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

Tvrtko Ursulin
2018-01-25T13:33:49Z

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

v2: Disallow legacy execbuf API.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@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 {