On Wed, May 27, 2015 at 07:54:44AM +0000, Zou, Nanhai wrote: > > -----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, I applied the kernel patch. Please push libdrm&beignet patches now (with the libdrm release+depencies done ofc). For the libdrm patch please make sure that any uapi header copies are verbatim copies from the kernel generated with $ make headers Thanks, Daniel > > 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 -- 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
