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 */ 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 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 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 100 101 static inline void resctrl_sched_in(struct task_struct *tsk) {} 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