Re: [Xen-devel] CONFIG_XEN_COMPAT_030002 broken?

["Jan Beulich" <jbeulich@xxxxxxxxxx>]

>>> Keir Fraser <keir@xxxxxxxxxxxxx> 14.11.06 12:50 >>>
>On 14/11/06 11:14, "Jan Beulich" <jbeulich@xxxxxxxxxx> wrote:
>
>>> By the way, the test of whether to poke in PAGE_USER can be done by looking
>>> at one of the initial mappings provided by the domain builder. If one of
>>> those ptes contains PAGE_USER, you know you need to use PAGE_USER for all
>>> kernel mappings.
>> 
>> How would this work? adjust_guest_l1e() (and BASE_PROT for dom0) forces
>> PAGE_USER on even on 3.0.3, so I still shouldn't find any L1 page table
>> entries
>> not having this bit set when looking at them from kernel code.
>
>Oh, good point! Okay then the more straightforward XENVER_version check will
>have to be used: 3.0.3 and newer, versus 3.0.2 and older.

More strait forward? The .3 is part of extraversion, so in order to do a 
comparison
one would have to parse that string (and hence make certain assumptions). That's
not nice for use in (early) feature detection. Maybe it'd be better to try and 
write
a page table entry without PAGE_USER, and check whether that bit got turned
on implicitly...

Jan

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