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
13struct drm_i915_private;
14struct drm_file;
15struct i915_drm_client;
16
17struct 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