From: Daniel Vetter <daniel@ffwll.ch>
To: Ben Widawsky <benjamin.widawsky@linux.intel.com>
Cc: Intel GFX <intel-gfx@lists.freedesktop.org>
Subject: Re: [PATCH] drm/i915: Prevent context obj from being corrupted
Date: Wed, 26 Mar 2014 08:04:38 +0100 [thread overview]
Message-ID: <20140326070438.GQ26878@phenom.ffwll.local> (raw)
In-Reply-To: <20140326062416.GP26878@phenom.ffwll.local>
On Wed, Mar 26, 2014 at 07:24:16AM +0100, Daniel Vetter wrote:
> On Tue, Mar 25, 2014 at 07:01:50PM -0700, Ben Widawsky wrote:
> > While the context is not being used, we can make the PTEs invalid, so
> > nothing can accidentally corrupt it. Systems tend to have a lot of
> > trouble when the context gets corrupted.
> >
> > NOTE: This is a slightly different patch than what I posted to Bugzilla.
> >
> > References: https://bugs.freedesktop.org/show_bug.cgi?id=75724
> > Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
>
> We could stop the aliasing ppgtt binder from always binding into the
> ppgtt. Which is the bug I'm signed up to fix, and which probably curbs 99%
> of all potential corruption. The last 1% is the kernel getting his
> kmapping wrong ...
Actually your patch doesn't accomplish much, since MI_UPDATE_GTT only
updates the global gtt, not the aliasing ppgtt. Which means that userspace
batches can still happily stomp all over your precious context objects.
See comment #5 in that bug report:
https://bugs.freedesktop.org/show_bug.cgi?id=75724#c5
Cheers, Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
next prev parent reply other threads:[~2014-03-26 7:04 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-26 2:01 [PATCH] drm/i915: Prevent context obj from being corrupted Ben Widawsky
2014-03-26 6:24 ` Daniel Vetter
2014-03-26 7:04 ` Daniel Vetter [this message]
2014-03-26 15:06 ` Ben Widawsky
2014-03-26 15:07 ` Ben Widawsky
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