On Thu, 2018-05-31 at 12:35 +0100, Chris Wilson wrote: > If the user has created a read-only object, they should not be allowed > to circumvent the write protection by using a GGTT mmapping. Deny it. > > Also most machines do not support read-only GGTT PTEs, so again we have > to reject attempted writes. Fortunately, this is known a priori, so we > can at least reject in the call to create the mmap with backup in the > fault handler. This is a little draconian as we could blatantly ignore > the write protection on the pages, but it is far simply to keep the > readonly object pure. (It is easier to lift a restriction than to impose > it later!) > > Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> > Cc: Jon Bloomfield <jon.bloomfield@xxxxxxxxx> > Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx> > Cc: Matthew Auld <matthew.william.auld@xxxxxxxxx> As discussed in IRC, this is no change to previous uAPI as read-only objects have not been available previously. And even afterwards, only GTT_MMAP on RO userptr will be rejected for platforms that don't have RO pages, so that's part of the newly implemented RO userptr. Reviewed-by: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx> Regards, Joonas -- Joonas Lahtinen Open Source Technology Center Intel Corporation _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
