x86/resctrl: Read telemetry events

Introduce intel_aet_read_event() to read telemetry events for resource
RDT_RESOURCE_PERF_PKG. There may be multiple aggregators tracking each
package, so scan all of them and add up all counters. Aggregators may return
an invalid data indication if they have received no records for a given RMID.
The user will see "Unavailable" if none of the aggregators on a package
provide valid counts.

Resctrl now uses readq() so depends on X86_64. Update Kconfig.

Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lore.kernel.org/20251217172121.12030-1-tony.luck@intel.com

arch/x86/Kconfig

@@ -542,7 +542,7 @@ config X86_CPU_RESCTRL
 
 config X86_CPU_RESCTRL_INTEL_AET
 	bool "Intel Application Energy Telemetry"
-	depends on X86_CPU_RESCTRL && CPU_SUP_INTEL && INTEL_PMT_TELEMETRY=y && INTEL_TPMI=y
+	depends on X86_64 && X86_CPU_RESCTRL && CPU_SUP_INTEL && INTEL_PMT_TELEMETRY=y && INTEL_TPMI=y
 	help
 	  Enable per-RMID telemetry events in resctrl.
 

arch/x86/kernel/cpu/resctrl/intel_aet.c

@@ -11,11 +11,15 @@
 
 #define pr_fmt(fmt)   "resctrl: " fmt
 
+#include <linux/bits.h>
 #include <linux/compiler_types.h>
+#include <linux/container_of.h>
 #include <linux/err.h>
+#include <linux/errno.h>
 #include <linux/init.h>
 #include <linux/intel_pmt_features.h>
 #include <linux/intel_vsec.h>
+#include <linux/io.h>
 #include <linux/printk.h>
 #include <linux/resctrl.h>
 #include <linux/resctrl_types.h>
@@ -232,3 +236,50 @@ void __exit intel_aet_exit(void)
 		}
 	}
 }
+
+#define DATA_VALID	BIT_ULL(63)
+#define DATA_BITS	GENMASK_ULL(62, 0)
+
+/*
+ * Read counter for an event on a domain (summing all aggregators on the
+ * domain). If an aggregator hasn't received any data for a specific RMID,
+ * the MMIO read indicates that data is not valid.  Return success if at
+ * least one aggregator has valid data.
+ */
+int intel_aet_read_event(int domid, u32 rmid, void *arch_priv, u64 *val)
+{
+	struct pmt_event *pevt = arch_priv;
+	struct event_group *e;
+	bool valid = false;
+	u64 total = 0;
+	u64 evtcount;
+	void *pevt0;
+	u32 idx;
+
+	pevt0 = pevt - pevt->idx;
+	e = container_of(pevt0, struct event_group, evts);
+	idx = rmid * e->num_events;
+	idx += pevt->idx;
+
+	if (idx * sizeof(u64) + sizeof(u64) > e->mmio_size) {
+		pr_warn_once("MMIO index %u out of range\n", idx);
+		return -EIO;
+	}
+
+	for (int i = 0; i < e->pfg->count; i++) {
+		if (!e->pfg->regions[i].addr)
+			continue;
+		if (e->pfg->regions[i].plat_info.package_id != domid)
+			continue;
+		evtcount = readq(e->pfg->regions[i].addr + idx * sizeof(u64));
+		if (!(evtcount & DATA_VALID))
+			continue;
+		total += evtcount & DATA_BITS;
+		valid = true;
+	}
+
+	if (valid)
+		*val = total;
+
+	return valid ? 0 : -EINVAL;
+}

arch/x86/kernel/cpu/resctrl/internal.h

@@ -225,9 +225,14 @@ void resctrl_arch_mbm_cntr_assign_set_one(struct rdt_resource *r);
 #ifdef CONFIG_X86_CPU_RESCTRL_INTEL_AET
 bool intel_aet_get_events(void);
 void __exit intel_aet_exit(void);
+int intel_aet_read_event(int domid, u32 rmid, void *arch_priv, u64 *val);
 #else
 static inline bool intel_aet_get_events(void) { return false; }
 static inline void __exit intel_aet_exit(void) { }
+static inline int intel_aet_read_event(int domid, u32 rmid, void *arch_priv, u64 *val)
+{
+	return -EINVAL;
+}
 #endif
 
 #endif /* _ASM_X86_RESCTRL_INTERNAL_H */

arch/x86/kernel/cpu/resctrl/monitor.c

@@ -251,6 +251,10 @@ int resctrl_arch_rmid_read(struct rdt_resource *r, struct rdt_domain_hdr *hdr,
 	int ret;
 
 	resctrl_arch_rmid_read_context_check();
+
+	if (r->rid == RDT_RESOURCE_PERF_PKG)
+		return intel_aet_read_event(hdr->id, rmid, arch_priv, val);
+
 	if (!domain_header_is_valid(hdr, RESCTRL_MON_DOMAIN, RDT_RESOURCE_L3))
 		return -EINVAL;
 

fs/resctrl/monitor.c

@@ -527,6 +527,20 @@ static int __mon_event_count(struct rdtgroup *rdtgrp, struct rmid_read *rr)
 			return __l3_mon_event_count(rdtgrp, rr);
 		else
 			return __l3_mon_event_count_sum(rdtgrp, rr);
+	case RDT_RESOURCE_PERF_PKG: {
+		u64 tval = 0;
+
+		rr->err = resctrl_arch_rmid_read(rr->r, rr->hdr, rdtgrp->closid,
+						 rdtgrp->mon.rmid, rr->evt->evtid,
+						 rr->evt->arch_priv,
+						 &tval, rr->arch_mon_ctx);
+		if (rr->err)
+			return rr->err;
+
+		rr->val += tval;
+
+		return 0;
+	}
 	default:
 		rr->err = -EINVAL;
 		return -EINVAL;