x86/resctrl: Access per-rmid structures by index

x86 systems identify traffic using the CLOSID and RMID. The CLOSID is
used to lookup the control policy, the RMID is used for monitoring. For
x86 these are independent numbers.
Arm's MPAM has equivalent features PARTID and PMG, where the PARTID is
used to lookup the control policy. The PMG in contrast is a small number
of bits that are used to subdivide PARTID when monitoring. The
cache-occupancy monitors require the PARTID to be specified when
monitoring.

This means MPAM's PMG field is not unique. There are multiple PMG-0, one
per allocated CLOSID/PARTID. If PMG is treated as equivalent to RMID, it
cannot be allocated as an independent number. Bitmaps like rmid_busy_llc
need to be sized by the number of unique entries for this resource.

Treat the combined CLOSID and RMID as an index, and provide architecture
helpers to pack and unpack an index. This makes the MPAM values unique.
The domain's rmid_busy_llc and rmid_ptrs[] are then sized by index, as
are domain mbm_local[] and mbm_total[].

x86 can ignore the CLOSID field when packing and unpacking an index, and
report as many indexes as RMID.

Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Shaopeng Tan <tan.shaopeng@fujitsu.com>
Reviewed-by: Babu Moger <babu.moger@amd.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Shaopeng Tan <tan.shaopeng@fujitsu.com>
Tested-by: Peter Newman <peternewman@google.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Tested-by: Carl Worth <carl@os.amperecomputing.com> # arm64
Link: https://lore.kernel.org/r/20240213184438.16675-7-james.morse@arm.com
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>

1 files changed, 7 insertions, 6 deletions

diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index ad7da7254f4d..a7dbc0e7e559 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -3853,8 +3853,8 @@ static void __init rdtgroup_setup_default(void)
 {
 	mutex_lock(&rdtgroup_mutex);
 
-	rdtgroup_default.closid = 0;
-	rdtgroup_default.mon.rmid = 0;
+	rdtgroup_default.closid = RESCTRL_RESERVED_CLOSID;
+	rdtgroup_default.mon.rmid = RESCTRL_RESERVED_RMID;
 	rdtgroup_default.type = RDTCTRL_GROUP;
 	INIT_LIST_HEAD(&rdtgroup_default.mon.crdtgrp_list);
 
@@ -3889,7 +3889,7 @@ void resctrl_offline_domain(struct rdt_resource *r, struct rdt_domain *d)
 
 	if (is_mbm_enabled())
 		cancel_delayed_work(&d->mbm_over);
-	if (is_llc_occupancy_enabled() && has_busy_rmid(r, d)) {
+	if (is_llc_occupancy_enabled() && has_busy_rmid(d)) {
 		/*
 		 * When a package is going down, forcefully
 		 * decrement rmid->ebusy. There is no way to know
@@ -3907,16 +3907,17 @@ void resctrl_offline_domain(struct rdt_resource *r, struct rdt_domain *d)
 
 static int domain_setup_mon_state(struct rdt_resource *r, struct rdt_domain *d)
 {
+	u32 idx_limit = resctrl_arch_system_num_rmid_idx();
 	size_t tsize;
 
 	if (is_llc_occupancy_enabled()) {
-		d->rmid_busy_llc = bitmap_zalloc(r->num_rmid, GFP_KERNEL);
+		d->rmid_busy_llc = bitmap_zalloc(idx_limit, GFP_KERNEL);
 		if (!d->rmid_busy_llc)
 			return -ENOMEM;
 	}
 	if (is_mbm_total_enabled()) {
 		tsize = sizeof(*d->mbm_total);
-		d->mbm_total = kcalloc(r->num_rmid, tsize, GFP_KERNEL);
+		d->mbm_total = kcalloc(idx_limit, tsize, GFP_KERNEL);
 		if (!d->mbm_total) {
 			bitmap_free(d->rmid_busy_llc);
 			return -ENOMEM;
@@ -3924,7 +3925,7 @@ static int domain_setup_mon_state(struct rdt_resource *r, struct rdt_domain *d)
 	}
 	if (is_mbm_local_enabled()) {
 		tsize = sizeof(*d->mbm_local);
-		d->mbm_local = kcalloc(r->num_rmid, tsize, GFP_KERNEL);
+		d->mbm_local = kcalloc(idx_limit, tsize, GFP_KERNEL);
 		if (!d->mbm_local) {
 			bitmap_free(d->rmid_busy_llc);
 			kfree(d->mbm_total);