xref: /openbmc/linux/arch/x86/include/asm/resctrl.h (revision 7fef0997)
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  * struct resctrl_pqr_state - State cache for the PQR MSR
12  * @cur_rmid:		The cached Resource Monitoring ID
13  * @cur_closid:	The cached Class Of Service ID
14  * @default_rmid:	The user assigned Resource Monitoring ID
15  * @default_closid:	The user assigned cached Class Of Service ID
16  *
17  * The upper 32 bits of MSR_IA32_PQR_ASSOC contain closid and the
18  * lower 10 bits rmid. The update to MSR_IA32_PQR_ASSOC always
19  * contains both parts, so we need to cache them. This also
20  * stores the user configured per cpu CLOSID and RMID.
21  *
22  * The cache also helps to avoid pointless updates if the value does
23  * not change.
24  */
25 struct resctrl_pqr_state {
26 	u32			cur_rmid;
27 	u32			cur_closid;
28 	u32			default_rmid;
29 	u32			default_closid;
30 };
31 
32 DECLARE_PER_CPU(struct resctrl_pqr_state, pqr_state);
33 
34 DECLARE_STATIC_KEY_FALSE(rdt_enable_key);
35 DECLARE_STATIC_KEY_FALSE(rdt_alloc_enable_key);
36 DECLARE_STATIC_KEY_FALSE(rdt_mon_enable_key);
37 
38 /*
39  * __resctrl_sched_in() - Writes the task's CLOSid/RMID to IA32_PQR_MSR
40  *
41  * Following considerations are made so that this has minimal impact
42  * on scheduler hot path:
43  * - This will stay as no-op unless we are running on an Intel SKU
44  *   which supports resource control or monitoring and we enable by
45  *   mounting the resctrl file system.
46  * - Caches the per cpu CLOSid/RMID values and does the MSR write only
47  *   when a task with a different CLOSid/RMID is scheduled in.
48  * - We allocate RMIDs/CLOSids globally in order to keep this as
49  *   simple as possible.
50  * Must be called with preemption disabled.
51  */
__resctrl_sched_in(struct task_struct * tsk)52 static inline void __resctrl_sched_in(struct task_struct *tsk)
53 {
54 	struct resctrl_pqr_state *state = this_cpu_ptr(&pqr_state);
55 	u32 closid = state->default_closid;
56 	u32 rmid = state->default_rmid;
57 	u32 tmp;
58 
59 	/*
60 	 * If this task has a closid/rmid assigned, use it.
61 	 * Else use the closid/rmid assigned to this cpu.
62 	 */
63 	if (static_branch_likely(&rdt_alloc_enable_key)) {
64 		tmp = READ_ONCE(tsk->closid);
65 		if (tmp)
66 			closid = tmp;
67 	}
68 
69 	if (static_branch_likely(&rdt_mon_enable_key)) {
70 		tmp = READ_ONCE(tsk->rmid);
71 		if (tmp)
72 			rmid = tmp;
73 	}
74 
75 	if (closid != state->cur_closid || rmid != state->cur_rmid) {
76 		state->cur_closid = closid;
77 		state->cur_rmid = rmid;
78 		wrmsr(MSR_IA32_PQR_ASSOC, rmid, closid);
79 	}
80 }
81 
resctrl_arch_round_mon_val(unsigned int val)82 static inline unsigned int resctrl_arch_round_mon_val(unsigned int val)
83 {
84 	unsigned int scale = boot_cpu_data.x86_cache_occ_scale;
85 
86 	/* h/w works in units of "boot_cpu_data.x86_cache_occ_scale" */
87 	val /= scale;
88 	return val * scale;
89 }
90 
resctrl_sched_in(struct task_struct * tsk)91 static inline void resctrl_sched_in(struct task_struct *tsk)
92 {
93 	if (static_branch_likely(&rdt_enable_key))
94 		__resctrl_sched_in(tsk);
95 }
96 
97 void resctrl_cpu_detect(struct cpuinfo_x86 *c);
98 
99 #else
100 
resctrl_sched_in(struct task_struct * tsk)101 static inline void resctrl_sched_in(struct task_struct *tsk) {}
resctrl_cpu_detect(struct cpuinfo_x86 * c)102 static inline void resctrl_cpu_detect(struct cpuinfo_x86 *c) {}
103 
104 #endif /* CONFIG_X86_CPU_RESCTRL */
105 
106 #endif /* _ASM_X86_RESCTRL_H */
107