Re: Re: Next steps with pv_ops for Xen

[Jeremy Fitzhardinge <jeremy@goop.org>]

Juan Quintela wrote:
> Hi,
>
> your console works great, but rest of patches are assuming:
>
> arch/x86/boot/compressed/notes-xen.c
> arch/x86/xen/early.c
>   

Yes, those are leftovers from a somewhat unsuccessful attempt at getting
ELF-in-bzImage booting working.  I need to go back and make bzImage
booting work properly.

I posted those patches as a source of possibly useful code
snippets/summary of things I've looked at so far, rather than something
that can be directly used.

> at least.  It looks as if there is missing another patche, could you
> take a look, please?
> Otherwise, I will take a look at what is missing.
>
> It breaks with:
>
> Intel machine check architecture supported.
> (XEN) traps.c:1734:d0 Domain attempted WRMSR 00000404 from 00000000:00000001 to
> ffffffff:ffffffff.
> Intel machine check reporting enabled on CPU#0.
> general protection fault: 0000 [#1] SMP
> Modules linked in:
>   

Hm.  Looks like Xen is getting upset about dom0 trying to disable
caching.  No, wait: 0xffffffff:ffffffff?  That's strange; I wonder if
its just misreporting the value, because the code doesn't look like its
trying to write that.

Either way, the fix is to implement xen_write_cr0, and mask off any bits
that Xen won't want us to set/clear (or if it doesn't allow dom0 to
change cr0, just ignore all updates).

    J