1 files changed, 108 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/i915_file_private.h b/drivers/gpu/drm/i915/i915_file_private.h
new file mode 100644
index 000000000000..fb16cc431b2a
--- /dev/null
+++ b/drivers/gpu/drm/i915/i915_file_private.h
@@ -0,0 +1,108 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright © 2021 Intel Corporation
+ */
+
+#ifndef __I915_FILE_PRIVATE_H__
+#define __I915_FILE_PRIVATE_H__
+
+#include <linux/mutex.h>
+#include <linux/types.h>
+#include <linux/xarray.h>
+
+struct drm_i915_private;
+struct drm_file;
+
+struct drm_i915_file_private {
+	struct drm_i915_private *dev_priv;
+
+	union {
+		struct drm_file *file;
+		struct rcu_head rcu;
+	};
+
+	/** @proto_context_lock: Guards all struct i915_gem_proto_context
+	 * operations
+	 *
+	 * This not only guards @proto_context_xa, but is always held
+	 * whenever we manipulate any struct i915_gem_proto_context,
+	 * including finalizing it on first actual use of the GEM context.
+	 *
+	 * See i915_gem_proto_context.
+	 */
+	struct mutex proto_context_lock;
+
+	/** @proto_context_xa: xarray of struct i915_gem_proto_context
+	 *
+	 * Historically, the context uAPI allowed 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.  Everything settable via one was settable
+	 * via the other.  While some params are fairly simple and setting
+	 * them on a live context is harmless such as 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.
+	 *
+	 * We have since disallowed setting these more complex parameters
+	 * on active contexts.  This works by delaying 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 a struct i915_gem_proto_context
+	 * right up until the point where we attempt to do something which
+	 * the proto-context can't handle.  Then the struct i915_gem_context
+	 * gets created.
+	 *
+	 * This is accomplished via a little xarray dance.  When
+	 * GEM_CONTEXT_CREATE is called, we create a struct
+	 * i915_gem_proto_context, reserve a slot in @context_xa but leave
+	 * it NULL, and place the proto-context in the corresponding slot
+	 * in @proto_context_xa.  Then, in i915_gem_context_lookup(), we
+	 * first check @context_xa.  If it's there, we return the struct
+	 * 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 struct i915_gem_proto_context is guarded by
+	 * @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.
+	 */
+	struct xarray proto_context_xa;
+
+	/** @context_xa: xarray of fully created i915_gem_context
+	 *
+	 * Write access to this xarray is guarded by @proto_context_lock.
+	 * Otherwise, writers may race with finalize_create_context_locked().
+	 *
+	 * See @proto_context_xa.
+	 */
+	struct xarray context_xa;
+	struct xarray vm_xa;
+
+	unsigned int bsd_engine;
+
+/*
+ * Every context ban increments per client ban score. Also
+ * hangs in short succession increments ban score. If ban threshold
+ * is reached, client is considered banned and submitting more work
+ * will fail. This is a stop gap measure to limit the badly behaving
+ * clients access to gpu. Note that unbannable contexts never increment
+ * the client ban score.
+ */
+#define I915_CLIENT_SCORE_HANG_FAST	1
+#define   I915_CLIENT_FAST_HANG_JIFFIES (60 * HZ)
+#define I915_CLIENT_SCORE_CONTEXT_BAN   3
+#define I915_CLIENT_SCORE_BANNED	9
+	/** ban_score: Accumulated score of all ctx bans and fast hangs. */
+	atomic_t ban_score;
+	unsigned long hang_timestamp;
+};
+
+#endif /* __I915_FILE_PRIVATE_H__ */