[PATCH v2 21/45] arm_mpam: resctrl: Add plumbing against arm64 task and cpu hooks
From: Ben Horgan <ben.horgan@arm.com>
Date: 2025-12-19 18:13:43
Also in:
kvmarm, lkml
Subsystem:
mpam driver, the rest · Maintainers:
James Morse, Ben Horgan, Linus Torvalds
From: James Morse <james.morse@arm.com> arm64 provides helpers for changing a tasks and a cpus mpam partid/pmg values. These are used to back a number of resctrl_arch_ functions. Connect them up. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Ben Horgan <ben.horgan@arm.com> --- drivers/resctrl/mpam_resctrl.c | 58 ++++++++++++++++++++++++++++++++++ include/linux/arm_mpam.h | 5 +++ 2 files changed, 63 insertions(+)
diff --git a/drivers/resctrl/mpam_resctrl.c b/drivers/resctrl/mpam_resctrl.c
index e5ec5438eca8..2f72ca66fb8c 100644
--- a/drivers/resctrl/mpam_resctrl.c
+++ b/drivers/resctrl/mpam_resctrl.c@@ -8,6 +8,7 @@ #include <linux/cpu.h> #include <linux/cpumask.h> #include <linux/errno.h> +#include <linux/limits.h> #include <linux/list.h> #include <linux/printk.h> #include <linux/rculist.h>
@@ -32,6 +33,8 @@ static DEFINE_MUTEX(domain_list_lock); static bool exposed_alloc_capable; static bool exposed_mon_capable; +static bool cdp_enabled; + bool resctrl_arch_alloc_capable(void) { return exposed_alloc_capable;
@@ -52,6 +55,61 @@ u32 resctrl_arch_get_num_closid(struct rdt_resource *ignored) return mpam_partid_max + 1; } +void resctrl_arch_sched_in(struct task_struct *tsk) +{ + lockdep_assert_preemption_disabled(); + + mpam_thread_switch(tsk); +} + +void resctrl_arch_set_cpu_default_closid_rmid(int cpu, u32 closid, u32 rmid) +{ + WARN_ON_ONCE(closid > U16_MAX); + WARN_ON_ONCE(rmid > U8_MAX); + + if (!cdp_enabled) { + mpam_set_cpu_defaults(cpu, closid, closid, rmid, rmid); + } else { + /* + * When CDP is enabled, resctrl halves the closid range and we + * use odd/even partid for one closid. + */ + u32 partid_d = resctrl_get_config_index(closid, CDP_DATA); + u32 partid_i = resctrl_get_config_index(closid, CDP_CODE); + + mpam_set_cpu_defaults(cpu, partid_d, partid_i, rmid, rmid); + } +} + +void resctrl_arch_sync_cpu_closid_rmid(void *info) +{ + struct resctrl_cpu_defaults *r = info; + + lockdep_assert_preemption_disabled(); + + if (r) { + resctrl_arch_set_cpu_default_closid_rmid(smp_processor_id(), + r->closid, r->rmid); + } + + resctrl_arch_sched_in(current); +} + +void resctrl_arch_set_closid_rmid(struct task_struct *tsk, u32 closid, u32 rmid) +{ + WARN_ON_ONCE(closid > U16_MAX); + WARN_ON_ONCE(rmid > U8_MAX); + + if (!cdp_enabled) { + mpam_set_task_partid_pmg(tsk, closid, closid, rmid, rmid); + } else { + u32 partid_d = resctrl_get_config_index(closid, CDP_DATA); + u32 partid_i = resctrl_get_config_index(closid, CDP_CODE); + + mpam_set_task_partid_pmg(tsk, partid_d, partid_i, rmid, rmid); + } +} + struct rdt_resource *resctrl_arch_get_resource(enum resctrl_res_level l) { if (l >= RDT_NUM_RESOURCES)
diff --git a/include/linux/arm_mpam.h b/include/linux/arm_mpam.h
index 2c7d1413a401..5a78299ec464 100644
--- a/include/linux/arm_mpam.h
+++ b/include/linux/arm_mpam.h@@ -52,6 +52,11 @@ static inline int mpam_ris_create(struct mpam_msc *msc, u8 ris_idx, bool resctrl_arch_alloc_capable(void); bool resctrl_arch_mon_capable(void); +void resctrl_arch_set_cpu_default_closid(int cpu, u32 closid); +void resctrl_arch_set_closid_rmid(struct task_struct *tsk, u32 closid, u32 rmid); +void resctrl_arch_set_cpu_default_closid_rmid(int cpu, u32 closid, u32 rmid); +void resctrl_arch_sched_in(struct task_struct *tsk); + /** * mpam_register_requestor() - Register a requestor with the MPAM driver * @partid_max: The maximum PARTID value the requestor can generate.
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2.43.0