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