[PATCH v8 next 02/10] arm_mpam: Add intPARTID and reqPARTID support for Narrow-PARTID feature

[Zeng Heng <zengheng4@huawei.com>]

Introduce Narrow-PARTID (partid_nrw) feature support, which enables
many-to-one mapping of request PARTIDs (reqPARTID) to internal PARTIDs
(intPARTID). This expands monitoring capability by allowing a single
control group to track more task types through multiple reqPARTIDs
per intPARTID, bypassing the PMG limit in some extent.

intPARTID: Internal PARTID used for control group configuration.
Configurations are synchronized to all reqPARTIDs mapped to the same
intPARTID. Count is indicated by MPAMF_PARTID_NRW_IDR.INTPARTID_MAX, or
defaults to PARTID count if Narrow-PARTID is unsupported.

reqPARTID: Request PARTID used to expand monitoring groups. Enables
a single control group to monitor more task types by multiple reqPARTIDs
within one intPARTID, overcoming the PMG count limitation.

For systems with homogeneous MSCs (all supporting Narrow-PARTID), the
driver exposes the full reqPARTID range directly. For heterogeneous
systems where some MSCs lack Narrow-PARTID support, the driver utilizes
PARTIDs beyond the intPARTID range as reqPARTIDs to expand monitoring
capacity.

So, the numbers of control group and monitoring group are calculated as:

  n = min(intPARTID, PARTID)  /* the number of control groups */
  l = min(reqPARTID, PARTID)  /* the number of monitoring groups */
  m = l // n                  /* monitoring groups per control group */

Where:

  intPARTID: intPARTIDs on Narrow-PARTID-capable MSCs
  reqPARTID: reqPARTIDs on Narrow-PARTID-capable MSCs
  PARTID:    PARTIDs on non-Narrow-PARTID-capable MSCs

Example: L3 cache (256 PARTIDs, without Narrow-PARTID feature) +
         MATA (32 intPARTIDs, 256 reqPARTIDs):

  n = min( 32, 256) =  32 intPARTIDs
  l = min(256, 256) = 256 reqPARTIDs
  m = 256 / 32 = 8 reqPARTIDs per intPARTID

Implementation notes:
  * Handle mixed MSC systems (some support Narrow-PARTID, some don't) by
    taking minimum number of intPARTIDs across all MSCs.
  * resctrl_arch_get_num_closid() now returns the number of intPARTIDs
    (was PARTID).

Signed-off-by: Zeng Heng <zengheng4@huawei.com>
---
 drivers/resctrl/mpam_devices.c  | 30 ++++++++++++++++++++----------
 drivers/resctrl/mpam_internal.h |  2 ++
 drivers/resctrl/mpam_resctrl.c  |  4 ++--
 3 files changed, 24 insertions(+), 12 deletions(-)

diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c
index 41b14344b16f..cf067bf5092e 100644
--- a/drivers/resctrl/mpam_devices.c
+++ b/drivers/resctrl/mpam_devices.c
@@ -63,6 +63,7 @@ static DEFINE_MUTEX(mpam_cpuhp_state_lock);
  * Generating traffic outside this range will result in screaming interrupts.
  */
 u16 mpam_partid_max;
+u16 mpam_intpartid_max;
 u8 mpam_pmg_max;
 static bool partid_max_init, partid_max_published;
 static DEFINE_SPINLOCK(partid_max_lock);
@@ -288,10 +289,12 @@ int mpam_register_requestor(u16 partid_max, u8 pmg_max)
 {
 	guard(spinlock)(&partid_max_lock);
 	if (!partid_max_init) {
+		mpam_intpartid_max = partid_max;
 		mpam_partid_max = partid_max;
 		mpam_pmg_max = pmg_max;
 		partid_max_init = true;
 	} else if (!partid_max_published) {
+		mpam_intpartid_max = min(mpam_intpartid_max, partid_max);
 		mpam_partid_max = min(mpam_partid_max, partid_max);
 		mpam_pmg_max = min(mpam_pmg_max, pmg_max);
 	} else {
@@ -931,7 +934,9 @@ static void mpam_ris_hw_probe(struct mpam_msc_ris *ris)
 		u16 partid_max = FIELD_GET(MPAMF_PARTID_NRW_IDR_INTPARTID_MAX, nrwidr);
 
 		mpam_set_feature(mpam_feat_partid_nrw, props);
-		msc->partid_max = min(msc->partid_max, partid_max);
+		msc->intpartid_max = min(msc->partid_max, partid_max);
+	} else {
+		msc->intpartid_max = msc->partid_max;
 	}
 }
 
@@ -995,6 +1000,7 @@ static int mpam_msc_hw_probe(struct mpam_msc *msc)
 
 	spin_lock(&partid_max_lock);
 	mpam_partid_max = min(mpam_partid_max, msc->partid_max);
+	mpam_intpartid_max = min(mpam_intpartid_max, msc->intpartid_max);
 	mpam_pmg_max = min(mpam_pmg_max, msc->pmg_max);
 	spin_unlock(&partid_max_lock);
 
@@ -1711,7 +1717,7 @@ static int mpam_reset_ris(void *arg)
 		return 0;
 
 	spin_lock(&partid_max_lock);
-	partid_max = mpam_partid_max;
+	partid_max = mpam_intpartid_max;
 	spin_unlock(&partid_max_lock);
 	for (partid = 0; partid <= partid_max; partid++)
 		mpam_reprogram_ris_partid(ris, partid, &reset_cfg);
@@ -1767,7 +1773,7 @@ static void mpam_reprogram_msc(struct mpam_msc *msc)
 	struct mpam_write_config_arg arg;
 
 	/*
-	 * No lock for mpam_partid_max as partid_max_published has been
+	 * No lock for mpam_intpartid_max as partid_max_published has been
 	 * set by mpam_enabled(), so the values can no longer change.
 	 */
 	mpam_assert_partid_sizes_fixed();
@@ -1784,7 +1790,7 @@ static void mpam_reprogram_msc(struct mpam_msc *msc)
 		arg.comp = ris->vmsc->comp;
 		arg.ris = ris;
 		reset = true;
-		for (partid = 0; partid <= mpam_partid_max; partid++) {
+		for (partid = 0; partid <= mpam_intpartid_max; partid++) {
 			cfg = &ris->vmsc->comp->cfg[partid];
 			if (!bitmap_empty(cfg->features, MPAM_FEATURE_LAST))
 				reset = false;
@@ -2607,7 +2613,7 @@ static void mpam_reset_component_cfg(struct mpam_component *comp)
 	if (!comp->cfg)
 		return;
 
-	for (i = 0; i <= mpam_partid_max; i++) {
+	for (i = 0; i <= mpam_intpartid_max; i++) {
 		comp->cfg[i] = (struct mpam_config) {};
 		if (cprops->cpbm_wd)
 			comp->cfg[i].cpbm = GENMASK(cprops->cpbm_wd - 1, 0);
@@ -2627,7 +2633,7 @@ static int __allocate_component_cfg(struct mpam_component *comp)
 	if (comp->cfg)
 		return 0;
 
-	comp->cfg = kzalloc_objs(*comp->cfg, mpam_partid_max + 1);
+	comp->cfg = kzalloc_objs(*comp->cfg, mpam_intpartid_max + 1);
 	if (!comp->cfg)
 		return -ENOMEM;
 
@@ -2694,7 +2700,7 @@ static void mpam_enable_once(void)
 	int err;
 
 	/*
-	 * Once the cpuhp callbacks have been changed, mpam_partid_max can no
+	 * Once the cpuhp callbacks have been changed, mpam_intpartid_max can no
 	 * longer change.
 	 */
 	spin_lock(&partid_max_lock);
@@ -2743,9 +2749,13 @@ static void mpam_enable_once(void)
 	mpam_register_cpuhp_callbacks(mpam_cpu_online, mpam_cpu_offline,
 				      "mpam:online");
 
-	/* Use printk() to avoid the pr_fmt adding the function name. */
-	printk(KERN_INFO "MPAM enabled with %u PARTIDs and %u PMGs\n",
-	       mpam_partid_max + 1, mpam_pmg_max + 1);
+	if (mpam_partid_max == mpam_intpartid_max)
+		/* Use printk() to avoid the pr_fmt adding the function name. */
+		printk(KERN_INFO "MPAM enabled with %u PARTIDs and %u PMGs\n",
+		       mpam_partid_max + 1, mpam_pmg_max + 1);
+	else
+		printk(KERN_INFO "MPAM enabled with %u reqPARTIDs, %u intPARTIDs and %u PMGs\n",
+		       mpam_partid_max + 1, mpam_intpartid_max + 1, mpam_pmg_max + 1);
 }
 
 static void mpam_reset_component_locked(struct mpam_component *comp)
diff --git a/drivers/resctrl/mpam_internal.h b/drivers/resctrl/mpam_internal.h
index 1914aefdcba9..790a90a5ccd9 100644
--- a/drivers/resctrl/mpam_internal.h
+++ b/drivers/resctrl/mpam_internal.h
@@ -81,6 +81,7 @@ struct mpam_msc {
 	 */
 	struct mutex		probe_lock;
 	bool			probed;
+	u16			intpartid_max;
 	u16			partid_max;
 	u8			pmg_max;
 	unsigned long		ris_idxs;
@@ -452,6 +453,7 @@ extern struct list_head mpam_classes;
 
 /* System wide partid/pmg values */
 extern u16 mpam_partid_max;
+extern u16 mpam_intpartid_max;
 extern u8 mpam_pmg_max;
 
 /* Scheduled work callback to enable mpam once all MSC have been probed */
diff --git a/drivers/resctrl/mpam_resctrl.c b/drivers/resctrl/mpam_resctrl.c
index 161fb8905e28..5f4364c8101a 100644
--- a/drivers/resctrl/mpam_resctrl.c
+++ b/drivers/resctrl/mpam_resctrl.c
@@ -223,7 +223,7 @@ int resctrl_arch_set_cdp_enabled(enum resctrl_res_level rid, bool enable)
 		mpam_resctrl_controls[RDT_RESOURCE_MBA].resctrl_res.alloc_capable = false;
 
 	if (enable) {
-		if (mpam_partid_max < 1)
+		if (mpam_intpartid_max < 1)
 			return -EINVAL;
 
 		partid_d = resctrl_get_config_index(RESCTRL_RESERVED_CLOSID, CDP_DATA);
@@ -254,7 +254,7 @@ static bool mpam_resctrl_hide_cdp(enum resctrl_res_level rid)
  */
 u32 resctrl_arch_get_num_closid(struct rdt_resource *ignored)
 {
-	return mpam_partid_max + 1;
+	return mpam_intpartid_max + 1;
 }
 
 u32 resctrl_arch_system_num_rmid_idx(void)
-- 
2.25.1