Over the last few years, we have debated how to extend the user API to
support an increase in the number of engines, that may be sparse and
even be heterogeneous within a class (not all video decoders created
equal). We settled on using (class, instance) tuples to identify a
specific engine, with an API for the user to construct a map of engines
to capabilities. Into this picture, we then add a challenge of virtual
engines; one user engine that maps behind the scenes to any number of
physical engines. To keep it general, we want the user to have full
control over that mapping. To that end, we allow the user to constrain a
context to define the set of engines that it can access, order fully
controlled by the user via (class, instance). With such precise control
in context setup, we can continue to use the existing execbuf uABI of
specifying a single index; only now it doesn't automagically map onto
the engines, it uses the user defined engine map from the context.
The I915_EXEC_DEFAULT slot is left empty, and invalid for use by
execbuf. It's use will be revealed in the next patch.
v2: Fixup freeing of local on success of get_engines()
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_gem_context.c | 204 +++++++++++++++++-
drivers/gpu/drm/i915/i915_gem_context_types.h | 4 +
drivers/gpu/drm/i915/i915_gem_execbuffer.c | 22 +-
include/uapi/drm/i915_drm.h | 42 +++-
4 files changed, 259 insertions(+), 13 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index 2cfc68b66944..86d9bea6f275 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -101,6 +101,21 @@ static struct i915_global_gem_context {
struct kmem_cache *slab_luts;
} global;
+static struct intel_engine_cs *
+lookup_user_engine(struct i915_gem_context *ctx,
+ unsigned long flags, u16 class, u16 instance)
+#define LOOKUP_USER_INDEX BIT(0)
+{
+ if (flags & LOOKUP_USER_INDEX) {
+ if (instance >= ctx->nengine)
+ return NULL;
+
+ return ctx->engines[instance];
+ }
+
+ return intel_engine_lookup_user(ctx->i915, class, instance);
+}
+
struct i915_lut_handle *i915_lut_handle_alloc(void)
{
return kmem_cache_alloc(global.slab_luts, GFP_KERNEL);
@@ -234,6 +249,8 @@ static void i915_gem_context_free(struct i915_gem_context *ctx)
release_hw_id(ctx);
i915_ppgtt_put(ctx->ppgtt);
+ kfree(ctx->engines);
+
rbtree_postorder_for_each_entry_safe(it, n, &ctx->hw_contexts, node)
it->ops->destroy(it);
@@ -1311,9 +1328,9 @@ static int set_sseu(struct i915_gem_context *ctx,
if (user_sseu.flags || user_sseu.rsvd)
return -EINVAL;
- engine = intel_engine_lookup_user(i915,
- user_sseu.engine_class,
- user_sseu.engine_instance);
+ engine = lookup_user_engine(ctx, 0,
+ user_sseu.engine_class,
+ user_sseu.engine_instance);
if (!engine)
return -EINVAL;
@@ -1331,9 +1348,154 @@ static int set_sseu(struct i915_gem_context *ctx,
args->size = sizeof(user_sseu);
+ return 0;
+};
+
+struct set_engines {
+ struct i915_gem_context *ctx;
+ struct intel_engine_cs **engines;
+ unsigned int nengine;
+};
+
+static const i915_user_extension_fn set_engines__extensions[] = {
+};
+
+static int
+set_engines(struct i915_gem_context *ctx,
+ const struct drm_i915_gem_context_param *args)
+{
+ struct i915_context_param_engines __user *user;
+ struct set_engines set = { .ctx = ctx };
+ u64 size, extensions;
+ unsigned int n;
+ int err;
+
+ user = u64_to_user_ptr(args->value);
+ size = args->size;
+ if (!size)
+ goto out;
