arch/x86/include/asm/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/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
  48 static inline bool resctrl_arch_alloc_capable(void)
  49 {
  50         return rdt_alloc_capable;
  51 }
  52
  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
  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
  65 static inline bool resctrl_arch_mon_capable(void)
  66 {
  67         return rdt_mon_capable;
  68 }
  69
  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
  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  */
  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
 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
 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
 142 static inline bool resctrl_arch_match_closid(struct task_struct *tsk, u32 closid)
 143 {
 144         return READ_ONCE(tsk->closid) == closid;
 145 }
 146
 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
 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
 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
 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;
 172 static inline void *resctrl_arch_mon_ctx_alloc(struct rdt_resource *r, int evtid)
 173 {
 174         might_sleep();
 175         return NULL;
 176 };
 177
 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
 185 static inline void resctrl_sched_in(struct task_struct *tsk) {}
 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 */