1195 Commits

Author SHA1 Message Date
Chris Wilson
f6a7c21c99 drm/i915/execlists: Verify we don't submit two identical CCIDs
Check that we do not submit two contexts into ELSP with the same CCID
[upper portion of the descriptor].

References: https://gitlab.freedesktop.org/drm/intel/-/issues/1793
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200428184751.11257-3-chris@chris-wilson.co.uk
2020-04-28 22:17:36 +01:00
Chris Wilson
5c4a53e3b1 drm/i915/execlists: Track inflight CCID
The presumption is that by using a circular counter that is twice as
large as the maximum ELSP submission, we would never reuse the same CCID
for two inflight contexts.

However, if we continually preempt an active context such that it always
remains inflight, it can be resubmitted with an arbitrary number of
paired contexts. As each of its paired contexts will use a new CCID,
eventually it will wrap and submit two ELSP with the same CCID.

Rather than use a simple circular counter, switch over to a small bitmap
of inflight ids so we can avoid reusing one that is still potentially
active.

Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/1796
Fixes: 2935ed5339c4 ("drm/i915: Remove logical HW ID")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: <stable@vger.kernel.org> # v5.5+
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200428184751.11257-2-chris@chris-wilson.co.uk
2020-04-28 22:17:36 +01:00
Chris Wilson
2632f174a2 drm/i915/execlists: Avoid reusing the same logical CCID
The bspec is confusing on the nature of the upper 32bits of the LRC
descriptor. Once upon a time, it said that it uses the upper 32b to
decide if it should perform a lite-restore, and so we must ensure that
each unique context submitted to HW is given a unique CCID [for the
duration of it being on the HW]. Currently, this is achieved by using
a small circular tag, and assigning every context submitted to HW a
new id. However, this tag is being cleared on repinning an inflight
context such that we end up re-using the 0 tag for multiple contexts.

To avoid accidentally clearing the CCID in the upper 32bits of the LRC
descriptor, split the descriptor into two dwords so we can update the
GGTT address separately from the CCID.

Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/1796
Fixes: 2935ed5339c4 ("drm/i915: Remove logical HW ID")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: <stable@vger.kernel.org> # v5.5+
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200428184751.11257-1-chris@chris-wilson.co.uk
2020-04-28 22:17:36 +01:00
Chris Wilson
96a4faf524 drm/i915/selftests: Tweak the tolerance for clock ticks to 12.5%
Give a small bump for our tolerance on comparing the expected vs
measured clock ticks/time from 10% to 12.5% to accommodate a bad result
on Sandybridge that was off by 10.3%. Hopefully, that is the worst we
will see.

Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/1802
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200428114307.5153-1-chris@chris-wilson.co.uk
2020-04-28 14:25:21 +01:00
Colin Ian King
d631461d5c drm/i915/gt: fix spelling mistake "evalution" -> "evaluation"
There is a spelling mistaking in a pr_notice message. Fix it.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20200428084920.1035125-1-colin.king@canonical.com
2020-04-28 09:53:59 +01:00
Chris Wilson
6dc0d028f5 drm/i915/gt: Fix up clock frequency
The bspec lists both the clock frequency and the effective interval. The
interval corresponds to observed behaviour, so adjust the frequency to
match.

v2: Mika rightfully asked if we could measure the clock frequency from a
selftest.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Acked-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200427154554.12736-1-chris@chris-wilson.co.uk
2020-04-27 17:34:33 +01:00
Chris Wilson
4243cd5388 drm/i915/gt: Sanitize GT first
We see that if the HW doesn't actually sleep, the HW may eat the poison
we set in its write-only HWSP during sanitize:

  intel_gt_resume.part.8: 0000:00:02.0
  __gt_unpark: 0000:00:02.0
  gt_sanitize: 0000:00:02.0 force:yes
  process_csb: 0000:00:02.0 vcs0: cs-irq head=5, tail=90
  process_csb: 0000:00:02.0 vcs0: csb[0]: status=0x5a5a5a5a:0x5a5a5a5a
  assert_pending_valid: Nothing pending for promotion!

The CS TAIL pointer should have been reset by reset_csb_pointers(), so
in this case it is likely that we have read back from the CPU cache and
so we must clflush our control over that page. In doing so, push the
sanitisation to the start of the GT sequence so that our poisoning is
assuredly before we start talking to the HW.

References: https://gitlab.freedesktop.org/drm/intel/-/issues/1794
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200427084000.10999-1-chris@chris-wilson.co.uk
2020-04-27 11:39:23 +01:00
Chris Wilson
2759e39535 drm/i915/gt: Check cacheline is valid before acquiring
The hwsp_cacheline pointer from i915_request is very, very flimsy. The
i915_request.timeline (and the hwsp_cacheline) are lost upon retiring
(after an RCU grace). Therefore we need to confirm that once we have the
right pointer for the cacheline, it is not in the process of being
retired and disposed of before we attempt to acquire a reference to the
cacheline.

<3>[  547.208237] BUG: KASAN: use-after-free in active_debug_hint+0x6a/0x70 [i915]
<3>[  547.208366] Read of size 8 at addr ffff88822a0d2710 by task gem_exec_parall/2536

<4>[  547.208547] CPU: 3 PID: 2536 Comm: gem_exec_parall Tainted: G     U            5.7.0-rc2-ged7a286b5d02d-kasan_117+ #1
<4>[  547.208556] Hardware name: Dell Inc. XPS 13 9350/, BIOS 1.4.12 11/30/2016
<4>[  547.208564] Call Trace:
<4>[  547.208579]  dump_stack+0x96/0xdb
<4>[  547.208707]  ? active_debug_hint+0x6a/0x70 [i915]
<4>[  547.208719]  print_address_description.constprop.6+0x16/0x310
<4>[  547.208841]  ? active_debug_hint+0x6a/0x70 [i915]
<4>[  547.208963]  ? active_debug_hint+0x6a/0x70 [i915]
<4>[  547.208975]  __kasan_report+0x137/0x190
<4>[  547.209106]  ? active_debug_hint+0x6a/0x70 [i915]
<4>[  547.209127]  kasan_report+0x32/0x50
<4>[  547.209257]  ? i915_gemfs_fini+0x40/0x40 [i915]
<4>[  547.209376]  active_debug_hint+0x6a/0x70 [i915]
<4>[  547.209389]  debug_print_object+0xa7/0x220
<4>[  547.209405]  ? lockdep_hardirqs_on+0x348/0x5f0
<4>[  547.209426]  debug_object_assert_init+0x297/0x430
<4>[  547.209449]  ? debug_object_free+0x360/0x360
<4>[  547.209472]  ? lock_acquire+0x1ac/0x8a0
<4>[  547.209592]  ? intel_timeline_read_hwsp+0x4f/0x840 [i915]
<4>[  547.209737]  ? i915_active_acquire_if_busy+0x66/0x120 [i915]
<4>[  547.209861]  i915_active_acquire_if_busy+0x66/0x120 [i915]
<4>[  547.209990]  ? __live_alloc.isra.15+0xc0/0xc0 [i915]
<4>[  547.210005]  ? rcu_read_lock_sched_held+0xd0/0xd0
<4>[  547.210017]  ? print_usage_bug+0x580/0x580
<4>[  547.210153]  intel_timeline_read_hwsp+0xbc/0x840 [i915]
<4>[  547.210284]  __emit_semaphore_wait+0xd5/0x480 [i915]
<4>[  547.210415]  ? i915_fence_get_timeline_name+0x110/0x110 [i915]
<4>[  547.210428]  ? lockdep_hardirqs_on+0x348/0x5f0
<4>[  547.210442]  ? _raw_spin_unlock_irq+0x2a/0x40
<4>[  547.210567]  ? __await_execution.constprop.51+0x2e0/0x570 [i915]
<4>[  547.210706]  i915_request_await_dma_fence+0x8f7/0xc70 [i915]

Fixes: 85bedbf191e8 ("drm/i915/gt: Eliminate the trylock for reading a timeline's hwsp")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: <stable@vger.kernel.org> # v5.6+
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200427093038.29219-1-chris@chris-wilson.co.uk
2020-04-27 11:39:23 +01:00
Chris Wilson
68ace460c5 drm/i915/execlists: Check preempt-timeout target before submit_ports
We evaluate *active, which is a pointer into execlists->inflight[]
during dequeue to decide how long a preempt-timeout we need to apply.
However, as soon as we do the submit_ports, the HW may send its ACK
interrupt causing us to promote execlists->pending[] tp
execlists->inflight[], overwriting the value of *active. We know *active
is only stable until we submit (as we only submit when there is no
pending promotion).

[   16.102328] BUG: KCSAN: data-race in execlists_dequeue+0x1449/0x1600 [i915]
[   16.102356]
[   16.102375] race at unknown origin, with read to 0xffff8881e9500488 of 8 bytes by task 429 on cpu 1:
[   16.102780]  execlists_dequeue+0x1449/0x1600 [i915]
[   16.103160]  __execlists_submission_tasklet+0x48/0x60 [i915]
[   16.103540]  execlists_submit_request+0x38e/0x3c0 [i915]
[   16.103940]  submit_notify+0x8f/0xc0 [i915]
[   16.104308]  __i915_sw_fence_complete+0x61/0x420 [i915]
[   16.104683]  i915_sw_fence_complete+0x58/0x80 [i915]
[   16.105054]  i915_sw_fence_commit+0x16/0x20 [i915]
[   16.105457]  __i915_request_queue+0x60/0x70 [i915]
[   16.105843]  i915_gem_do_execbuffer+0x2d6b/0x4230 [i915]
[   16.106227]  i915_gem_execbuffer2_ioctl+0x2b0/0x580 [i915]
[   16.106257]  drm_ioctl_kernel+0xe9/0x130
[   16.106279]  drm_ioctl+0x27d/0x45e
[   16.106311]  ksys_ioctl+0x89/0xb0
[   16.106336]  __x64_sys_ioctl+0x42/0x60
[   16.106370]  do_syscall_64+0x6e/0x2c0
[   16.106397]  entry_SYSCALL_64_after_hwframe+0x44/0xa9

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200426094231.21995-1-chris@chris-wilson.co.uk
2020-04-27 11:36:59 +01:00
Mika Kuoppala
b8a1181122 drm/i915: Use indirect ctx bb to mend CMD_BUF_CCTL
Use indirect ctx bb to load cmd buffer control value
from context image to avoid corruption.

v2: add to lrc layout (Chris)
v3: end to a cacheline (Chris)
v4: add to lrc fixed (Chris)
v5: value in offset+1

Testcase: igt/i915_selftest/gt_lrc
Signed-off-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20200424230632.30333-1-mika.kuoppala@linux.intel.com
2020-04-25 19:08:56 +01:00
Mika Kuoppala
1dd47b54ba drm/i915: Add live selftests for indirect ctx batchbuffers
Indirect ctx batchbuffers are a hw feature of which
batch can be run, by hardware, during context restoration stage.
Driver can setup a batchbuffer and also an offset into the
context image. When context image is marshalled from
memory to registers, and when the offset from the start of
context register state is equal of what driver pre-determined,
batch will run. So one can manipulate context restoration
process at cacheline granularity, given some limitations,
as you need to have rudimentaries in place before you can
run a batch.

Add selftest which will write the ring start register
to a canary spot. This will test that hardware will run a
batchbuffer for the context in question.

v2: request wait fix, naming (Chris)
v3: test order (Chris)
v4: rebase

Signed-off-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20200424214841.28076-3-mika.kuoppala@linux.intel.com
2020-04-25 19:08:18 +01:00
Mika Kuoppala
685d21096f drm/i915: Add per ctx batchbuffer wa for timestamp
Restoration of a previous timestamp can collide
with updating the timestamp, causing a value corruption.

Combat this issue by using indirect ctx bb to
modify the context image during restoring process.

We can preload value into scratch register. From which
we then do the actual write with LRR. LRR is faster and
thus less error prone as probability of race drops.

v2: tidying (Chris)
v3: lrr for all engines
v4: grp
v5: reg bit
v6: wa_bb_offset, virtual engines (Chris)

References: HSDES#16010904313
Testcase: igt/i915_selftest/gt_lrc
Suggested-by: Joseph Koston <joseph.koston@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20200424230546.30271-1-mika.kuoppala@linux.intel.com
2020-04-25 18:39:32 +01:00
Mika Kuoppala
168c6d231b drm/i915: Add engine scratch register to live_lrc_fixed
General purpose registers are per engine and
in a fixed location. Add to live_lrc_fixed.

Signed-off-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20200424214841.28076-1-mika.kuoppala@linux.intel.com
2020-04-25 17:58:33 +01:00
Chris Wilson
9c878557b1 drm/i915/gt: Use the RPM config register to determine clk frequencies
For many configuration details within RC6 and RPS we are programming
intervals for the internal clocks. From gen11, these clocks are
configuration via the RPM_CONFIG and so for convenience, we would like
to convert to/from more natural units (ns).

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Andi Shyti <andi.shyti@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Andi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200424162805.25920-2-chris@chris-wilson.co.uk
2020-04-24 19:10:17 +01:00
Chris Wilson
555a322429 drm/i915/gt: Trace RPS events
Add tracek to the RPS events (interrupts, worker, enabling, threshold
selection, frequency setting), so that if we have to debug reticent HW
we have some traces to start from.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Andi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200424162805.25920-1-chris@chris-wilson.co.uk
2020-04-24 18:38:46 +01:00
Chris Wilson
1ebf7aaf3a drm/i915/gt: Prefer soft-rc6 over RPS DOWN_TIMEOUT
The RPS DOWN_TIMEOUT interrupt is signaled after a period of rc6, and
upon receipt of that interrupt we reprogram the GPU clocks down to the
next idle notch [to help convserve power during rc6]. However, on
execlists, we benefit from soft-rc6 immediately parking the GPU and
setting idle frequencies upon idling [within a jiffie], and here the
interrupt prevents us from restarting from our last frequency.

In the process, we can simply opt for a static pm_events mask and rely
on the enable/disable interrupts to flush the worker on parking.

This will reduce the amount of oscillation observed during steady
workloads with microsleeps, as each time the rc6 timeout occurs we
immediately follow with a waitboost for a dropped frame.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Andi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200422001703.1697-1-chris@chris-wilson.co.uk
2020-04-24 17:20:58 +01:00
Chris Wilson
50689771c8 drm/i915: Only close vma we open
The history of i915_vma_close() is confusing, as is its use. As the
lifetime of the i915_vma is currently bounded by the object it is
attached to, we needed a means of identify when a vma was no longer in
use by userspace (via the user's fd). This is further complicated by
that only ppgtt vma should be closed at the user's behest, as the ggtt
were always shared.

Now that we attach the vma to a lut on the user's context, the open
count does indicate how many unique and open context/vm are referencing
this vma from the user. As such, we can and should just use the
open_count to track when the vma is still in use by userspace.

It's a poor man's replacement for reference counting.

Closes: https://gitlab.freedesktop.org/drm/intel/issues/1193
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Andi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200422190558.30509-1-chris@chris-wilson.co.uk
2020-04-24 11:24:45 +01:00
Mika Kuoppala
b4892e4404 drm/i915: Make define for lrc state offset
More often than not, we need a byte offset into lrc
register state from the start of the hw state. Make it so.

Signed-off-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20200423182355.21837-3-mika.kuoppala@linux.intel.com
2020-04-24 00:52:14 +01:00
Mika Kuoppala
f1cc6acf22 drm/i915/selftests: Add context batchbuffers registers to live_lrc_fixed
Add per ctx bb and indirect ctx bb register locations to live_lrc_fixed
for verification.

Signed-off-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20200423224159.22078-1-chris@chris-wilson.co.uk
2020-04-24 00:36:13 +01:00
Chris Wilson
b97f77baa8 drm/i915/gt: Check carefully for an idle engine in wait-for-idle
intel_gt_wait_for_idle() tries to wait until all the outstanding requests
are retired and the GPU is idle. As a side effect of retiring requests,
we may submit more work to flush any pm barriers, and so the
wait-for-idle tries to flush the background pm work and catch the new
requests. However, if the work completed in the background before we
were able to flush, it would queue the extra barrier request without us
noticing -- and so we would return from wait-for-idle with one request
remaining. (This breaks e.g. record_default_state where we need to wait
until that barrier is retired, and it may slow suspend down by causing
us to wait on the background retirement worker as opposed to immediately
retiring the barrier.)

However, since we track if there has been a submission since the engine
pm barrier, we can very quickly detect if the idle barrier is still
outstanding.

Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/1763
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200423085940.28168-1-chris@chris-wilson.co.uk
2020-04-23 16:16:32 +01:00
Chris Wilson
36fe164d8d drm/i915/gt: Carefully order virtual_submission_tasklet
During the virtual engine's submission tasklet, we take the request and
insert into the submission queue on each of our siblings. This seems
quite simply, and so no problems with ordering. However, the sibling
execlists' submission tasklets may run concurrently with the virtual
engine's tasklet, submitting the request to HW before the virtual
finishes its task of telling all the siblings. If this happens, the
sibling tasklet may *reorder* the ve->sibling[] array that the virtual
engine tasklet is processing. This can *only* reorder within the
elements already processed by the virtual engine, nevertheless the
race is detected by KCSAN:

[  185.580014] BUG: KCSAN: data-race in execlists_dequeue [i915] / virtual_submission_tasklet [i915]
[  185.580054]
[  185.580076] write to 0xffff8881f1919860 of 8 bytes by interrupt on cpu 2:
[  185.580553]  execlists_dequeue+0x6ad/0x1600 [i915]
[  185.581044]  __execlists_submission_tasklet+0x48/0x60 [i915]
[  185.581517]  execlists_submission_tasklet+0xd3/0x170 [i915]
[  185.581554]  tasklet_action_common.isra.0+0x42/0x90
[  185.581585]  __do_softirq+0xc8/0x206
[  185.581613]  run_ksoftirqd+0x15/0x20
[  185.581641]  smpboot_thread_fn+0x15a/0x270
[  185.581669]  kthread+0x19a/0x1e0
[  185.581695]  ret_from_fork+0x1f/0x30
[  185.581717]
[  185.581736] read to 0xffff8881f1919860 of 8 bytes by interrupt on cpu 0:
[  185.582231]  virtual_submission_tasklet+0x10e/0x5c0 [i915]
[  185.582265]  tasklet_action_common.isra.0+0x42/0x90
[  185.582291]  __do_softirq+0xc8/0x206
[  185.582315]  run_ksoftirqd+0x15/0x20
[  185.582340]  smpboot_thread_fn+0x15a/0x270
[  185.582368]  kthread+0x19a/0x1e0
[  185.582395]  ret_from_fork+0x1f/0x30
[  185.582417]

We can prevent this race by checking for the ve->request after looking
up the sibling array.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200423115315.26825-1-chris@chris-wilson.co.uk
2020-04-23 16:14:27 +01:00
Chris Wilson
15501287b1 drm/i915/execlists: Drop request-before-CS assertion
When we migrated to execlists, one of the conditions we wanted to test
for was whether the breadcrumb seqno was being written before the
breadcumb interrupt was delivered. This was following on from issues
observed on previous generations which were not so strongly ordered. With
the removal of the missed interrupt detection, we have not reliable
means of detecting the out-of-order seqno/interrupt but instead tried to
assert that the relationship between the CS event interrupt and the
breadwrite should be strongly ordered. However, Icelake proves it is
possible for the HW implementation to forget about minor little details
such as write ordering and so the order between *processing* the CS
event and the breadcrumb is unreliable.

Remove the unreliable assertion, but leave a debug telltale in case we
have reason to suspect.

Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/1658
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200422141749.28709-1-chris@chris-wilson.co.uk
2020-04-22 17:17:50 +01:00
Chris Wilson
c92724de6d drm/i915/selftests: Try to detect rollback during batchbuffer preemption
Since batch buffers dominant execution time, most preemption requests
should naturally occur during execution of a batch buffer. We wish to
verify that should a preemption occur within a batch buffer, when we
come to restart that batch buffer, it occurs at the interrupted
instruction and most importantly does not rollback to an earlier point.

v2: Do not clear the GPR at the start of the batch, but rely on them
being clear for new contexts.

Suggested-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200422100903.25216-1-chris@chris-wilson.co.uk
2020-04-22 15:42:52 +01:00
Chris Wilson
cbb6f8805a drm/i915/selftests: Disable heartbeat around RPS interrupt testing
For verifying reciving the EI interrupts, we need to hold the GPU in
very precise conditions (in terms of C0 cycles during the EI). If we
preempt the busy load to handle the heartbeat, this may perturb the busy
load causing us to miss the interrupt.

The other tests, while not as time sensitive, may also be slightly
perturbed, so apply the heartbeat protection across all the
measurements.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200422083855.26842-1-chris@chris-wilson.co.uk
2020-04-22 10:59:46 +01:00
Chris Wilson
33883310cd drm/i915/selftests: Unroll the CS frequency loop
Having noticed that MI_BB_START is incurring a memory stall (see the
correlation with uncore frequency), we have to unroll the loop in order
to diminish the impact of the MI_BB_START on the instruction throughput.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200421171351.19575-1-chris@chris-wilson.co.uk
2020-04-21 20:48:45 +01:00
Chris Wilson
bd3ec9e758 drm/i915/gt: Poison residual state [HWSP] across resume.
Since we may lose the content of any buffer when we relinquish control
of the system (e.g. suspend/resume), we have to be careful not to rely
on regaining control. A good method to detect when we might be using
garbage is by always injecting that garbage prior to first use on
load/resume/etc.

v2: Drop sanitize callback on cleanup
v3: Move seqno reset to timeline enter, so we reset all timelines.
However, this is done on every activation during runtime and not reset.
The similar level of paranoia we apply to correcting context state after
a period of inactivity.

Suggested-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Venkata Ramana Nayana <venkata.ramana.nayana@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200421092504.7416-1-chris@chris-wilson.co.uk
2020-04-21 16:27:39 +01:00
Chris Wilson
cf9ba27840 drm/i915/selftests: Disable C-states when measuring RPS frequency response
Let's isolate the impact of cpu frequency selection on determing the GPU
throughput in response to selection of RPS frequencies.

For real systems, we do have to be concerned with the impact of
integrating c-states, p-states and rp-states, but for the sake of
proving whether or not RPS works, one baby step at a time.

For the record, as one would hope, it does not seem to impact on the
measured performance, but we do it anyway to reduce the number of
variables. Later, we can extend the testing to encourage the the
cpu/pkg to try and sleep while the GPU is busy.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200421142236.8614-1-chris@chris-wilson.co.uk
Link: https://patchwork.freedesktop.org/patch/msgid/20200421142236.8614-1-chris@chris-wilson.co.uk
2020-04-21 16:24:34 +01:00
Chris Wilson
4ea6b1c456 drm/i915/selftests: Show the full scaling curve on failure
If we detect that the RPS end points do not scale perfectly, take the
time to measure all the in between values as well. We are aborting the
test, so we might as well spend the available time gathering critical
debug information instead.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200421124636.22554-1-chris@chris-wilson.co.uk
2020-04-21 16:24:34 +01:00
Chris Wilson
74f103928d drm/i915/selftests: Show the pstate limits on any failure to reset min
We want to see the pstate limits whenever we fail to set the minimum
frequency as that may help for debugging.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200420203040.8984-1-chris@chris-wilson.co.uk
2020-04-21 09:39:35 +01:00
Chris Wilson
e42a969e72 drm/i915/selftests: Exercise dynamic reclocking with RPS
After having testing all the RPS controls individually, we need to take
a step back and check how our RPS worker integrates them to perform
dynamic GPU reclocking. So do that by submitting a spinner and wait and
see what happens.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200420172739.11620-6-chris@chris-wilson.co.uk
2020-04-20 20:08:07 +01:00
Chris Wilson
6b36fc9442 drm/i915/selftests: Show the pcode frequency table on error
If we encounter an error while scaling, read back the frequency tables
from the pcu.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200420172739.11620-5-chris@chris-wilson.co.uk
2020-04-20 20:08:07 +01:00
Chris Wilson
0eaccc4b18 drm/i915/selftests: Split RPS frequency measurement
Split the frequency measurement into two modes, so that we can judge the
impact of the llc setup on top of the pure CS frequency scaling.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200420172739.11620-4-chris@chris-wilson.co.uk
2020-04-20 20:08:07 +01:00
Chris Wilson
9938ee2e63 drm/i915/selftests: Check RPS controls
Check that the GPU does respond to our RPS frequency requests by setting
our desired frequency.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200420172739.11620-3-chris@chris-wilson.co.uk
2020-04-20 20:08:06 +01:00
Chris Wilson
a740f5c5f6 drm/i915/selftests: Skip energy consumption tests if not controlling freq
If we can not manipulate the frequency with RPS, then comparing min/max
power consumption is pointless / misleading. We will leave the warning
about not being able to control the frequency selection via RPS to other
tests so as not to confuse this more specialised check.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200420172739.11620-2-chris@chris-wilson.co.uk
2020-04-20 20:08:06 +01:00
Chris Wilson
4ba74e53ad drm/i915/selftests: Verify frequency scaling with RPS
One of the core tenents of reclocking the GPU is that its throughput
scales with the clock frequency. We can observe this by incrementing a
loop counter on the GPU, and compare the different execution rates at
the notional RPS frequencies.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200420172739.11620-1-chris@chris-wilson.co.uk
2020-04-20 20:08:06 +01:00
Chris Wilson
f153f6395a drm/i915/gt: Move the late flush_submission in retire to the end
Avoid flushing the submission queue (of others) under the client's
timeline lock, but instead move it to the end so that we may catch more.

References: https://gitlab.freedesktop.org/drm/intel/-/issues/1066
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200420125356.26614-2-chris@chris-wilson.co.uk
2020-04-20 16:56:23 +01:00
Michael J. Ruhl
31a02eb70b drm/i915: Refactor setting dma info to a common helper
DMA_MASK bit values are different for different generations.

This will become more difficult to manage over time with the open
coded usage of different versions of the device.

Fix by:
  disallow setting of dma mask in AGP path (< GEN(5) for i915,
  add dma_mask_size to the device info configuration,
  updating open code call sequence to the latest interface,
  refactoring into a common function for setting the dma segment
  and mask info

Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Michael J. Ruhl <michael.j.ruhl@intel.com>
cc: Brian Welty <brian.welty@intel.com>
cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20200417195107.68732-1-michael.j.ruhl@intel.com
2020-04-18 07:49:11 +01:00
Chris Wilson
c43dd6b414 drm/i915/selftests: Check power consumption at min/max frequencies
A basic premise of RPS is that at lower frequencies, not only do we run
slower, but we save power compared to higher frequencies. For example,
when idle, we set the minimum frequency just in case there is some
residual current. Since the power curve should be a physical
relationship, if we find no power saving it's likely that we've broken
our frequency handling, so test!

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Andi Shyti <andi.shyti@intel.com>
Reviewed-by: Andi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200417152018.13079-2-chris@chris-wilson.co.uk
2020-04-17 18:48:51 +01:00
Chris Wilson
d4e3d455a1 drm/i915/selftests: Move gpu energy measurement into its own little lib
Move the handy utility to measure the GPU energy consumption using RAPL
msr into a common lib so that it can be reused easily.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Andi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200417152018.13079-1-chris@chris-wilson.co.uk
2020-04-17 18:48:51 +01:00
Chris Wilson
a50717dbf4 drm/i915/selftests: Take the engine wakeref around __rps_up_interrupt
Since we are touching the device to read the registers, we are required
to ensure the device is awake at the time. Currently, we believe
ourselves to be inside the active request [thus an active engine
wakeref], but since that may be retired in the background, we can
spontaneously lose the wakeref and the ability to probe the HW.

<4> [379.686703] RPM wakelock ref not held during HW access
<4> [379.686805] WARNING: CPU: 7 PID: 4869 at ./drivers/gpu/drm/i915/intel_runtime_pm.h:115 gen12_fwtable_read32+0x233/0x300 [i915]
<4> [379.686808] Modules linked in: i915(+) vgem snd_hda_codec_hdmi mei_hdcp x86_pkg_temp_thermal coretemp crct10dif_pclmul crc32_pclmul ax88179_178a usbnet mii ghash_clmulni_intel snd_intel_dspcfg snd_hda_codec snd_hwdep snd_hda_core snd_pcm e1000e mei_me ptp mei pps_core intel_lpss_pci prime_numbers [last unloaded: i915]
<4> [379.686827] CPU: 7 PID: 4869 Comm: i915_selftest Tainted: G     U            5.7.0-rc1-CI-CI_DRM_8313+ #1
<4> [379.686830] Hardware name: Intel Corporation Tiger Lake Client Platform/TigerLake U DDR4 SODIMM RVP, BIOS TGLSFWI1.R00.2457.A13.1912190237 12/19/2019
<4> [379.686883] RIP: 0010:gen12_fwtable_read32+0x233/0x300 [i915]
<4> [379.686887] Code: d8 ea e0 0f 0b e9 19 fe ff ff 80 3d ad 12 2d 00 00 0f 85 17 fe ff ff 48 c7 c7 b0 32 3e a0 c6 05 99 12 2d 00 01 e8 2d d8 ea e0 <0f> 0b e9 fd fd ff ff 8b 05 c4 75 56 e2 85 c0 0f 85 84 00 00 00 48
<4> [379.686889] RSP: 0018:ffffc90000727970 EFLAGS: 00010286
<4> [379.686892] RAX: 0000000000000000 RBX: ffff88848cc20ee8 RCX: 0000000000000001
<4> [379.686894] RDX: 0000000080000001 RSI: ffff88843b1f0900 RDI: 00000000ffffffff
<4> [379.686896] RBP: 0000000000000000 R08: ffff88843b1f0900 R09: 0000000000000000
<4> [379.686898] R10: 0000000000000000 R11: 0000000000000000 R12: 000000000000a058
<4> [379.686900] R13: 0000000000000001 R14: ffff88848cc2bf30 R15: 00000000ffffffea
<4> [379.686902] FS:  00007f7d63f5e300(0000) GS:ffff8884a0180000(0000) knlGS:0000000000000000
<4> [379.686904] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
<4> [379.686907] CR2: 000055e5c30f4988 CR3: 000000042e190002 CR4: 0000000000760ee0
<4> [379.686910] PKRU: 55555554
<4> [379.686911] Call Trace:
<4> [379.686986]  live_rps_interrupt+0xb14/0xc10 [i915]
<4> [379.687051]  ? intel_rps_unpark+0xb0/0xb0 [i915]
<4> [379.687057]  ? __trace_bprintk+0x57/0x80
<4> [379.687143]  __i915_subtests+0xb8/0x210 [i915]
<4> [379.687222]  ? __i915_live_teardown+0x50/0x50 [i915]
<4> [379.687291]  ? __intel_gt_live_setup+0x30/0x30 [i915]
<4> [379.687361]  __run_selftests+0x112/0x170 [i915]
<4> [379.687431]  i915_live_selftests+0x2c/0x60 [i915]
<4> [379.687491]  i915_pci_probe+0x93/0x1b0 [i915]

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Andi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200417093928.17822-2-chris@chris-wilson.co.uk
2020-04-17 14:47:30 +01:00
Chris Wilson
9d7e560f43 drm/i915/selftests: Delay spinner before waiting for an interrupt
It seems that although (perhaps because of the memory stall?) the
spinner has signaled that it has started, it still takes some time to
spin up to 100% utilisation of the HW. Since the test depends on the
full utilisation of the HW to trigger the RPS interrupt, wait a little
bit and flush the interrupt status to be sure that the event we see if
from the spinner.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Andi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200417093928.17822-1-chris@chris-wilson.co.uk
2020-04-17 14:47:15 +01:00
Chris Wilson
23122a4d99 drm/i915/gt: Scrub execlists state on resume
Before we resume, we reset the HW so we restart from a known good state.
However, as a part of the reset process, we drain our pending CS event
queue -- and if we are resuming that does not correspond to internal
state. On setup, we are scrubbing the CS pointers, but alas only on
setup.

Apply the sanitization not just to setup, but to all resumes.

Reported-by: Venkata Ramana Nayana <venkata.ramana.nayana@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Venkata Ramana Nayana <venkata.ramana.nayana@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200416114117.3460-1-chris@chris-wilson.co.uk
2020-04-17 13:56:00 +01:00
Joonas Lahtinen
2b703bbda2 Merge drm/drm-next into drm-intel-next-queued
Backmerging in order to pull "topic/phy-compliance".

Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
2020-04-16 14:35:16 +03:00
Chris Wilson
a080bd994c drm/i915/gt: Update PMINTRMSK holding fw
If we use a non-forcewaked write to PMINTRMSK, it does not take effect
until much later, if at all, causing a loss of RPS interrupts and no GPU
reclocking, leaving the GPU running at the wrong frequency for long
periods of time.

Reported-by: Francisco Jerez <currojerez@riseup.net>
Suggested-by: Francisco Jerez <currojerez@riseup.net>
Fixes: 35cc7f32c298 ("drm/i915/gt: Use non-forcewake writes for RPS")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Francisco Jerez <currojerez@riseup.net>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Andi Shyti <andi.shyti@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Andi Shyti <andi.shyti@intel.com>
Reviewed-by: Francisco Jerez <currojerez@riseup.net>
Cc: <stable@vger.kernel.org> # v5.6+
Link: https://patchwork.freedesktop.org/patch/msgid/20200415170318.16771-2-chris@chris-wilson.co.uk
2020-04-16 00:21:31 +01:00
Chris Wilson
46495adc6c drm/i915/selftests: Exercise basic RPS interrupt generation
Since we depend upon RPS generating interrupts after evaluation
intervals to determine when to up/down clock the GPU, it is imperative
that we successfully enable interrupt generation! Verify that we do see
an interrupt if we keep the GPU busy for an entire EI.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Andi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200415170318.16771-1-chris@chris-wilson.co.uk
2020-04-16 00:21:18 +01:00
Matt Roper
2a040f0d08 drm/i915/tgl: Initialize multicast register steering for workarounds
Even though the bspec is missing gen12 register details for the MCR
selector register (0xFDC), this is confirmed by hardware folks to be a
mistake; the register does exist and we do indeed need to steer
multicast register reads to an appropriate instance the same as we did
on gen11.

Note that despite the lack of documentation we were still using the MCR
selector to read INSTDONE and such in read_subslice_reg() too.

Cc: Matt Atwood <matthew.s.atwood@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200414211118.2787489-4-matthew.d.roper@intel.com
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
2020-04-15 15:29:20 -07:00
Chris Wilson
c1b5ea926d drm/i915/selftests: Check for an already completed timeslice
With timeslice yielding on a semaphore, we may complete timeslices much
faster than we were expecting and already have yielded the stuck
request. Before complaining that timeslicing is not enabled, check that
we haven't already applied the switch.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Andi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200410081638.19893-1-chris@chris-wilson.co.uk
2020-04-10 14:15:27 +01:00
Chris Wilson
fbaa1229d3 drm/i915/selftests: Take an explicit ref for rq->batch
Since we are peeking into the batch object of the request, it is
beholden on us to hold a reference to it.

Closes: https://gitlab.freedesktop.org/drm/intel/issues/1634
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200408091723.28937-1-chris@chris-wilson.co.uk
2020-04-08 13:40:07 +01:00
Chris Wilson
dd345efe8a drm/i915/gt: Mark up racy check of breadcrumb irq enabled
We control b->irq_enabled inside the b->irq_lock, but we check before
entering the spinlock whether or not the interrupt is currently
unmasked.

[ 1511.735208] BUG: KCSAN: data-race in __intel_breadcrumbs_disarm_irq [i915] / intel_engine_disarm_breadcrumbs [i915]
[ 1511.735231]
[ 1511.735242] write to 0xffff8881f75fc214 of 1 bytes by interrupt on cpu 2:
[ 1511.735440]  __intel_breadcrumbs_disarm_irq+0x4b/0x160 [i915]
[ 1511.735635]  signal_irq_work+0x337/0x710 [i915]
[ 1511.735652]  irq_work_run_list+0xd7/0x110
[ 1511.735666]  irq_work_run+0x1d/0x50
[ 1511.735681]  smp_irq_work_interrupt+0x21/0x30
[ 1511.735701]  irq_work_interrupt+0xf/0x20
[ 1511.735722]  __do_softirq+0x6f/0x206
[ 1511.735736]  irq_exit+0xcd/0xe0
[ 1511.735756]  do_IRQ+0x44/0xc0
[ 1511.735773]  ret_from_intr+0x0/0x1c
[ 1511.735787]  schedule+0x0/0xb0
[ 1511.735803]  worker_thread+0x194/0x670
[ 1511.735823]  kthread+0x19a/0x1e0
[ 1511.735837]  ret_from_fork+0x1f/0x30
[ 1511.735848]
[ 1511.735867] read to 0xffff8881f75fc214 of 1 bytes by task 432 on cpu 1:
[ 1511.736068]  intel_engine_disarm_breadcrumbs+0x22/0x80 [i915]
[ 1511.736263]  __engine_park+0x107/0x5d0 [i915]
[ 1511.736453]  ____intel_wakeref_put_last+0x44/0x90 [i915]
[ 1511.736648]  __intel_wakeref_put_last+0x5a/0x70 [i915]
[ 1511.736842]  intel_context_exit_engine+0xf2/0x100 [i915]
[ 1511.737044]  i915_request_retire+0x6b2/0x770 [i915]
[ 1511.737244]  retire_requests+0x7a/0xd0 [i915]
[ 1511.737438]  intel_gt_retire_requests_timeout+0x3a7/0x6f0 [i915]
[ 1511.737633]  i915_drop_caches_set+0x1e7/0x260 [i915]
[ 1511.737650]  simple_attr_write+0xfa/0x110
[ 1511.737665]  full_proxy_write+0x94/0xc0
[ 1511.737679]  __vfs_write+0x4b/0x90
[ 1511.737697]  vfs_write+0xfc/0x280
[ 1511.737718]  ksys_write+0x78/0x100
[ 1511.737732]  __x64_sys_write+0x44/0x60
[ 1511.737751]  do_syscall_64+0x6e/0x2c0
[ 1511.737769]  entry_SYSCALL_64_after_hwframe+0x44/0xa9

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200408092916.5355-1-chris@chris-wilson.co.uk
2020-04-08 13:40:07 +01:00
Chris Wilson
32a55a109f drm/i915/gt: Mark up racy read of intel_ring.head
The intel_ring.head is updated as the requests are retired, but is
sampled at any time as we submit requests. Furthermore, it tracks
RING_HEAD which is inherently asynchronous.

[  148.630314] BUG: KCSAN: data-race in execlists_dequeue [i915] / i915_request_retire [i915]
[  148.630349]
[  148.630374] write to 0xffff8881f4e28ddc of 4 bytes by task 90 on cpu 2:
[  148.630752]  i915_request_retire+0xed/0x770 [i915]
[  148.631123]  retire_requests+0x7a/0xd0 [i915]
[  148.631491]  engine_retire+0xa6/0xe0 [i915]
[  148.631523]  process_one_work+0x3af/0x640
[  148.631552]  worker_thread+0x80/0x670
[  148.631581]  kthread+0x19a/0x1e0
[  148.631609]  ret_from_fork+0x1f/0x30
[  148.631629]
[  148.631652] read to 0xffff8881f4e28ddc of 4 bytes by task 14288 on cpu 3:
[  148.632019]  execlists_dequeue+0x1300/0x1680 [i915]
[  148.632384]  __execlists_submission_tasklet+0x48/0x60 [i915]
[  148.632770]  execlists_submit_request+0x38e/0x3c0 [i915]
[  148.633146]  submit_notify+0x8f/0xc0 [i915]
[  148.633512]  __i915_sw_fence_complete+0x5d/0x3e0 [i915]
[  148.633875]  i915_sw_fence_complete+0x58/0x80 [i915]
[  148.634238]  i915_sw_fence_commit+0x16/0x20 [i915]
[  148.634613]  __i915_request_queue+0x60/0x70 [i915]
[  148.634985]  i915_gem_do_execbuffer+0x2de0/0x42b0 [i915]
[  148.635366]  i915_gem_execbuffer2_ioctl+0x2ab/0x580 [i915]
[  148.635400]  drm_ioctl_kernel+0xe9/0x130
[  148.635429]  drm_ioctl+0x27d/0x45e
[  148.635456]  ksys_ioctl+0x89/0xb0
[  148.635482]  __x64_sys_ioctl+0x42/0x60
[  148.635510]  do_syscall_64+0x6e/0x2c0
[  148.635542]  entry_SYSCALL_64_after_hwframe+0x44/0xa9

[  645.071436] BUG: KCSAN: data-race in gen8_emit_fini_breadcrumb [i915] / i915_request_retire [i915]
[  645.071456]
[  645.071467] write to 0xffff8881efe403dc of 4 bytes by task 14668 on cpu 3:
[  645.071647]  i915_request_retire+0xed/0x770 [i915]
[  645.071824]  i915_request_create+0x6c/0x160 [i915]
[  645.072000]  i915_gem_do_execbuffer+0x206d/0x42b0 [i915]
[  645.072177]  i915_gem_execbuffer2_ioctl+0x2ab/0x580 [i915]
[  645.072194]  drm_ioctl_kernel+0xe9/0x130
[  645.072208]  drm_ioctl+0x27d/0x45e
[  645.072222]  ksys_ioctl+0x89/0xb0
[  645.072235]  __x64_sys_ioctl+0x42/0x60
[  645.072248]  do_syscall_64+0x6e/0x2c0
[  645.072263]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[  645.072275]
[  645.072285] read to 0xffff8881efe403dc of 4 bytes by interrupt on cpu 2:
[  645.072458]  gen8_emit_fini_breadcrumb+0x158/0x300 [i915]
[  645.072636]  __i915_request_submit+0x204/0x430 [i915]
[  645.072809]  execlists_dequeue+0x8e1/0x1680 [i915]
[  645.072982]  __execlists_submission_tasklet+0x48/0x60 [i915]
[  645.073154]  execlists_submit_request+0x38e/0x3c0 [i915]
[  645.073330]  submit_notify+0x8f/0xc0 [i915]
[  645.073499]  __i915_sw_fence_complete+0x5d/0x3e0 [i915]
[  645.073668]  i915_sw_fence_wake+0xc2/0x130 [i915]
[  645.073836]  __i915_sw_fence_complete+0x2cf/0x3e0 [i915]
[  645.074006]  i915_sw_fence_complete+0x58/0x80 [i915]
[  645.074175]  dma_i915_sw_fence_wake+0x3e/0x80 [i915]
[  645.074344]  signal_irq_work+0x62f/0x710 [i915]
[  645.074360]  irq_work_run_list+0xd7/0x110
[  645.074373]  irq_work_run+0x1d/0x50
[  645.074386]  smp_irq_work_interrupt+0x21/0x30
[  645.074400]  irq_work_interrupt+0xf/0x20
[  645.074414]  _raw_spin_unlock_irqrestore+0x34/0x40
[  645.074585]  execlists_submission_tasklet+0xde/0x170 [i915]
[  645.074602]  tasklet_action_common.isra.0+0x42/0x90
[  645.074617]  __do_softirq+0xc8/0x206
[  645.074629]  irq_exit+0xcd/0xe0
[  645.074642]  do_IRQ+0x44/0xc0
[  645.074654]  ret_from_intr+0x0/0x1c
[  645.074667]  finish_task_switch+0x73/0x230
[  645.074679]  __schedule+0x1c5/0x4c0
[  645.074691]  schedule+0x45/0xb0
[  645.074704]  worker_thread+0x194/0x670
[  645.074716]  kthread+0x19a/0x1e0
[  645.074729]  ret_from_fork+0x1f/0x30

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200407221832.15465-1-chris@chris-wilson.co.uk
2020-04-08 13:40:07 +01:00