Re: [Xen-devel] Xen debugging question (x86-64)

[Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>]

A spontaneous reboot with no error output is almost certainly a triple
fault. Since we have a double fault handler that should trigger on
ring-0 stack overflow, the cause is very likely that you have written
an invalid pagetable base into %cr3. If you do this then even the
double-fault handler is inaccessible and you are toast.

I'd add tracing to write_cr3() in Xen, perhaps gated on
current->domain->id == 1, and I would check that the new domain's page
tables has the Xen mappings correctly copied into the Xen reserved
area in the PML4.

 -- Keir

> Hey guys,
>       I have the x86-64 domU building code for libxc just about ready. It
> totally gets through the library and creates the domain. But once it
> does it reboots the machine (and no output to show what happened via the
> serial console).  What techniques would you guys use find out (excluding
> excessive printks ....I'm doing that right now) what is going on in xen
> and tracing back to the problem in this situation?
> -- 
> Jerone Young
> IBM Linux Technology Center
> jyoung5@xxxxxxxxxx
> 512-838-1157 (T/L: 678-1157)
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-devel
> 


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