drm/i915/guc: Add a selftest for FAST_REQUEST errors

There is a mechanism for reporting errors from fire and forget H2G
messages. This is the only way to find out about almost any error in
the GuC backend submission path. So it would be useful to know that it
is working.

v2: Fix some dumb over-complications and a couple of typos - review
feedback from Daniele.

Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231114010016.234570-3-John.C.Harrison@Intel.com

drm/i915/guc: Fix potential null pointer deref in GuC 'steal id' test

It was noticed that if the very first 'stealing' request failed to
create for some reason then the 'steal all ids' loop would immediately
exit with 'last' still being NULL. The test would attempt to continue
but using a null pointer. Fix that by aborting the test if it fails to
create any requests at all.

Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230802184940.911753-1-John.C.Harrison@Intel.com

drm/i915/guc: More debug print updates - GuC selftests

Update a bunch more debug prints to use the new GT based scheme.

v2: Also change prints to use %pe for error values (MichalW).
Fix a context leak on error due to a -- being too early.
Use the correct header file for the debug macros.

Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230207050717.1833718-5-John.C.Harrison@Intel.com

drm/i915/guc: skip scrub_ctbs selftest if reset is disabled

The test needs GT reset to trigger the scrubbing logic, so we can only
run it when reset is enabled.

Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: John Harrison <john.c.harrison@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220708224158.929327-1-daniele.ceraolospurio@intel.com

drm/i915/guc: Don't use pr_err when not necessary

A bunch of code was copy/pasted using pr_err as the default way to
report errors. However, drm_err is significantly more useful in
identifying where the error came from. So update the code to use that
instead.

Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220715004028.2126239-1-John.C.Harrison@Intel.com

drm/i915/guc: Better name for context id limit

The LRC descriptor pool is going away. So, stop using it as the limit
for how many context ids are available. Instead, size the pool
according to the number of contexts allowed. Note that this is just a
naming change, the actual limit is identical in value.

While at it, also update a kzalloc(sizeof()*count) to be a
kcalloc(count,size).

Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220302003357.4188363-4-John.C.Harrison@Intel.com

drm/i915/selftests: Use less in contexts steal guc id test

Using more guc_ids in the stealing guc id test has no real benefit.
Tearing down lots of contexts all at the same time takes a bit of time
due to the H2G / G2H ping-pong with the GuC. On some slower platforms
this can cause timeous when flushing the test as the GT isn't idle when
this ping-pong is happening. Reduce the number of guc ids to speed up
the flushing of the test.

Link: https://gitlab.freedesktop.org/drm/intel/-/issues/4821
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220122000822.25616-1-matthew.brost@intel.com

drm/i915/gt: Use to_gt() helper

Use to_gt() helper consistently throughout the codebase.
Pure mechanical s/i915->gt/to_gt(i915). No functional changes.

Signed-off-by: Michał Winiarski <michal.winiarski@intel.com>
Signed-off-by: Andi Shyti <andi.shyti@linux.intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211214193346.21231-5-andi.shyti@linux.intel.com

drm/i915/guc: Selftest for stealing of guc ids

Testing the stealing of guc ids is hard from user space as we have 64k
guc_ids. Add a selftest, which artificially reduces the number of guc
ids, and forces a steal.

The test creates a spinner which is used to block all subsequent
submissions until it completes. Next, a loop creates a context and a NOP
request each iteration until the guc_ids are exhausted (request creation
returns -EAGAIN). The spinner is ended, unblocking all requests created
in the loop. At this point all guc_ids are exhausted but are available
to steal. Try to create another request which should successfully steal
a guc_id. Wait on last request to complete, idle GPU, verify a guc_id
was stolen via a counter, and exit the test. Test also artificially
reduces the number of guc_ids so the test runs in a timely manner.

v2:
(John Harrison)
- s/stole/stolen
- Fix some wording in test description
- Rework indexing into context array
- Add test description to commit message
- Fix typo in commit message
(Checkpatch)
- s/guc/(guc) in NUMBER_MULTI_LRC_GUC_ID
v3:
(John Harrison)
- Set array value to NULL after extracting error
- Fix a few typos in comments / error messages
- Delete redundant comment in commit message

Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211214170500.28569-8-matthew.brost@intel.com

drm/i915/selftests: Add initial GuC selftest for scrubbing lost G2H

While debugging an issue with full GT resets I went down a rabbit hole
thinking the scrubbing of lost G2H wasn't working correctly. This proved
to be incorrect as this was working just fine but this chase inspired me
to write a selftest to prove that this works. This simple selftest
injects errors dropping various G2H and then issues a full GT reset
proving that the scrubbing of these G2H doesn't blow up.

v2:
(Daniel Vetter)
- Use ifdef instead of macros for selftests
v3:
(Checkpatch)
- A space after 'switch' statement
v4:
(Daniele)
- A comment saying GT won't idle if G2H are lost

Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210909164744.31249-12-matthew.brost@intel.com