1 /* SPDX-License-Identifier: MIT */
2 /*
3  * Copyright © 2021 Intel Corporation
4  */
5 
6 #ifndef __I915_FILE_PRIVATE_H__
7 #define __I915_FILE_PRIVATE_H__
8 
9 #include <linux/mutex.h>
10 #include <linux/types.h>
11 #include <linux/xarray.h>
12 
13 struct drm_i915_private;
14 struct drm_file;
15 struct i915_drm_client;
16 
17 struct drm_i915_file_private {
18 	struct drm_i915_private *i915;
19 
20 	union {
21 		struct drm_file *file;
22 		struct rcu_head rcu;
23 	};
24 
25 	/** @proto_context_lock: Guards all struct i915_gem_proto_context
26 	 * operations
27 	 *
28 	 * This not only guards @proto_context_xa, but is always held
29 	 * whenever we manipulate any struct i915_gem_proto_context,
30 	 * including finalizing it on first actual use of the GEM context.
31 	 *
32 	 * See i915_gem_proto_context.
33 	 */
34 	struct mutex proto_context_lock;
35 
36 	/** @proto_context_xa: xarray of struct i915_gem_proto_context
37 	 *
38 	 * Historically, the context uAPI allowed for two methods of
39 	 * setting context parameters: SET_CONTEXT_PARAM and
40 	 * CONTEXT_CREATE_EXT_SETPARAM.  The former is allowed to be called
41 	 * at any time while the later happens as part of
42 	 * GEM_CONTEXT_CREATE.  Everything settable via one was settable
43 	 * via the other.  While some params are fairly simple and setting
44 	 * them on a live context is harmless such as the context priority,
45 	 * others are far trickier such as the VM or the set of engines.
46 	 * In order to swap out the VM, for instance, we have to delay
47 	 * until all current in-flight work is complete, swap in the new
48 	 * VM, and then continue.  This leads to a plethora of potential
49 	 * race conditions we'd really rather avoid.
50 	 *
51 	 * We have since disallowed setting these more complex parameters
52 	 * on active contexts.  This works by delaying the creation of the
53 	 * actual context until after the client is done configuring it
54 	 * with SET_CONTEXT_PARAM.  From the perspective of the client, it
55 	 * has the same u32 context ID the whole time.  From the
56 	 * perspective of i915, however, it's a struct i915_gem_proto_context
57 	 * right up until the point where we attempt to do something which
58 	 * the proto-context can't handle.  Then the struct i915_gem_context
59 	 * gets created.
60 	 *
61 	 * This is accomplished via a little xarray dance.  When
62 	 * GEM_CONTEXT_CREATE is called, we create a struct
63 	 * i915_gem_proto_context, reserve a slot in @context_xa but leave
64 	 * it NULL, and place the proto-context in the corresponding slot
65 	 * in @proto_context_xa.  Then, in i915_gem_context_lookup(), we
66 	 * first check @context_xa.  If it's there, we return the struct
67 	 * i915_gem_context and we're done.  If it's not, we look in
68 	 * @proto_context_xa and, if we find it there, we create the actual
69 	 * context and kill the proto-context.
70 	 *
71 	 * In order for this dance to work properly, everything which ever
72 	 * touches a struct i915_gem_proto_context is guarded by
73 	 * @proto_context_lock, including context creation.  Yes, this
74 	 * means context creation now takes a giant global lock but it
75 	 * can't really be helped and that should never be on any driver's
76 	 * fast-path anyway.
77 	 */
78 	struct xarray proto_context_xa;
79 
80 	/** @context_xa: xarray of fully created i915_gem_context
81 	 *
82 	 * Write access to this xarray is guarded by @proto_context_lock.
83 	 * Otherwise, writers may race with finalize_create_context_locked().
84 	 *
85 	 * See @proto_context_xa.
86 	 */
87 	struct xarray context_xa;
88 	struct xarray vm_xa;
89 
90 	unsigned int bsd_engine;
91 
92 /*
93  * Every context ban increments per client ban score. Also
94  * hangs in short succession increments ban score. If ban threshold
95  * is reached, client is considered banned and submitting more work
96  * will fail. This is a stop gap measure to limit the badly behaving
97  * clients access to gpu. Note that unbannable contexts never increment
98  * the client ban score.
99  */
100 #define I915_CLIENT_SCORE_HANG_FAST	1
101 #define   I915_CLIENT_FAST_HANG_JIFFIES (60 * HZ)
102 #define I915_CLIENT_SCORE_CONTEXT_BAN   3
103 #define I915_CLIENT_SCORE_BANNED	9
104 	/** ban_score: Accumulated score of all ctx bans and fast hangs. */
105 	atomic_t ban_score;
106 	unsigned long hang_timestamp;
107 
108 	struct i915_drm_client *client;
109 };
110 
111 #endif /* __I915_FILE_PRIVATE_H__ */
112