likely cause for xm restore failure?

likely cause for xm restore failure?

[Kip Macy]

I'm seeing the following when trying to restore a variant of linux on
xen, is this most likely to be caused by a bug in P2M handling in the
guest that is being saved?

      -Kip


(XEN) DOM0: (file=memory.c, line=917) Bad type (saw 20000000 != exp
e0000000) for pfn 00001ab9
(XEN)
(XEN) DOM0: (file=memory.c, line=952) Error while validating pfn
000011b0 for type 27de0000. caf=80000003 taf=27de0001
(XEN)
(XEN) DOM0: (file=memory.c, line=387) Attempt to create linear p.t.
with write perms
(XEN) DOM0: (file=memory.c, line=952) Error while validating pfn
0007ffbd for type 40000000. caf=80000002 taf=40000001
(XEN)
(XEN) DOM0: (file=memory.c, line=356) Bad page type for pfn 0007ffbd (00000000)
(XEN) DOM0: (file=memory.c, line=995) Error while pinning pfn 0007ffbd

RE: likely cause for xm restore failure?

[Ian Pratt]

 
> I'm seeing the following when trying to restore a variant of 
> linux on xen, is this most likely to be caused by a bug in 
> P2M handling in the guest that is being saved?

The restore code probably doesn't handle linear pt's as used by FreeBSD
correctly. This is actually a bit icky, as we need to make sure that the
subject L2's is pinned before the linear mapping is created, otherwise
the pin will fail. Given that we process the pages as soon as they
arrive, this is hard to ensure. The easiest soloution would be to just
defer the pagetable procesing for guests that use linear mapping, or
have code to clean up if a type chck fails.

Ian   
 
>       -Kip
> 
> 
> (XEN) DOM0: (file=memory.c, line=917) Bad type (saw 20000000 != exp
> e0000000) for pfn 00001ab9
> (XEN)
> (XEN) DOM0: (file=memory.c, line=952) Error while validating 
> pfn 000011b0 for type 27de0000. caf=80000003 taf=27de0001
> (XEN)
> (XEN) DOM0: (file=memory.c, line=387) Attempt to create linear p.t.
> with write perms
> (XEN) DOM0: (file=memory.c, line=952) Error while validating 
> pfn 0007ffbd for type 40000000. caf=80000002 taf=40000001
> (XEN)
> (XEN) DOM0: (file=memory.c, line=356) Bad page type for pfn 
> 0007ffbd (00000000)
> (XEN) DOM0: (file=memory.c, line=995) Error while pinning pfn 0007ffbd
> 
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