Re: [Xen-devel] Re: [PATCH 0/6] xen: don't call vmalloc_sync_all()when mapping foreign pages

From: David Vrabel
Date: Fri Sep 23 2011 - 07:16:29 EST


On 22/09/11 22:19, Jeremy Fitzhardinge wrote:
>
> But I'd be happier pretending that vmalloc_sync_* just doesn't exist,
> and deal with it at the hypercall level - in the short term, by just
> making sure that the callers touch all those pages before passing them
> into the hypercall.

I don't think you can access the pages at the addresses allocated with
alloc_vm_area() because the pages don't exist yet and there's a check of
pte_present() in vmalloc_fault() and I think an Oops will be reported.

David
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