device"
> 
> This is not entirely possible, since "reboot after panic" is a guest
> setting while "run without pvpanic device" is a host setting (that the
> guest administrator may not even have access to: Ronen's case is a good
> example of this, because the "administrator" there is the WHQL harness).
> 
> However, I think this is a driver problem.  The driver should just probe
> the "reboot after panic" setting and not issue the outb to the pvpanic port.
> 
> Paolo

This might or might not be possible on different OS-es.
What exactly is gained by doing vmstop on outb of pvpanic?
We want a notification about the panic but
adding yet another way to halt seems kind of useless.
Why not let VM continue? If it wants to stop it
can always call halt.