x86,fs/resctrl: Handle domain creation/deletion for RDT_RESOURCE_PERF_PKG

The L3 resource has several requirements for domains. There are per-domain
structures that hold the 64-bit values of counters, and elements to keep
track of the overflow and limbo threads.

None of these are needed for the PERF_PKG resource. The hardware counters
are wide enough that they do not wrap around for decades.

Define a new rdt_perf_pkg_mon_domain structure which just consists of the
standard rdt_domain_hdr to keep track of domain id and CPU mask.

Update resctrl_online_mon_domain() for RDT_RESOURCE_PERF_PKG. The only action
needed for this resource is to create and populate domain directories if a
domain is added while resctrl is mounted.

Similarly resctrl_offline_mon_domain() only needs to remove domain directories.

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

Author: aegl

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

@@ -580,6 +580,10 @@ static void domain_add_cpu_mon(int cpu, struct rdt_resource *r)
 		if (!hdr)
 			l3_mon_domain_setup(cpu, id, r, add_pos);
 		break;
+	case RDT_RESOURCE_PERF_PKG:
+		if (!hdr)
+			intel_aet_mon_domain_setup(cpu, id, r, add_pos);
+		break;
 	default:
 		pr_warn_once("Unknown resource rid=%d\n", r->rid);
 		break;
@@ -679,6 +683,19 @@ static void domain_remove_cpu_mon(int cpu, struct rdt_resource *r)
 		l3_mon_domain_free(hw_dom);
 		break;
 	}
+	case RDT_RESOURCE_PERF_PKG: {
+		struct rdt_perf_pkg_mon_domain *pkgd;
+
+		if (!domain_header_is_valid(hdr, RESCTRL_MON_DOMAIN, RDT_RESOURCE_PERF_PKG))
+			return;
+
+		pkgd = container_of(hdr, struct rdt_perf_pkg_mon_domain, hdr);
+		resctrl_offline_mon_domain(r, hdr);
+		list_del_rcu(&hdr->list);
+		synchronize_rcu();
+		kfree(pkgd);
+		break;
+	}
 	default:
 		pr_warn_once("Unknown resource rid=%d\n", r->rid);
 		break;

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

@@ -14,15 +14,20 @@
 #include <linux/bits.h>
 #include <linux/compiler_types.h>
 #include <linux/container_of.h>
+#include <linux/cpumask.h>
 #include <linux/err.h>
 #include <linux/errno.h>
+#include <linux/gfp_types.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/rculist.h>
+#include <linux/rcupdate.h>
 #include <linux/resctrl.h>
 #include <linux/resctrl_types.h>
+#include <linux/slab.h>
 #include <linux/stddef.h>
 #include <linux/topology.h>
 #include <linux/types.h>
@@ -283,3 +288,27 @@ int intel_aet_read_event(int domid, u32 rmid, void *arch_priv, u64 *val)
 
 	return valid ? 0 : -EINVAL;
 }
+
+void intel_aet_mon_domain_setup(int cpu, int id, struct rdt_resource *r,
+				struct list_head *add_pos)
+{
+	struct rdt_perf_pkg_mon_domain *d;
+	int err;
+
+	d = kzalloc_node(sizeof(*d), GFP_KERNEL, cpu_to_node(cpu));
+	if (!d)
+		return;
+
+	d->hdr.id = id;
+	d->hdr.type = RESCTRL_MON_DOMAIN;
+	d->hdr.rid = RDT_RESOURCE_PERF_PKG;
+	cpumask_set_cpu(cpu, &d->hdr.cpu_mask);
+	list_add_tail_rcu(&d->hdr.list, add_pos);
+
+	err = resctrl_online_mon_domain(r, &d->hdr);
+	if (err) {
+		list_del_rcu(&d->hdr.list);
+		synchronize_rcu();
+		kfree(d);
+	}
+}

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

@@ -87,6 +87,14 @@ static inline struct rdt_hw_l3_mon_domain *resctrl_to_arch_mon_dom(struct rdt_l3
 	return container_of(r, struct rdt_hw_l3_mon_domain, d_resctrl);
 }
 
+/**
+ * struct rdt_perf_pkg_mon_domain - CPUs sharing an package scoped resctrl monitor resource
+ * @hdr:	common header for different domain types
+ */
+struct rdt_perf_pkg_mon_domain {
+	struct rdt_domain_hdr	hdr;
+};
+
 /**
  * struct msr_param - set a range of MSRs from a domain
  * @res:       The resource to use
@@ -226,13 +234,18 @@ void resctrl_arch_mbm_cntr_assign_set_one(struct rdt_resource *r);
 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);
+void intel_aet_mon_domain_setup(int cpu, int id, struct rdt_resource *r,
+				struct list_head *add_pos);
 #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;
 }
+
+static inline void intel_aet_mon_domain_setup(int cpu, int id, struct rdt_resource *r,
+					      struct list_head *add_pos) { }
 #endif
 
 #endif /* _ASM_X86_RESCTRL_INTERNAL_H */

fs/resctrl/rdtgroup.c

@@ -4308,18 +4308,20 @@ void resctrl_offline_mon_domain(struct rdt_resource *r, struct rdt_domain_hdr *h
 
 	mutex_lock(&rdtgroup_mutex);
 
-	if (!domain_header_is_valid(hdr, RESCTRL_MON_DOMAIN, RDT_RESOURCE_L3))
-		goto out_unlock;
-
-	d = container_of(hdr, struct rdt_l3_mon_domain, hdr);
-
 	/*
 	 * If resctrl is mounted, remove all the
 	 * per domain monitor data directories.
 	 */
 	if (resctrl_mounted && resctrl_arch_mon_capable())
 		rmdir_mondata_subdir_allrdtgrp(r, hdr);
 
+	if (r->rid != RDT_RESOURCE_L3)
+		goto out_unlock;
+
+	if (!domain_header_is_valid(hdr, RESCTRL_MON_DOMAIN, RDT_RESOURCE_L3))
+		goto out_unlock;
+
+	d = container_of(hdr, struct rdt_l3_mon_domain, hdr);
 	if (resctrl_is_mbm_enabled())
 		cancel_delayed_work(&d->mbm_over);
 	if (resctrl_is_mon_event_enabled(QOS_L3_OCCUP_EVENT_ID) && has_busy_rmid(d)) {
@@ -4416,6 +4418,9 @@ int resctrl_online_mon_domain(struct rdt_resource *r, struct rdt_domain_hdr *hdr
 
 	mutex_lock(&rdtgroup_mutex);
 
+	if (r->rid != RDT_RESOURCE_L3)
+		goto mkdir;
+
 	if (!domain_header_is_valid(hdr, RESCTRL_MON_DOMAIN, RDT_RESOURCE_L3))
 		goto out_unlock;
 
@@ -4433,6 +4438,8 @@ int resctrl_online_mon_domain(struct rdt_resource *r, struct rdt_domain_hdr *hdr
 	if (resctrl_is_mon_event_enabled(QOS_L3_OCCUP_EVENT_ID))
 		INIT_DELAYED_WORK(&d->cqm_limbo, cqm_handle_limbo);
 
+mkdir:
+	err = 0;
 	/*
 	 * If the filesystem is not mounted then only the default resource group
 	 * exists. Creation of its directories is deferred until mount time