If we are doing a normal GPU reset triggered after detecting a long
period of stalled work, we can take our time and allow the engines to
quiesce. Since we've stopped submission to the engine, and if we wait
long enough an innocent context should complete, leaving the engine idle.
So by waiting a short amount of time, we should prevent clobbering other
users when resetting a stuck context.
Suggested-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Suggested-by: NJon Bloomfield <jon.bloomfield@intel.com>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191023133108.21401-1-chris@chris-wilson.co.uk

Engines belong to the GT so make it indicative in the API.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191022094726.3001-6-tvrtko.ursulin@linux.intel.com

Engines belong to the GT so make it indicative in the API.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191022094726.3001-5-tvrtko.ursulin@linux.intel.com

Engines belong to the GT so make it indicative in the API.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191022094726.3001-4-tvrtko.ursulin@linux.intel.com

Engines belong to the GT so make it indicative in the API.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191022094726.3001-3-tvrtko.ursulin@linux.intel.com

Engines belong to the GT so make it indicative in the API.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191022094726.3001-2-tvrtko.ursulin@linux.intel.com

Where the function, or code segment, operates on intel_gt, we need to
start passing it instead of i915 to for_each_engine(_masked).

This is another partial step in migration of i915->engines[] to
gt->engines[].
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191017094500.21831-2-tvrtko.ursulin@linux.intel.com

Medium term goal is to eliminate the i915->engine[] array and to get there
we have recently introduced equivalent array in intel_gt. Now we need to
migrate the code further towards this state.

This next step is to eliminate usage of i915->engines[] from the
for_each_engine_masked iterator.

For this to work we also need to use engine->id as index when populating
the gt->engine[] array and adjust the default engine set indexing to use
engine->legacy_idx instead of assuming gt->engines[] indexing.

v2:
  * Populate gt->engine[] earlier.
  * Check that we don't duplicate engine->legacy_idx

v3:
  * Work around the initialization order issue between default_engines()
    and intel_engines_driver_register() which sets engine->legacy_idx for
    now. It will be fixed properly later.

v4:
  * Merge with forgotten v2.5.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191017161852.8836-1-tvrtko.ursulin@linux.intel.com

We perform timeslicing immediately upon receipt of a request that may be
put into the second ELSP slot. The idea behind this was that since we
didn't install the timer if the second ELSP slot was empty, we would not
have any idea of how long ELSP[0] had been running and so giving the
newcomer a chance on the GPU was fair. However, this causes us extra
busy work that we may be able to avoid if we wait a jiffie for the first
timeslice as normal.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191016100851.4979-1-chris@chris-wilson.co.uk

The active/pending execlists is no longer protected by the
engine->active.lock, but is serialised by the tasklet instead. Update
the locking around the debug and stats to follow suit.

v2: local_bh_disable() to prevent recursing into the tasklet in case we
trigger a softirq (Tvrtko)

Fixes: df403069 ("drm/i915/execlists: Lift process_csb() out of the irq-off spinlock")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191009160906.16195-1-chris@chris-wilson.co.uk

Assign a separate lockclass to the perma-pinned timelines of the
kernel_context, such that we can use them from within the user timelines
should we ever need to inject GPU operations to fixup faults during
request construction.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Matthew Auld <matthew.william.auld@gmail.com>
Reviewed-by: NMatthew Auld <matthew.william.auld@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191008185941.15228-1-chris@chris-wilson.co.uk

A common bane of ours is arbitrary delays in ksoftirqd processing our
submission tasklet. Give the submission tasklet a kick before we wait to
avoid those delays eating into a tight timeout.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NStuart Summers <stuart.summers@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191008105655.13256-1-chris@chris-wilson.co.uk

Avoid going to the base i915 device when we already have a path from gt
to the runtime powermanagement interface. The benefit is that it looks a
bit more self-consistent to always be acquiring the gt->uncore->rpm for
use with the gt->uncore.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191007154531.1750-1-chris@chris-wilson.co.uk

Explosions during early driver init on the error path. Make sure we fail
gracefully.

[ 9547.672258] BUG: kernel NULL pointer dereference, address: 000000000000007c
[ 9547.672288] #PF: supervisor read access in kernel mode
[ 9547.672292] #PF: error_code(0x0000) - not-present page
[ 9547.672296] PGD 8000000846b41067 P4D 8000000846b41067 PUD 797034067 PMD 0
[ 9547.672303] Oops: 0000 [#1] SMP PTI
[ 9547.672307] CPU: 1 PID: 25634 Comm: i915_selftest Tainted: G     U            5.3.0-rc8+ #73
[ 9547.672313] Hardware name:  /NUC6i7KYB, BIOS KYSKLi70.86A.0050.2017.0831.1924 08/31/2017
[ 9547.672395] RIP: 0010:intel_context_unpin+0x9/0x100 [i915]
[ 9547.672400] Code: 6b 60 00 e9 17 ff ff ff bd fc ff ff ff e9 7c ff ff ff 66 66 2e 0f 1f 84 00 00 00 00
 00 0f 1f 40 00 0f 1f 44 00 00 41 54 55 53 <8b> 47 7c 83 f8 01 74 26 8d 48 ff f0 0f b1 4f 7c 48 8d 57 7c
 75 05
[ 9547.672413] RSP: 0018:ffffae8ac24ff878 EFLAGS: 00010246
[ 9547.672417] RAX: ffff944a1b7842d0 RBX: ffff944a1b784000 RCX: ffff944a12dd6fa8
[ 9547.672422] RDX: ffff944a1b7842c0 RSI: ffff944a12dd5328 RDI: 0000000000000000
[ 9547.672428] RBP: 0000000000000000 R08: ffff944a11e5d840 R09: 0000000000000000
[ 9547.672433] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
[ 9547.672438] R13: ffffffffc11aaf00 R14: 00000000ffffffe4 R15: ffff944a0e29bf38
[ 9547.672443] FS:  00007fc259b88ac0(0000) GS:ffff944a1f880000(0000) knlGS:0000000000000000
[ 9547.672449] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 9547.672454] CR2: 000000000000007c CR3: 0000000853346003 CR4: 00000000003606e0
[ 9547.672459] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 9547.672464] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 9547.672469] Call Trace:
[ 9547.672518]  intel_engine_cleanup_common+0xe3/0x270 [i915]
[ 9547.672567]  execlists_destroy+0xe/0x30 [i915]
[ 9547.672669]  intel_engines_init+0x94/0xf0 [i915]
[ 9547.672749]  i915_gem_init+0x191/0x950 [i915]
Signed-off-by: NMatthew Auld <matthew.auld@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190927173409.31175-2-matthew.auld@intel.com

The request->timeline is only valid until the request is retired (i.e.
before it is completed). Upon retiring the request, the context may be
unpinned and freed, and along with it the timeline may be freed. We
therefore need to be very careful when chasing rq->timeline that the
pointer does not disappear beneath us. The vast majority of users are in
a protected context, either during request construction or retirement,
where the timeline->mutex is held and the timeline cannot disappear. It
is those few off the beaten path (where we access a second timeline) that
need extra scrutiny -- to be added in the next patch after first adding
the warnings about dangerous access.

One complication, where we cannot use the timeline->mutex itself, is
during request submission onto hardware (under spinlocks). Here, we want
to check on the timeline to finalize the breadcrumb, and so we need to
impose a second rule to ensure that the request->timeline is indeed
valid. As we are submitting the request, it's context and timeline must
be pinned, as it will be used by the hardware. Since it is pinned, we
know the request->timeline must still be valid, and we cannot submit the
idle barrier until after we release the engine->active.lock, ergo while
submitting and holding that spinlock, a second thread cannot release the
timeline.

v2: Don't be lazy inside selftests; hold the timeline->mutex for as long
as we need it, and tidy up acquiring the timeline with a bit of
refactoring (i915_active_add_request)
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190919111912.21631-1-chris@chris-wilson.co.uk

Include the active context register state when dumping the engine.
Suggested-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: NStuart Summers <stuart.summers@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190915203701.29163-1-chris@chris-wilson.co.uk

We've been ignoring similar coherency issues in IGT for Broadwater, and
specifically Broadwater (original gen4) and not, for example, Crestline
(same generation as Broadwater, but the mobile variant). Without any
means to reproduce locally (I have a 965GM but alas no 965G), fixing will
be slow, so tell CI to ignore any failure until we are ready with a fix.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Acked-by: NMatthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190826133837.6784-1-chris@chris-wilson.co.uk

Refactor instdone loops to use the new intel_sseu_has_subslice
function.
Signed-off-by: NStuart Summers <stuart.summers@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190823160307.180813-10-stuart.summers@intel.com

Re-use Gen11 context size for now.

[ Lucas: this is a temporary enabling patch that needs to be confirmed:
         we need to check BSpec 46255 and recompute ]
Signed-off-by: NDaniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: NLucas De Marchi <lucas.demarchi@intel.com>
Acked-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190817093902.2171-27-lucas.demarchi@intel.com

If we only call process_csb() from the tasklet, though we lose the
ability to bypass ksoftirqd interrupt processing on direct submission
paths, we can push it out of the irq-off spinlock.

The penalty is that we then allow schedule_out to be called concurrently
with schedule_in requiring us to handle the usage count (baked into the
pointer itself) atomically.

As we do kick the tasklets (via local_bh_enable()) after our submission,
there is a possibility there to see if we can pull the local softirq
processing back from the ksoftirqd.

v2: Store the 'switch_priority_hint' on submission, so that we can
safely check during process_csb().
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190816171608.11760-1-chris@chris-wilson.co.uk

Forgo the struct_mutex requirement for request retirement as we have
been transitioning over to only using the timeline->mutex for
controlling the lifetime of a request on that timeline.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMatthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190815205709.24285-4-chris@chris-wilson.co.uk

Use render class instead of RCS0 when printing CCID.
Signed-off-by: NStuart Summers <stuart.summers@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190813174121.129593-2-stuart.summers@intel.com

Some IGT would like to know the mmio address of each engine so make it
available.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NStuart Summers <stuart.summers@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190813215707.14703-1-chris@chris-wilson.co.uk

Now that we can atomically acquire the engine wakeref, make use of it
when check whether the RING registers are idle.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190812091045.29587-7-chris@chris-wilson.co.uk

Move the timeline from being inside the intel_ring to intel_context
itself. This saves much pointer dancing and makes the relations of the
context to its timeline much clearer.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMatthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190809182518.20486-4-chris@chris-wilson.co.uk

Push the ring creation flags from the outer GEM context to the inner
intel_context to avoid an unsightly back-reference from inside the
backend.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NAndi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190809182518.20486-3-chris@chris-wilson.co.uk

As we need to acquire a mutex to serialise the final
intel_wakeref_put, we need to ensure that we are in process context at
that time. However, we want to allow operation on the intel_wakeref from
inside timer and other hardirq context, which means that need to defer
that final put to a workqueue.

Inside the final wakeref puts, we are safe to operate in any context, as
we are simply marking up the HW and state tracking for the potential
sleep. It's only the serialisation with the potential sleeping getting
that requires careful wait avoidance. This allows us to retain the
immediate processing as before (we only need to sleep over the same
races as the current mutex_lock).

v2: Add a selftest to ensure we exercise the code while lockdep watches.
v3: That test was extremely loud and complained about many things!
v4: Not a whale!

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=111295
References: https://bugs.freedesktop.org/show_bug.cgi?id=111245
References: https://bugs.freedesktop.org/show_bug.cgi?id=111256
Fixes: 18398904 ("drm/i915: Only recover active engines")
Fixes: 51fbd8de ("drm/i915/pmu: Atomically acquire the gt_pm wakeref")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190808202758.10453-1-chris@chris-wilson.co.uk

Ignore the central i915->kernel_context for allocating an engine, as
that GEM context is being phased out. For internal clients, we just need
the per-engine logical state, so allocate it at the point of use.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190808110612.23539-1-chris@chris-wilson.co.uk

During engine setup, we may find that some engines are fused off causing
a misalignment between internal names and the instances seen by users,
e.g. (I915_ENGINE_CLASS_VIDEO_DECODE, 1) may be vcs2 in hardware.
Normally this is invisible to the user, but a few debug interfaces (and
our own internal tracing) use the original HW name not the name the user
would expect as formed from their class:instance tuple. Replace our
internal name with the uabi name for consistency with, for example, error
states.

v2: Keep the pretty printing of class name in the selftest

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=111311Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190807110431.8130-1-chris@chris-wilson.co.uk

To maintain a fast lookup from a GT centric irq handler, we want the
engine lookup tables on the intel_gt. To avoid having multiple copies of
the same multi-dimension lookup table, move the generic user engine
lookup into an rbtree (for fast and flexible indexing).

v2: Split uabi_instance cf uabi_class
v3: Set uabi_class/uabi_instance after collating all engines to provide a
stable uabi across parallel unordered construction.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com> #v2
Link: https://patchwork.freedesktop.org/patch/msgid/20190806124300.24945-2-chris@chris-wilson.co.uk

Switch to tracking activity via i915_active on individual nodes, only
keeping a list of retired objects in the cache, and reaping the cache
when the engine itself idles.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMatthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190804124826.30272-2-chris@chris-wilson.co.uk

With i915 added to i915_inject_probe_failure we can use dedicated
printk when injecting artificial load failure.

Also make this function look like other i915 functions that return
error code and make it more flexible to return any provided error
code instead of previously assumed -ENODEV.
Signed-off-by: NMichal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190802184055.31988-2-michal.wajdeczko@intel.com

fls returns bit positions starting from one for the lsb and the MCR
register expects zero based (sub)slice addressing.

Incorrent MCR programming can have the effect of directing MMIO reads of
registers in the 0xb100-0xb3ff range to invalid subslice returning zeroes
instead of actual content.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Fixes: 1e40d4ae ("drm/i915/cnl: Implement WaProgramMgsrForCorrectSliceSpecificMmioReads")
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190717180624.20354-2-tvrtko.ursulin@linux.intel.com
(cherry picked from commit 15160879)
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

We cannot let the request be retired and freed while we are trying to
dump it during error capture. It is not sufficient just to grab a
reference to the request, as during retirement we may free the ring
which we are also dumping. So take the engine lock to prevent retiring
and freeing of the request.
Reported-by: NAlex Shumsky <alexthreed@gmail.com>
Fixes: 83c31783 ("drm/i915: Dump the ringbuffer of the active request for debugging")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Alex Shumsky <alexthreed@gmail.com>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190715080946.15593-6-chris@chris-wilson.co.uk
(cherry picked from commit cfe7288c)
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

A couple issues were present in this code:

1.
fls() usage was incorrect causing off by one in subslice mask lookup,
which in other words means subslice mask of all zeroes is always used
(subslice mask of a slice which is not present, or even out of bounds
array access), rendering the checks in wa_init_mcr either futile or
random.

2.
Condition in WARN_ON was not correct. It is doing a bitwise and operation
between a positive (present subslices) and negative mask (disabled L3
banks).

This means that with corrected fls() usage the assert would always
incorrectly fail.

We could fix this by inverting the fuse bits in the check, but instead do
one better and improve the code so it not only asserts, but finds the
first common index between the two masks and only warns if no such index
can be found.

v2:
 * Simplify check for logic and redability.
 * Improve commentary explaining what is really happening ie. what the
   assert is really trying to check and why.

v3:
 * Find first common index instead of just asserting.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Fixes: fe864b76 ("drm/i915: Implement WaProgramMgsrForL3BankSpecificMmioReads")
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> # v1
Cc: Michał Winiarski <michal.winiarski@intel.com>
Cc: Stuart Summers <stuart.summers@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190717180624.20354-4-tvrtko.ursulin@linux.intel.com

Instead of re-calculating the MCR selector in read_subslice_reg do the
rwm on its existing value and restore it when done.

This consolidates MCR programming to one place for cnl+, and avoids
re-calculating its default value on older platforms during hangcheck.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190717180624.20354-3-tvrtko.ursulin@linux.intel.com

fls returns bit positions starting from one for the lsb and the MCR
register expects zero based (sub)slice addressing.

Incorrent MCR programming can have the effect of directing MMIO reads of
registers in the 0xb100-0xb3ff range to invalid subslice returning zeroes
instead of actual content.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Fixes: 1e40d4ae ("drm/i915/cnl: Implement WaProgramMgsrForCorrectSliceSpecificMmioReads")
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190717180624.20354-2-tvrtko.ursulin@linux.intel.com

Preempt-to-busy uses a GPU semaphore to enforce an idle-barrier across
preemption, but mediated gvt does not fully support semaphores.

v2: Fiddle around with the flags and settle on using has-semaphores for
the core bits so that we retain the ability to preempt our own
semaphores.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Cc: Xiaolin Zhang <xiaolin.zhang@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Acked-by: NZhenyu Wang <zhenyuw@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190709091233.8573-1-chris@chris-wilson.co.uk

We cannot let the request be retired and freed while we are trying to
dump it during error capture. It is not sufficient just to grab a
reference to the request, as during retirement we may free the ring
which we are also dumping. So take the engine lock to prevent retiring
and freeing of the request.
Reported-by: NAlex Shumsky <alexthreed@gmail.com>
Fixes: 83c31783 ("drm/i915: Dump the ringbuffer of the active request for debugging")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Alex Shumsky <alexthreed@gmail.com>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190715080946.15593-6-chris@chris-wilson.co.uk

Having taken the first step in encapsulating the functionality by moving
the related files under gt/, the next step is to start encapsulating by
passing around the relevant structs rather than the global
drm_i915_private. In this step, we pass intel_gt to intel_reset.c
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Reviewed-by: NDaniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190712192953.9187-1-chris@chris-wilson.co.uk