On Fri, Sep 19, 2014 at 09:05:57AM +0100, Chris Wilson wrote: > On Sat, Sep 20, 2014 at 02:47:02AM +0800, Jike Song wrote: > > From: Yu Zhang <yu.c.zhang@xxxxxxxxx> > > If all entries may have prefetch issues, > > then this special guard page is necessary, to protect unexpected > > accesses into GTT entries partitioned out by other VMs. Otherwise, > > we may only need one guard page at the end of the physical GTT space. > > I am a bit dubious how this works when userspace still believes that it > can access the whole mappable aperture, and then how every driver > attempts to pin its own planes, rings and whatnot (since it still > believes that it is talking to the actual hardware and that the hardware > requires access to its virtual address). The host should be able to move the > ranges around in order to accommodate userspace in any particular guest > (hence a balloon interface I presume). But I don't see how that is > possible, and you don't explain it either. Yeah this is something we need to fix, either by pimping i915 fault support to be able to split up a big bo into chunks, or by telling userspace about the massively reduced contiguous mapping size. It should be tracked somewhere as a todo task ... -Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
