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 */ 191