[Intel-gfx] [PATCH 1/5] drm/i915/gtt: Add read only pages to gen8_pte_encode

[Chris Wilson]

Quoting Matthew Auld (2018-05-31 15:43:14)
> On 31 May 2018 at 12:35, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> > From: Jon Bloomfield <jon.bloomfield at intel.com>
> >
> > We can set a bit inside the ppGTT PTE to indicate a page is read-only;
> > writes from the GPU will be discarded. We can use this to protect pages
> > and in particular support read-only userptr mappings (necessary for
> > importing PROT_READ vma).
> >
> > Signed-off-by: Jon Bloomfield <jon.bloomfield at intel.com>
> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> > Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
> > Cc: Matthew Auld <matthew.william.auld at gmail.com>
> > Reviewed-by: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
> 
> fwiw I didn't see any surprises with ro 2M/64K PTEs when testing locally.
> 
> For the series:
> Reviewed-by: Matthew Auld <matthew.william.auld at gmail.com>

I think I'd like to see a selftest also exercising the ro nature before
pushing. Thanks for the review, stick around there'll be another patch
to come :)
-Chris