[PATCH v8 next 10/10] arm_mpam: Add mpam_sync_config() for dynamic rmid expansion

[Zeng Heng]

Add mpam_sync_config() to synchronize configuration when dynamically
expanding rmid resources. When binding a new reqpartid to a control group,
the driver maps the reqpartid to the corresponding intpartid or applies
the control group's existing configuration to new partid if without
Narrow-PARTID feature.

Extend mpam_apply_config() with the 'sync' work mode:
  * Sync mode: mpam_sync_config() calls this to apply existing
    configuration without updating config.
  * Update (non-sync) mode: resctrl_arch_update_one() calls this to
    compare, update, and apply configuration. This mode retains the
    original behavior.

Signed-off-by: Zeng Heng <zengheng4@xxxxxxxxxx>
---
 drivers/resctrl/mpam_devices.c  | 23 ++++++++++++++++++-----
 drivers/resctrl/mpam_internal.h |  2 +-
 drivers/resctrl/mpam_resctrl.c  | 29 ++++++++++++++++++++++++++---
 3 files changed, 45 insertions(+), 9 deletions(-)

diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c
index cf94b45b4f9e..47345b8add3c 100644
--- a/drivers/resctrl/mpam_devices.c
+++ b/drivers/resctrl/mpam_devices.c
@@ -1762,6 +1762,7 @@ struct mpam_write_config_arg {
 	struct mpam_msc_ris *ris;
 	struct mpam_component *comp;
 	u16 partid;
+	bool sync;
 };
 
 static int __write_config(void *arg)
@@ -1770,6 +1771,15 @@ static int __write_config(void *arg)
 	struct mpam_write_config_arg *c = arg;
 	u32 reqpartid;
 
+	if (c->sync) {
+		/* c->partid should be within the range of reqPARTIDs */
+		WARN_ON_ONCE(c->partid < closid_num);
+
+		mpam_reprogram_ris_partid(c->ris, c->partid,
+					 &c->comp->cfg[req2intpartid(c->partid)]);
+		return 0;
+	}
+
 	/* c->partid should be within the range of intPARTIDs */
 	WARN_ON_ONCE(c->partid >= closid_num);
 
@@ -2942,7 +2952,7 @@ static bool mpam_update_config(struct mpam_config *cfg,
 }
 
 int mpam_apply_config(struct mpam_component *comp, u16 partid,
-		      struct mpam_config *cfg)
+		      struct mpam_config *cfg, bool sync)
 {
 	struct mpam_write_config_arg arg;
 	struct mpam_msc_ris *ris;
@@ -2951,14 +2961,17 @@ int mpam_apply_config(struct mpam_component *comp, u16 partid,
 
 	lockdep_assert_cpus_held();
 
-	/* Don't pass in the current config! */
-	WARN_ON_ONCE(&comp->cfg[partid] == cfg);
+	if (!sync) {
+		/* The partid is within the range of intPARTIDs */
+		WARN_ON_ONCE(partid >= resctrl_arch_get_num_closid(NULL));
 
-	if (!mpam_update_config(&comp->cfg[partid], cfg))
-		return 0;
+		if (!mpam_update_config(&comp->cfg[partid], cfg))
+			return 0;
+	}
 
 	arg.comp = comp;
 	arg.partid = partid;
+	arg.sync = sync;
 
 	guard(srcu)(&mpam_srcu);
 	list_for_each_entry_srcu(vmsc, &comp->vmsc, comp_list,
diff --git a/drivers/resctrl/mpam_internal.h b/drivers/resctrl/mpam_internal.h
index 16ce968344d0..90c8f8d16c79 100644
--- a/drivers/resctrl/mpam_internal.h
+++ b/drivers/resctrl/mpam_internal.h
@@ -464,7 +464,7 @@ void mpam_disable(struct work_struct *work);
 void mpam_reset_class_locked(struct mpam_class *class);
 
 int mpam_apply_config(struct mpam_component *comp, u16 partid,
-		      struct mpam_config *cfg);
+		      struct mpam_config *cfg, bool sync);
 
 int mpam_msmon_read(struct mpam_component *comp, struct mon_cfg *ctx,
 		    enum mpam_device_features, u64 *val);
diff --git a/drivers/resctrl/mpam_resctrl.c b/drivers/resctrl/mpam_resctrl.c
index 2762462d80e5..5a97a7f18670 100644
--- a/drivers/resctrl/mpam_resctrl.c
+++ b/drivers/resctrl/mpam_resctrl.c
@@ -1329,15 +1329,15 @@ int resctrl_arch_update_one(struct rdt_resource *r, struct rdt_ctrl_domain *d,
 	 */
 	if (mpam_resctrl_hide_cdp(r->rid)) {
 		partid = resctrl_get_config_index(closid, CDP_CODE);
-		err = mpam_apply_config(dom->ctrl_comp, partid, &cfg);
+		err = mpam_apply_config(dom->ctrl_comp, partid, &cfg, false);
 		if (err)
 			return err;
 
 		partid = resctrl_get_config_index(closid, CDP_DATA);
-		return mpam_apply_config(dom->ctrl_comp, partid, &cfg);
+		return mpam_apply_config(dom->ctrl_comp, partid, &cfg, false);
 	}
 
-	return mpam_apply_config(dom->ctrl_comp, partid, &cfg);
+	return mpam_apply_config(dom->ctrl_comp, partid, &cfg, false);
 }
 
 int resctrl_arch_update_domains(struct rdt_resource *r, u32 closid)
@@ -1718,6 +1718,23 @@ static void update_rmid_entries_for_reqpartid(u32 reqpartid)
 		rmid_entry_reassign_closid(closid, req_pmg2rmid(reqpartid, pmg));
 }
 
+static int mpam_sync_config(u32 reqpartid)
+{
+	struct mpam_component *comp;
+	struct mpam_class *class;
+	int err;
+
+	list_for_each_entry(class, &mpam_classes, classes_list) {
+		list_for_each_entry(comp, &class->components, class_list) {
+			err = mpam_apply_config(comp, reqpartid, NULL, true);
+			if (err)
+				return err;
+		}
+	}
+
+	return 0;
+}
+
 int resctrl_arch_rmid_expand(u32 closid)
 {
 	int i;
@@ -1729,14 +1746,20 @@ int resctrl_arch_rmid_expand(u32 closid)
 		if (reqpartid_map[i] >= resctrl_arch_get_num_closid(NULL)) {
 			if (cdp_enabled) {
 				reqpartid_map[i] = resctrl_get_config_index(closid, CDP_DATA);
+				mpam_sync_config(i);
+
 				/*
 				 * Reqpartids are always allocated in
 				 * pairs, never out-of-bounds access.
 				 */
 				reqpartid_map[i + 1] = resctrl_get_config_index(closid, CDP_CODE);
+				mpam_sync_config(i + 1);
+
 			} else {
 				reqpartid_map[i] = resctrl_get_config_index(closid, CDP_NONE);
+				mpam_sync_config(i);
 			}
+
 			update_rmid_entries_for_reqpartid(i);
 			return i;
 		}
-- 
2.25.1