[ofa-general] Re: [patch] my mmu notifiers

[Andrea Arcangeli]

On Wed, Feb 20, 2008 at 12:11:57AM +0100, Nick Piggin wrote:
> Sorry, I realise I still didn't get this through my head yet (and also
> have not seen your patch recently). So I don't know exactly what you
> are doing...

The last version was posted here:

http://marc.info/?l=kvm-devel&m=120321732521533&w=2

> But why does _anybody_ (why does Christoph's patches) need to invalidate
> when they are going to be more permissive? This should be done lazily by
> the driver, I would have thought.

This can be done lazily by the driver yes. The place where I've an
invalidate_pages in mprotect however can also become less permissive.
It's simpler to invalidate always and it's not guaranteed the
secondary mmu page fault is capable of refreshing the spte across a
writeprotect fault. In the future this can be changed to
mprotect_pages though, so no page fault will happen in the secondary
mmu.