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 u32 tmp;
106
107 /*
108 * If this task has a closid/rmid assigned, use it.
109 * Else use the closid/rmid assigned to this cpu.
110 */
111 if (static_branch_likely(&rdt_alloc_enable_key)) {
112 tmp = READ_ONCE(tsk->closid);
113 if (tmp)
114 closid = tmp;
115 }
116
117 if (static_branch_likely(&rdt_mon_enable_key)) {
118 tmp = READ_ONCE(tsk->rmid);
119 if (tmp)
120 rmid = tmp;
121 }
122
123 if (closid != state->cur_closid || rmid != state->cur_rmid) {
124 state->cur_closid = closid;
125 state->cur_rmid = rmid;
126 wrmsr(MSR_IA32_PQR_ASSOC, low: rmid, high: closid);
127 }
128}
129
130static inline unsigned int resctrl_arch_round_mon_val(unsigned int val)
131{
132 unsigned int scale = boot_cpu_data.x86_cache_occ_scale;
133
134 /* h/w works in units of "boot_cpu_data.x86_cache_occ_scale" */
135 val /= scale;
136 return val * scale;
137}
138
139static inline void resctrl_arch_set_cpu_default_closid_rmid(int cpu, u32 closid,
140 u32 rmid)
141{
142 WRITE_ONCE(per_cpu(pqr_state.default_closid, cpu), closid);
143 WRITE_ONCE(per_cpu(pqr_state.default_rmid, cpu), rmid);
144}
145
146static inline void resctrl_arch_set_closid_rmid(struct task_struct *tsk,
147 u32 closid, u32 rmid)
148{
149 WRITE_ONCE(tsk->closid, closid);
150 WRITE_ONCE(tsk->rmid, rmid);
151}
152
153static inline bool resctrl_arch_match_closid(struct task_struct *tsk, u32 closid)
154{
155 return READ_ONCE(tsk->closid) == closid;
156}
157
158static inline bool resctrl_arch_match_rmid(struct task_struct *tsk, u32 ignored,
159 u32 rmid)
160{
161 return READ_ONCE(tsk->rmid) == rmid;
162}
163
164static inline void resctrl_arch_sched_in(struct task_struct *tsk)
165{
166 if (static_branch_likely(&rdt_enable_key))
167 __resctrl_sched_in(tsk);
168}
169
170static inline void resctrl_arch_rmid_idx_decode(u32 idx, u32 *closid, u32 *rmid)
171{
172 *rmid = idx;
173 *closid = X86_RESCTRL_EMPTY_CLOSID;
174}
175
176static inline u32 resctrl_arch_rmid_idx_encode(u32 ignored, u32 rmid)
177{
178 return rmid;
179}
180
181/* x86 can always read an rmid, nothing needs allocating */
182struct rdt_resource;
183static inline void *resctrl_arch_mon_ctx_alloc(struct rdt_resource *r,
184 enum resctrl_event_id evtid)
185{
186 might_sleep();
187 return NULL;
188}
189
190static inline void resctrl_arch_mon_ctx_free(struct rdt_resource *r,
191 enum resctrl_event_id evtid,
192 void *ctx) { }
193
194void resctrl_cpu_detect(struct cpuinfo_x86 *c);
195
196#else
197
198static inline void resctrl_arch_sched_in(struct task_struct *tsk) {}
199static inline void resctrl_cpu_detect(struct cpuinfo_x86 *c) {}
200
201#endif /* CONFIG_X86_CPU_RESCTRL */
202
203#endif /* _ASM_X86_RESCTRL_H */
204

source code of linux/arch/x86/include/asm/resctrl.h