[PATCH v15 23/34] fs/resctrl: Support counter read/reset with mbm_event assignment mode

[Babu Moger <babu.moger@amd.com>]

When "mbm_event" counter assignment mode is enabled, the architecture
requires a counter ID to read the event data.

Introduce an is_cntr field in struct rmid_read to indicate whether counter
assignment mode is in use.

Update the logic to call resctrl_arch_cntr_read() and
resctrl_arch_reset_cntr() when the assignment mode is active.

Declare mbm_cntr_get() in fs/resctrl/internal.h to make it accessible to
other functions within fs/resctrl.

Suggested-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Babu Moger <babu.moger@amd.com>
---
v15: New patch to add is_cntr in rmid_read as discussed in
     https://lore.kernel.org/lkml/b4b14670-9cb0-4f65-abd5-39db996e8da9@intel.com/
---
 fs/resctrl/ctrlmondata.c |  8 ++++++++
 fs/resctrl/internal.h    |  5 +++++
 fs/resctrl/monitor.c     | 42 +++++++++++++++++++++++++++++++++-------
 3 files changed, 48 insertions(+), 7 deletions(-)

diff --git a/fs/resctrl/ctrlmondata.c b/fs/resctrl/ctrlmondata.c
index ad7ffc6acf13..ce766b2cdfc1 100644
--- a/fs/resctrl/ctrlmondata.c
+++ b/fs/resctrl/ctrlmondata.c
@@ -569,6 +569,14 @@ void mon_event_read(struct rmid_read *rr, struct rdt_resource *r,
 		return;
 	}
 
+	if (resctrl_arch_mbm_cntr_assign_enabled(r) && resctrl_is_mbm_event(evtid)) {
+		if (mbm_cntr_get(r, d, rdtgrp, evtid) < 0) {
+			rr->err = -ENOENT;
+			return;
+		}
+		rr->is_cntr = true;
+	}
+
 	cpu = cpumask_any_housekeeping(cpumask, RESCTRL_PICK_ANY_CPU);
 
 	/*
diff --git a/fs/resctrl/internal.h b/fs/resctrl/internal.h
index 647a0466ffa0..fb4fec4a4cdc 100644
--- a/fs/resctrl/internal.h
+++ b/fs/resctrl/internal.h
@@ -110,6 +110,8 @@ struct mon_data {
  *	   domains in @r sharing L3 @ci.id
  * @evtid: Which monitor event to read.
  * @first: Initialize MBM counter when true.
+ * @is_cntr: Is the counter valid? true if "mbm_event" counter assignment mode is
+ *	   enabled and it is an MBM event.
  * @ci_id: Cacheinfo id for L3. Only set when @d is NULL. Used when summing domains.
  * @err:   Error encountered when reading counter.
  * @val:   Returned value of event counter. If @rgrp is a parent resource group,
@@ -124,6 +126,7 @@ struct rmid_read {
 	struct rdt_mon_domain	*d;
 	enum resctrl_event_id	evtid;
 	bool			first;
+	bool			is_cntr;
 	unsigned int		ci_id;
 	int			err;
 	u64			val;
@@ -391,6 +394,8 @@ int rdtgroup_assign_cntr_event(struct rdt_mon_domain *d, struct rdtgroup *rdtgrp
 			       struct mon_evt *mevt);
 void rdtgroup_unassign_cntr_event(struct rdt_mon_domain *d, struct rdtgroup *rdtgrp,
 				  struct mon_evt *mevt);
+int mbm_cntr_get(struct rdt_resource *r, struct rdt_mon_domain *d,
+		 struct rdtgroup *rdtgrp, enum resctrl_event_id evtid);
 
 #ifdef CONFIG_RESCTRL_FS_PSEUDO_LOCK
 int rdtgroup_locksetup_enter(struct rdtgroup *rdtgrp);
diff --git a/fs/resctrl/monitor.c b/fs/resctrl/monitor.c
index 73f507942b6d..35faca7ff3b1 100644
--- a/fs/resctrl/monitor.c
+++ b/fs/resctrl/monitor.c
@@ -366,9 +366,21 @@ static int __mon_event_count(struct rdtgroup *rdtgrp, struct rmid_read *rr)
 	struct mbm_state *m;
 	int err, ret;
 	u64 tval = 0;
+	int cntr_id;
+
+	if (rr->is_cntr) {
+		cntr_id = mbm_cntr_get(rr->r, rr->d, rdtgrp, rr->evtid);
+		if (cntr_id < 0) {
+			rr->err = -ENOENT;
+			return -EINVAL;
+		}
+	}
 
 	if (rr->first) {
-		resctrl_arch_reset_rmid(rr->r, rr->d, closid, rmid, rr->evtid);
+		if (rr->is_cntr)
+			resctrl_arch_reset_cntr(rr->r, rr->d, closid, rmid, cntr_id, rr->evtid);
+		else
+			resctrl_arch_reset_rmid(rr->r, rr->d, closid, rmid, rr->evtid);
 		m = get_mbm_state(rr->d, closid, rmid, rr->evtid);
 		if (m)
 			memset(m, 0, sizeof(struct mbm_state));
@@ -379,8 +391,12 @@ static int __mon_event_count(struct rdtgroup *rdtgrp, struct rmid_read *rr)
 		/* Reading a single domain, must be on a CPU in that domain. */
 		if (!cpumask_test_cpu(cpu, &rr->d->hdr.cpu_mask))
 			return -EINVAL;
-		rr->err = resctrl_arch_rmid_read(rr->r, rr->d, closid, rmid,
-						 rr->evtid, &tval, rr->arch_mon_ctx);
+		if (rr->is_cntr)
+			rr->err = resctrl_arch_cntr_read(rr->r, rr->d, closid, rmid, cntr_id,
+							 rr->evtid, &tval, rr->arch_mon_ctx);
+		else
+			rr->err = resctrl_arch_rmid_read(rr->r, rr->d, closid, rmid,
+							 rr->evtid, &tval, rr->arch_mon_ctx);
 		if (rr->err)
 			return rr->err;
 
@@ -405,8 +421,12 @@ static int __mon_event_count(struct rdtgroup *rdtgrp, struct rmid_read *rr)
 	list_for_each_entry(d, &rr->r->mon_domains, hdr.list) {
 		if (d->ci_id != rr->ci_id)
 			continue;
-		err = resctrl_arch_rmid_read(rr->r, d, closid, rmid,
-					     rr->evtid, &tval, rr->arch_mon_ctx);
+		if (rr->is_cntr)
+			err = resctrl_arch_cntr_read(rr->r, d, closid, rmid, cntr_id,
+						     rr->evtid, &tval, rr->arch_mon_ctx);
+		else
+			err = resctrl_arch_rmid_read(rr->r, d, closid, rmid,
+						     rr->evtid, &tval, rr->arch_mon_ctx);
 		if (!err) {
 			rr->val += tval;
 			ret = 0;
@@ -620,6 +640,14 @@ static void mbm_update_one_event(struct rdt_resource *r, struct rdt_mon_domain *
 		return;
 	}
 
+	if (resctrl_arch_mbm_cntr_assign_enabled(r) && resctrl_is_mbm_event(evtid)) {
+		if (mbm_cntr_get(r, d, rdtgrp, evtid) < 0) {
+			rr.err = -ENOENT;
+			return;
+		}
+		rr.is_cntr = true;
+	}
+
 	__mon_event_count(rdtgrp, &rr);
 
 	/*
@@ -982,8 +1010,8 @@ static void resctrl_config_cntr(struct rdt_resource *r, struct rdt_mon_domain *d
  * Return:
  * Valid counter ID on success, or -ENOENT on failure.
  */
-static int mbm_cntr_get(struct rdt_resource *r, struct rdt_mon_domain *d,
-			struct rdtgroup *rdtgrp, enum resctrl_event_id evtid)
+int mbm_cntr_get(struct rdt_resource *r, struct rdt_mon_domain *d,
+		 struct rdtgroup *rdtgrp, enum resctrl_event_id evtid)
 {
 	int cntr_id;
 
-- 
2.34.1