[PATCH v6 07/12] x86/resctrl: Add sysfs interface to read mbm_total_bytes event configuration

[Babu Moger]

The current event configuration can be viewed by the user by reading
the configuration file /sys/fs/resctrl/info/L3_MON/mbm_total_config.

Following are the types of events supported:

====  ===========================================================
Bits   Description
====  ===========================================================
6      Dirty Victims from the QOS domain to all types of memory
5      Reads to slow memory in the non-local NUMA domain
4      Reads to slow memory in the local NUMA domain
3      Non-temporal writes to non-local NUMA domain
2      Non-temporal writes to local NUMA domain
1      Reads to memory in the non-local NUMA domain
0      Reads to memory in the local NUMA domain
====  ===========================================================

By default, the mbm_total_bytes configuration is set to 0x7f to count
all the event types. The event configuration settings are domain
specific. Changing the configuration on one CPU in a domain would
affect the whole domain.

For example:
    $cat /sys/fs/resctrl/info/L3_MON/mbm_total_config
    0=0x7f;1=0x7f;2=0x7f;3=0x7f

    In this case, the event mbm_total_bytes is currently configured
    with 0x7f on domains 0 to 3.

Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
---
 arch/x86/kernel/cpu/resctrl/core.c     |    3 +
 arch/x86/kernel/cpu/resctrl/internal.h |    2 +
 arch/x86/kernel/cpu/resctrl/rdtgroup.c |   76 ++++++++++++++++++++++++++++++++
 3 files changed, 81 insertions(+)

diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index 46813b1c50c2..758c5d7553a4 100644
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -826,6 +826,9 @@ static __init bool get_rdt_mon_resources(void)
 	if (!rdt_mon_features)
 		return false;
 
+	if (mon_configurable)
+		mbm_config_rftype_init();
+
 	return !rdt_get_mon_l3_config(r, mon_configurable);
 }
 
diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index b458f768f30c..326a1b582f38 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -15,6 +15,7 @@
 #define MSR_IA32_MBA_THRTL_BASE		0xd50
 #define MSR_IA32_MBA_BW_BASE		0xc0000200
 #define MSR_IA32_SMBA_BW_BASE		0xc0000280
+#define MSR_IA32_EVT_CFG_BASE		0xc0000400
 
 #define MSR_IA32_QM_CTR			0x0c8e
 #define MSR_IA32_QM_EVTSEL		0x0c8d
@@ -541,5 +542,6 @@ bool has_busy_rmid(struct rdt_resource *r, struct rdt_domain *d);
 void __check_limbo(struct rdt_domain *d, bool force_free);
 void rdt_domain_reconfigure_cdp(struct rdt_resource *r);
 void __init thread_throttle_mode_init(void);
+void __init mbm_config_rftype_init(void);
 
 #endif /* _ASM_X86_RESCTRL_INTERNAL_H */
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 5f0ef1bf4c78..0982845594d0 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -1423,6 +1423,67 @@ static int rdtgroup_size_show(struct kernfs_open_file *of,
 	return ret;
 }
 
+struct mon_config_info {
+	u32 evtid;
+	u32 mon_config;
+};
+
+static void mon_event_config_read(void *info)
+{
+	struct mon_config_info *mon_info = info;
+	u32 h, msr_index;
+
+	switch (mon_info->evtid) {
+	case QOS_L3_MBM_TOTAL_EVENT_ID:
+		msr_index = 0;
+		break;
+	case QOS_L3_MBM_LOCAL_EVENT_ID:
+		msr_index = 1;
+		break;
+	default:
+		/* Not expected to come here */
+		return;
+	}
+
+	rdmsr(MSR_IA32_EVT_CFG_BASE + msr_index, mon_info->mon_config, h);
+}
+
+static void mondata_config_read(struct rdt_domain *d, struct mon_config_info *mon_info)
+{
+	smp_call_function_any(&d->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_domain *dom;
+	bool sep = false;
+
+	list_for_each_entry(dom, &r->domains, list) {
+		if (sep)
+			seq_puts(s, ";");
+
+		mon_info.evtid = evtid;
+		mondata_config_read(dom, &mon_info);
+
+		seq_printf(s, "%d=0x%02x", dom->id, mon_info.mon_config);
+		sep = true;
+	}
+	seq_puts(s, "\n");
+
+	return 0;
+}
+
+static int mbm_total_config_show(struct kernfs_open_file *of,
+				 struct seq_file *seq, void *v)
+{
+	struct rdt_resource *r = of->kn->parent->priv;
+
+	mbm_config_show(seq, r, QOS_L3_MBM_TOTAL_EVENT_ID);
+
+	return 0;
+}
+
 /* rdtgroup information files for one cache resource. */
 static struct rftype res_common_files[] = {
 	{
@@ -1521,6 +1582,12 @@ static struct rftype res_common_files[] = {
 		.seq_show	= max_threshold_occ_show,
 		.fflags		= RF_MON_INFO | RFTYPE_RES_CACHE,
 	},
+	{
+		.name		= "mbm_total_config",
+		.mode		= 0644,
+		.kf_ops		= &rdtgroup_kf_single_ops,
+		.seq_show	= mbm_total_config_show,
+	},
 	{
 		.name		= "cpus",
 		.mode		= 0644,
@@ -1627,6 +1694,15 @@ void __init thread_throttle_mode_init(void)
 	rft->fflags = RF_CTRL_INFO | RFTYPE_RES_MB;
 }
 
+void __init mbm_config_rftype_init(void)
+{
+	struct rftype *rft;
+
+	rft = rdtgroup_get_rftype_by_name("mbm_total_config");
+	if (rft)
+		rft->fflags = RF_MON_INFO | RFTYPE_RES_CACHE;
+}
+
 /**
  * rdtgroup_kn_mode_restrict - Restrict user access to named resctrl file
  * @r: The resource group with which the file is associated.