Re: [PATCH v2 34/45] arm_mpam: resctrl: Add resctrl_arch_rmid_read() and resctrl_arch_reset_rmid()
From: Jonathan Cameron <jonathan.cameron@huawei.com>
Date: 2026-01-06 14:43:51
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On Fri, 19 Dec 2025 18:11:36 +0000 Ben Horgan [off-list ref] wrote:
From: James Morse <james.morse@arm.com> resctrl uses resctrl_arch_rmid_read() to read counters. CDP emulation means the counter may need reading in three different ways. The same goes for reset. The helpers behind the resctrl_arch_ functions will be re-used for the ABMC equivalent functions. Add the rounding helper for checking monitor values while we're here. Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Ben Horgan <ben.horgan@arm.com>
Trivial stuff only. Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
quoted hunk ↗ jump to hunk
--- Changes since rfc: cfg intialisation style code flow at end of read_mon_cdp_safe() --- drivers/resctrl/mpam_resctrl.c | 159 +++++++++++++++++++++++++++++++++ include/linux/arm_mpam.h | 5 ++ 2 files changed, 164 insertions(+)diff --git a/drivers/resctrl/mpam_resctrl.c b/drivers/resctrl/mpam_resctrl.c index 638c84cdcfb6..8a1263986145 100644 --- a/drivers/resctrl/mpam_resctrl.c +++ b/drivers/resctrl/mpam_resctrl.c@@ -354,6 +354,165 @@ void resctrl_arch_mon_ctx_free(struct rdt_resource *r, resctrl_arch_mon_ctx_free_no_wait(evtid, mon_idx); } +static int
Whilst I don't really care, this does seem inconsistent from other functions static int __read_mon(... probably for consistent looking code.
+__read_mon(struct mpam_resctrl_mon *mon, struct mpam_component *mon_comp,
+ enum mpam_device_features mon_type,
+ int mon_idx,
+ enum resctrl_conf_type cdp_type, u32 closid, u32 rmid, u64 *val)
+{
+ struct mon_cfg cfg;
+
+ if (!mpam_is_enabled())
+ return -EINVAL;
+
+ /* Shift closid to account for CDP */
+ closid = resctrl_get_config_index(closid, cdp_type);
+
+ if (mon_idx == USE_PRE_ALLOCATED) {
+ int mbwu_idx = resctrl_arch_rmid_idx_encode(closid, rmid);
+
+ mon_idx = mon->mbwu_idx_to_mon[mbwu_idx];
+ if (mon_idx == -1) {
+ if (mpam_resctrl_abmc_enabled()) {
+ /* Report Unassigned */
+ return -ENOENT;
+ }
+ /* Report Unavailable */
+ return -EINVAL;
+ }
+ }
+
+ if (irqs_disabled()) {
+ /* Check if we can access this domain without an IPI */
+ return -EIO;
+ }
+
+ cfg = (struct mon_cfg) {
+ .mon = mon_idx,
+ .match_pmg = true,
+ .partid = closid,
+ .pmg = rmid,
+ };
+
+ return mpam_msmon_read(mon_comp, &cfg, mon_type, val);
+}+/* MBWU when not in ABMC mode, and CSU counters. */ +int resctrl_arch_rmid_read(struct rdt_resource *r, struct rdt_mon_domain *d,
Odd tab before *r.
+ u32 closid, u32 rmid, enum resctrl_event_id eventid,
+ u64 *val, void *arch_mon_ctx)
+{
+ struct mpam_resctrl_dom *l3_dom;
+ struct mpam_component *mon_comp;
+ u32 mon_idx = *(u32 *)arch_mon_ctx;
+ enum mpam_device_features mon_type;
+ struct mpam_resctrl_mon *mon = &mpam_resctrl_counters[eventid];
+
+ resctrl_arch_rmid_read_context_check();
+
+ if (eventid >= QOS_NUM_EVENTS || !mon->class)
+ return -EINVAL;
+
+ l3_dom = container_of(d, struct mpam_resctrl_dom, resctrl_mon_dom);
+ mon_comp = l3_dom->mon_comp[eventid];
+
+ switch (eventid) {
+ case QOS_L3_OCCUP_EVENT_ID:
+ mon_type = mpam_feat_msmon_csu;
+ break;
+ case QOS_L3_MBM_LOCAL_EVENT_ID:
+ case QOS_L3_MBM_TOTAL_EVENT_ID:
+ mon_type = mpam_feat_msmon_mbwu;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return read_mon_cdp_safe(mon, mon_comp, mon_type, mon_idx,
+ closid, rmid, val);
+}