Re: xm save + restore crashes Windows 2008 32-bit (4.0.2-rc2-pre)

[Tim Deegan <Tim.Deegan@citrix.com>]

At 10:43 +0000 on 25 Jan (1295952215), James Harper wrote:
> > > I should know if the problem exists on intel very soon. I'm guessing
> not
> > > or I wouldn't be the first one posting about it... either that or
> there
> > > is something else going on.
> > 
> > It was on AMD that I saw it too.  If I read them correctly, Ian's
> > regression tests are passing HVM save/restore for at least some
> Windows
> > versions on AMD too, so it may be very specific.
> > 
> 
> Definitely AMD specific. Works fine on my Intel system.
> 
> I'm guessing it's missing the save and/or restore of some critical part
> of the CPU state for the domain that causes an immediate crash when
> return to user mode. Any suggestions as to where to start looking?

I'm trying to set it up here as well but I'm away from the office and
getting the VGA console as far as my screen is proving tricky.

Can you try:
 - xl pause <domid>
 - xen-hvmctx <domid> >before
 - xl save <domid> save-file
 - xl restore -p save-file
 - xl list
 - xen-hvmctx <new-domid> >after
 - diff -u before after

There should be a few differences to do with timers and TSCs but there
might be some other smoking gun.  Of course it's possible that some
piece of state got added that didn't get into the save/restore code at
all.  It's also possible that some vital piece of memory isn't getting
saved properly but that's less likely to be AMD-specific. 

Cheers,

Tim.

-- 
Tim Deegan <Tim.Deegan@citrix.com>
Principal Software Engineer, Xen Platform Team
Citrix Systems UK Ltd.  (Company #02937203, SL9 0BG)