Re: [patch 06/26] Xen-paravirt_ops: paravirt_ops: allocate a fixmap slot

Jeremy Fitzhardinge
2007-02-27T18:55:22Z

Ingo Molnar wrote:
> * Jeremy Fitzhardinge <jeremy@goop.org> wrote:
>
>
>> Allocate a fixmap slot for use by a paravirt_ops implementation. Xen
>> uses this to map the hypervisor's shared info page, which doesn't have
>> a pseudo-physical page number, and therefore can't be mapped
>> ordinarily.
>>
>
> why not vmalloc it on the guest side? fixmaps are bad for this purpose
> for a general paravirt implementation, it limits the size of the shared
> info page, etc.

Yes. vmalloc would have the annoying side-effect of actually allocating
some pages which would be shadowed by the remapping, but I guess
get_vm_area would do the job. I'll give it a go.

J