This reverts commit 88be76cdafc7 ("drm/i915: Allow userspace to specify ringsize on construction"). This API was originally added for OpenCL but the compute-runtime PR has sat open for a year without action so we can still pull it out if we want. I argue we should drop it for three reasons:

1. If the compute-runtime PR has sat open for a year, this clearly isn't that important.

2. It's a very leaky API. Ring size is an implementation detail of the current execlist scheduler and really only makes sense there. It can't apply to the older ring-buffer scheduler on pre-execlist hardware because that's shared across all contexts and it won't apply to the GuC scheduler that's in the pipeline.

3. Having userspace set a ring size in bytes is a bad solution to the problem of having too small a ring. There is no way that userspace has the information to know how to properly set the ring size so it's just going to detect the feature and always set it to the maximum of 512K. This is what the compute-runtime PR does. The scheduler in i915, on the other hand, does have the information to make an informed choice. It could detect if the ring size is a problem and grow it itself. Or, if that's too hard, we could just increase the default size from 16K to 32K or even 64K instead of relying on userspace to do it.

Let's drop this API for now and, if someone decides they really care about solving this problem, they can do it properly.

Signed-off-by: Jason Ekstrand jason@jlekstrand.net Reviewed-by: Daniel Vetter daniel.vetter@ffwll.ch --- drivers/gpu/drm/i915/Makefile | 1 - drivers/gpu/drm/i915/gem/i915_gem_context.c | 85 +------------------ drivers/gpu/drm/i915/gt/intel_context_param.c | 63 -------------- drivers/gpu/drm/i915/gt/intel_context_param.h | 3 - include/uapi/drm/i915_drm.h | 20 +---- 5 files changed, 4 insertions(+), 168 deletions(-) delete mode 100644 drivers/gpu/drm/i915/gt/intel_context_param.c

diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile index d0d936d9137bc..afa22338fa343 100644 --- a/drivers/gpu/drm/i915/Makefile +++ b/drivers/gpu/drm/i915/Makefile @@ -88,7 +88,6 @@ gt-y += \ gt/gen8_ppgtt.o \ gt/intel_breadcrumbs.o \ gt/intel_context.o \ - gt/intel_context_param.o \ gt/intel_context_sseu.o \ gt/intel_engine_cs.o \ gt/intel_engine_heartbeat.o \ diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c index 188dee13e017d..650364a0dae28 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c @@ -1334,63 +1334,6 @@ static int set_ppgtt(struct drm_i915_file_private *file_priv, return err; }

-static int __apply_ringsize(struct intel_context *ce, void *sz) -{ - return intel_context_set_ring_size(ce, (unsigned long)sz); -} - -static int set_ringsize(struct i915_gem_context *ctx, - struct drm_i915_gem_context_param *args) -{ - if (!HAS_LOGICAL_RING_CONTEXTS(ctx->i915)) - return -ENODEV; - - if (args->size) - return -EINVAL; - - if (!IS_ALIGNED(args->value, I915_GTT_PAGE_SIZE)) - return -EINVAL; - - if (args->value < I915_GTT_PAGE_SIZE) - return -EINVAL; - - if (args->value > 128 * I915_GTT_PAGE_SIZE) - return -EINVAL; - - return context_apply_all(ctx, - __apply_ringsize, - __intel_context_ring_size(args->value)); -} - -static int __get_ringsize(struct intel_context *ce, void *arg) -{ - long sz; - - sz = intel_context_get_ring_size(ce); - GEM_BUG_ON(sz > INT_MAX); - - return sz; /* stop on first engine */ -} - -static int get_ringsize(struct i915_gem_context *ctx, - struct drm_i915_gem_context_param *args) -{ - int sz; - - if (!HAS_LOGICAL_RING_CONTEXTS(ctx->i915)) - return -ENODEV; - - if (args->size) - return -EINVAL; - - sz = context_apply_all(ctx, __get_ringsize, NULL); - if (sz < 0) - return sz; - - args->value = sz; - return 0; -} - int i915_gem_user_to_context_sseu(struct intel_gt *gt, const struct drm_i915_gem_context_param_sseu *user, @@ -2036,11 +1979,8 @@ static int ctx_setparam(struct drm_i915_file_private *fpriv, ret = set_persistence(ctx, args); break;

- case I915_CONTEXT_PARAM_RINGSIZE: - ret = set_ringsize(ctx, args); - break; - case I915_CONTEXT_PARAM_BAN_PERIOD: + case I915_CONTEXT_PARAM_RINGSIZE: default: ret = -EINVAL; break; @@ -2068,18 +2008,6 @@ static int create_setparam(struct i915_user_extension __user *ext, void *data) return ctx_setparam(arg->fpriv, arg->ctx, &local.param); }

-static int copy_ring_size(struct intel_context *dst, - struct intel_context *src) -{ - long sz; - - sz = intel_context_get_ring_size(src); - if (sz < 0) - return sz; - - return intel_context_set_ring_size(dst, sz); -} - static int clone_engines(struct i915_gem_context *dst, struct i915_gem_context *src) { @@ -2124,12 +2052,6 @@ static int clone_engines(struct i915_gem_context *dst, }

intel_context_set_gem(clone->engines[n], dst); - - /* Copy across the preferred ringsize */ - if (copy_ring_size(clone->engines[n], e->engines[n])) { - __free_engines(clone, n + 1); - goto err_unlock; - } } clone->num_engines = n; i915_sw_fence_complete(&e->fence); @@ -2489,11 +2411,8 @@ int i915_gem_context_getparam_ioctl(struct drm_device *dev, void *data, args->value = i915_gem_context_is_persistent(ctx); break;

- case I915_CONTEXT_PARAM_RINGSIZE: - ret = get_ringsize(ctx, args); - break; - case I915_CONTEXT_PARAM_BAN_PERIOD: + case I915_CONTEXT_PARAM_RINGSIZE: default: ret = -EINVAL; break; diff --git a/drivers/gpu/drm/i915/gt/intel_context_param.c b/drivers/gpu/drm/i915/gt/intel_context_param.c deleted file mode 100644 index 65dcd090245d6..0000000000000 --- a/drivers/gpu/drm/i915/gt/intel_context_param.c +++ /dev/null @@ -1,63 +0,0 @@ -// SPDX-License-Identifier: MIT -/* - * Copyright © 2019 Intel Corporation - */ - -#include "i915_active.h" -#include "intel_context.h" -#include "intel_context_param.h" -#include "intel_ring.h" - -int intel_context_set_ring_size(struct intel_context *ce, long sz) -{ - int err; - - if (intel_context_lock_pinned(ce)) - return -EINTR; - - err = i915_active_wait(&ce->active); - if (err < 0) - goto unlock; - - if (intel_context_is_pinned(ce)) { - err = -EBUSY; /* In active use, come back later! */ - goto unlock; - } - - if (test_bit(CONTEXT_ALLOC_BIT, &ce->flags)) { - struct intel_ring *ring; - - /* Replace the existing ringbuffer */ - ring = intel_engine_create_ring(ce->engine, sz); - if (IS_ERR(ring)) { - err = PTR_ERR(ring); - goto unlock; - } - - intel_ring_put(ce->ring); - ce->ring = ring; - - /* Context image will be updated on next pin */ - } else { - ce->ring = __intel_context_ring_size(sz); - } - -unlock: - intel_context_unlock_pinned(ce); - return err; -} - -long intel_context_get_ring_size(struct intel_context *ce) -{ - long sz = (unsigned long)READ_ONCE(ce->ring); - - if (test_bit(CONTEXT_ALLOC_BIT, &ce->flags)) { - if (intel_context_lock_pinned(ce)) - return -EINTR; - - sz = ce->ring->size; - intel_context_unlock_pinned(ce); - } - - return sz; -} diff --git a/drivers/gpu/drm/i915/gt/intel_context_param.h b/drivers/gpu/drm/i915/gt/intel_context_param.h index 3ecacc675f414..dffedd983693d 100644 --- a/drivers/gpu/drm/i915/gt/intel_context_param.h +++ b/drivers/gpu/drm/i915/gt/intel_context_param.h @@ -10,9 +10,6 @@

#include "intel_context.h"

-int intel_context_set_ring_size(struct intel_context *ce, long sz); -long intel_context_get_ring_size(struct intel_context *ce); - static inline int intel_context_set_watchdog_us(struct intel_context *ce, u64 timeout_us) { diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h index c2c7759b7d2ee..ad8f1a0f587f6 100644 --- a/include/uapi/drm/i915_drm.h +++ b/include/uapi/drm/i915_drm.h @@ -1723,24 +1723,8 @@ struct drm_i915_gem_context_param { */ #define I915_CONTEXT_PARAM_PERSISTENCE 0xb

-/* - * I915_CONTEXT_PARAM_RINGSIZE: - * - * Sets the size of the CS ringbuffer to use for logical ring contexts. This - * applies a limit of how many batches can be queued to HW before the caller - * is blocked due to lack of space for more commands. - * - * Only reliably possible to be set prior to first use, i.e. during - * construction. At any later point, the current execution must be flushed as - * the ring can only be changed while the context is idle. Note, the ringsize - * can be specified as a constructor property, see - * I915_CONTEXT_CREATE_EXT_SETPARAM, but can also be set later if required. - * - * Only applies to the current set of engine and lost when those engines - * are replaced by a new mapping (see I915_CONTEXT_PARAM_ENGINES). - * - * Must be between 4 - 512 KiB, in intervals of page size [4 KiB]. - * Default is 16 KiB. +/* This API has been removed. On the off chance someone somewhere has + * attempted to use it, never re-use this context param number. */ #define I915_CONTEXT_PARAM_RINGSIZE 0xc /* Must be kept compact -- no holes and well documented */

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 --- drivers/gpu/drm/i915/gem/i915_gem_context.c | 16 ++-------------- .../gpu/drm/i915/gem/i915_gem_context_types.h | 1 - drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c | 8 -------- include/uapi/drm/i915_drm.h | 4 ++++ 4 files changed, 6 insertions(+), 23 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c index ec999b7ca50f4..868c18c08a0b1 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c @@ -1920,15 +1920,6 @@ static int ctx_setparam(struct drm_i915_file_private *fpriv, int ret = 0;

switch (args->param) { - case I915_CONTEXT_PARAM_NO_ZEROMAP: - if (args->size) - ret = -EINVAL; - else if (args->value) - set_bit(UCONTEXT_NO_ZEROMAP, &ctx->user_flags); - else - clear_bit(UCONTEXT_NO_ZEROMAP, &ctx->user_flags); - break; - case I915_CONTEXT_PARAM_NO_ERROR_CAPTURE: if (args->size) ret = -EINVAL; @@ -1978,6 +1969,7 @@ static int ctx_setparam(struct drm_i915_file_private *fpriv, ret = set_persistence(ctx, args); break;

+ case I915_CONTEXT_PARAM_NO_ZEROMAP: case I915_CONTEXT_PARAM_BAN_PERIOD: case I915_CONTEXT_PARAM_RINGSIZE: default: @@ -2358,11 +2350,6 @@ int i915_gem_context_getparam_ioctl(struct drm_device *dev, void *data, return -ENOENT;

switch (args->param) { - case I915_CONTEXT_PARAM_NO_ZEROMAP: - args->size = 0; - args->value = test_bit(UCONTEXT_NO_ZEROMAP, &ctx->user_flags); - break; - case I915_CONTEXT_PARAM_GTT_SIZE: args->size = 0; rcu_read_lock(); @@ -2410,6 +2397,7 @@ int i915_gem_context_getparam_ioctl(struct drm_device *dev, void *data, args->value = i915_gem_context_is_persistent(ctx); break;

+ case I915_CONTEXT_PARAM_NO_ZEROMAP: case I915_CONTEXT_PARAM_BAN_PERIOD: case I915_CONTEXT_PARAM_RINGSIZE: default: diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context_types.h b/drivers/gpu/drm/i915/gem/i915_gem_context_types.h index 340473aa70de0..5ae71ec936f7c 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_context_types.h +++ b/drivers/gpu/drm/i915/gem/i915_gem_context_types.h @@ -129,7 +129,6 @@ struct i915_gem_context { * @user_flags: small set of booleans controlled by the user */ unsigned long user_flags; -#define UCONTEXT_NO_ZEROMAP 0 #define UCONTEXT_NO_ERROR_CAPTURE 1 #define UCONTEXT_BANNABLE 2 #define UCONTEXT_RECOVERABLE 3 diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c index 297143511f99b..b812f313422a9 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c @@ -290,7 +290,6 @@ struct i915_execbuffer { struct intel_context *reloc_context;

u64 invalid_flags; /** Set of execobj.flags that are invalid */ - u32 context_flags; /** Set of execobj.flags to insert from the ctx */

u64 batch_len; /** Length of batch within object */ u32 batch_start_offset; /** Location within object of batch */ @@ -541,9 +540,6 @@ eb_validate_vma(struct i915_execbuffer *eb, entry->flags |= EXEC_OBJECT_NEEDS_GTT | __EXEC_OBJECT_NEEDS_MAP; }

- if (!(entry->flags & EXEC_OBJECT_PINNED)) - entry->flags |= eb->context_flags; - return 0; }

@@ -750,10 +746,6 @@ static int eb_select_context(struct i915_execbuffer *eb) if (rcu_access_pointer(ctx->vm)) eb->invalid_flags |= EXEC_OBJECT_NEEDS_GTT;

- eb->context_flags = 0; - if (test_bit(UCONTEXT_NO_ZEROMAP, &ctx->user_flags)) - eb->context_flags |= __EXEC_OBJECT_NEEDS_BIAS; - return 0; }

diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h index ad8f1a0f587f6..e527f5f7e0dea 100644 --- a/include/uapi/drm/i915_drm.h +++ b/include/uapi/drm/i915_drm.h @@ -1639,6 +1639,10 @@ struct drm_i915_gem_context_param { __u32 size; __u64 param; #define I915_CONTEXT_PARAM_BAN_PERIOD 0x1 +/* I915_CONTEXT_PARAM_NO_ZEROMAP has been removed. On the off chance + * someone somewhere has attempted to use it, never re-use this context + * param number. + */ #define I915_CONTEXT_PARAM_NO_ZEROMAP 0x2 #define I915_CONTEXT_PARAM_GTT_SIZE 0x3 #define I915_CONTEXT_PARAM_NO_ERROR_CAPTURE 0x4

None of the callbacks we use with it return an error code anymore; they all return 0 unconditionally.

Signed-off-by: Jason Ekstrand jason@jlekstrand.net Reviewed-by: Daniel Vetter daniel.vetter@ffwll.ch --- drivers/gpu/drm/i915/gem/i915_gem_context.c | 26 +++++++-------------- 1 file changed, 8 insertions(+), 18 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c index 9a8a96e4346e4..6f1e5c2c5b113 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c @@ -718,32 +718,25 @@ __context_engines_await(const struct i915_gem_context *ctx, return engines; }

-static int +static void context_apply_all(struct i915_gem_context *ctx, - int (*fn)(struct intel_context *ce, void *data), + void (*fn)(struct intel_context *ce, void *data), void *data) { struct i915_gem_engines_iter it; struct i915_gem_engines *e; struct intel_context *ce; - int err = 0;

e = __context_engines_await(ctx, NULL); - for_each_gem_engine(ce, e, it) { - err = fn(ce, data); - if (err) - break; - } + for_each_gem_engine(ce, e, it) + fn(ce, data); i915_sw_fence_complete(&e->fence); - - return err; }

-static int __apply_ppgtt(struct intel_context *ce, void *vm) +static void __apply_ppgtt(struct intel_context *ce, void *vm) { i915_vm_put(ce->vm); ce->vm = i915_vm_get(vm); - return 0; }

static struct i915_address_space * @@ -783,10 +776,9 @@ static void __set_timeline(struct intel_timeline **dst, intel_timeline_put(old); }

-static int __apply_timeline(struct intel_context *ce, void *timeline) +static void __apply_timeline(struct intel_context *ce, void *timeline) { __set_timeline(&ce->timeline, timeline); - return 0; }

static void __assign_timeline(struct i915_gem_context *ctx, @@ -1841,19 +1833,17 @@ set_persistence(struct i915_gem_context *ctx, return __context_set_persistence(ctx, args->value); }

-static int __apply_priority(struct intel_context *ce, void *arg) +static void __apply_priority(struct intel_context *ce, void *arg) { struct i915_gem_context *ctx = arg;

if (!intel_engine_has_timeslices(ce->engine)) - return 0; + return;

if (ctx->sched.priority >= I915_PRIORITY_NORMAL) intel_context_set_use_semaphores(ce); else intel_context_clear_use_semaphores(ce); - - return 0; }

static int set_priority(struct i915_gem_context *ctx,

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 --- drivers/gpu/drm/i915/gem/i915_gem_context.c | 49 +++++-------------- .../gpu/drm/i915/gem/i915_gem_context_types.h | 14 +++++- .../gpu/drm/i915/gem/i915_gem_execbuffer.c | 16 ++++++ 3 files changed, 40 insertions(+), 39 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c index 97613e529aab3..aa792c9517e16 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c @@ -67,6 +67,8 @@ #include <linux/log2.h> #include <linux/nospec.h>

+#include <drm/drm_syncobj.h> + #include "gt/gen6_ppgtt.h" #include "gt/intel_context.h" #include "gt/intel_context_param.h" @@ -224,10 +226,6 @@ static void intel_context_set_gem(struct intel_context *ce, ce->vm = vm; }

- GEM_BUG_ON(ce->timeline); - if (ctx->timeline) - ce->timeline = intel_timeline_get(ctx->timeline); - if (ctx->sched.priority >= I915_PRIORITY_NORMAL && intel_engine_has_timeslices(ce->engine)) __set_bit(CONTEXT_USE_SEMAPHORES, &ce->flags); @@ -351,9 +349,6 @@ void i915_gem_context_release(struct kref *ref) mutex_destroy(&ctx->engines_mutex); mutex_destroy(&ctx->lut_mutex);

- if (ctx->timeline) - intel_timeline_put(ctx->timeline); - put_pid(ctx->pid); mutex_destroy(&ctx->mutex);

@@ -570,6 +565,9 @@ static void context_close(struct i915_gem_context *ctx) if (vm) i915_vm_close(vm);

+ if (ctx->syncobj) + drm_syncobj_put(ctx->syncobj); + ctx->file_priv = ERR_PTR(-EBADF);

/* @@ -765,33 +763,11 @@ static void __assign_ppgtt(struct i915_gem_context *ctx, i915_vm_close(vm); }

-static void __set_timeline(struct intel_timeline **dst, - struct intel_timeline *src) -{ - struct intel_timeline *old = *dst; - - *dst = src ? intel_timeline_get(src) : NULL; - - if (old) - intel_timeline_put(old); -} - -static void __apply_timeline(struct intel_context *ce, void *timeline) -{ - __set_timeline(&ce->timeline, timeline); -} - -static void __assign_timeline(struct i915_gem_context *ctx, - struct intel_timeline *timeline) -{ - __set_timeline(&ctx->timeline, timeline); - context_apply_all(ctx, __apply_timeline, timeline); -} - static struct i915_gem_context * i915_gem_create_context(struct drm_i915_private *i915, unsigned int flags) { struct i915_gem_context *ctx; + int ret;

if (flags & I915_CONTEXT_CREATE_FLAGS_SINGLE_TIMELINE && !HAS_EXECLISTS(i915)) @@ -820,16 +796,13 @@ i915_gem_create_context(struct drm_i915_private *i915, unsigned int flags) }

if (flags & I915_CONTEXT_CREATE_FLAGS_SINGLE_TIMELINE) { - struct intel_timeline *timeline; - - timeline = intel_timeline_create(&i915->gt); - if (IS_ERR(timeline)) { + ret = drm_syncobj_create(&ctx->syncobj, + DRM_SYNCOBJ_CREATE_SIGNALED, + NULL); + if (ret) { context_close(ctx); - return ERR_CAST(timeline); + return ERR_PTR(ret); } - - __assign_timeline(ctx, timeline); - intel_timeline_put(timeline); }

trace_i915_context_create(ctx); diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context_types.h b/drivers/gpu/drm/i915/gem/i915_gem_context_types.h index 676592e27e7d2..df76767f0c41b 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_context_types.h +++ b/drivers/gpu/drm/i915/gem/i915_gem_context_types.h @@ -83,7 +83,19 @@ struct i915_gem_context { struct i915_gem_engines __rcu *engines; struct mutex engines_mutex; /* guards writes to engines */

- struct intel_timeline *timeline; + /** + * @syncobj: Shared timeline syncobj + * + * When the SHARED_TIMELINE flag is set on context creation, we + * emulate a single timeline across all engines using this syncobj. + * For every execbuffer2 call, this syncobj is used as both an in- + * and out-fence. Unlike the real intel_timeline, this doesn't + * provide perfect atomic in-order guarantees if the client races + * with itself by calling execbuffer2 twice concurrently. However, + * if userspace races with itself, that's not likely to yield well- + * defined results anyway so we choose to not care. + */ + struct drm_syncobj *syncobj;

/** * @vm: unique address space (GTT) diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c index b812f313422a9..d640bba6ad9ab 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c @@ -3460,6 +3460,16 @@ i915_gem_do_execbuffer(struct drm_device *dev, goto err_vma; }

+ if (unlikely(eb.gem_context->syncobj)) { + struct dma_fence *fence; + + fence = drm_syncobj_fence_get(eb.gem_context->syncobj); + err = i915_request_await_dma_fence(eb.request, fence); + dma_fence_put(fence); + if (err) + goto err_ext; + } + if (in_fence) { if (args->flags & I915_EXEC_FENCE_SUBMIT) err = i915_request_await_execution(eb.request, @@ -3517,6 +3527,12 @@ i915_gem_do_execbuffer(struct drm_device *dev, fput(out_fence->file); } } + + if (unlikely(eb.gem_context->syncobj)) { + drm_syncobj_replace_fence(eb.gem_context->syncobj, + &eb.request->fence); + } + i915_request_put(eb.request);

err_vma:

This adds a bunch of complexity which the media driver has never actually used. The media driver does technically bond a balanced engine to another engine but the balanced engine only has one engine in the sibling set. This doesn't actually result in a virtual engine.

This functionality was originally added to handle cases where we may have more than two video engines and media might want to load-balance their bonded submits by, for instance, submitting to a balanced vcs0-1 as the primary and then vcs2-3 as the secondary. However, no such hardware has shipped thus far and, if we ever want to enable such use-cases in the future, we'll use the up-and-coming parallel submit API which targets GuC submission.

This makes I915_CONTEXT_ENGINES_EXT_BOND a total no-op. We leave the validation code in place in case we ever decide we want to do something interesting with the bonding information.

v2 (Jason Ekstrand): - Don't delete quite as much code.

v3 (Tvrtko Ursulin): - Add some history to the commit message

Signed-off-by: Jason Ekstrand jason@jlekstrand.net Reviewed-by: Daniel Vetter daniel.vetter@ffwll.ch --- drivers/gpu/drm/i915/gem/i915_gem_context.c | 18 +- .../drm/i915/gt/intel_execlists_submission.c | 69 ------ .../drm/i915/gt/intel_execlists_submission.h | 4 - drivers/gpu/drm/i915/gt/selftest_execlists.c | 229 ------------------ 4 files changed, 6 insertions(+), 314 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c index fed3538de9241..5e159fb526631 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c @@ -1552,6 +1552,12 @@ set_engines__bond(struct i915_user_extension __user *base, void *data) } virtual = set->engines->engines[idx]->engine;

+ if (intel_engine_is_virtual(virtual)) { + drm_dbg(&i915->drm, + "Bonding with virtual engines not allowed\n"); + return -EINVAL; + } + err = check_user_mbz(&ext->flags); if (err) return err; @@ -1592,18 +1598,6 @@ set_engines__bond(struct i915_user_extension __user *base, void *data) n, ci.engine_class, ci.engine_instance); return -EINVAL; } - - /* - * A non-virtual engine has no siblings to choose between; and - * a submit fence will always be directed to the one engine. - */ - if (intel_engine_is_virtual(virtual)) { - err = intel_virtual_engine_attach_bond(virtual, - master, - bond); - if (err) - return err; - } }

return 0; diff --git a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c index 0e8c320927d15..14378b28169b7 100644 --- a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c +++ b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c @@ -181,18 +181,6 @@ struct virtual_engine { int prio; } nodes[I915_NUM_ENGINES];

- /* - * Keep track of bonded pairs -- restrictions upon on our selection - * of physical engines any particular request may be submitted to. - * If we receive a submit-fence from a master engine, we will only - * use one of sibling_mask physical engines. - */ - struct ve_bond { - const struct intel_engine_cs *master; - intel_engine_mask_t sibling_mask; - } *bonds; - unsigned int num_bonds; - /* And finally, which physical engines this virtual engine maps onto. */ unsigned int num_siblings; struct intel_engine_cs *siblings[]; @@ -3307,7 +3295,6 @@ static void rcu_virtual_context_destroy(struct work_struct *wrk) intel_breadcrumbs_free(ve->base.breadcrumbs); intel_engine_free_request_pool(&ve->base);

- kfree(ve->bonds); kfree(ve); }

@@ -3560,33 +3547,13 @@ static void virtual_submit_request(struct i915_request *rq) spin_unlock_irqrestore(&ve->base.active.lock, flags); }

-static struct ve_bond * -virtual_find_bond(struct virtual_engine *ve, - const struct intel_engine_cs *master) -{ - int i; - - for (i = 0; i < ve->num_bonds; i++) { - if (ve->bonds[i].master == master) - return &ve->bonds[i]; - } - - return NULL; -} - static void virtual_bond_execute(struct i915_request *rq, struct dma_fence *signal) { - struct virtual_engine *ve = to_virtual_engine(rq->engine); intel_engine_mask_t allowed, exec; - struct ve_bond *bond;

allowed = ~to_request(signal)->engine->mask;

- bond = virtual_find_bond(ve, to_request(signal)->engine); - if (bond) - allowed &= bond->sibling_mask; - /* Restrict the bonded request to run on only the available engines */ exec = READ_ONCE(rq->execution_mask); while (!try_cmpxchg(&rq->execution_mask, &exec, exec & allowed)) @@ -3736,42 +3703,6 @@ intel_execlists_create_virtual(struct intel_engine_cs **siblings, return ERR_PTR(err); }

-int intel_virtual_engine_attach_bond(struct intel_engine_cs *engine, - const struct intel_engine_cs *master, - const struct intel_engine_cs *sibling) -{ - struct virtual_engine *ve = to_virtual_engine(engine); - struct ve_bond *bond; - int n; - - /* Sanity check the sibling is part of the virtual engine */ - for (n = 0; n < ve->num_siblings; n++) - if (sibling == ve->siblings[n]) - break; - if (n == ve->num_siblings) - return -EINVAL; - - bond = virtual_find_bond(ve, master); - if (bond) { - bond->sibling_mask |= sibling->mask; - return 0; - } - - bond = krealloc(ve->bonds, - sizeof(*bond) * (ve->num_bonds + 1), - GFP_KERNEL); - if (!bond) - return -ENOMEM; - - bond[ve->num_bonds].master = master; - bond[ve->num_bonds].sibling_mask = sibling->mask; - - ve->bonds = bond; - ve->num_bonds++; - - return 0; -} - void intel_execlists_show_requests(struct intel_engine_cs *engine, struct drm_printer *m, void (*show_request)(struct drm_printer *m, diff --git a/drivers/gpu/drm/i915/gt/intel_execlists_submission.h b/drivers/gpu/drm/i915/gt/intel_execlists_submission.h index bab3d37cf3f98..ad4f3e1a0fded 100644 --- a/drivers/gpu/drm/i915/gt/intel_execlists_submission.h +++ b/drivers/gpu/drm/i915/gt/intel_execlists_submission.h @@ -36,10 +36,6 @@ struct intel_context * intel_execlists_create_virtual(struct intel_engine_cs **siblings, unsigned int count);

-int intel_virtual_engine_attach_bond(struct intel_engine_cs *engine, - const struct intel_engine_cs *master, - const struct intel_engine_cs *sibling); - bool intel_engine_in_execlists_submission_mode(const struct intel_engine_cs *engine);

diff --git a/drivers/gpu/drm/i915/gt/selftest_execlists.c b/drivers/gpu/drm/i915/gt/selftest_execlists.c index 01d9896dd4844..a0e75b71a3374 100644 --- a/drivers/gpu/drm/i915/gt/selftest_execlists.c +++ b/drivers/gpu/drm/i915/gt/selftest_execlists.c @@ -4311,234 +4311,6 @@ static int live_virtual_preserved(void *arg) return 0; }

-static int bond_virtual_engine(struct intel_gt *gt, - unsigned int class, - struct intel_engine_cs **siblings, - unsigned int nsibling, - unsigned int flags) -#define BOND_SCHEDULE BIT(0) -{ - struct intel_engine_cs *master; - struct i915_request *rq[16]; - enum intel_engine_id id; - struct igt_spinner spin; - unsigned long n; - int err; - - /* - * A set of bonded requests is intended to be run concurrently - * across a number of engines. We use one request per-engine - * and a magic fence to schedule each of the bonded requests - * at the same time. A consequence of our current scheduler is that - * we only move requests to the HW ready queue when the request - * becomes ready, that is when all of its prerequisite fences have - * been signaled. As one of those fences is the master submit fence, - * there is a delay on all secondary fences as the HW may be - * currently busy. Equally, as all the requests are independent, - * they may have other fences that delay individual request - * submission to HW. Ergo, we do not guarantee that all requests are - * immediately submitted to HW at the same time, just that if the - * rules are abided by, they are ready at the same time as the - * first is submitted. Userspace can embed semaphores in its batch - * to ensure parallel execution of its phases as it requires. - * Though naturally it gets requested that perhaps the scheduler should - * take care of parallel execution, even across preemption events on - * different HW. (The proper answer is of course "lalalala".) - * - * With the submit-fence, we have identified three possible phases - * of synchronisation depending on the master fence: queued (not - * ready), executing, and signaled. The first two are quite simple - * and checked below. However, the signaled master fence handling is - * contentious. Currently we do not distinguish between a signaled - * fence and an expired fence, as once signaled it does not convey - * any information about the previous execution. It may even be freed - * and hence checking later it may not exist at all. Ergo we currently - * do not apply the bonding constraint for an already signaled fence, - * as our expectation is that it should not constrain the secondaries - * and is outside of the scope of the bonded request API (i.e. all - * userspace requests are meant to be running in parallel). As - * it imposes no constraint, and is effectively a no-op, we do not - * check below as normal execution flows are checked extensively above. - * - * XXX Is the degenerate handling of signaled submit fences the - * expected behaviour for userpace? - */ - - GEM_BUG_ON(nsibling >= ARRAY_SIZE(rq) - 1); - - if (igt_spinner_init(&spin, gt)) - return -ENOMEM; - - err = 0; - rq[0] = ERR_PTR(-ENOMEM); - for_each_engine(master, gt, id) { - struct i915_sw_fence fence = {}; - struct intel_context *ce; - - if (master->class == class) - continue; - - ce = intel_context_create(master); - if (IS_ERR(ce)) { - err = PTR_ERR(ce); - goto out; - } - - memset_p((void *)rq, ERR_PTR(-EINVAL), ARRAY_SIZE(rq)); - - rq[0] = igt_spinner_create_request(&spin, ce, MI_NOOP); - intel_context_put(ce); - if (IS_ERR(rq[0])) { - err = PTR_ERR(rq[0]); - goto out; - } - i915_request_get(rq[0]); - - if (flags & BOND_SCHEDULE) { - onstack_fence_init(&fence); - err = i915_sw_fence_await_sw_fence_gfp(&rq[0]->submit, - &fence, - GFP_KERNEL); - } - - i915_request_add(rq[0]); - if (err < 0) - goto out; - - if (!(flags & BOND_SCHEDULE) && - !igt_wait_for_spinner(&spin, rq[0])) { - err = -EIO; - goto out; - } - - for (n = 0; n < nsibling; n++) { - struct intel_context *ve; - - ve = intel_execlists_create_virtual(siblings, nsibling); - if (IS_ERR(ve)) { - err = PTR_ERR(ve); - onstack_fence_fini(&fence); - goto out; - } - - err = intel_virtual_engine_attach_bond(ve->engine, - master, - siblings[n]); - if (err) { - intel_context_put(ve); - onstack_fence_fini(&fence); - goto out; - } - - err = intel_context_pin(ve); - intel_context_put(ve); - if (err) { - onstack_fence_fini(&fence); - goto out; - } - - rq[n + 1] = i915_request_create(ve); - intel_context_unpin(ve); - if (IS_ERR(rq[n + 1])) { - err = PTR_ERR(rq[n + 1]); - onstack_fence_fini(&fence); - goto out; - } - i915_request_get(rq[n + 1]); - - err = i915_request_await_execution(rq[n + 1], - &rq[0]->fence, - ve->engine->bond_execute); - i915_request_add(rq[n + 1]); - if (err < 0) { - onstack_fence_fini(&fence); - goto out; - } - } - onstack_fence_fini(&fence); - intel_engine_flush_submission(master); - igt_spinner_end(&spin); - - if (i915_request_wait(rq[0], 0, HZ / 10) < 0) { - pr_err("Master request did not execute (on %s)!\n", - rq[0]->engine->name); - err = -EIO; - goto out; - } - - for (n = 0; n < nsibling; n++) { - if (i915_request_wait(rq[n + 1], 0, - MAX_SCHEDULE_TIMEOUT) < 0) { - err = -EIO; - goto out; - } - - if (rq[n + 1]->engine != siblings[n]) { - pr_err("Bonded request did not execute on target engine: expected %s, used %s; master was %s\n", - siblings[n]->name, - rq[n + 1]->engine->name, - rq[0]->engine->name); - err = -EINVAL; - goto out; - } - } - - for (n = 0; !IS_ERR(rq[n]); n++) - i915_request_put(rq[n]); - rq[0] = ERR_PTR(-ENOMEM); - } - -out: - for (n = 0; !IS_ERR(rq[n]); n++) - i915_request_put(rq[n]); - if (igt_flush_test(gt->i915)) - err = -EIO; - - igt_spinner_fini(&spin); - return err; -} - -static int live_virtual_bond(void *arg) -{ - static const struct phase { - const char *name; - unsigned int flags; - } phases[] = { - { "", 0 }, - { "schedule", BOND_SCHEDULE }, - { }, - }; - struct intel_gt *gt = arg; - struct intel_engine_cs *siblings[MAX_ENGINE_INSTANCE + 1]; - unsigned int class; - int err; - - if (intel_uc_uses_guc_submission(&gt->uc)) - return 0; - - for (class = 0; class <= MAX_ENGINE_CLASS; class++) { - const struct phase *p; - int nsibling; - - nsibling = select_siblings(gt, class, siblings); - if (nsibling < 2) - continue; - - for (p = phases; p->name; p++) { - err = bond_virtual_engine(gt, - class, siblings, nsibling, - p->flags); - if (err) { - pr_err("%s(%s): failed class=%d, nsibling=%d, err=%d\n", - __func__, p->name, class, nsibling, err); - return err; - } - } - } - - return 0; -} - static int reset_virtual_engine(struct intel_gt *gt, struct intel_engine_cs **siblings, unsigned int nsibling) @@ -4712,7 +4484,6 @@ int intel_execlists_live_selftests(struct drm_i915_private *i915) SUBTEST(live_virtual_mask), SUBTEST(live_virtual_preserved), SUBTEST(live_virtual_slice), - SUBTEST(live_virtual_bond), SUBTEST(live_virtual_reset), };

This was only ever used for FENCE_SUBMIT automatic engine selection which was removed in the previous commit.

Signed-off-by: Jason Ekstrand jason@jlekstrand.net Reviewed-by: Daniel Vetter daniel.vetter@ffwll.ch --- .../gpu/drm/i915/gem/i915_gem_execbuffer.c | 3 +- drivers/gpu/drm/i915/i915_request.c | 42 ++++--------------- drivers/gpu/drm/i915/i915_request.h | 4 +- 3 files changed, 9 insertions(+), 40 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c index efb2fa3522a42..7024adcd5cf15 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c @@ -3473,8 +3473,7 @@ i915_gem_do_execbuffer(struct drm_device *dev, if (in_fence) { if (args->flags & I915_EXEC_FENCE_SUBMIT) err = i915_request_await_execution(eb.request, - in_fence, - NULL); + in_fence); else err = i915_request_await_dma_fence(eb.request, in_fence); diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c index 970d8f4986bbe..53f23ce40dd63 100644 --- a/drivers/gpu/drm/i915/i915_request.c +++ b/drivers/gpu/drm/i915/i915_request.c @@ -49,7 +49,6 @@ struct execute_cb { struct irq_work work; struct i915_sw_fence *fence; - void (*hook)(struct i915_request *rq, struct dma_fence *signal); struct i915_request *signal; };

@@ -180,17 +179,6 @@ static void irq_execute_cb(struct irq_work *wrk) kmem_cache_free(global.slab_execute_cbs, cb); }

-static void irq_execute_cb_hook(struct irq_work *wrk) -{ - struct execute_cb *cb = container_of(wrk, typeof(*cb), work); - - cb->hook(container_of(cb->fence, struct i915_request, submit), - &cb->signal->fence); - i915_request_put(cb->signal); - - irq_execute_cb(wrk); -} - static __always_inline void __notify_execute_cb(struct i915_request *rq, bool (*fn)(struct irq_work *wrk)) { @@ -517,17 +505,12 @@ static bool __request_in_flight(const struct i915_request *signal) static int __await_execution(struct i915_request *rq, struct i915_request *signal, - void (*hook)(struct i915_request *rq, - struct dma_fence *signal), gfp_t gfp) { struct execute_cb *cb;

- if (i915_request_is_active(signal)) { - if (hook) - hook(rq, &signal->fence); + if (i915_request_is_active(signal)) return 0; - }

cb = kmem_cache_alloc(global.slab_execute_cbs, gfp); if (!cb) @@ -537,12 +520,6 @@ __await_execution(struct i915_request *rq, i915_sw_fence_await(cb->fence); init_irq_work(&cb->work, irq_execute_cb);

- if (hook) { - cb->hook = hook; - cb->signal = i915_request_get(signal); - cb->work.func = irq_execute_cb_hook; - } - /* * Register the callback first, then see if the signaler is already * active. This ensures that if we race with the @@ -1253,7 +1230,7 @@ emit_semaphore_wait(struct i915_request *to, goto await_fence;

/* Only submit our spinner after the signaler is running! */ - if (__await_execution(to, from, NULL, gfp)) + if (__await_execution(to, from, gfp)) goto await_fence;

if (__emit_semaphore_wait(to, from, from->fence.seqno)) @@ -1284,16 +1261,14 @@ static int intel_timeline_sync_set_start(struct intel_timeline *tl,

static int __i915_request_await_execution(struct i915_request *to, - struct i915_request *from, - void (*hook)(struct i915_request *rq, - struct dma_fence *signal)) + struct i915_request *from) { int err;

GEM_BUG_ON(intel_context_is_barrier(from->context));

/* Submit both requests at the same time */ - err = __await_execution(to, from, hook, I915_FENCE_GFP); + err = __await_execution(to, from, I915_FENCE_GFP); if (err) return err;

@@ -1406,9 +1381,7 @@ i915_request_await_external(struct i915_request *rq, struct dma_fence *fence)

int i915_request_await_execution(struct i915_request *rq, - struct dma_fence *fence, - void (*hook)(struct i915_request *rq, - struct dma_fence *signal)) + struct dma_fence *fence) { struct dma_fence **child = &fence; unsigned int nchild = 1; @@ -1441,8 +1414,7 @@ i915_request_await_execution(struct i915_request *rq,

if (dma_fence_is_i915(fence)) ret = __i915_request_await_execution(rq, - to_request(fence), - hook); + to_request(fence)); else ret = i915_request_await_external(rq, fence); if (ret < 0) @@ -1468,7 +1440,7 @@ await_request_submit(struct i915_request *to, struct i915_request *from) &from->submit, I915_FENCE_GFP); else - return __i915_request_await_execution(to, from, NULL); + return __i915_request_await_execution(to, from); }

static int diff --git a/drivers/gpu/drm/i915/i915_request.h b/drivers/gpu/drm/i915/i915_request.h index 270f6cd37650c..63b087a7f5707 100644 --- a/drivers/gpu/drm/i915/i915_request.h +++ b/drivers/gpu/drm/i915/i915_request.h @@ -352,9 +352,7 @@ int i915_request_await_object(struct i915_request *to, int i915_request_await_dma_fence(struct i915_request *rq, struct dma_fence *fence); int i915_request_await_execution(struct i915_request *rq, - struct dma_fence *fence, - void (*hook)(struct i915_request *rq, - struct dma_fence *signal)); + struct dma_fence *fence);

void i915_request_add(struct i915_request *rq);

As far as I can tell, the only real reason for this is to avoid taking a reference to the i915_gem_context. The cost of those two atomics probably pales in comparison to the cost of the ioctl itself so we're really not buying ourselves anything here. We're about to make context lookup a tiny bit more complicated, so let's get rid of the one hand- rolled case.

Some usermode drivers such as our Vulkan driver call GET_RESET_STATS on every execbuf so the perf here could theoretically be an issue. If this ever does become a performance issue for any such userspace drivers, they can use set CONTEXT_PARAM_RECOVERABLE to false and look for -EIO coming from execbuf to check for hangs instead.

v2 (Daniel Vetter): - Add a comment in the commit message about recoverable contexts

Signed-off-by: Jason Ekstrand jason@jlekstrand.net Reviewed-by: Daniel Vetter daniel.vetter@ffwll.ch --- drivers/gpu/drm/i915/gem/i915_gem_context.c | 13 ++++--------- drivers/gpu/drm/i915/i915_drv.h | 8 +------- 2 files changed, 5 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c index 2b9207b557cc9..910d31cb043e9 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c @@ -2090,16 +2090,13 @@ int i915_gem_context_reset_stats_ioctl(struct drm_device *dev, struct drm_i915_private *i915 = to_i915(dev); struct drm_i915_reset_stats *args = data; struct i915_gem_context *ctx; - int ret;

if (args->flags || args->pad) return -EINVAL;

- ret = -ENOENT; - rcu_read_lock(); - ctx = __i915_gem_context_lookup_rcu(file->driver_priv, args->ctx_id); + ctx = i915_gem_context_lookup(file->driver_priv, args->ctx_id); if (!ctx) - goto out; + return -ENOENT;

/* * We opt for unserialised reads here. This may result in tearing @@ -2116,10 +2113,8 @@ int i915_gem_context_reset_stats_ioctl(struct drm_device *dev, args->batch_active = atomic_read(&ctx->guilty_count); args->batch_pending = atomic_read(&ctx->active_count);

- ret = 0; -out: - rcu_read_unlock(); - return ret; + i915_gem_context_put(ctx); + return 0; }

/* GEM context-engines iterator: for_each_gem_engine() */ diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index 39b5e019c1a5b..48316d273af66 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -1857,19 +1857,13 @@ struct drm_gem_object *i915_gem_prime_import(struct drm_device *dev,

struct dma_buf *i915_gem_prime_export(struct drm_gem_object *gem_obj, int flags);

-static inline struct i915_gem_context * -__i915_gem_context_lookup_rcu(struct drm_i915_file_private *file_priv, u32 id) -{ - return xa_load(&file_priv->context_xa, id); -} - static inline struct i915_gem_context * i915_gem_context_lookup(struct drm_i915_file_private *file_priv, u32 id) { struct i915_gem_context *ctx;

rcu_read_lock(); - ctx = __i915_gem_context_lookup_rcu(file_priv, id); + ctx = xa_load(&file_priv->context_xa, id); if (ctx && !kref_get_unless_zero(&ctx->ref)) ctx = NULL; rcu_read_unlock();

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 --- Documentation/gpu/i915.rst | 2 + .../gpu/drm/i915/gem/i915_gem_context_types.h | 43 ++++++++++++++++--- 2 files changed, 38 insertions(+), 7 deletions(-)

diff --git a/Documentation/gpu/i915.rst b/Documentation/gpu/i915.rst index 486c720f38907..0529e5183982e 100644 --- a/Documentation/gpu/i915.rst +++ b/Documentation/gpu/i915.rst @@ -422,6 +422,8 @@ Batchbuffer Parsing User Batchbuffer Execution --------------------------

+.. kernel-doc:: drivers/gpu/drm/i915/gem/i915_gem_context_types.h + .. kernel-doc:: drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c :doc: User command execution

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context_types.h b/drivers/gpu/drm/i915/gem/i915_gem_context_types.h index df76767f0c41b..5f0673a2129f9 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_context_types.h +++ b/drivers/gpu/drm/i915/gem/i915_gem_context_types.h @@ -30,19 +30,39 @@ struct i915_address_space; struct intel_timeline; struct intel_ring;

+/** + * struct i915_gem_engines - A set of engines + */ struct i915_gem_engines { union { + /** @link: Link in i915_gem_context::stale::engines */ struct list_head link; + + /** @rcu: RCU to use when freeing */ struct rcu_head rcu; }; + + /** @fence: Fence used for delayed destruction of engines */ struct i915_sw_fence fence; + + /** @ctx: i915_gem_context backpointer */ struct i915_gem_context *ctx; + + /** @num_engines: Number of engines in this set */ unsigned int num_engines; + + /** @engines: Array of engines */ struct intel_context *engines[]; };

+/** + * struct i915_gem_engines_iter - Iterator for an i915_gem_engines set + */ struct i915_gem_engines_iter { + /** @idx: Index into i915_gem_engines::engines */ unsigned int idx; + + /** @engines: Engine set being iterated */ const struct i915_gem_engines *engines; };

@@ -53,10 +73,10 @@ struct i915_gem_engines_iter { * logical hardware state for a particular client. */ struct i915_gem_context { - /** i915: i915 device backpointer */ + /** @i915: i915 device backpointer */ struct drm_i915_private *i915;

- /** file_priv: owning file descriptor */ + /** @file_priv: owning file descriptor */ struct drm_i915_file_private *file_priv;

/** @@ -81,7 +101,9 @@ struct i915_gem_context { * CONTEXT_USER_ENGINES flag is set). */ struct i915_gem_engines __rcu *engines; - struct mutex engines_mutex; /* guards writes to engines */ + + /** @engines_mutex: guards writes to engines */ + struct mutex engines_mutex;

/** * @syncobj: Shared timeline syncobj @@ -118,7 +140,7 @@ struct i915_gem_context { */ struct pid *pid;

- /** link: place with &drm_i915_private.context_list */ + /** @link: place with &drm_i915_private.context_list */ struct list_head link;

/** @@ -153,11 +175,13 @@ struct i915_gem_context { #define CONTEXT_CLOSED 0 #define CONTEXT_USER_ENGINES 1

+ /** @mutex: guards everything that isn't engines or handles_vma */ struct mutex mutex;

+ /** @sched: scheduler parameters */ struct i915_sched_attr sched;

- /** guilty_count: How many times this context has caused a GPU hang. */ + /** @guilty_count: How many times this context has caused a GPU hang. */ atomic_t guilty_count; /** * @active_count: How many times this context was active during a GPU @@ -171,15 +195,17 @@ struct i915_gem_context { unsigned long hang_timestamp[2]; #define CONTEXT_FAST_HANG_JIFFIES (120 * HZ) /* 3 hangs within 120s? Banned! */

- /** remap_slice: Bitmask of cache lines that need remapping */ + /** @remap_slice: Bitmask of cache lines that need remapping */ u8 remap_slice;

/** - * handles_vma: rbtree to look up our context specific obj/vma for + * @handles_vma: rbtree to look up our context specific obj/vma for * the user handle. (user handles are per fd, but the binding is * per vm, which may be one per context or shared with the global GTT) */ struct radix_tree_root handles_vma; + + /** @lut_mutex: Locks handles_vma */ struct mutex lut_mutex;

/** @@ -191,8 +217,11 @@ struct i915_gem_context { */ char name[TASK_COMM_LEN + 8];

+ /** @stale: tracks stale engines to be destroyed */ struct { + /** @lock: guards engines */ spinlock_t lock; + /** @engines: list of stale engines */ struct list_head engines; } stale; };

For now this is a no-op because everyone passes in a null SSEU but it lets us get some of the error handling and selftest refactoring plumbed through.

Signed-off-by: Jason Ekstrand jason@jlekstrand.net --- drivers/gpu/drm/i915/gem/i915_gem_context.c | 41 +++++++++++++++---- .../gpu/drm/i915/gem/selftests/mock_context.c | 6 ++- 2 files changed, 36 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c index f8f3f514b4265..d247fb223aac7 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c @@ -320,9 +320,12 @@ context_get_vm_rcu(struct i915_gem_context *ctx) } while (1); }

-static void intel_context_set_gem(struct intel_context *ce, - struct i915_gem_context *ctx) +static int intel_context_set_gem(struct intel_context *ce, + struct i915_gem_context *ctx, + struct intel_sseu sseu) { + int ret = 0; + GEM_BUG_ON(rcu_access_pointer(ce->gem_context)); RCU_INIT_POINTER(ce->gem_context, ctx);

@@ -349,6 +352,12 @@ static void intel_context_set_gem(struct intel_context *ce,

intel_context_set_watchdog_us(ce, (u64)timeout_ms * 1000); } + + /* A valid SSEU has no zero fields */ + if (sseu.slice_mask && !WARN_ON(ce->engine->class != RENDER_CLASS)) + ret = intel_context_reconfigure_sseu(ce, sseu); + + return ret; }

static void __free_engines(struct i915_gem_engines *e, unsigned int count) @@ -416,7 +425,8 @@ static struct i915_gem_engines *alloc_engines(unsigned int count) return e; }

-static struct i915_gem_engines *default_engines(struct i915_gem_context *ctx) +static struct i915_gem_engines *default_engines(struct i915_gem_context *ctx, + struct intel_sseu rcs_sseu) { const struct intel_gt *gt = &ctx->i915->gt; struct intel_engine_cs *engine; @@ -429,6 +439,8 @@ static struct i915_gem_engines *default_engines(struct i915_gem_context *ctx)

for_each_engine(engine, gt, id) { struct intel_context *ce; + struct intel_sseu sseu = {}; + int ret;

if (engine->legacy_idx == INVALID_ENGINE) continue; @@ -442,10 +454,18 @@ static struct i915_gem_engines *default_engines(struct i915_gem_context *ctx) goto free_engines; }

- intel_context_set_gem(ce, ctx); - e->engines[engine->legacy_idx] = ce; e->num_engines = max(e->num_engines, engine->legacy_idx + 1); + + if (engine->class == RENDER_CLASS) + sseu = rcs_sseu; + + ret = intel_context_set_gem(ce, ctx, sseu); + if (ret) { + err = ERR_PTR(ret); + goto free_engines; + } + }

return e; @@ -759,6 +779,7 @@ __create_context(struct drm_i915_private *i915, { struct i915_gem_context *ctx; struct i915_gem_engines *e; + struct intel_sseu null_sseu = {}; int err; int i;

@@ -776,7 +797,7 @@ __create_context(struct drm_i915_private *i915, INIT_LIST_HEAD(&ctx->stale.engines);

mutex_init(&ctx->engines_mutex); - e = default_engines(ctx); + e = default_engines(ctx, null_sseu); if (IS_ERR(e)) { err = PTR_ERR(e); goto err_free; @@ -1543,6 +1564,7 @@ set_engines__load_balance(struct i915_user_extension __user *base, void *data) struct intel_engine_cs *stack[16]; struct intel_engine_cs **siblings; struct intel_context *ce; + struct intel_sseu null_sseu = {}; u16 num_siblings, idx; unsigned int n; int err; @@ -1615,7 +1637,7 @@ set_engines__load_balance(struct i915_user_extension __user *base, void *data) goto out_siblings; }

- intel_context_set_gem(ce, set->ctx); + intel_context_set_gem(ce, set->ctx, null_sseu);

if (cmpxchg(&set->engines->engines[idx], NULL, ce)) { intel_context_put(ce); @@ -1723,6 +1745,7 @@ set_engines(struct i915_gem_context *ctx, struct drm_i915_private *i915 = ctx->i915; struct i915_context_param_engines __user *user = u64_to_user_ptr(args->value); + struct intel_sseu null_sseu = {}; struct set_engines set = { .ctx = ctx }; unsigned int num_engines, n; u64 extensions; @@ -1732,7 +1755,7 @@ set_engines(struct i915_gem_context *ctx, if (!i915_gem_context_user_engines(ctx)) return 0;

- set.engines = default_engines(ctx); + set.engines = default_engines(ctx, null_sseu); if (IS_ERR(set.engines)) return PTR_ERR(set.engines);

@@ -1789,7 +1812,7 @@ set_engines(struct i915_gem_context *ctx, return PTR_ERR(ce); }

- intel_context_set_gem(ce, ctx); + intel_context_set_gem(ce, ctx, null_sseu);

set.engines->engines[n] = ce; } diff --git a/drivers/gpu/drm/i915/gem/selftests/mock_context.c b/drivers/gpu/drm/i915/gem/selftests/mock_context.c index e0f512ef7f3c6..cbeefd060e97b 100644 --- a/drivers/gpu/drm/i915/gem/selftests/mock_context.c +++ b/drivers/gpu/drm/i915/gem/selftests/mock_context.c @@ -14,6 +14,7 @@ mock_context(struct drm_i915_private *i915, { struct i915_gem_context *ctx; struct i915_gem_engines *e; + struct intel_sseu null_sseu = {};

ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); if (!ctx) @@ -31,7 +32,7 @@ mock_context(struct drm_i915_private *i915, i915_gem_context_set_persistence(ctx);

mutex_init(&ctx->engines_mutex); - e = default_engines(ctx); + e = default_engines(ctx, null_sseu); if (IS_ERR(e)) goto err_free; RCU_INIT_POINTER(ctx->engines, e); @@ -112,6 +113,7 @@ live_context_for_engine(struct intel_engine_cs *engine, struct file *file) { struct i915_gem_engines *engines; struct i915_gem_context *ctx; + struct intel_sseu null_sseu = {}; struct intel_context *ce;

engines = alloc_engines(1); @@ -130,7 +132,7 @@ live_context_for_engine(struct intel_engine_cs *engine, struct file *file) return ERR_CAST(ce); }

- intel_context_set_gem(ce, ctx); + intel_context_set_gem(ce, ctx, null_sseu); engines->engines[0] = ce; engines->num_engines = 1;

We're about to start doing lazy context creation which means contexts get created in i915_gem_context_lookup and we may start having more errors than -ENOENT.

Signed-off-by: Jason Ekstrand jason@jlekstrand.net Reviewed-by: Daniel Vetter daniel.vetter@ffwll.ch --- drivers/gpu/drm/i915/gem/i915_gem_context.c | 12 ++++++------ drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c | 4 ++-- drivers/gpu/drm/i915/i915_drv.h | 2 +- drivers/gpu/drm/i915/i915_perf.c | 4 ++-- 4 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c index d68c111bc824a..76662175e6980 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c @@ -2636,8 +2636,8 @@ int i915_gem_context_getparam_ioctl(struct drm_device *dev, void *data, int ret = 0;

ctx = i915_gem_context_lookup(file_priv, args->ctx_id); - if (!ctx) - return -ENOENT; + if (IS_ERR(ctx)) + return PTR_ERR(ctx);

switch (args->param) { case I915_CONTEXT_PARAM_GTT_SIZE: @@ -2705,8 +2705,8 @@ int i915_gem_context_setparam_ioctl(struct drm_device *dev, void *data, int ret;

ctx = i915_gem_context_lookup(file_priv, args->ctx_id); - if (!ctx) - return -ENOENT; + if (IS_ERR(ctx)) + return PTR_ERR(ctx);

ret = ctx_setparam(file_priv, ctx, args);

@@ -2725,8 +2725,8 @@ int i915_gem_context_reset_stats_ioctl(struct drm_device *dev, return -EINVAL;

ctx = i915_gem_context_lookup(file->driver_priv, args->ctx_id); - if (!ctx) - return -ENOENT; + if (IS_ERR(ctx)) + return PTR_ERR(ctx);

/* * We opt for unserialised reads here. This may result in tearing diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c index 7024adcd5cf15..de14b26f3b2d5 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c @@ -739,8 +739,8 @@ static int eb_select_context(struct i915_execbuffer *eb) struct i915_gem_context *ctx;

ctx = i915_gem_context_lookup(eb->file->driver_priv, eb->args->rsvd1); - if (unlikely(!ctx)) - return -ENOENT; + if (unlikely(IS_ERR(ctx))) + return PTR_ERR(ctx);

eb->gem_context = ctx; if (rcu_access_pointer(ctx->vm)) diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index fee2342219da1..d7bd732ceacfc 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -1868,7 +1868,7 @@ i915_gem_context_lookup(struct drm_i915_file_private *file_priv, u32 id) ctx = NULL; rcu_read_unlock();

- return ctx; + return ctx ? ctx : ERR_PTR(-ENOENT); }

static inline struct i915_address_space * diff --git a/drivers/gpu/drm/i915/i915_perf.c b/drivers/gpu/drm/i915/i915_perf.c index de8ebc34af0ff..dfc2a5c067c29 100644 --- a/drivers/gpu/drm/i915/i915_perf.c +++ b/drivers/gpu/drm/i915/i915_perf.c @@ -3414,10 +3414,10 @@ i915_perf_open_ioctl_locked(struct i915_perf *perf, struct drm_i915_file_private *file_priv = file->driver_priv;

specific_ctx = i915_gem_context_lookup(file_priv, ctx_handle); - if (!specific_ctx) { + if (IS_ERR(specific_ctx)) { DRM_DEBUG("Failed to look up context with ID %u for opening perf stream\n", ctx_handle); - ret = -ENOENT; + ret = PTR_ERR(specific_ctx); goto err; } }

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.

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 at which point 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.

Signed-off-by: Jason Ekstrand jason@jlekstrand.net --- drivers/gpu/drm/i915/gem/i915_gem_context.c | 211 ++++++++++++++---- drivers/gpu/drm/i915/gem/i915_gem_context.h | 3 + .../gpu/drm/i915/gem/i915_gem_context_types.h | 54 +++++ .../gpu/drm/i915/gem/selftests/mock_context.c | 5 +- drivers/gpu/drm/i915/i915_drv.h | 24 +- 5 files changed, 239 insertions(+), 58 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c index 8288af0d33245..f7c83730ee07f 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c @@ -298,6 +298,42 @@ proto_context_create(struct drm_i915_private *i915, unsigned int flags) return err; }

+static int proto_context_register_locked(struct drm_i915_file_private *fpriv, + struct i915_gem_proto_context *pc, + u32 *id) +{ + int ret; + void *old; + + lockdep_assert_held(&fpriv->proto_context_lock); + + ret = xa_alloc(&fpriv->context_xa, id, NULL, xa_limit_32b, GFP_KERNEL); + if (ret) + return ret; + + old = xa_store(&fpriv->proto_context_xa, *id, pc, GFP_KERNEL); + if (xa_is_err(old)) { + xa_erase(&fpriv->context_xa, *id); + return xa_err(old); + } + GEM_BUG_ON(old); + + return 0; +} + +static int proto_context_register(struct drm_i915_file_private *fpriv, + struct i915_gem_proto_context *pc, + u32 *id) +{ + int ret; + + mutex_lock(&fpriv->proto_context_lock); + ret = proto_context_register_locked(fpriv, pc, id); + mutex_unlock(&fpriv->proto_context_lock); + + return ret; +} + static int set_proto_ctx_vm(struct drm_i915_file_private *fpriv, struct i915_gem_proto_context *pc, const struct drm_i915_gem_context_param *args) @@ -1448,12 +1484,12 @@ void i915_gem_init__contexts(struct drm_i915_private *i915) init_contexts(&i915->gem.contexts); }

-static int gem_context_register(struct i915_gem_context *ctx, - struct drm_i915_file_private *fpriv, - u32 *id) +static void gem_context_register(struct i915_gem_context *ctx, + struct drm_i915_file_private *fpriv, + u32 id) { struct drm_i915_private *i915 = ctx->i915; - int ret; + void *old;

ctx->file_priv = fpriv;

@@ -1462,19 +1498,12 @@ static int gem_context_register(struct i915_gem_context *ctx, current->comm, pid_nr(ctx->pid));

/* And finally expose ourselves to userspace via the idr */ - ret = xa_alloc(&fpriv->context_xa, id, ctx, xa_limit_32b, GFP_KERNEL); - if (ret) - goto err_pid; + old = xa_store(&fpriv->context_xa, id, ctx, GFP_KERNEL); + GEM_BUG_ON(old);

spin_lock(&i915->gem.contexts.lock); list_add_tail(&ctx->link, &i915->gem.contexts.list); spin_unlock(&i915->gem.contexts.lock); - - return 0; - -err_pid: - put_pid(fetch_and_zero(&ctx->pid)); - return ret; }

int i915_gem_context_open(struct drm_i915_private *i915, @@ -1484,9 +1513,12 @@ int i915_gem_context_open(struct drm_i915_private *i915, struct i915_gem_proto_context *pc; struct i915_gem_context *ctx; int err; - u32 id;

- xa_init_flags(&file_priv->context_xa, XA_FLAGS_ALLOC); + mutex_init(&file_priv->proto_context_lock); + xa_init_flags(&file_priv->proto_context_xa, XA_FLAGS_ALLOC); + + /* 0 reserved for the default context */ + xa_init_flags(&file_priv->context_xa, XA_FLAGS_ALLOC1);

/* 0 reserved for invalid/unassigned ppgtt */ xa_init_flags(&file_priv->vm_xa, XA_FLAGS_ALLOC1); @@ -1504,28 +1536,31 @@ int i915_gem_context_open(struct drm_i915_private *i915, goto err; }

- err = gem_context_register(ctx, file_priv, &id); - if (err < 0) - goto err_ctx; + gem_context_register(ctx, file_priv, 0);

- GEM_BUG_ON(id); return 0;

-err_ctx: - context_close(ctx); err: xa_destroy(&file_priv->vm_xa); xa_destroy(&file_priv->context_xa); + xa_destroy(&file_priv->proto_context_xa); + mutex_destroy(&file_priv->proto_context_lock); return err; }

void i915_gem_context_close(struct drm_file *file) { struct drm_i915_file_private *file_priv = file->driver_priv; + struct i915_gem_proto_context *pc; struct i915_address_space *vm; struct i915_gem_context *ctx; unsigned long idx;

+ xa_for_each(&file_priv->proto_context_xa, idx, pc) + proto_context_close(pc); + xa_destroy(&file_priv->proto_context_xa); + mutex_destroy(&file_priv->proto_context_lock); + xa_for_each(&file_priv->context_xa, idx, ctx) context_close(ctx); xa_destroy(&file_priv->context_xa); @@ -2480,12 +2515,73 @@ static bool client_is_banned(struct drm_i915_file_private *file_priv) return atomic_read(&file_priv->ban_score) >= I915_CLIENT_SCORE_BANNED; }

+static inline struct i915_gem_context * +__context_lookup(struct drm_i915_file_private *file_priv, u32 id) +{ + struct i915_gem_context *ctx; + + rcu_read_lock(); + ctx = xa_load(&file_priv->context_xa, id); + if (ctx && !kref_get_unless_zero(&ctx->ref)) + ctx = NULL; + rcu_read_unlock(); + + return ctx; +} + +struct i915_gem_context * +lazy_create_context_locked(struct drm_i915_file_private *file_priv, + struct i915_gem_proto_context *pc, u32 id) +{ + struct i915_gem_context *ctx; + void *old; + + lockdep_assert_held(&file_priv->proto_context_lock); + + ctx = i915_gem_create_context(file_priv->dev_priv, pc); + if (IS_ERR(ctx)) + return ctx; + + gem_context_register(ctx, file_priv, id); + + old = xa_erase(&file_priv->proto_context_xa, id); + GEM_BUG_ON(old != pc); + proto_context_close(pc); + + /* One for the xarray and one for the caller */ + return i915_gem_context_get(ctx); +} + +struct i915_gem_context * +i915_gem_context_lookup(struct drm_i915_file_private *file_priv, u32 id) +{ + struct i915_gem_proto_context *pc; + struct i915_gem_context *ctx; + + ctx = __context_lookup(file_priv, id); + if (ctx) + return ctx; + + mutex_lock(&file_priv->proto_context_lock); + /* Try one more time under the lock */ + ctx = __context_lookup(file_priv, id); + if (!ctx) { + pc = xa_load(&file_priv->proto_context_xa, id); + if (!pc) + ctx = ERR_PTR(-ENOENT); + else + ctx = lazy_create_context_locked(file_priv, pc, id); + } + mutex_unlock(&file_priv->proto_context_lock); + + return ctx; +} + int i915_gem_context_create_ioctl(struct drm_device *dev, void *data, struct drm_file *file) { struct drm_i915_private *i915 = to_i915(dev); struct drm_i915_gem_context_create_ext *args = data; - struct i915_gem_context *ctx; struct create_ext ext_data; int ret; u32 id; @@ -2517,28 +2613,21 @@ int i915_gem_context_create_ioctl(struct drm_device *dev, void *data, create_extensions, ARRAY_SIZE(create_extensions), &ext_data); - if (ret) { - proto_context_close(ext_data.pc); - return ret; - } + if (ret) + goto err_pc; }

- ctx = i915_gem_create_context(i915, ext_data.pc); - proto_context_close(ext_data.pc); - if (IS_ERR(ctx)) - return PTR_ERR(ctx); - - ret = gem_context_register(ctx, ext_data.fpriv, &id); + ret = proto_context_register(ext_data.fpriv, ext_data.pc, &id); if (ret < 0) - goto err_ctx; + goto err_pc;

args->ctx_id = id; drm_dbg(&i915->drm, "HW context %d created\n", args->ctx_id);

return 0;

-err_ctx: - context_close(ctx); +err_pc: + proto_context_close(ext_data.pc); return ret; }

@@ -2547,6 +2636,7 @@ int i915_gem_context_destroy_ioctl(struct drm_device *dev, void *data, { struct drm_i915_gem_context_destroy *args = data; struct drm_i915_file_private *file_priv = file->driver_priv; + struct i915_gem_proto_context *pc; struct i915_gem_context *ctx;

if (args->pad != 0) @@ -2555,11 +2645,21 @@ int i915_gem_context_destroy_ioctl(struct drm_device *dev, void *data, if (!args->ctx_id) return -ENOENT;

+ mutex_lock(&file_priv->proto_context_lock); ctx = xa_erase(&file_priv->context_xa, args->ctx_id); - if (!ctx) + pc = xa_erase(&file_priv->proto_context_xa, args->ctx_id); + mutex_unlock(&file_priv->proto_context_lock); + + if (!ctx && !pc) return -ENOENT; + GEM_WARN_ON(ctx && pc); + + if (pc) + proto_context_close(pc); + + if (ctx) + context_close(ctx);

- context_close(ctx); return 0; }

@@ -2692,16 +2792,41 @@ int i915_gem_context_setparam_ioctl(struct drm_device *dev, void *data, { struct drm_i915_file_private *file_priv = file->driver_priv; struct drm_i915_gem_context_param *args = data; + struct i915_gem_proto_context *pc; struct i915_gem_context *ctx; - int ret; + int ret = 0;

- ctx = i915_gem_context_lookup(file_priv, args->ctx_id); - if (IS_ERR(ctx)) - return PTR_ERR(ctx); + ctx = __context_lookup(file_priv, args->ctx_id); + if (ctx) + goto set_ctx_param;

- ret = ctx_setparam(file_priv, ctx, args); + mutex_lock(&file_priv->proto_context_lock); + ctx = __context_lookup(file_priv, args->ctx_id); + if (ctx) + goto unlock; + + pc = xa_load(&file_priv->proto_context_xa, args->ctx_id); + if (!pc) { + ret = -ENOENT; + goto unlock; + } + + /* FIXME: We should consider disallowing SET_CONTEXT_PARAM for most + * things on future platforms. Clients should be using + * CONTEXT_CREATE_EXT_PARAM instead. + */ + ret = set_proto_ctx_param(file_priv, pc, args); + +unlock: + mutex_unlock(&file_priv->proto_context_lock); + +set_ctx_param: + if (!ret && ctx) + ret = ctx_setparam(file_priv, ctx, args); + + if (ctx) + i915_gem_context_put(ctx);

- i915_gem_context_put(ctx); return ret; }

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.h b/drivers/gpu/drm/i915/gem/i915_gem_context.h index b5c908f3f4f22..20411db84914a 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_context.h +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.h @@ -133,6 +133,9 @@ int i915_gem_context_setparam_ioctl(struct drm_device *dev, void *data, int i915_gem_context_reset_stats_ioctl(struct drm_device *dev, void *data, struct drm_file *file);

+struct i915_gem_context * +i915_gem_context_lookup(struct drm_i915_file_private *file_priv, u32 id); + static inline struct i915_gem_context * i915_gem_context_get(struct i915_gem_context *ctx) { diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context_types.h b/drivers/gpu/drm/i915/gem/i915_gem_context_types.h index 2ac341f805c8f..b673061f4f5ba 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_context_types.h +++ b/drivers/gpu/drm/i915/gem/i915_gem_context_types.h @@ -122,6 +122,60 @@ struct i915_gem_proto_engine { * an i915_gem_context. This is used to gather parameters provided either * through creation flags or via SET_CONTEXT_PARAM so that, when we create * the final i915_gem_context, those parameters can be immutable. + * + * The 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. When these were initially added, 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. To avoid some truly nasty race conditions, we don't + * allow setting the VM or the set of engines on live contexts. + * + * The way we dealt with this without breaking older userspace that sets + * the VM or engine set via SET_CONTEXT_PARAM is to delay 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 at which point 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. + * + * At the time we made this change (April, 2021), we did a fairly complete + * audit of existing userspace to ensure this wouldn't break anything: + * + * - Mesa/i965 didn't use the engines or VM APIs at all + * + * - Mesa/ANV used the engines API but via CONTEXT_CREATE_EXT_SETPARAM and + * didn't use the VM API. + * + * - Mesa/iris didn't use the engines or VM APIs at all + * + * - The open-source compute-runtime didn't yet use the engines API but + * did use the VM API via SET_CONTEXT_PARAM. However, CONTEXT_SETPARAM + * was always the second ioctl on that context, immediately following + * GEM_CONTEXT_CREATE. + * + * - The media driver sets engines and bonding/balancing via + * SET_CONTEXT_PARAM. However, CONTEXT_SETPARAM to set the VM was + * always the second ioctl on that context, immediately following + * GEM_CONTEXT_CREATE and setting engines immediately followed that. + * + * In order for this dance to work properly, any modification to an + * i915_gem_proto_context that is exposed to the client via + * drm_i915_file_private::proto_context_xa must be guarded by + * drm_i915_file_private::proto_context_lock. The exception is when a + * proto-context has not yet been exposed such as when handling + * CONTEXT_CREATE_SET_PARAM during GEM_CONTEXT_CREATE. */ struct i915_gem_proto_context { /** @vm: See i915_gem_context::vm */ diff --git a/drivers/gpu/drm/i915/gem/selftests/mock_context.c b/drivers/gpu/drm/i915/gem/selftests/mock_context.c index cbeefd060e97b..61aaac4a334cf 100644 --- a/drivers/gpu/drm/i915/gem/selftests/mock_context.c +++ b/drivers/gpu/drm/i915/gem/selftests/mock_context.c @@ -81,6 +81,7 @@ void mock_init_contexts(struct drm_i915_private *i915) struct i915_gem_context * live_context(struct drm_i915_private *i915, struct file *file) { + struct drm_i915_file_private *fpriv = to_drm_file(file)->driver_priv; struct i915_gem_proto_context *pc; struct i915_gem_context *ctx; int err; @@ -97,10 +98,12 @@ live_context(struct drm_i915_private *i915, struct file *file)

i915_gem_context_set_no_error_capture(ctx);

- err = gem_context_register(ctx, to_drm_file(file)->driver_priv, &id); + err = xa_alloc(&fpriv->context_xa, &id, NULL, xa_limit_32b, GFP_KERNEL); if (err < 0) goto err_ctx;

+ gem_context_register(ctx, fpriv, id); + return ctx;

err_ctx: diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index d7bd732ceacfc..8b00292e1ae56 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -201,6 +201,16 @@ struct drm_i915_file_private { struct rcu_head rcu; };

+ /** @proto_context_lock: Guards all i915_gem_proto_context operations + * + * See i915_gem_proto_context. + */ + struct mutex proto_context_lock; + + /** @proto_context_xa: xarray of i915_gem_proto_context */ + struct xarray proto_context_xa; + + /** @context_xa: xarray of fully created i915_gem_context */ struct xarray context_xa; struct xarray vm_xa;

@@ -1857,20 +1867,6 @@ struct drm_gem_object *i915_gem_prime_import(struct drm_device *dev,

struct dma_buf *i915_gem_prime_export(struct drm_gem_object *gem_obj, int flags);

-static inline struct i915_gem_context * -i915_gem_context_lookup(struct drm_i915_file_private *file_priv, u32 id) -{ - struct i915_gem_context *ctx; - - rcu_read_lock(); - ctx = xa_load(&file_priv->context_xa, id); - if (ctx && !kref_get_unless_zero(&ctx->ref)) - ctx = NULL; - rcu_read_unlock(); - - return ctx ? ctx : ERR_PTR(-ENOENT); -} - static inline struct i915_address_space * i915_gem_vm_lookup(struct drm_i915_file_private *file_priv, u32 id) {