In ABMC mode, the hardware counter should be assigned to read the MBM
events.
Report "Unassigned" in case the user attempts to read the events without
assigning the counter.
Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
---
v5: New patch.
---
Documentation/arch/x86/resctrl.rst | 4 ++++
arch/x86/kernel/cpu/resctrl/ctrlmondata.c | 19 ++++++++++++++-----
2 files changed, 18 insertions(+), 5 deletions(-)
diff --git a/Documentation/arch/x86/resctrl.rst b/Documentation/arch/x86/resctrl.rst
index 4907d0758118..11b7a5f26b40 100644
--- a/Documentation/arch/x86/resctrl.rst
+++ b/Documentation/arch/x86/resctrl.rst
@@ -284,6 +284,10 @@ with the following files:
until the user unassigns it manually. There is no need to worry
about counters being reset during this period.
+ In ABMC mode, the MBM event counters will return "Unassigned" if
+ the hardware counter is not assigned to the event. Users need to
+ assign a counter manually to read the events.
+
Without ABMC enabled, monitoring will work in "legacy" mode
without assignment option.
diff --git a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
index 50fa1fe9a073..e60b469b7d12 100644
--- a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
+++ b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
@@ -562,7 +562,7 @@ int rdtgroup_mondata_show(struct seq_file *m, void *arg)
struct rdtgroup *rdtgrp;
struct rdt_resource *r;
union mon_data_bits md;
- int ret = 0;
+ int ret = 0, index;
rdtgrp = rdtgroup_kn_lock_live(of->kn);
if (!rdtgrp) {
@@ -609,12 +609,21 @@ int rdtgroup_mondata_show(struct seq_file *m, void *arg)
checkresult:
- if (rr.err == -EIO)
+ if (rr.err == -EIO) {
seq_puts(m, "Error\n");
- else if (rr.err == -EINVAL)
- seq_puts(m, "Unavailable\n");
- else
+ } else if (rr.err == -EINVAL) {
+ if (resctrl_arch_get_abmc_enabled()) {
+ index = mon_event_config_index_get(evtid);
+ if (rdtgrp->mon.cntr_id[index] == MON_CNTR_UNSET)
+ seq_puts(m, "Unassigned\n");
+ else
+ seq_puts(m, "Unavailable\n");
+ } else {
+ seq_puts(m, "Unavailable\n");
+ }
+ } else {
seq_printf(m, "%llu\n", rr.val);
+ }
out:
rdtgroup_kn_unlock(of->kn);
--
2.34.1
