[PATCH v1 15/20] x86/resctrl: Pass the required parameters into resctrl_arch_rmid_read()

[James Morse]

resctrl_arch_rmid_read() is intended as the function that an
architecture agnostic resctrl filesystem driver can use to
read a value in bytes from a counter. Currently the function returns
the mbm values in chunks directly from hardware.

To convert this to bytes, some correction and overflow calculations
are needed. These depend on the resource and domain structures.
Overflow detection requires the old chunks value. None of this
is available to resctrl_arch_rmid_read(). MPAM requires the
resource and domain structures to find the MMIO device that holds
the counter.

Pass the resource and domain to resctrl_arch_rmid_read(). The
old chunks value is available as prev_msr or prev_bw_msr. Merge
rmid_dirty() with its only caller, the name is kept as a local
variable.
This is all a little noisy for __mon_event_count(), as the switch
statement work is now before the resctrl_arch_rmid_read() call.

Signed-off-by: James Morse <james.morse@xxxxxxx>
---
 arch/x86/kernel/cpu/resctrl/monitor.c | 33 +++++++++++++++------------
 include/linux/resctrl.h               | 15 +++++++++++-
 2 files changed, 32 insertions(+), 16 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
index e7c43c40ff28..aa85cfd95904 100644
--- a/arch/x86/kernel/cpu/resctrl/monitor.c
+++ b/arch/x86/kernel/cpu/resctrl/monitor.c
@@ -164,10 +164,14 @@ void resctrl_arch_reset_rmid(struct rdt_resource *r, struct rdt_domain *d,
 		memset(m, 0, sizeof(*m));
 }
 
-int resctrl_arch_rmid_read(u32 rmid, enum resctrl_event_id eventid, u64 *val)
+int resctrl_arch_rmid_read(struct rdt_resource	*r, struct rdt_domain *d,
+			   u32 rmid, enum resctrl_event_id eventid, u64 *val)
 {
 	u64 msr_val;
 
+	if (!cpumask_test_cpu(smp_processor_id(), &d->cpu_mask))
+		return -EINVAL;
+
 	/*
 	 * As per the SDM, when IA32_QM_EVTSEL.EvtID (bits 7:0) is configured
 	 * with a valid event code for supported resource type and the bits
@@ -189,16 +193,6 @@ int resctrl_arch_rmid_read(u32 rmid, enum resctrl_event_id eventid, u64 *val)
 	return 0;
 }
 
-static bool rmid_dirty(struct rmid_entry *entry)
-{
-	u64 val = 0;
-
-	if (resctrl_arch_rmid_read(entry->rmid, QOS_L3_OCCUP_EVENT_ID, &val))
-		return true;
-
-	return val >= resctrl_cqm_threshold;
-}
-
 /*
  * Check the RMIDs that are marked as busy for this domain. If the
  * reported LLC occupancy is below the threshold clear the busy bit and
@@ -210,6 +204,8 @@ void __check_limbo(struct rdt_domain *d, bool force_free)
 	struct rmid_entry *entry;
 	struct rdt_resource *r;
 	u32 crmid = 1, nrmid;
+	bool rmid_dirty;
+	u64 val = 0;
 
 	r = &rdt_resources_all[RDT_RESOURCE_L3].r_resctrl;
 
@@ -225,7 +221,14 @@ void __check_limbo(struct rdt_domain *d, bool force_free)
 			break;
 
 		entry = __rmid_entry(nrmid);
-		if (force_free || !rmid_dirty(entry)) {
+
+		if (resctrl_arch_rmid_read(r, d, entry->rmid,
+					   QOS_L3_OCCUP_EVENT_ID, &val))
+			rmid_dirty = true;
+		else
+			rmid_dirty = (val >= resctrl_cqm_threshold);
+
+		if (force_free || !rmid_dirty) {
 			clear_bit(entry->rmid, d->rmid_busy_llc);
 			if (!--entry->busy) {
 				rmid_limbo_count--;
@@ -275,7 +278,7 @@ static void add_rmid_to_limbo(struct rmid_entry *entry)
 	cpu = get_cpu();
 	list_for_each_entry(d, &r->domains, list) {
 		if (cpumask_test_cpu(cpu, &d->cpu_mask)) {
-			err = resctrl_arch_rmid_read(entry->rmid,
+			err = resctrl_arch_rmid_read(r, d, entry->rmid,
 						     QOS_L3_OCCUP_EVENT_ID,
 						     &val);
 			if (err || val <= resctrl_cqm_threshold)
@@ -333,7 +336,7 @@ static int __mon_event_count(u32 rmid, struct rmid_read *rr)
 	if (rr->first)
 		resctrl_arch_reset_rmid(rr->r, rr->d, rmid, rr->evtid);
 
-	rr->err = resctrl_arch_rmid_read(rmid, rr->evtid, &tval);
+	rr->err = resctrl_arch_rmid_read(rr->r, rr->d, rmid, rr->evtid, &tval);
 	if (rr->err)
 		return -EINVAL;
 
@@ -374,7 +377,7 @@ static void mbm_bw_count(u32 rmid, struct rmid_read *rr)
 	struct mbm_state *m = &rr->d->mbm_local[rmid];
 	u64 tval = 0, cur_bw, chunks, bw_chunks;
 
-	if (resctrl_arch_rmid_read(rmid, rr->evtid, &tval))
+	if (resctrl_arch_rmid_read(rr->r, rr->d, rmid, rr->evtid, &tval))
 		return;
 
 	chunks = mbm_overflow_count(m->prev_msr, tval, hw_res->mbm_width);
diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index 543f6d0599a9..530df8e195c0 100644
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -228,7 +228,20 @@ void resctrl_arch_get_config(struct rdt_resource *r, struct rdt_domain *d,
 			     u32 *value);
 int resctrl_online_domain(struct rdt_resource *r, struct rdt_domain *d);
 void resctrl_offline_domain(struct rdt_resource *r, struct rdt_domain *d);
-int resctrl_arch_rmid_read(u32 rmid, enum resctrl_event_id eventid, u64 *res);
+
+/**
+ * resctrl_arch_rmid_read() - Read the eventid counter correpsonding to rmid
+ *			      for this resource and domain.
+ * @r:			The resource that the counter should be read from.
+ * @d:			The domain that the counter should be read from.
+ * @rmid:		The rmid of the counter to read.
+ * @eventid:		The eventid to read, e.g. L3 occupancy.
+ * @val:		The result of the counter read in chunks.
+ *
+ * Returns 0 on success, or -EIO, -EINVAL etc on error.
+ */
+int resctrl_arch_rmid_read(struct rdt_resource *r, struct rdt_domain *d,
+			   u32 rmid, enum resctrl_event_id eventid, u64 *val);
 
 /**
  * resctrl_arch_reset_rmid() - Reset any private state associated with rmid
-- 
2.30.2