Context switch (and execlist submission) should happen only when
other contexts are not active, otherwise pre-emption occurs.
To assure this, we place context switch requests in a queue and those
request are later consumed when the right context switch interrupt is
received (still TODO).
v2: Use a spinlock, do not remove the requests on unqueue (wait for
context switch completion).
Signed-off-by: Thomas Daniel <thomas.daniel@intel.com>
v3: Several rebases and code changes. Use unique ID.
v4:
- Move the queue/lock init to the late ring initialization.
- Damien's kmalloc review comments: check return, use sizeof(*req),
do not cast.
v5:
- Do not reuse drm_i915_gem_request. Instead, create our own.
- New namespace.
Signed-off-by: Michel Thierry <michel.thierry@intel.com> (v1)
Signed-off-by: Oscar Mateo <oscar.mateo@intel.com> (v2-v5)
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
[davnet: Checkpatch + wash-up s/BUG_ON/WARN_ON/.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Each logical ring context has the tail pointer in the context object,
so update it before submission.
v2: New namespace.
Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
A context switch occurs by submitting a context descriptor to the
ExecList Submission Port. Given that we can now initialize a context,
it's possible to begin implementing the context switch by creating the
descriptor and submitting it to ELSP (actually two, since the ELSP
has two ports).
The context object must be mapped in the GGTT, which means it must exist
in the 0-4GB graphics VA range.
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
v2: This code has changed quite a lot in various rebases. Of particular
importance is that now we use the globally unique Submission ID to send
to the hardware. Also, context pages are now pinned unconditionally to
GGTT, so there is no need to bind them.
v3: Use LRCA[31:12] as hwCtxId[19:0]. This guarantees that the HW context
ID we submit to the ELSP is globally unique and != 0 (Bspec requirements
of the software use-only bits of the Context ID in the Context Descriptor
Format) without the hassle of the previous submission Id construction.
Also, re-add the ELSP porting read (it was dropped somewhere during the
rebases).
v4:
- Squash with "drm/i915/bdw: Add forcewake lock around ELSP writes" (BSPEC
says: "SW must set Force Wakeup bit to prevent GT from entering C6 while
ELSP writes are in progress") as noted by Thomas Daniel
(thomas.daniel@intel.com).
- Rename functions and use an execlists/intel_execlists_ namespace.
- The BUG_ON only checked that the LRCA was <32 bits, but it didn't make
sure that it was properly aligned. Spotted by Alistair Mcaulay
<alistair.mcaulay@intel.com>.
v5:
- Improved source code comments as suggested by Chris Wilson.
- No need to abstract submit_ctx away, as pointed by Brad Volkin.
Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
[danvet: Checkpatch. Sigh.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
On a previous iteration of this patch, I created an Execlists
version of __i915_add_request and asbtracted it away as a
vfunc. Daniel Vetter wondered then why that was needed:
"with the clean split in command submission I expect every
function to know wether it'll submit to an lrc (everything in
intel_lrc.c) or wether it'll submit to a legacy ring (existing
code), so I don't see a need for an add_request vfunc."
The honest, hairy truth is that this patch is the glue keeping
the whole logical ring puzzle together:
- i915_add_request is used by intel_ring_idle, which in turn is
used by i915_gpu_idle, which in turn is used in several places
inside the eviction and gtt codes.
- Also, it is used by i915_gem_check_olr, which is littered all
over i915_gem.c
- ...
If I were to duplicate all the code that directly or indirectly
uses __i915_add_request, I'll end up creating a separate driver.
To show the differences between the existing legacy version and
the new Execlists one, this time I have special-cased
__i915_add_request instead of adding an add_request vfunc. I
hope this helps to untangle this Gordian knot.
Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
[danvet: Adjust to ringbuf->FIXME_lrc_ctx per the discussion with
Thomas Daniel.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
The execlist patches have a bit a convoluted and long history and due
to that have the actual submission still misplaced deeply burried in
the low-level ringbuffer handling code. This design goes back to the
legacy ringbuffer code with its tricky lazy request and simple work
submissiion using ring tail writes. For that reason they need a
ring->ctx backpointer.
The goal is to unburry that code and move it up into a level where the
full execlist context is available so that we can ditch this
backpointer. Until that's done make it really obvious that there's
work still to be done.
Cc: Oscar Mateo <oscar.mateo@intel.com>
Cc: Thomas Daniel <thomas.daniel@intel.com>
Acked-by: Thomas Daniel <thomas.daniel@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
There's a bit a confusion since we track the global gtt,
the aliasing and real ppgtt in the ctx->vm pointer. And not
all callers really bother to check for the different cases and just
presume that it points to a real ppgtt.
Now looking closely we don't actually need ->vm to always point at an
address space - the only place that cares actually has fixup code
already to decide whether to look at the per-proces or the global
address space.
So switch to just tracking the ppgtt directly and ditch all the
extraneous code.
v2: Fixup the ppgtt debugfs file to not oops on a NULL ctx->ppgtt.
Also drop the early exit - without aliasing ppgtt we want to dump all
the ppgtts of the contexts if we have full ppgtt.
v3: Actually git add the compile fix.
Reviewed-by: Michel Thierry <michel.thierry@intel.com>
Cc: "Thierry, Michel" <michel.thierry@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
OTC-Jira: VIZ-3724
[danvet: Resolve conflicts with execlist patches while applying.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
The normal flip function places things in the ring in the legacy
way, so we either fix that or force MMIO flips always as we do in
this patch.
Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
[danvet: Checkpatch. Fucking again.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This is what i915_gem_do_execbuffer calls when it wants to execute some
worload in an Execlists world.
v2: Check arguments before doing stuff in intel_execlists_submission. Also,
get rel_constants parsing right.
Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
[danvet: Drop the chipset flush, that's pre-gen6. And appease
checkpatch a bit .... again!]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
We need to attend context switch interrupts from all rings. Also, fixed writing
IMR/IER and added HWSTAM at ring init time.
Notice that, if added to irq_enable_mask, the context switch interrupts would
be incorrectly masked out when the user interrupts are due to no users waiting
on a sequence number. Therefore, this commit adds a bitmask of interrupts to
be kept unmasked at all times.
v2: Disable HWSTAM, as suggested by Damien (nobody listens to these interrupts,
anyway).
v3: Add new get/put_irq functions.
Signed-off-by: Thomas Daniel <thomas.daniel@intel.com> (v1)
Signed-off-by: Oscar Mateo <oscar.mateo@intel.com> (v2 & v3)
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
[danvet: Drop the GEN8_ prefix from the context switch interrupt
define and move it to its brethren.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This is a hard one, since there is no direct hardware ring to
control when in Execlists.
We reuse intel_ring_idle here, but it should be fine as long
as i915_add_request does the ring thing.
Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Same as the legacy-style ring->flush.
v2: The BSD invalidate bit still exists in GEN8! Add it for the VCS
rings (but still consolidate the blt and bsd ring flushes into one).
This was noticed by Brad Volkin.
v3: The command for BSD and for other rings is slightly different:
get it exactly the same as in gen6_ring_flush + gen6_bsd_ring_flush
Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
[danvet: Checkpatch.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Very similar to the legacy add_request, only modified to account for
logical ringbuffer.
v2: Use MI_GLOBAL_GTT, as suggested by Brad Volkin.
v3: Unify render and non-render in the same function, as noticed by
Brad Volkin.
Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Well, new-ish: if all this code looks familiar, that's because it's
a clone of the existing submission mechanism (with some modifications
here and there to adapt it to LRCs and Execlists).
And why did we do this instead of reusing code, one might wonder?
Well, there are some fears that the differences are big enough that
they will end up breaking all platforms.
Also, Execlists offer several advantages, like control over when the
GPU is done with a given workload, that can help simplify the
submission mechanism, no doubt. I am interested in getting Execlists
to work first and foremost, but in the future this parallel submission
mechanism will help us to fine tune the mechanism without affecting
old gens.
v2: Pass the ringbuffer only (whenever possible).
Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
[danvet: Appease checkpatch. Again. And drop the legacy sarea gunk
that somehow crept in.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
No mistery here: the seqno is still retrieved from the engine's
HW status page (the one in the default context. For the moment,
I see no reason to worry about other context's HWS page).
Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Logical rings do not need most of the initialization their
legacy ringbuffer counterparts do: we just need the pipe
control object for the render ring, enable Execlists on the
hardware and a few workarounds.
v2: Squash with: "drm/i915: Extract pipe control fini & make
init outside accesible".
Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
[danvet: Make checkpatch happy.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Allocate and populate the default LRC for every ring, call
gen-specific init/cleanup, init/fini the command parser and
set the status page (now inside the LRC object). These are
things all engines/rings have in common.
Stopping the ring before cleanup and initializing the seqnos
is left as a TODO task (we need more infrastructure in place
before we can achieve this).
v2: Check the ringbuffer backing obj for ring_is_initialized,
instead of the context backing obj (similar, but not exactly
the same).
Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Execlists are indeed a brave new world with respect to workload
submission to the GPU.
In previous version of these series, I have tried to impact the
legacy ringbuffer submission path as little as possible (mostly,
passing the context around and using the correct ringbuffer when I
needed one) but Daniel is afraid (probably with a reason) that
these changes and, especially, future ones, will end up breaking
older gens.
This commit and some others coming next will try to limit the
damage by creating an alternative path for workload submission.
The first step is here: laying out a new ring init/fini.
Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
For the most part, logical ring context objects are similar to hardware
contexts in that the backing object is meant to be opaque. There are
some exceptions where we need to poke certain offsets of the object for
initialization, updating the tail pointer or updating the PDPs.
For our basic execlist implementation we'll only need our PPGTT PDs,
and ringbuffer addresses in order to set up the context. With previous
patches, we have both, so start prepping the context to be load.
Before running a context for the first time you must populate some
fields in the context object. These fields begin 1 PAGE + LRCA, ie. the
first page (in 0 based counting) of the context image. These same
fields will be read and written to as contexts are saved and restored
once the system is up and running.
Many of these fields are completely reused from previous global
registers: ringbuffer head/tail/control, context control matches some
previous MI_SET_CONTEXT flags, and page directories. There are other
fields which we don't touch which we may want in the future.
v2: CTX_LRI_HEADER_0 is MI_LOAD_REGISTER_IMM(14) for render and (11)
for other engines.
v3: Several rebases and general changes to the code.
v4: Squash with "Extract LR context object populating"
Also, Damien's review comments:
- Set the Force Posted bit on the LRI header, as the BSpec suggest we do.
- Prevent warning when compiling a 32-bits kernel without HIGHMEM64.
- Add a clarifying comment to the context population code.
v5: Damien's review comments:
- The third MI_LOAD_REGISTER_IMM in the context does not set Force Posted.
- Remove dead code.
v6: Add a note about the (presumed) differences between BDW and CHV state
contexts. Also, Brad's review comments:
- Use the _MASKED_BIT_ENABLE, upper_32_bits and lower_32_bits macros.
- Be less magical about how we set the ring size in the context.
Signed-off-by: Ben Widawsky <ben@bwidawsk.net> (v1)
Signed-off-by: Rafael Barbalho <rafael.barbalho@intel.com> (v2)
Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Any given ringbuffer is unequivocally tied to one context and one engine.
By setting the appropriate pointers to them, the ringbuffer struct holds
all the infromation you might need to submit a workload for processing,
Execlists style.
v2: Drop ring->ctx since that looks terribly ill-defined for legacy
ringbuffer submission.
Signed-off-by: Oscar Mateo <oscar.mateo@intel.com> (v1)
Acked-by: Damien Lespiau <damien.lespiau@intel.com> (v2)
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
As we have said a couple of times by now, logical ring contexts have
their own ringbuffers: not only the backing pages, but the whole
management struct.
In a previous version of the series, this was achieved with two separate
patches:
drm/i915/bdw: Allocate ringbuffer backing objects for default global LRC
drm/i915/bdw: Allocate ringbuffer for user-created LRCs
Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Now that we have the ability to allocate our own context backing objects
and we have multiplexed one of them per engine inside the context structs,
we can finally allocate and free them correctly.
Regarding the context size, reading the register to calculate the sizes
can work, I think, however the docs are very clear about the actual
context sizes on GEN8, so just hardcode that and use it.
v2: Rebased on top of the Full PPGTT series. It is important to notice
that at this point we have one global default context per engine, all
of them using the aliasing PPGTT (as opposed to the single global
default context we have with legacy HW contexts).
v3:
- Go back to one single global default context, this time with multiple
backing objects inside.
- Use different context sizes for non-render engines, as suggested by
Damien (still hardcoded, since the information about the context size
registers in the BSpec is, well, *lacking*).
- Render ctx size is 20 (or 19) pages, but not 21 (caught by Damien).
- Move default context backing object creation to intel_init_ring (so
that we don't waste memory in rings that might not get initialized).
v4:
- Reuse the HW legacy context init/fini.
- Create a separate free function.
- Rename the functions with an intel_ preffix.
v5: Several rebases to account for the changes in the previous patches.
Signed-off-by: Ben Widawsky <ben@bwidawsk.net> (v1)
Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
For the moment this is just a placeholder, but it shows one of the
main differences between the good ol' HW contexts and the shiny
new Logical Ring Contexts: LR contexts allocate and free their
own backing objects. Another difference is that the allocation is
deferred (as the create function name suggests), but that does not
happen in this patch yet, because for the moment we are only dealing
with the default context.
Early in the series we had our own gen8_gem_context_init/fini
functions, but the truth is they now look almost the same as the
legacy hw context init/fini functions. We can always split them
later if this ceases to be the case.
Also, we do not fall back to legacy ringbuffers when logical ring
context initialization fails (not very likely to happen and, even
if it does, hw contexts would probably fail as well).
v2: Daniel says "explain, do not showcase".
Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
[danvet: s/BUG_ON/WARN_ON/.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Depending upon one module option to be sanitized (through USES_PPGTT)
for the other is a bit too fragile for my taste. At least WARN about
this.
Cc: Ben Widawsky <ben@bwidawsk.net>
Cc: Damien Lespiau <damien.lespiau@intel.com>
Cc: Oscar Mateo <oscar.mateo@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
GEN8 brings an expansion of the HW contexts: "Logical Ring Contexts".
These expanded contexts enable a number of new abilities, especially
"Execlists".
The macro is defined to off until we have things in place to hope to
work.
v2: Rename "advanced contexts" to the more correct "logical ring
contexts".
v3: Add a module parameter to enable execlists. Execlist are relatively
new, and so it'd be wise to be able to switch back to ring submission
to debug subtle problems that will inevitably arise.
v4: Add an intel_enable_execlists function.
v5: Sanitize early, as suggested by Daniel. Remove lrc_enabled.
Signed-off-by: Ben Widawsky <ben@bwidawsk.net> (v1)
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com> (v3)
Signed-off-by: Oscar Mateo <oscar.mateo@intel.com> (v2, v4 & v5)
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Some legacy HW context code assumptions don't make sense for this new
submission method, so we will place this stuff in a separate file.
Note for reviewers: I've carefully considered the best name for this file
and this was my best option (other possibilities were intel_lr_context.c
or intel_execlist.c). I am open to a certain bikeshedding on this matter,
anyway.
And some point in time, it would be a good idea to split intel_lrc.c/.h
even further, but for the moment just shove everything together.
v2: Change to intel_lrc.c
v3: Squash together with the header file addition
Signed-off-by: Oscar Mateo <oscar.mateo@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Michel Thierry