[PATCH v7 07/12] x86/resctrl: Add sysfs interface to read mbm_total_bytes event configuration

Babu Moger
2022-10-17T22:27:47Z

The current event configuration can be viewed by the user by reading
the configuration file /sys/fs/resctrl/info/L3_MON/mbm_total_config.
The event configuration settings are domain specific and will affect all
the CPUs in the domain.

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.

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@amd.com>
---
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.