[Intel-xe] [PATCH v3 0/6] LRC debugfs and general instruction tweaks

[Matt Roper]

During device probe, workarounds that target registers in an engine's
LRC image are applied and then a snapshot of the context image is saved
as the "default LRC" which is later copied as the starting point for all
new contexts.  Internally the engine state is encoded as a batchbuffer
that the hardware can execute on context switch to restore the relevant
registers and other state information.

"LRC workarounds" are those which target registers that are part of the
an engine's LRC; the driver programs the registers with the desired
updates before triggering creation of the default LRC snapshot, thus
ensuring that the necessary settings are inherited by all new contexts
that get created.

There's an upcoming workaround that will require the driver to emit not
only updates to specific registers at driver init, but also some
non-register state (e.g., 3DSTATE_* instructions) before snapshotting
the default LRC.  This is also expected to become necessary for
non-workaround initialization on future platforms as well.

Before we start making these updates to the initial engine state and
default LRC, it's helpful to be able to see exactly what's inside the
context image.  The changes here add some debugfs entries that dump each
engine type's default LRC with some basic instruction header decoding.
E.g.,

        $ sudo cat /sys/kernel/debug/dri/0/gt0/default_lrc_ccs
        [0x00000000] MI_NOOP (1 dwords)
        [0x1108101d] MI_LOAD_REGISTER_IMM: 15 regs
         - 0x1a244 = 0xffff0048
         - 0x1a034 = 0x000000f8
         - 0x1a030 = 0x000000f8
         - 0x1a038 = 0x00fa0000
         - 0x1a03c = 0x00003001
         - 0x1a168 = 0x00000000
         - 0x1a140 = 0x00400004
         - 0x1a110 = 0x00000000
         - 0x1a1c0 = 0x00000000
         - 0x1a1c4 = 0x00000000
         - 0x1a1c8 = 0x00000000
         - 0x1a180 = 0x00000080
         - 0x1a2b4 = 0x00000000
         - 0x1a120 = 0x00000000
         - 0x1a124 = 0x00000000
        [0x00000000] MI_NOOP (1 dwords)
        [0x11081011] MI_LOAD_REGISTER_IMM: 9 regs
<...snip...>
        [0x00000000] MI_NOOP (6 dwords)
        [0x6904ff02] PIPELINE_SELECT (1 dwords)
        [0x61010014] STATE_BASE_ADDRESS (22 dwords)
        [0x61020001] STATE_SIP (3 dwords)
        [0x61050000] STATE_COMPUTE_MODE (2 dwords)
        [0x79190002] 3DSTATE_BINDING_TABLE_POOL_ALLOC (4 dwords)
        [0x79040002] 3DSTATE_CHROMA_KEY (4 dwords)
        [0x79040002] 3DSTATE_CHROMA_KEY (4 dwords)
        [0x61060004] 3DSTATE_BTD (6 dwords)
        [0x00000000] MI_NOOP (114 dwords)
        [0x05000001] MI_BATCH_BUFFER_END

A few other changes are made to the general way GPU instructions are
defined in the Xe driver to make the definitions more consistent and
easier to re-use in the new dumping logic.

v2:
 - Use "instr" instead of "inst" as the short form of "instruction"
   everywhere.
 - Tighten bounds checking while parsing context to ensure we don't
   overshoot the end if we get instructions with malformed lengths or if
   we otherwise mis-parse something.
 - Include raw hex form of instruction header in output.
 - Add parsing for a couple instructions that the hardware is still
   generating in the context image, even though they're technically not
   supposed to exist on these platforms.

v3:
 - Add check to dump_gfxpipe_command() to ensure we don't encounter
   num_dw > remaining_dw.

Cc: Lucas De Marchi <lucas.demarchi at intel.com>

Matt Roper (6):
  drm/xe: Make MI_FLUSH_DW immediate size more explicit
  drm/xe: Separate number of registers from MI_LRI opcode
  drm/xe: Clarify number of dwords/qwords stored by MI_STORE_DATA_IMM
  drm/xe: Extract MI_* instructions to their own header
  drm/xe/debugfs: Add dump of default LRCs' MI instructions
  drm/xe/debugfs: Include GFXPIPE commands in LRC dump

 .../drm/xe/instructions/xe_gfxpipe_commands.h | 108 +++++++++
 .../gpu/drm/xe/instructions/xe_instr_defs.h   |  32 +++
 .../gpu/drm/xe/instructions/xe_mi_commands.h  |  61 +++++
 drivers/gpu/drm/xe/regs/xe_gpu_commands.h     |  33 ---
 drivers/gpu/drm/xe/xe_bb.c                    |   1 +
 drivers/gpu/drm/xe/xe_execlist.c              |   1 +
 drivers/gpu/drm/xe/xe_gt.c                    |   3 +-
 drivers/gpu/drm/xe/xe_gt_debugfs.c            |  46 ++++
 drivers/gpu/drm/xe/xe_lrc.c                   | 208 +++++++++++++++++-
 drivers/gpu/drm/xe/xe_lrc.h                   |   5 +
 drivers/gpu/drm/xe/xe_migrate.c               |  10 +-
 drivers/gpu/drm/xe/xe_ring_ops.c              |  21 +-
 12 files changed, 477 insertions(+), 52 deletions(-)
 create mode 100644 drivers/gpu/drm/xe/instructions/xe_gfxpipe_commands.h
 create mode 100644 drivers/gpu/drm/xe/instructions/xe_instr_defs.h
 create mode 100644 drivers/gpu/drm/xe/instructions/xe_mi_commands.h

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2.41.0