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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/jump_label.h>
8#include <linux/percpu.h>
9#include <linux/resctrl_types.h>
10#include <linux/sched.h>
11
12#include <asm/msr.h>
13
14/*
15 * This value can never be a valid CLOSID, and is used when mapping a
16 * (closid, rmid) pair to an index and back. On x86 only the RMID is
17 * needed. The index is a software defined value.
18 */
19#define X86_RESCTRL_EMPTY_CLOSID ((u32)~0)
20
21/**
22 * struct resctrl_pqr_state - State cache for the PQR MSR
23 * @cur_rmid: The cached Resource Monitoring ID
24 * @cur_closid: The cached Class Of Service ID
25 * @default_rmid: The user assigned Resource Monitoring ID
26 * @default_closid: The user assigned cached Class Of Service ID
27 *
28 * The upper 32 bits of MSR_IA32_PQR_ASSOC contain closid and the
29 * lower 10 bits rmid. The update to MSR_IA32_PQR_ASSOC always
30 * contains both parts, so we need to cache them. This also
31 * stores the user configured per cpu CLOSID and RMID.
32 *
33 * The cache also helps to avoid pointless updates if the value does
34 * not change.
35 */
36struct resctrl_pqr_state {
37 u32 cur_rmid;
38 u32 cur_closid;
39 u32 default_rmid;
40 u32 default_closid;
41};
42
43DECLARE_PER_CPU(struct resctrl_pqr_state, pqr_state);
44
45extern bool rdt_alloc_capable;
46extern bool rdt_mon_capable;
47
48DECLARE_STATIC_KEY_FALSE(rdt_enable_key);
49DECLARE_STATIC_KEY_FALSE(rdt_alloc_enable_key);
50DECLARE_STATIC_KEY_FALSE(rdt_mon_enable_key);
51
52static inline bool resctrl_arch_alloc_capable(void)
53{
54 return rdt_alloc_capable;
55}
56
57static inline void resctrl_arch_enable_alloc(void)
58{
59 static_branch_enable_cpuslocked(&rdt_alloc_enable_key);
60 static_branch_inc_cpuslocked(&rdt_enable_key);
61}
62
63static inline void resctrl_arch_disable_alloc(void)
64{
65 static_branch_disable_cpuslocked(&rdt_alloc_enable_key);
66 static_branch_dec_cpuslocked(&rdt_enable_key);
67}
68
69static inline bool resctrl_arch_mon_capable(void)
70{
71 return rdt_mon_capable;
72}
73
74static inline void resctrl_arch_enable_mon(void)
75{
76 static_branch_enable_cpuslocked(&rdt_mon_enable_key);
77 static_branch_inc_cpuslocked(&rdt_enable_key);
78}
79
80static inline void resctrl_arch_disable_mon(void)
81{
82 static_branch_disable_cpuslocked(&rdt_mon_enable_key);
83 static_branch_dec_cpuslocked(&rdt_enable_key);
84}
85
86/*
87 * __resctrl_sched_in() - Writes the task's CLOSid/RMID to IA32_PQR_MSR
88 *
89 * Following considerations are made so that this has minimal impact
90 * on scheduler hot path:
91 * - This will stay as no-op unless we are running on an Intel SKU
92 * which supports resource control or monitoring and we enable by
93 * mounting the resctrl file system.
94 * - Caches the per cpu CLOSid/RMID values and does the MSR write only
95 * when a task with a different CLOSid/RMID is scheduled in.
96 * - We allocate RMIDs/CLOSids globally in order to keep this as
97 * simple as possible.
98 * Must be called with preemption disabled.
99 */
100static inline void __resctrl_sched_in(struct task_struct *tsk)
101{
102 struct resctrl_pqr_state *state = this_cpu_ptr(&pqr_state);
103 u32 closid = READ_ONCE(state->default_closid);
104 u32 rmid = READ_ONCE(state->default_rmid);
105 struct msr val;
106 u32 tmp;
107
108 /*
109 * If this task has a closid/rmid assigned, use it.
110 * Else use the closid/rmid assigned to this cpu.
111 */
112 if (static_branch_likely(&rdt_alloc_enable_key)) {
113 tmp = READ_ONCE(tsk->closid);
114 if (tmp)
115 closid = tmp;
116 }
117
118 if (static_branch_likely(&rdt_mon_enable_key)) {
119 tmp = READ_ONCE(tsk->rmid);
120 if (tmp)
121 rmid = tmp;
122 }
123
124 if (closid != state->cur_closid || rmid != state->cur_rmid) {
125 state->cur_closid = closid;
126 state->cur_rmid = rmid;
127 val.l = rmid;
128 val.h = closid;
129 wrmsrq(MSR_IA32_PQR_ASSOC, val.q);
130 }
131}
132
133static inline unsigned int resctrl_arch_round_mon_val(unsigned int val)
134{
135 unsigned int scale = boot_cpu_data.x86_cache_occ_scale;
136
137 /* h/w works in units of "boot_cpu_data.x86_cache_occ_scale" */
138 val /= scale;
139 return val * scale;
140}
141
142static inline void resctrl_arch_set_cpu_default_closid_rmid(int cpu, u32 closid,
143 u32 rmid)
144{
145 WRITE_ONCE(per_cpu(pqr_state.default_closid, cpu), closid);
146 WRITE_ONCE(per_cpu(pqr_state.default_rmid, cpu), rmid);
147}
148
149static inline void resctrl_arch_set_closid_rmid(struct task_struct *tsk,
150 u32 closid, u32 rmid)
151{
152 WRITE_ONCE(tsk->closid, closid);
153 WRITE_ONCE(tsk->rmid, rmid);
154}
155
156static inline bool resctrl_arch_match_closid(struct task_struct *tsk, u32 closid)
157{
158 return READ_ONCE(tsk->closid) == closid;
159}
160
161static inline bool resctrl_arch_match_rmid(struct task_struct *tsk, u32 ignored,
162 u32 rmid)
163{
164 return READ_ONCE(tsk->rmid) == rmid;
165}
166
167static inline void resctrl_arch_sched_in(struct task_struct *tsk)
168{
169 if (static_branch_likely(&rdt_enable_key))
170 __resctrl_sched_in(tsk);
171}
172
173static inline void resctrl_arch_rmid_idx_decode(u32 idx, u32 *closid, u32 *rmid)
174{
175 *rmid = idx;
176 *closid = X86_RESCTRL_EMPTY_CLOSID;
177}
178
179static inline u32 resctrl_arch_rmid_idx_encode(u32 ignored, u32 rmid)
180{
181 return rmid;
182}
183
184/* x86 can always read an rmid, nothing needs allocating */
185struct rdt_resource;
186static inline void *resctrl_arch_mon_ctx_alloc(struct rdt_resource *r,
187 enum resctrl_event_id evtid)
188{
189 might_sleep();
190 return NULL;
191}
192
193static inline void resctrl_arch_mon_ctx_free(struct rdt_resource *r,
194 enum resctrl_event_id evtid,
195 void *ctx) { }
196
197void resctrl_cpu_detect(struct cpuinfo_x86 *c);
198
199#else
200
201static inline void resctrl_arch_sched_in(struct task_struct *tsk) {}
202static inline void resctrl_cpu_detect(struct cpuinfo_x86 *c) {}
203
204#endif /* CONFIG_X86_CPU_RESCTRL */
205
206#endif /* _ASM_X86_RESCTRL_H */