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

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

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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. :(

Cheers,

Tim.

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

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diff -r 9b453f96dd46 xen/arch/x86/hvm/svm/vmcb.c
--- a/xen/arch/x86/hvm/svm/vmcb.c	Fri Jan 21 16:03:04 2011 +0000
+++ b/xen/arch/x86/hvm/svm/vmcb.c	Tue Jan 25 14:36:32 2011 +0000
@@ -280,6 +280,7 @@ int svm_create_vmcb(struct vcpu *v)
     }
 
     arch_svm->vmcb_pa = virt_to_maddr(arch_svm->vmcb);
+    arch_svm->vmcb_in_sync = 1;
 
     return 0;
 }

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