drm/i915/gem: reconcile Excess struct member kernel-doc warnings

Document nested struct members with full names as described in
Documentation/doc-guide/kernel-doc.rst.

i915_gem_context_types.h:420: warning: Excess struct member 'lock' description in 'i915_gem_context'

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: intel-gfx@lists.freedesktop.org
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Signed-off-by: Andi Shyti <andi.shyti@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231226195432.10891-1-rdunlap@infradead.org

drm/i915/gem: reconcile Excess struct member kernel-doc warnings

Document nested struct members with full names as described in
Documentation/doc-guide/kernel-doc.rst.

i915_gem_context_types.h:420: warning: Excess struct member 'lock' description in 'i915_gem_context'

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: intel-gfx@lists.freedesktop.org
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Signed-off-by: Andi Shyti <andi.shyti@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231226195432.10891-1-rdunlap@infradead.org
(cherry picked from commit 7353c3d7c15017140a8b984e41f94be0bf535e73)
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

drm/i915: Record which client owns a VM

To enable accounting of indirect client memory usage (such as page tables)
in the following patch, lets start recording the creator of each PPGTT.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Aravind Iddamsetty <aravind.iddamsetty@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231107101806.608990-2-tvrtko.ursulin@linux.intel.com

drm/i915: Fixup kerneldoc in struct i915_gem_context

Mixup in rebasing and patchwork re-runs made me push the wrong version of
the patch. Or I even forgot to send out the fixed version. Fix it up.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Fixes: 49bd54b390c2 ("drm/i915: Track all user contexts per client")
Cc: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20220405155345.3292769-1-tvrtko.ursulin@linux.intel.com

drm/i915: Track all user contexts per client

We soon want to start answering questions like how much GPU time is the
context belonging to a client which exited still using.

To enable this we start tracking all context belonging to a client on a
separate list.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Aravind Iddamsetty <aravind.iddamsetty@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220401142205.3123159-5-tvrtko.ursulin@linux.intel.com

drm/i915: Make GEM contexts track DRM clients

Make GEM contexts keep a reference to i915_drm_client for the whole of
of their lifetime which will come handy in following patches.

v2: Don't bother supporting selftests contexts from debugfs. (Chris)
v3 (Lucas): Finish constructing ctx before adding it to the list
v4 (Ram): Rebase.
v5: Trivial rebase for proto ctx changes.
v6: Rebase after clients no longer track name and pid.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> # v5
Reviewed-by: Aravind Iddamsetty <aravind.iddamsetty@intel.com> # v5
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220401142205.3123159-3-tvrtko.ursulin@linux.intel.com

drm/i915/guc: Connect UAPI to GuC multi-lrc interface

Introduce 'set parallel submit' extension to connect UAPI to GuC
multi-lrc interface. Kernel doc in new uAPI should explain it all.

IGT: https://patchwork.freedesktop.org/patch/447008/?series=93071&rev=1
media UMD: https://github.com/intel/media-driver/pull/1252

v2:
(Daniel Vetter)
- Add IGT link and placeholder for media UMD link
v3:
(Kernel test robot)
- Fix warning in unpin engines call
(John Harrison)
- Reword a bunch of the kernel doc
v4:
(John Harrison)
- Add comment why perma-pin is done after setting gem context
- Update some comments / docs for proto contexts
v5:
(John Harrison)
- Rework perma-pin comment
- Add BUG_IN if context is pinned when setting gem context

Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
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/20211014172005.27155-17-matthew.brost@intel.com

drm/i915/pxp: interfaces for using protected objects

This api allow user mode to create protected buffers and to mark
contexts as making use of such objects. Only when using contexts
marked in such a way is the execution guaranteed to work as expected.

Contexts can only be marked as using protected content at creation time
(i.e. the parameter is immutable) and they must be both bannable and not
recoverable. Given that the protected session gets invalidated on
suspend, contexts created this way hold a runtime pm wakeref until
they're either destroyed or invalidated.

All protected objects and contexts will be considered invalid when the
PXP session is destroyed and all new submissions using them will be
rejected. All intel contexts within the invalidated gem contexts will be
marked banned. Userspace can detect that an invalidation has occurred via
the RESET_STATS ioctl, where we report it the same way as a ban due to a
hang.

v5: squash patches, rebase on proto_ctx, update kerneldoc

v6: rebase on obj create_ext changes

v7: Use session counter to check if an object it valid, hold wakeref in
context, don't add a new flag to RESET_STATS (Daniel)

v8: don't increase guilty count for contexts banned during pxp
invalidation (Rodrigo)

v9: better comments, avoid wakeref put race between pxp_inval and
context_close, add usage examples (Rodrigo)

v10: modify internal set/get-protected-context functions to not
return -ENODEV when setting PXP param to false or getting param
when running on pxp-unsupported hw or getting param when i915
was built with CONFIG_PXP off

Signed-off-by: Alan Previn <alan.previn.teres.alexis@intel.com>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Bommu Krishnaiah <krishnaiah.bommu@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Cc: Jason Ekstrand <jason@jlekstrand.net>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210924191452.1539378-11-alan.previn.teres.alexis@intel.com

drm/i915: Drop __rcu from gem_context->vm

It's been invariant since

commit ccbc1b97948ab671335e950271e39766729736c3
Author: Jason Ekstrand <jason@jlekstrand.net>
Date: Thu Jul 8 10:48:30 2021 -0500

drm/i915/gem: Don't allow changing the VM on running contexts (v4)

this just completes the deed. I've tried to split out prep work for
more careful review as much as possible, this is what's left:

- get_ppgtt gets simplified since we don't need to grab a temporary
reference - we can rely on the temporary reference for the gem_ctx
while we inspect the vm. The new vm_id still needs a full
i915_vm_open ofc. This also removes the final caller of context_get_vm_rcu

- A pile of selftests can now just look at ctx->vm instead of
rcu_dereference_protected( , true) or similar things.

- All callers of i915_gem_context_vm also disappear.

- I've changed the hugepage selftest to set scrub_64K without any
locking, because when we inspect that setting we're also not taking
any locks either. It works because it's a selftests that's careful
(single threaded gives you nice ordering) and not a live driver
where races can happen from anywhere.

These can only be split up further if we have some intermediate state
with a bunch more rcu_dereference_protected(ctx->vm, true), just to
shut up lockdep and sparse.

The conversion to __rcu happened in

commit a4e7ccdac38ec8335d9e4e2656c1a041c77feae1
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date: Fri Oct 4 14:40:09 2019 +0100

drm/i915: Move context management under GEM

Note that we're not breaking the actual bugfix in there: The real
bugfix is pushing the i915_vm_relase onto a separate worker, to avoid
locking inversion issues. The rcu conversion was just thrown in for
entertainment value on top (no vm lookup isn't even close to anything
that's a hotpath where removing the single spinlock can be measured).

v2: Rebase over the change to move the i915_vm_put() into
i915_gem_context_release().

v3: Trivial conflict against repainted shed.

Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Jon Bloomfield <jon.bloomfield@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: "Thomas Hellström" <thomas.hellstrom@linux.intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Jason Ekstrand <jason@jlekstrand.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20210902142057.929669-9-daniel.vetter@ffwll.ch

drm/i915: Release i915_gem_context from a worker

The only reason for this really is the i915_gem_engines->fence
callback engines_notify(), which exists purely as a fairly funky
reference counting scheme for that. Otherwise all other callers are
from process context, and generally fairly benign locking context.

Unfortunately untangling that requires some major surgery, and we have
a few i915_gem_context reference counting bugs that need fixing, and
they blow in the current hardirq calling context, so we need a
stop-gap measure.

Put a FIXME comment in when this should be removable again.

v2: Fix mock_context(), noticed by intel-gfx-ci.

Acked-by: Acked-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Jon Bloomfield <jon.bloomfield@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: "Thomas Hellström" <thomas.hellstrom@linux.intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Jason Ekstrand <jason@jlekstrand.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20210902142057.929669-1-daniel.vetter@ffwll.ch

drm/i915/gem: Delay context creation (v3)

The current context uAPI allows for two methods of setting context
parameters: SET_CONTEXT_PARAM and CONTEXT_CREATE_EXT_SETPARAM. The
former is allowed to be called at any time while the later happens as
part of GEM_CONTEXT_CREATE. Currently, everything settable via one is
settable via the other. While some params are fairly simple and setting
them on a live context is harmless such as the context priority, others
are far trickier such as the VM or the set of engines. In order to swap
out the VM, for instance, we have to delay until all current in-flight
work is complete, swap in the new VM, and then continue. This leads to
a plethora of potential race conditions we'd really rather avoid.

In previous patches, we added a i915_gem_proto_context struct which is
capable of storing and tracking all such create parameters. This commit
delays the creation of the actual context until after the client is done
configuring it with SET_CONTEXT_PARAM. From the perspective of the
client, it has the same u32 context ID the whole time. From the
perspective of i915, however, it's an i915_gem_proto_context right up
until the point where we attempt to do something which the proto-context
can't handle. Then the real context gets created.

This is accomplished via a little xarray dance. When GEM_CONTEXT_CREATE
is called, we create a proto-context, reserve a slot in context_xa but
leave it NULL, the proto-context in the corresponding slot in
proto_context_xa. Then, whenever we go to look up a context, we first
check context_xa. If it's there, we return the i915_gem_context and
we're done. If it's not, we look in proto_context_xa and, if we find it
there, we create the actual context and kill the proto-context.

In order for this dance to work properly, everything which ever touches
a proto-context is guarded by drm_i915_file_private::proto_context_lock,
including context creation. Yes, this means context creation now takes
a giant global lock but it can't really be helped and that should never
be on any driver's fast-path anyway.

v2 (Daniel Vetter):
- Commit message grammatical fixes.
- Use WARN_ON instead of GEM_BUG_ON
- Rename lazy_create_context_locked to finalize_create_context_locked
- Rework the control-flow logic in the setparam ioctl
- Better documentation all around

v3 (kernel test robot):
- Make finalize_create_context_locked static

Signed-off-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210708154835.528166-25-jason@jlekstrand.net

drm/i915/gem: Use the proto-context to handle create parameters (v5)

This means that the proto-context needs to grow support for engine
configuration information as well as setparam logic. Fortunately, we'll
be deleting a lot of setparam logic on the primary context shortly so it
will hopefully balance out.

There's an extra bit of fun here when it comes to setting SSEU and the
way it interacts with PARAM_ENGINES. Unfortunately, thanks to
SET_CONTEXT_PARAM and not being allowed to pick the order in which we
handle certain parameters, we have think about those interactions.

v2 (Daniel Vetter):
- Add a proto_context_free_user_engines helper
- Comment on SSEU in the commit message
- Use proto_context_set_persistence in set_proto_ctx_param

v3 (Daniel Vetter):
- Fix a doc comment
- Do an explicit HAS_FULL_PPGTT check in set_proto_ctx_vm instead of
relying on pc->vm != NULL.
- Handle errors for CONTEXT_PARAM_PERSISTENCE
- Don't allow more resetting user engines
- Rework initialization of UCONTEXT_PERSISTENCE

v4 (Jason Ekstrand):
- Move hand-rolled initialization of UCONTEXT_PERSISTENCE to an
earlier patch

v5 (Jason Ekstrand):
- Move proto_context_set_persistence to this patch

Signed-off-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210708154835.528166-22-jason@jlekstrand.net

drm/i915/gem: Add an intermediate proto_context struct (v5)

The current context uAPI allows for two methods of setting context
parameters: SET_CONTEXT_PARAM and CONTEXT_CREATE_EXT_SETPARAM. The
former is allowed to be called at any time while the later happens as
part of GEM_CONTEXT_CREATE. Currently, everything settable via one is
settable via the other. While some params are fairly simple and setting
them on a live context is harmless such the context priority, others are
far trickier such as the VM or the set of engines. In order to swap out
the VM, for instance, we have to delay until all current in-flight work
is complete, swap in the new VM, and then continue. This leads to a
plethora of potential race conditions we'd really rather avoid.

Unfortunately, both methods of setting the VM and the engine set are in
active use today so we can't simply disallow setting the VM or engine
set vial SET_CONTEXT_PARAM. In order to work around this wart, this
commit adds a proto-context struct which contains all the context create
parameters.

v2 (Daniel Vetter):
- Better commit message
- Use __set/clear_bit instead of set/clear_bit because there's no race
and we don't need the atomics

v3 (Daniel Vetter):
- Use manual bitops and BIT() instead of __set_bit

v4 (Daniel Vetter):
- Add a changelog to the commit message
- Better hyperlinking in docs
- Create the default PPGTT in i915_gem_create_context

v5 (Daniel Vetter):
- Hand-roll the initialization of UCONTEXT_PERSISTENCE

Signed-off-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210708154835.528166-17-jason@jlekstrand.net

drm/i915: Add gem/i915_gem_context.h to the docs

In order to prevent kernel doc warnings, also fill out docs for any
missing fields and fix those that forgot the "@".

Signed-off-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210708154835.528166-16-jason@jlekstrand.net

drm/i915: Implement SINGLE_TIMELINE with a syncobj (v4)

This API is entirely unnecessary and I'd love to get rid of it. If
userspace wants a single timeline across multiple contexts, they can
either use implicit synchronization or a syncobj, both of which existed
at the time this feature landed. The justification given at the time
was that it would help GL drivers which are inherently single-timeline.
However, neither of our GL drivers actually wanted the feature. i965
was already in maintenance mode at the time and iris uses syncobj for
everything.

Unfortunately, as much as I'd love to get rid of it, it is used by the
media driver so we can't do that. We can, however, do the next-best
thing which is to embed a syncobj in the context and do exactly what
we'd expect from userspace internally. This isn't an entirely identical
implementation because it's no longer atomic if userspace races with
itself by calling execbuffer2 twice simultaneously from different
threads. It won't crash in that case; it just doesn't guarantee any
ordering between those two submits. It also means that sync files
exported from different engines on a SINGLE_TIMELINE context will have
different fence contexts. This is visible to userspace if it looks at
the obj_name field of sync_fence_info.

Moving SINGLE_TIMELINE to a syncobj emulation has a couple of technical
advantages beyond mere annoyance. One is that intel_timeline is no
longer an api-visible object and can remain entirely an implementation
detail. This may be advantageous as we make scheduler changes going
forward. Second is that, together with deleting the CLONE_CONTEXT API,
we should now have a 1:1 mapping between intel_context and
intel_timeline which may help us reduce locking.

v2 (Tvrtko Ursulin):
- Update the comment on i915_gem_context::syncobj to mention that it's
an emulation and the possible race if userspace calls execbuffer2
twice on the same context concurrently.
v2 (Jason Ekstrand):
- Wrap the checks for eb.gem_context->syncobj in unlikely()
- Drop the dma_fence reference
- Improved commit message

v3 (Jason Ekstrand):
- Move the dma_fence_put() to before the error exit

v4 (Tvrtko Ursulin):
- Add a comment about fence contexts to the commit message

Signed-off-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210708154835.528166-8-jason@jlekstrand.net

drm/i915/gem: Set the watchdog timeout directly in intel_context_set_gem (v2)

Instead of handling it like a context param, unconditionally set it when
intel_contexts are created. For years we've had the idea of a watchdog
uAPI floating about. The aim was for media, so that they could set very
tight deadlines for their transcodes jobs, so that if you have a corrupt
bitstream (especially for decoding) you don't hang your desktop too
hard. But it's been stuck in limbo since forever, and this simplifies
things a bit in preparation for the proto-context work. If we decide to
actually make said uAPI a reality, we can do it through the proto-
context easily enough.

This does mean that we move from reading the request_timeout_ms param
once per engine when engines are created instead of once at context
creation. If someone changes request_timeout_ms between creating a
context and setting engines, it will mean that they get the new timeout.
If someone races setting request_timeout_ms and context creation, they
can theoretically end up with different timeouts. However, since both
of these are fairly harmless and require changing kernel params, we
don't care.

v2 (Tvrtko Ursulin):
- Add a comment about races with request_timeout_ms

Signed-off-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210708154835.528166-5-jason@jlekstrand.net

drm/i915: Drop I915_CONTEXT_PARAM_NO_ZEROMAP

The idea behind this param is to support OpenCL drivers with relocations
because OpenCL reserves 0x0 for NULL and, if we placed memory there, it
would confuse CL kernels. It was originally sent out as part of a patch
series including libdrm [1] and Beignet [2] support. However, the
libdrm and Beignet patches never landed in their respective upstream
projects so this API has never been used. It's never been used in Mesa
or any other driver, either.

Dropping this API allows us to delete a small bit of code.

[1]: https://lists.freedesktop.org/archives/intel-gfx/2015-May/067030.html
[2]: https://lists.freedesktop.org/archives/intel-gfx/2015-May/067031.html

Signed-off-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210708154835.528166-4-jason@jlekstrand.net

drm/i915: Fail too long user submissions by default

A new Kconfig option CONFIG_DRM_I915_REQUEST_TIMEOUT is added, defaulting
to 20s, and this timeout is applied to all users contexts using the
previously added watchdog facility.

Result of this is that any user submission will simply fail after this
timeout, either causing a reset (for non-preemptable), or incomplete
results.

This can have an effect that workloads which used to work fine will
suddenly start failing. Even workloads comprised of short batches but in
long dependency chains can be terminated.

And because of lack of agreement on usefulness and safety of fence error
propagation this partial execution can be invisible to userspace even if
it is "listening" to returned fence status.

Another interaction is with hangcheck where care needs to be taken timeout
is not set lower or close to three times the heartbeat interval. Otherwise
a hang in any application can cause complete termination of all
submissions from unrelated clients. Any users modifying the per engine
heartbeat intervals therefore need to be aware of this potential denial of
service to avoid inadvertently enabling it.

Given all this I am personally not convinced the scheme is a good idea.
Intuitively it feels object importers would be better positioned to
enforce the time they are willing to wait for something to complete.

v2:
* Improved commit message and Kconfig text.
* Pull in some helper code from patch which got dropped.

v3:
* Bump timeout to 20s to see if it helps Tigerlake.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Matthew Auld <matthew.auld@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210324121335.2307063-7-tvrtko.ursulin@linux.intel.com

drm/i915/gem: Drop free_work for GEM contexts

The free_list and worker was introduced in commit 5f09a9c8ab6b ("drm/i915:
Allow contexts to be unreferenced locklessly"), but subsequently made
redundant by the removal of the last sleeping lock in commit 2935ed5339c4
("drm/i915: Remove logical HW ID"). As we can now free the GEM context
immediately from any context, remove the deferral of the free_list

v2: Lift removing the context from the global list into close().

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>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201215152138.8158-1-chris@chris-wilson.co.uk

drm/i915/gem: Split the context's obj:vma lut into its own mutex

Rather than reuse the common ctx->mutex for locking the execbuffer LUT,
split it into its own lock to avoid being taken [as part of ctx->mutex]
at inappropriate times. In particular to avoid the inversion from taking
the timeline->mutex for the whole execbuf submission in the next patch.

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/20200703004306.11117-1-chris@chris-wilson.co.uk

drm/i915/gem: use spinlock_t instead of struct spinlock

spinlock_t is one case where the typedef is to be preferred over struct
spinlock.

Fixes: 42fb60de3129 ("drm/i915/gem: Don't leak non-persistent requests on changing engines")
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200217184219.15325-1-jani.nikula@intel.com

drm/i915/gem: Don't leak non-persistent requests on changing engines

If we have a set of active engines marked as being non-persistent, we
lose track of those if the user replaces those engines with
I915_CONTEXT_PARAM_ENGINES. As part of our uABI contract is that
non-persistent requests are terminated if they are no longer being
tracked by the user's context (in order to prevent a lost request
causing an untracked and so unstoppable GPU hang), we need to apply the
same context cancellation upon changing engines.

v2: Track stale engines[] so we only reap at context closure.
v3: Tvrtko spotted races with closing contexts and set-engines, so add a
veneer of kill-everything paranoia to clean up after losing a race.

Fixes: a0e047156cde ("drm/i915/gem: Make context persistence optional")
Testcase: igt/gem_ctx_peristence/replace
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/20200211144831.1011498-1-chris@chris-wilson.co.uk

drm/i915: Drop GEM context as a direct link from i915_request

Keep the intel_context as being the primary state for i915_request, with
the GEM context a backpointer from the low level state for the rarer
cases we need client information. Our goal is to remove such references
to clients from the backend, and leave the HW submission agnostic to
client interfaces and self-contained.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Andi Shyti <andi.shyti@intel.com>
Reviewed-by: Andi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191220101230.256839-1-chris@chris-wilson.co.uk

drm/i915/gem: Excise the per-batch whitelist from the context

One does not lightly add a new hidden struct_mutex dependency deep within
the execbuf bowels! The immediate suspicion in seeing the whitelist
cached on the context, is that it is intended to be preserved between
batches, as the kernel is quite adept at caching small allocations
itself. But no, it's sole purpose is to serialise command submission in
order to save a kmalloc on a slow, slow path!

By removing the whitelist dependency from the context, our freedom to
chop the big struct_mutex is greatly augmented.

v2: s/set_bit/__set_bit/ as the whitelist shall never be accessed
concurrently.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191128113424.3885958-1-chris@chris-wilson.co.uk

drm/i915/gem: Embed context/timeline name inside the GEM context

Use a small char buffer inside the i915_gem_context to store the user
friendly name so that ctx->name has the same lifetime as the RCU
protected GEM context. That is, e.g. when using print_request() that
prints the timeline name (ctx->name), the name will not be prematurely
freed upon the context being closed and the last reference dropped.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191111114323.5833-2-chris@chris-wilson.co.uk

drm/i915/cmdparser: Add support for backward jumps

To keep things manageable, the pre-gen9 cmdparser does not
attempt to track any form of nested BB_START's. This did not
prevent usermode from using nested starts, or even chained
batches because the cmdparser is not strictly enforced pre gen9.

Instead, the existence of a nested BB_START would cause the batch
to be emitted in insecure mode, and any privileged capabilities
would not be available.

For Gen9, the cmdparser becomes mandatory (for BCS at least), and
so not providing any form of nested BB_START support becomes
overly restrictive. Any such batch will simply not run.

We make heavy use of backward jumps in igt, and it is much easier
to add support for this restricted subset of nested jumps, than to
rewrite the whole of our test suite to avoid them.

Add the required logic to support limited backward jumps, to
instructions that have already been validated by the parser.

Note that it's not sufficient to simply approve any BB_START
that jumps backwards in the buffer because this would allow an
attacker to embed a rogue instruction sequence within the
operand words of a harmless instruction (say LRI) and jump to
that.

We introduce a bit array to track every instr offset successfully
validated, and test the target of BB_START against this. If the
target offset hits, it is re-written to the same offset in the
shadow buffer and the BB_START cmd is allowed.

Note: This patch deliberately ignores checkpatch issues in the
cmdtables, in order to match the style of the surrounding code.
We'll correct the entire file in one go in a later patch.

v2: set dispatch secure late (Mika)
v3: rebase (Mika)
v4: Clear whitelist on each parse
Minor review updates (Chris)
v5: Correct backward jump batching
v6: fix compilation error due to struct eb shuffle (Mika)

Cc: Tony Luck <tony.luck@intel.com>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Tyler Hicks <tyhicks@canonical.com>
Signed-off-by: Jon Bloomfield <jon.bloomfield@intel.com>
Signed-off-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Chris Wilson <chris.p.wilson@intel.com>

drm/i915/gem: Make context persistence optional

Our existing behaviour is to allow contexts and their GPU requests to
persist past the point of closure until the requests are complete. This
allows clients to operate in a 'fire-and-forget' manner where they can
setup a rendering pipeline and hand it over to the display server and
immediately exit. As the rendering pipeline is kept alive until
completion, the display server (or other consumer) can use the results
in the future and present them to the user.

The compute model is a little different. They have little to no buffer
sharing between processes as their kernels tend to operate on a
continuous stream, feeding the results back to the client application.
These kernels operate for an indeterminate length of time, with many
clients wishing that the kernel was always running for as long as they
keep feeding in the data, i.e. acting like a DSP.

Not all clients want this persistent "desktop" behaviour and would prefer
that the contexts are cleaned up immediately upon closure. This ensures
that when clients are run without hangchecking (e.g. for compute kernels
of indeterminate runtime), any GPU hang or other unexpected workloads
are terminated with the process and does not continue to hog resources.

The default behaviour for new contexts is the legacy persistence mode,
as some desktop applications are dependent upon the existing behaviour.
New clients will have to opt in to immediate cleanup on context
closure. If the hangchecking modparam is disabled, so is persistent
context support -- all contexts will be terminated on closure.

We expect this behaviour change to be welcomed by compute users, who
have often been caught between a rock and a hard place. They disable
hangchecking to avoid their kernels being "unfairly" declared hung, but
have also experienced true hangs that the system was then unable to
clean up. Naturally, this leads to bug reports.

Testcase: igt/gem_ctx_persistence
Link: https://github.com/intel/compute-runtime/pull/228
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Cc: Jon Bloomfield <jon.bloomfield@intel.com>
Reviewed-by: Jon Bloomfield <jon.bloomfield@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Acked-by: Jason Ekstrand <jason@jlekstrand.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20191029202338.8841-1-chris@chris-wilson.co.uk

drm/i915/perf: allow holding preemption on filtered ctx

We would like to make use of perf in Vulkan. The Vulkan API is much
lower level than OpenGL, with applications directly exposed to the
concept of command buffers (pretty much equivalent to our batch
buffers). In Vulkan, queries are always limited in scope to a command
buffer. In OpenGL, the lack of command buffer concept meant that
queries' duration could span multiple command buffers.

With that restriction gone in Vulkan, we would like to simplify
measuring performance just by measuring the deltas between the counter
snapshots written by 2 MI_RECORD_PERF_COUNT commands, rather than the
more complex scheme we currently have in the GL driver, using 2
MI_RECORD_PERF_COUNT commands and doing some post processing on the
stream of OA reports, coming from the global OA buffer, to remove any
unrelated deltas in between the 2 MI_RECORD_PERF_COUNT.

Disabling preemption only apply to a single context with which want to
query performance counters for and is considered a privileged
operation, by default protected by CAP_SYS_ADMIN. It is possible to
enable it for a normal user by disabling the paranoid stream setting.

v2: Store preemption setting in intel_context (Chris)

v3: Use priorities to avoid preemption rather than the HW mechanism

v4: Just modify the port priority reporting function

v5: Add nopreempt flag on gem context and always flag requests
appropriately, regarless of OA reconfiguration.

Link: https://gitlab.freedesktop.org/mesa/mesa/merge_requests/932
Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@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/20191014201404.22468-4-chris@chris-wilson.co.uk

drm/i915: Move context management under GEM

Keep track of the GEM contexts underneath i915->gem.contexts and assign
them their own lock for the purposes of list management.

v2: Focus on lock tracking; ctx->vm is protected by ctx->mutex
v3: Correct split with removal of logical HW ID

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/20191004134015.13204-15-chris@chris-wilson.co.uk

drm/i915: Remove logical HW ID

With the introduction of ctx->engines[] we allow multiple logical
contexts to be used on the same engine (e.g. with virtual engines).
According to bspec, aach logical context requires a unique tag in order
for context-switching to occur correctly between them. [Simple
experiments show that it is not so easy to trick the HW into performing
a lite-restore with matching logical IDs, though my memory from early
Broadwell experiments do suggest that it should be generating
lite-restores.]

We only need to keep a unique tag for the active lifetime of the
context, and for as long as we need to identify that context. The HW
uses the tag to determine if it should use a lite-restore (why not the
LRCA?) and passes the tag back for various status identifies. The only
status we need to track is for OA, so when using perf, we assign the
specific context a unique tag.

v2: Calculate required number of tags to fill ELSP.

Fixes: 976b55f0e1db ("drm/i915: Allow a context to define its set of engines")
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=111895
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191004134015.13204-14-chris@chris-wilson.co.uk

drm/i915: Push the ring creation flags to the backend

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: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Andi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190809182518.20486-3-chris@chris-wilson.co.uk

drm/i915: Remove lrc default desc from GEM context

We only compute the lrc_descriptor() on pinning the context, i.e.
infrequently, so we do not benefit from storing the template as the
addressing mode is also fixed for the lifetime of the intel_context.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Prathap Kumar Valsan <prathap.kumar.valsan@intel.com>
Acked-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190730133035.1977-9-chris@chris-wilson.co.uk

drm/i915: Rename i915_timeline to intel_timeline and move under gt

Move all timeline code under gt and rename to intel_gt prefix.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Suggested-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190621070811.7006-32-tvrtko.ursulin@linux.intel.com

drm/i915: Pull kref into i915_address_space

Make the kref common to both derived structs (i915_ggtt and i915_ppgtt)
so that we can safely reference count an abstract ctx->vm address space.

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/20190611091238.15808-1-chris@chris-wilson.co.uk

drm/i915: Move object close under its own lock

Use i915_gem_object_lock() to guard the LUT and active reference to
allow us to break free of struct_mutex for handling GEM_CLOSE.

Testcase: igt/gem_close_race
Testcase: igt/gem_exec_parallel
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/20190606112320.9704-1-chris@chris-wilson.co.uk

drm/i915: Move more GEM objects under gem/

Continuing the theme of separating out the GEM clutter.

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/20190528092956.14910-8-chris@chris-wilson.co.uk