RE: xm save + restore crashes Windows 200832-bit(4.0.2-rc2-pre) (AMD only)

["James Harper" <james.harper@bendigoit.com.au>]

> 
> At 13:35 +0000 on 25 Jan (1295962540), James Harper wrote:
> > So the problem is somewhere past hvm_set_segment_register, and
because
> > it's amd only, probably in or beyond svm_set_segment_register. The
first
> > thing I notice in that routine is that there is a case for those 4
> > registers... although all it seems to do is svm_sync_vmcb before and
> > svm_vmload after setting. I don't know what those two do though.
> 
> Hmm; I suspect the bug here is actually in the save side -- the
syncing
> of the vmcb in the save routine is not conditional on v == current,
and
> the "already synced" bit that it would otherwise gate on isn't
properly
> initialized.
> 
> Try the attached patch; I'm sorry to say that I suspect it will fix
the
> odd output of xen_hvmctx but probably won't fix the BSOD. :(
> 

Just to clarify, in the restore path I print the values to be saved to
the segment registers, then I read the segment registers and print the
values that are in them. They aren't the same. Doesn't that sound like a
problem on the restore side?

James