resctrl.h

  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, rmid, 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 */