xref: /linux/arch/x86/include/asm/resctrl.h (revision c9f016e72b5cc7d4d68fac51f8e72c8c7a69c06e)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_X86_RESCTRL_H
3 #define _ASM_X86_RESCTRL_H
4 
5 #ifdef CONFIG_X86_CPU_RESCTRL
6 
7 #include <linux/sched.h>
8 #include <linux/jump_label.h>
9 
10 /*
11  * This value can never be a valid CLOSID, and is used when mapping a
12  * (closid, rmid) pair to an index and back. On x86 only the RMID is
13  * needed. The index is a software defined value.
14  */
15 #define X86_RESCTRL_EMPTY_CLOSID         ((u32)~0)
16 
17 /**
18  * struct resctrl_pqr_state - State cache for the PQR MSR
19  * @cur_rmid:		The cached Resource Monitoring ID
20  * @cur_closid:	The cached Class Of Service ID
21  * @default_rmid:	The user assigned Resource Monitoring ID
22  * @default_closid:	The user assigned cached Class Of Service ID
23  *
24  * The upper 32 bits of MSR_IA32_PQR_ASSOC contain closid and the
25  * lower 10 bits rmid. The update to MSR_IA32_PQR_ASSOC always
26  * contains both parts, so we need to cache them. This also
27  * stores the user configured per cpu CLOSID and RMID.
28  *
29  * The cache also helps to avoid pointless updates if the value does
30  * not change.
31  */
32 struct resctrl_pqr_state {
33 	u32			cur_rmid;
34 	u32			cur_closid;
35 	u32			default_rmid;
36 	u32			default_closid;
37 };
38 
39 DECLARE_PER_CPU(struct resctrl_pqr_state, pqr_state);
40 
41 extern bool rdt_alloc_capable;
42 extern bool rdt_mon_capable;
43 
44 DECLARE_STATIC_KEY_FALSE(rdt_enable_key);
45 DECLARE_STATIC_KEY_FALSE(rdt_alloc_enable_key);
46 DECLARE_STATIC_KEY_FALSE(rdt_mon_enable_key);
47 
resctrl_arch_alloc_capable(void)48 static inline bool resctrl_arch_alloc_capable(void)
49 {
50 	return rdt_alloc_capable;
51 }
52 
resctrl_arch_enable_alloc(void)53 static inline void resctrl_arch_enable_alloc(void)
54 {
55 	static_branch_enable_cpuslocked(&rdt_alloc_enable_key);
56 	static_branch_inc_cpuslocked(&rdt_enable_key);
57 }
58 
resctrl_arch_disable_alloc(void)59 static inline void resctrl_arch_disable_alloc(void)
60 {
61 	static_branch_disable_cpuslocked(&rdt_alloc_enable_key);
62 	static_branch_dec_cpuslocked(&rdt_enable_key);
63 }
64 
resctrl_arch_mon_capable(void)65 static inline bool resctrl_arch_mon_capable(void)
66 {
67 	return rdt_mon_capable;
68 }
69 
resctrl_arch_enable_mon(void)70 static inline void resctrl_arch_enable_mon(void)
71 {
72 	static_branch_enable_cpuslocked(&rdt_mon_enable_key);
73 	static_branch_inc_cpuslocked(&rdt_enable_key);
74 }
75 
resctrl_arch_disable_mon(void)76 static inline void resctrl_arch_disable_mon(void)
77 {
78 	static_branch_disable_cpuslocked(&rdt_mon_enable_key);
79 	static_branch_dec_cpuslocked(&rdt_enable_key);
80 }
81 
82 /*
83  * __resctrl_sched_in() - Writes the task's CLOSid/RMID to IA32_PQR_MSR
84  *
85  * Following considerations are made so that this has minimal impact
86  * on scheduler hot path:
87  * - This will stay as no-op unless we are running on an Intel SKU
88  *   which supports resource control or monitoring and we enable by
89  *   mounting the resctrl file system.
90  * - Caches the per cpu CLOSid/RMID values and does the MSR write only
91  *   when a task with a different CLOSid/RMID is scheduled in.
92  * - We allocate RMIDs/CLOSids globally in order to keep this as
93  *   simple as possible.
94  * Must be called with preemption disabled.
95  */
__resctrl_sched_in(struct task_struct * tsk)96 static inline void __resctrl_sched_in(struct task_struct *tsk)
97 {
98 	struct resctrl_pqr_state *state = this_cpu_ptr(&pqr_state);
99 	u32 closid = state->default_closid;
100 	u32 rmid = state->default_rmid;
101 	u32 tmp;
102 
103 	/*
104 	 * If this task has a closid/rmid assigned, use it.
105 	 * Else use the closid/rmid assigned to this cpu.
106 	 */
107 	if (static_branch_likely(&rdt_alloc_enable_key)) {
108 		tmp = READ_ONCE(tsk->closid);
109 		if (tmp)
110 			closid = tmp;
111 	}
112 
113 	if (static_branch_likely(&rdt_mon_enable_key)) {
114 		tmp = READ_ONCE(tsk->rmid);
115 		if (tmp)
116 			rmid = tmp;
117 	}
118 
119 	if (closid != state->cur_closid || rmid != state->cur_rmid) {
120 		state->cur_closid = closid;
121 		state->cur_rmid = rmid;
122 		wrmsr(MSR_IA32_PQR_ASSOC, rmid, closid);
123 	}
124 }
125 
resctrl_arch_round_mon_val(unsigned int val)126 static inline unsigned int resctrl_arch_round_mon_val(unsigned int val)
127 {
128 	unsigned int scale = boot_cpu_data.x86_cache_occ_scale;
129 
130 	/* h/w works in units of "boot_cpu_data.x86_cache_occ_scale" */
131 	val /= scale;
132 	return val * scale;
133 }
134 
resctrl_arch_set_closid_rmid(struct task_struct * tsk,u32 closid,u32 rmid)135 static inline void resctrl_arch_set_closid_rmid(struct task_struct *tsk,
136 						u32 closid, u32 rmid)
137 {
138 	WRITE_ONCE(tsk->closid, closid);
139 	WRITE_ONCE(tsk->rmid, rmid);
140 }
141 
resctrl_arch_match_closid(struct task_struct * tsk,u32 closid)142 static inline bool resctrl_arch_match_closid(struct task_struct *tsk, u32 closid)
143 {
144 	return READ_ONCE(tsk->closid) == closid;
145 }
146 
resctrl_arch_match_rmid(struct task_struct * tsk,u32 ignored,u32 rmid)147 static inline bool resctrl_arch_match_rmid(struct task_struct *tsk, u32 ignored,
148 					   u32 rmid)
149 {
150 	return READ_ONCE(tsk->rmid) == rmid;
151 }
152 
resctrl_sched_in(struct task_struct * tsk)153 static inline void resctrl_sched_in(struct task_struct *tsk)
154 {
155 	if (static_branch_likely(&rdt_enable_key))
156 		__resctrl_sched_in(tsk);
157 }
158 
resctrl_arch_rmid_idx_decode(u32 idx,u32 * closid,u32 * rmid)159 static inline void resctrl_arch_rmid_idx_decode(u32 idx, u32 *closid, u32 *rmid)
160 {
161 	*rmid = idx;
162 	*closid = X86_RESCTRL_EMPTY_CLOSID;
163 }
164 
resctrl_arch_rmid_idx_encode(u32 ignored,u32 rmid)165 static inline u32 resctrl_arch_rmid_idx_encode(u32 ignored, u32 rmid)
166 {
167 	return rmid;
168 }
169 
170 /* x86 can always read an rmid, nothing needs allocating */
171 struct rdt_resource;
resctrl_arch_mon_ctx_alloc(struct rdt_resource * r,int evtid)172 static inline void *resctrl_arch_mon_ctx_alloc(struct rdt_resource *r, int evtid)
173 {
174 	might_sleep();
175 	return NULL;
176 };
177 
resctrl_arch_mon_ctx_free(struct rdt_resource * r,int evtid,void * ctx)178 static inline void resctrl_arch_mon_ctx_free(struct rdt_resource *r, int evtid,
179 					     void *ctx) { };
180 
181 void resctrl_cpu_detect(struct cpuinfo_x86 *c);
182 
183 #else
184 
resctrl_sched_in(struct task_struct * tsk)185 static inline void resctrl_sched_in(struct task_struct *tsk) {}
resctrl_cpu_detect(struct cpuinfo_x86 * c)186 static inline void resctrl_cpu_detect(struct cpuinfo_x86 *c) {}
187 
188 #endif /* CONFIG_X86_CPU_RESCTRL */
189 
190 #endif /* _ASM_X86_RESCTRL_H */
191