Hi Bradley - Apologies for my procrastination with the review; I don't easily recall as tedious a review as the command and register tables. And I sure have reviewed a lot of miserable stuff in the past. Most infuriatingly, I did not find a single real bug in the code! I think we'll need to automate some things going forward, for example listing the non-conforming length encoding with Damien's tools for cross checking. There are a few subtle points we need to discuss (separate mails internally) but all in all this series is: Reviewed-by: Jani Nikula <jani.nikula@xxxxxxxxx> On Tue, 18 Feb 2014, bradley.d.volkin@xxxxxxxxx wrote: > From: Brad Volkin <bradley.d.volkin@xxxxxxxxx> > > Certain OpenGL features (e.g. transform feedback, performance monitoring) > require userspace code to submit batches containing commands such as > MI_LOAD_REGISTER_IMM to access various registers. Unfortunately, some > generations of the hardware will noop these commands in "unsecure" batches > (which includes all userspace batches submitted via i915) even though the > commands may be safe and represent the intended programming model of the device. > > This series introduces a software command parser similar in operation to the > command parsing done in hardware for unsecure batches. However, the software > parser allows some operations that would be noop'd by hardware, if the parser > determines the operation is safe, and submits the batch as "secure" to prevent > hardware parsing. Currently the series implements this on IVB and HSW. > > The series has one piece of prep work, one patch for the parser logic, and a > handful of patches to fill out the tables which drive the parser. There are > follow-up patches to libdrm and to i-g-t. The i-g-t tests are basic and do not > test all of the commands used by the parser on the assumption that I'm likely > to make the same mistakes in both the parser and the test. > > I've previously run the i-g-t gem_* tests, the piglit quick tests, and generally > used Ubuntu 13.10 IVB and HSW systems with the parser running. Aside from a > failure described below, I did not see any regressions. > > At this point there are a couple of required/potential improvements. > > 1) Chained batches. The parser currently allows MI_BATCH_BUFFER_START commands > in userspace batches without parsing them. The media driver uses chained > batches, so a solution is required. I'm still working through the > requirements but don't want to continue delaying the review process for what > I have so far. > 2) Command buffer copy. To avoid CPU modifications to buffers after parsing, and > to avoid GPU modifications to buffers via EUs or commands in the batch, we > should copy the userspace batch buffer to memory that userspace does not > have access to, map it into GGTT, and execute that batch buffer. I have a > sense of how to do this for 1st-level batches, but it may need changes to > tie in with the chained batch parsing, so I've again held off. > 3) Coherency. I've previously found a coherency issue on VLV when reading the > batch buffer from the CPU during execbuffer2. Userspace writes the batch via > pwrite fast path before calling execbuffer2. The parser reads stale data. > This works fine on IVB and HSW, so I believe it's an LLC vs. non-LLC issue. > It's possible that the shmem pread refactoring fixes this, I just have not > been able to retest due to lack of a VLV system. > > v2: > - Significantly reorder series > - Scan secure batches (i.e. I915_EXEC_SECURE) > - Check that parser tables are sorted during init > - Fixed gem_cpu_reloc regression > - HAS_CMD_PARSER -> CMD_PARSER_VERSION getparam > - Additional tests > > v3: > - Don't actually send batches as secure yet > - Improved documentation and commenting > - Many other small cleanups throughout > > Brad Volkin (13): > drm/i915: Refactor shmem pread setup > drm/i915: Implement command buffer parsing logic > drm/i915: Initial command parser table definitions > drm/i915: Reject privileged commands > drm/i915: Allow some privileged commands from master > drm/i915: Add register whitelists for mesa > drm/i915: Add register whitelist for DRM master > drm/i915: Enable register whitelist checks > drm/i915: Reject commands that explicitly generate interrupts > drm/i915: Enable PPGTT command parser checks > drm/i915: Reject commands that would store to global HWS page > drm/i915: Add a CMD_PARSER_VERSION getparam > drm/i915: Enable command parsing by default > > drivers/gpu/drm/i915/Makefile | 1 + > drivers/gpu/drm/i915/i915_cmd_parser.c | 918 +++++++++++++++++++++++++++++ > drivers/gpu/drm/i915/i915_dma.c | 3 + > drivers/gpu/drm/i915/i915_drv.h | 103 ++++ > drivers/gpu/drm/i915/i915_gem.c | 51 +- > drivers/gpu/drm/i915/i915_gem_execbuffer.c | 18 + > drivers/gpu/drm/i915/i915_params.c | 5 + > drivers/gpu/drm/i915/i915_reg.h | 96 +++ > drivers/gpu/drm/i915/intel_ringbuffer.c | 2 + > drivers/gpu/drm/i915/intel_ringbuffer.h | 32 + > include/uapi/drm/i915_drm.h | 1 + > 11 files changed, 1216 insertions(+), 14 deletions(-) > create mode 100644 drivers/gpu/drm/i915/i915_cmd_parser.c > > -- > 1.8.3.2 > > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@xxxxxxxxxxxxxxxxxxxxx > http://lists.freedesktop.org/mailman/listinfo/intel-gfx -- Jani Nikula, Intel Open Source Technology Center _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
