Userspace may leave predication enabled upon return from the batch
buffer, which has the consequent of preventing all operation from the
ring from being executed, including all the synchronisation, coherency
control, arbitration and user signaling. This is more than just a local
gpu hang in one client, as the user has the ability to prevent the
kernel from applying critical workarounds and can cause a full GT reset.
We could simply execute MI_SET_PREDICATE upon return from the user
batch, but this has the repercussion of modifying the user's context
state. Instead, we opt to execute a fixup batch which by mixing
predicated operations can determine the state of the
SET_PREDICATE_RESULT register and restore it prior to the next userspace
batch. This allows us to protect the kernel's ring without changing the
uABI.
Suggested-by: Zbigniew Kempczynski <zbigniew.kempczynski@intel.com>
Signed-off-by: Chris Wilson <chris.p.wilson@intel.com>
Cc: Zbigniew Kempczynski <zbigniew.kempczynski@intel.com>
Cc: Thomas Hellstrom <thomas.hellstrom@intel.com>
Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220425152317.4275-4-ramalingam.c@intel.com
GPU hangs have been observed when multiple engines write to the
same aux_inv register at the same time. To avoid this each engine
should only invalidate its own auxiliary table. The function
gen12_emit_flush_xcs() currently invalidate the auxiliary table for
all engines because the rq->engine is not necessarily the engine
eventually carrying out the request, and potentially the engine
could even be a virtual one (with engine->instance being -1).
With the MMIO remap feature, we can actually set bit 17 of MI_LRI
instruction and let the hardware to figure out the local aux_inv
register at runtime to avoid invalidating auxiliary table for all
engines.
Bspec: 45728
v2: Invalidate AUX table for indirect context as well.
Cc: Stuart Summers <stuart.summers@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: Chris Wilson <chris.p.wilson@intel.com>
Signed-off-by: Fei Yang <fei.yang@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220328171650.1900674-1-fei.yang@intel.com
These functions are independent from the backend used and can therefore
be split out of the exelists submission file, so they can be re-used by
the upcoming GuC submission backend.
Based on a patch by Chris Wilson.
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201209233618.4287-3-chris@chris-wilson.co.uk
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
