[PATCH v8 12/25] x86/resctrl: Remove MSR reading of event configuration value

[Babu Moger]

The event configuration is domain specific and initialized during domain
initialization. The values are stored in struct rdt_hw_mon_domain.

It is not required to read the configuration register every time user asks
for it. Use the value stored in struct rdt_hw_mon_domain instead.

Introduce resctrl_arch_mon_event_config_get() and
resctrl_arch_mon_event_config_set() to get/set architecture domain specific
mbm_total_cfg/mbm_local_cfg values.

Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
---
v8: Renamed
    resctrl_arch_event_config_get() to resctrl_arch_mon_event_config_get().
    resctrl_arch_event_config_set() to resctrl_arch_mon_event_config_set().

v7: Removed check if (val == INVALID_CONFIG_VALUE) as resctrl_arch_event_config_get
    already prints warning.
    Kept the Event config value definitions as is.

v6: Fixed inconstancy with types. Made all the types to u32 for config
    value.
    Removed few rdt_last_cmd_puts as it is not necessary.
    Removed unused config value definitions.
    Few more updates to commit message.

v5: Introduced resctrl_arch_event_config_get and
    resctrl_arch_event_config_get() based on our discussion.
    https://lore.kernel.org/lkml/68e861f9-245d-4496-a72e-46fc57d19c62@xxxxxxx/

v4: New patch.
---
 arch/x86/kernel/cpu/resctrl/rdtgroup.c | 103 ++++++++++++++-----------
 include/linux/resctrl.h                |   4 +
 2 files changed, 62 insertions(+), 45 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 91ffd9d24883..ba90e520150f 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -1597,10 +1597,57 @@ static int rdtgroup_size_show(struct kernfs_open_file *of,
 }
 
 struct mon_config_info {
+	struct rdt_mon_domain *d;
 	u32 evtid;
 	u32 mon_config;
 };
 
+u32 resctrl_arch_mon_event_config_get(struct rdt_mon_domain *d,
+				      enum resctrl_event_id eventid)
+{
+	struct rdt_hw_mon_domain *hw_dom = resctrl_to_arch_mon_dom(d);
+
+	switch (eventid) {
+	case QOS_L3_OCCUP_EVENT_ID:
+		break;
+	case QOS_L3_MBM_TOTAL_EVENT_ID:
+		return hw_dom->mbm_total_cfg;
+	case QOS_L3_MBM_LOCAL_EVENT_ID:
+		return hw_dom->mbm_local_cfg;
+	}
+
+	/* Never expect to get here */
+	WARN_ON_ONCE(1);
+
+	return INVALID_CONFIG_VALUE;
+}
+
+void resctrl_arch_mon_event_config_set(void *info)
+{
+	struct mon_config_info *mon_info = info;
+	struct rdt_hw_mon_domain *hw_dom;
+	unsigned int index;
+
+	index = mon_event_config_index_get(mon_info->evtid);
+	if (index == INVALID_CONFIG_INDEX)
+		return;
+
+	wrmsr(MSR_IA32_EVT_CFG_BASE + index, mon_info->mon_config, 0);
+
+	hw_dom = resctrl_to_arch_mon_dom(mon_info->d);
+
+	switch (mon_info->evtid) {
+	case QOS_L3_OCCUP_EVENT_ID:
+		break;
+	case QOS_L3_MBM_TOTAL_EVENT_ID:
+		hw_dom->mbm_total_cfg = mon_info->mon_config;
+		break;
+	case QOS_L3_MBM_LOCAL_EVENT_ID:
+		hw_dom->mbm_local_cfg =  mon_info->mon_config;
+		break;
+	}
+}
+
 /**
  * mon_event_config_index_get - get the hardware index for the
  *                              configurable event
@@ -1623,33 +1670,11 @@ unsigned int mon_event_config_index_get(u32 evtid)
 	}
 }
 
-static void mon_event_config_read(void *info)
-{
-	struct mon_config_info *mon_info = info;
-	unsigned int index;
-	u64 msrval;
-
-	index = mon_event_config_index_get(mon_info->evtid);
-	if (index == INVALID_CONFIG_INDEX) {
-		pr_warn_once("Invalid event id %d\n", mon_info->evtid);
-		return;
-	}
-	rdmsrl(MSR_IA32_EVT_CFG_BASE + index, msrval);
-
-	/* Report only the valid event configuration bits */
-	mon_info->mon_config = msrval & MAX_EVT_CONFIG_BITS;
-}
-
-static void mondata_config_read(struct rdt_mon_domain *d, struct mon_config_info *mon_info)
-{
-	smp_call_function_any(&d->hdr.cpu_mask, mon_event_config_read, mon_info, 1);
-}
-
 static int mbm_config_show(struct seq_file *s, struct rdt_resource *r, u32 evtid)
 {
-	struct mon_config_info mon_info = {0};
 	struct rdt_mon_domain *dom;
 	bool sep = false;
+	u32 val;
 
 	cpus_read_lock();
 	mutex_lock(&rdtgroup_mutex);
@@ -1658,11 +1683,8 @@ static int mbm_config_show(struct seq_file *s, struct rdt_resource *r, u32 evtid
 		if (sep)
 			seq_puts(s, ";");
 
-		memset(&mon_info, 0, sizeof(struct mon_config_info));
-		mon_info.evtid = evtid;
-		mondata_config_read(dom, &mon_info);
-
-		seq_printf(s, "%d=0x%02x", dom->hdr.id, mon_info.mon_config);
+		val = resctrl_arch_mon_event_config_get(dom, evtid);
+		seq_printf(s, "%d=0x%02x", dom->hdr.id, val);
 		sep = true;
 	}
 	seq_puts(s, "\n");
@@ -1693,33 +1715,23 @@ static int mbm_local_bytes_config_show(struct kernfs_open_file *of,
 	return 0;
 }
 
-static void mon_event_config_write(void *info)
-{
-	struct mon_config_info *mon_info = info;
-	unsigned int index;
-
-	index = mon_event_config_index_get(mon_info->evtid);
-	if (index == INVALID_CONFIG_INDEX) {
-		pr_warn_once("Invalid event id %d\n", mon_info->evtid);
-		return;
-	}
-	wrmsr(MSR_IA32_EVT_CFG_BASE + index, mon_info->mon_config, 0);
-}
 
 static void mbm_config_write_domain(struct rdt_resource *r,
 				    struct rdt_mon_domain *d, u32 evtid, u32 val)
 {
 	struct mon_config_info mon_info = {0};
+	u32 config_val;
 
 	/*
-	 * Read the current config value first. If both are the same then
+	 * Check the current config value first. If both are the same then
 	 * no need to write it again.
 	 */
-	mon_info.evtid = evtid;
-	mondata_config_read(d, &mon_info);
-	if (mon_info.mon_config == val)
+	config_val = resctrl_arch_mon_event_config_get(d, evtid);
+	if (config_val == INVALID_CONFIG_VALUE || config_val == val)
 		return;
 
+	mon_info.d = d;
+	mon_info.evtid = evtid;
 	mon_info.mon_config = val;
 
 	/*
@@ -1728,7 +1740,8 @@ static void mbm_config_write_domain(struct rdt_resource *r,
 	 * are scoped at the domain level. Writing any of these MSRs
 	 * on one CPU is observed by all the CPUs in the domain.
 	 */
-	smp_call_function_any(&d->hdr.cpu_mask, mon_event_config_write,
+	smp_call_function_any(&d->hdr.cpu_mask,
+			      resctrl_arch_mon_event_config_set,
 			      &mon_info, 1);
 
 	/*
diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index 5a4d6adec974..54eacc8a9d49 100644
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -354,6 +354,10 @@ void resctrl_arch_reset_rmid(struct rdt_resource *r, struct rdt_mon_domain *d,
  */
 void resctrl_arch_reset_rmid_all(struct rdt_resource *r, struct rdt_mon_domain *d);
 
+void resctrl_arch_mon_event_config_set(void *info);
+u32 resctrl_arch_mon_event_config_get(struct rdt_mon_domain *d,
+				      enum resctrl_event_id eventid);
+
 extern unsigned int resctrl_rmid_realloc_threshold;
 extern unsigned int resctrl_rmid_realloc_limit;
 
-- 
2.34.1