RE: [Xen-devel] AMD crash on restore. bug in MTRR restore.4.0.2-rc2-pre

["James Harper" <james.harper@xxxxxxxxxxxxxxxx>]

By saving the sysenter msrs in my PV drivers before the suspend
hypercall and restoring them after, save/restore now works fine.

Does nobody else see a save/restore failure on AMD as a blocker to
4.0.2? It it something particular to my exact AMD CPU and OS (Windows
2008 x32)?

James

> -----Original Message-----
> From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx [mailto:xen-devel-
> bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of James Harper
> Sent: Thursday, 27 January 2011 13:32
> To: xen-devel@xxxxxxxxxxxxxxxxxxx
> Cc: Tim Deegan
> Subject: RE: [Xen-devel] AMD crash on restore. bug in MTRR
restore.4.0.2-rc2-
> pre
> 
> Additionally, WinDbg tells me that MSR's 175, and 176 are wiped out by
> save/restore:
> 
> immediately before suspend
> kd> rdmsr 174
> msr[174] = 00000000`00000008
> kd> rdmsr 175
> msr[175] = 00000000`8039e000
> kd> rdmsr 176
> msr[176] = 00000000`816a4950
> 
> immediately after restore
> kd> rdmsr 174
> msr[174] = 00000000`00000000
> kd> rdmsr 175
> msr[175] = 00000000`00000000
> kd> rdmsr 176
> msr[176] = 00000000`00000000
> 
> although you're never too sure with WinDbg...
> 
> James
> 
> > -----Original Message-----
> > From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx [mailto:xen-devel-
> > bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of James Harper
> > Sent: Wednesday, 26 January 2011 17:19
> > To: xen-devel@xxxxxxxxxxxxxxxxxxx
> > Cc: Tim Deegan
> > Subject: [Xen-devel] AMD crash on restore. bug in MTRR restore.
> 4.0.2-rc2-pre
> >
> > The mtrr save code on my AMD system reads the first MTRR as
> > 0x00000000f0000000,0x000000fff8000800. When it tries to restore in
> > mtrr_var_range_msr_set, 0x000000fff8000800 is rejected as invalid
and
> > not restored.
> >
> > Commenting out the check against the mask, as well as Tim's patch to
> fix
> > the segment registers makes the output of xen-hvmctx match before
the
> > save and after the restore.
> >
> > Windows still crashes on restore though so I don't know if this has
> > anything to do with it.
> >
> > James
> >
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@xxxxxxxxxxxxxxxxxxx
> > http://lists.xensource.com/xen-devel
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-devel

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