> -----Original Message----- > From: Intel-gfx [mailto:intel-gfx-bounces@xxxxxxxxxxxxxxxxxxxxx] On Behalf Of > Daniel Vetter > Sent: Thursday, May 21, 2015 12:01 AM > To: Chris Wilson; intel-gfx > Subject: Re: [PATCH 00/03] Preventing zero GPU virtual address > allocation > > On Wed, May 20, 2015 at 03:14:06PM +0100, Chris Wilson wrote: > > On Wed, May 20, 2015 at 03:09:43PM +0100, Chris Wilson wrote: > > > On Wed, May 20, 2015 at 04:54:19PM +0300, David Weinehall wrote: > > > > This patch series (one patch each for libdrm, the kernel, and > > > > beignet) aims to provide a means to add a context-specific means > > > > to prevent a mapping to GPU virtual address zero. This is needed > > > > at least by Beignet (possibly in other use-cases too, though I > > > > don't know of any > > > > other) to allow use of address zero to represent NULL. > > > > > > Urm, you cannot allow absolute addressing period. What happens to > > > the object at 0 when the user reads from it or writes to it? You > > > have to have an object at 0 for the user's NULL pointer access. > > > > I'll mollify that: outside of full-ppgtt where you need to share the VM. > > The description is misleading, the new flag doesn't prevent anything from > getting mapped at 0 but only prevents any bo submitted through execbuf on > the given context from being bound at address 0. If that would happen > compute kernels using NULL checks for some things would fall over. > > Essentially it applies the PIN_BIAS for all execbuf objects, which works even on > ggtt execbufs. > > Patches themselves look good, but we miss the igt to update the invalid ctx > flags testcase. And a bare minimal function testcase (which checks the reloc > offset with and without a ctx with this flag set) would be nice too. > With that and an r-b from the beignet developers I'll pull this in. > -Daniel Hi, We can verify the patches work for Beignet. Thanks Zou Nanhai > -- > Daniel Vetter > Software Engineer, Intel Corporation > http://blog.ffwll.ch > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@xxxxxxxxxxxxxxxxxxxxx > http://lists.freedesktop.org/mailman/listinfo/intel-gfx _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
