[Intel-gfx] [RFC 08/10] drm/i915: Allow creating virtual contexts

[Tvrtko Ursulin]

From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>

Virtual context imply the target engine will be picked by the driver.

v2: Disallow legacy execbuf API.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
---
 drivers/gpu/drm/i915/i915_gem_context.c    | 15 ++++++++++-----
 drivers/gpu/drm/i915/i915_gem_context.h    |  2 ++
 drivers/gpu/drm/i915/i915_gem_execbuffer.c |  6 ++++++
 include/uapi/drm/i915_drm.h                |  2 +-
 4 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index 22b0fa170fcf..8f5f23b0dd34 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -667,15 +667,18 @@ int i915_gem_context_create_ioctl(struct drm_device *dev, void *data,
 	unsigned int flags = CREATE_VM | CREATE_TIMELINE;
 	int err;
 
-	if (!dev_priv->engine[RCS]->context_size)
-		return -ENODEV;
-
-	if (args->pad != 0)
+	if (args->flags & ~I915_GEM_CONTEXT_SHARE_GTT)
 		return -EINVAL;
 
-	if (args->flags & ~I915_GEM_CONTEXT_SHARE_GTT)
+	if (args->virtual > 1)
 		return -EINVAL;
 
+	if (!dev_priv->engine[RCS]->context_size)
+		return -ENODEV;
+
+	if (args->virtual && !HAS_BSD2(dev_priv))
+		return -ENODEV;
+
 	if (client_is_banned(file_priv)) {
 		DRM_DEBUG("client %s[%d] banned from creating ctx\n",
 			  current->comm,
@@ -716,6 +719,8 @@ int i915_gem_context_create_ioctl(struct drm_device *dev, void *data,
 
 	GEM_BUG_ON(i915_gem_context_is_kernel(ctx));
 
+	ctx->virtual = args->virtual;
+
 	args->ctx_id = ctx->user_handle;
 	DRM_DEBUG("HW context %d created\n", args->ctx_id);
 
diff --git a/drivers/gpu/drm/i915/i915_gem_context.h b/drivers/gpu/drm/i915/i915_gem_context.h
index cfa69b12a6b2..5afe050718b8 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.h
+++ b/drivers/gpu/drm/i915/i915_gem_context.h
@@ -149,6 +149,8 @@ struct i915_gem_context {
 	 */
 	int priority;
 
+	unsigned int virtual;
+
 	/** ggtt_offset_bias: placement restriction for context objects */
 	u32 ggtt_offset_bias;
 
diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index 78340ceb1105..fa1806ed9be6 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -2026,6 +2026,9 @@ static int eb_select_engine_class_instance(struct i915_execbuffer *eb)
 		  I915_EXEC_ENGINE_CAP_SHIFT;
 	struct intel_engine_cs *engine;
 
+	if (instance && eb->ctx->virtual)
+		return -EINVAL;
+
 	engine = intel_engine_lookup_user(eb->i915, class, instance);
 
 	if (engine && ((caps & engine->caps) != caps))
@@ -2068,6 +2071,9 @@ static int eb_select_engine(struct i915_execbuffer *eb, struct drm_file *file)
 		return -EINVAL;
 	}
 
+	if (user_ring_id == I915_EXEC_BSD && eb->ctx->virtual)
+		return -EINVAL;
+
 	if (user_ring_id == I915_EXEC_BSD && HAS_BSD2(dev_priv)) {
 		unsigned int bsd_idx = flags & I915_EXEC_BSD_MASK;
 
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index 8b8b70c5a50b..42eb34b9c014 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -1431,7 +1431,7 @@ struct drm_i915_gem_context_create_v2 {
 	__u32 flags;
 #define I915_GEM_CONTEXT_SHARE_GTT 0x1
 	__u32 share_ctx;
-	__u32 pad;
+	__u32 virtual;
 };
 
 struct drm_i915_gem_context_destroy {
-- 
2.14.1