linux-kernel - [PATCH v5 18/29] x86/resctrl: Count valid telemetry aggregators per package

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Message-ID: <20250521225049.132551-19-tony.luck@intel.com>
Date: Wed, 21 May 2025 15:50:36 -0700
From: Tony Luck <tony.luck@...el.com>
To: Fenghua Yu <fenghuay@...dia.com>,
	Reinette Chatre <reinette.chatre@...el.com>,
	Maciej Wieczor-Retman <maciej.wieczor-retman@...el.com>,
	Peter Newman <peternewman@...gle.com>,
	James Morse <james.morse@....com>,
	Babu Moger <babu.moger@....com>,
	Drew Fustini <dfustini@...libre.com>,
	Dave Martin <Dave.Martin@....com>,
	Anil Keshavamurthy <anil.s.keshavamurthy@...el.com>,
	Chen Yu <yu.c.chen@...el.com>
Cc: x86@...nel.org,
	linux-kernel@...r.kernel.org,
	patches@...ts.linux.dev,
	Tony Luck <tony.luck@...el.com>
Subject: [PATCH v5 18/29] x86/resctrl: Count valid telemetry aggregators per package

There may be multiple telemetry aggregators per package, each enumerated
by a telemetry region structure in the feature group.

Scan the array of telemetry region structures and count how many are
in each package in preparation to allocate structures to save the MMIO
addresses for each in a convenient format for use when reading event
counters.

Sanity check that the telemetry region structures have a valid
package_id and that the size they report for the MMIO space is as
large as expected from the XML description of the registers in
the region.

Signed-off-by: Tony Luck <tony.luck@...el.com>
---
 arch/x86/kernel/cpu/resctrl/intel_aet.c | 45 ++++++++++++++++++++++++-
 1 file changed, 44 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/resctrl/intel_aet.c b/arch/x86/kernel/cpu/resctrl/intel_aet.c
index df73b9476c4d..ffcb54be54ea 100644
--- a/arch/x86/kernel/cpu/resctrl/intel_aet.c
+++ b/arch/x86/kernel/cpu/resctrl/intel_aet.c
@@ -14,6 +14,7 @@
 #include <linux/cleanup.h>
 #include <linux/cpu.h>
 #include <linux/resctrl.h>
+#include <linux/slab.h>
 
 /* Temporary - delete from final version */
 #include "fake_intel_aet_features.h"
@@ -26,6 +27,7 @@
  *			within the OOBMSM driver that contains data for all
  *			telemetry regions.
  * @guid:		Unique number per XML description file.
+ * @mmio_size:		Number of bytes of MMIO registers for this group.
  */
 struct event_group {
 	/* Data fields used by this code. */
@@ -33,6 +35,7 @@ struct event_group {
 
 	/* Remaining fields initialized from XML file. */
 	u32				guid;
+	size_t				mmio_size;
 };
 
 /*
@@ -41,6 +44,7 @@ struct event_group {
  */
 static struct event_group energy_0x26696143 = {
 	.guid		= 0x26696143,
+	.mmio_size	= (576 * 2 + 3) * 8,
 };
 
 /*
@@ -49,6 +53,7 @@ static struct event_group energy_0x26696143 = {
  */
 static struct event_group perf_0x26557651 = {
 	.guid		= 0x26557651,
+	.mmio_size	= (576 * 7 + 3) * 8,
 };
 
 static struct event_group *known_event_groups[] = {
@@ -58,9 +63,47 @@ static struct event_group *known_event_groups[] = {
 
 #define NUM_KNOWN_GROUPS ARRAY_SIZE(known_event_groups)
 
-/* Stub for now */
+static bool skip_this_region(struct telemetry_region *tr, struct event_group *e)
+{
+	if (tr->guid != e->guid)
+		return true;
+	if (tr->plat_info.package_id >= topology_max_packages()) {
+		pr_warn_once("Bad package %d in guid 0x%x\n", tr->plat_info.package_id,
+			     tr->guid);
+		return true;
+	}
+	if (tr->size < e->mmio_size) {
+		pr_warn_once("MMIO space too small for guid 0x%x\n", e->guid);
+		return true;
+	}
+
+	return false;
+}
+
+/*
+ * Configure events from one pmt_feature_group.
+ * 1) Count how many per package.
+ * 2...) To be continued.
+ */
 static int configure_events(struct event_group *e, struct pmt_feature_group *p)
 {
+	int *pkgcounts __free(kfree) = NULL;
+	struct telemetry_region *tr;
+	int num_pkgs;
+
+	num_pkgs = topology_max_packages();
+	pkgcounts = kcalloc(num_pkgs, sizeof(*pkgcounts), GFP_KERNEL);
+	if (!pkgcounts)
+		return -ENOMEM;
+
+	/* Get per-package counts of telemetry_regions for this event group */
+	for (int i = 0; i < p->count; i++) {
+		tr = &p->regions[i];
+		if (skip_this_region(tr, e))
+			continue;
+		pkgcounts[tr->plat_info.package_id]++;
+	}
+
 	return -EINVAL;
 }
 
-- 
2.49.0