[PATCH v2 4/8] perf/amd/ibs: Advertise zen4_ibs_extensions as pmu capability attribute

Ravi Bangoria
2022-05-09T04:55:56Z

PMU driver can advertise certain feature via capability attribute('caps'
sysfs directory) which can be consumed by userspace tools like perf. Add
zen4_ibs_extensions capability attribute for IBS pmus. This attribute
will be enabled when CPUID_Fn8000001B_EAX[11] is set.

With patch on Zen4:

$ ls /sys/bus/event_source/devices/ibs_op/caps
zen4_ibs_extensions

Signed-off-by: Ravi Bangoria <ravi.bangoria@amd.com>
---
arch/x86/events/amd/ibs.c | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)

diff --git a/arch/x86/events/amd/ibs.c b/arch/x86/events/amd/ibs.c
index 52d2eb9ff19a..12b0fd4a0328 100644
--- a/arch/x86/events/amd/ibs.c
+++ b/arch/x86/events/amd/ibs.c
@@ -527,8 +527,14 @@ static struct attribute_group empty_format_group = {
.attrs = attrs_empty,
};

+static struct attribute_group empty_caps_group = {
+ .name = "caps",
+ .attrs = attrs_empty,
+};
+
static const struct attribute_group *empty_attr_groups[] = {
&empty_format_group,
+ &empty_caps_group,
NULL,
};

@@ -536,6 +542,7 @@ PMU_FORMAT_ATTR(rand_en, "config:57");
PMU_FORMAT_ATTR(cnt_ctl, "config:19");
PMU_EVENT_ATTR_STRING(l3missonly, fetch_l3missonly, "config:59");
PMU_EVENT_ATTR_STRING(l3missonly, op_l3missonly, "config:16");
+PMU_EVENT_ATTR_STRING(zen4_ibs_extensions, zen4_ibs_extensions, "1");

static umode_t
zen4_ibs_extensions_is_visible(struct kobject *kobj, struct attribute *attr, int i)
@@ -553,6 +560,11 @@ static struct attribute *fetch_l3missonly_attrs[] = {
NULL,
};

+static struct attribute *zen4_ibs_extensions_attrs[] = {
+ &zen4_ibs_extensions.attr.attr,
+ NULL,
+};
+
static struct attribute_group group_rand_en = {
.name = "format",
.attrs = rand_en_attrs,
@@ -564,13 +576,21 @@ static struct attribute_group group_fetch_l3missonly = {
.is_visible = zen4_ibs_extensions_is_visible,
};

+static struct attribute_group group_zen4_ibs_extensions = {
+ .name = "caps",
+ .attrs = zen4_ibs_extensions_attrs,
+ .is_visible = zen4_ibs_extensions_is_visible,
+};
+
static const struct attribute_group *fetch_attr_groups[] = {
&group_rand_en,
+ &empty_caps_group,
NULL,
};

static const struct attribute_group *fetch_attr_update[] = {
&group_fetch_l3missonly,
+ &group_zen4_ibs_extensions,
NULL,
};

@@ -605,6 +625,7 @@ static struct attribute_group group_op_l3missonly = {
static const struct attribute_group *op_attr_update[] = {
&group_cnt_ctl,
&group_op_l3missonly,
+ &group_zen4_ibs_extensions,
NULL,
};

--
2.27.0