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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Performance monitoring support for Virtual Processor Area(VPA) based counters
*
* Copyright (C) 2024 IBM Corporation
*/
#define pr_fmt(fmt) "vpa_pmu: " fmt
#include <linux/module.h>
#include <linux/perf_event.h>
#include <asm/kvm_ppc.h>
#include <asm/kvm_book3s_64.h>
#define MODULE_VERS "1.0"
#define MODULE_NAME "pseries_vpa_pmu"
#define EVENT(_name, _code) enum{_name = _code}
#define VPA_PMU_EVENT_VAR(_id) event_attr_##_id
#define VPA_PMU_EVENT_PTR(_id) (&event_attr_##_id.attr.attr)
static ssize_t vpa_pmu_events_sysfs_show(struct device *dev,
struct device_attribute *attr, char *page)
{
struct perf_pmu_events_attr *pmu_attr;
pmu_attr = container_of(attr, struct perf_pmu_events_attr, attr);
return sprintf(page, "event=0x%02llx\n", pmu_attr->id);
}
#define VPA_PMU_EVENT_ATTR(_name, _id) \
PMU_EVENT_ATTR(_name, VPA_PMU_EVENT_VAR(_id), _id, \
vpa_pmu_events_sysfs_show)
EVENT(L1_TO_L2_CS_LAT, 0x1);
EVENT(L2_TO_L1_CS_LAT, 0x2);
EVENT(L2_RUNTIME_AGG, 0x3);
VPA_PMU_EVENT_ATTR(l1_to_l2_lat, L1_TO_L2_CS_LAT);
VPA_PMU_EVENT_ATTR(l2_to_l1_lat, L2_TO_L1_CS_LAT);
VPA_PMU_EVENT_ATTR(l2_runtime_agg, L2_RUNTIME_AGG);
static struct attribute *vpa_pmu_events_attr[] = {
VPA_PMU_EVENT_PTR(L1_TO_L2_CS_LAT),
VPA_PMU_EVENT_PTR(L2_TO_L1_CS_LAT),
VPA_PMU_EVENT_PTR(L2_RUNTIME_AGG),
NULL
};
static const struct attribute_group vpa_pmu_events_group = {
.name = "events",
.attrs = vpa_pmu_events_attr,
};
PMU_FORMAT_ATTR(event, "config:0-31");
static struct attribute *vpa_pmu_format_attr[] = {
&format_attr_event.attr,
NULL,
};
static struct attribute_group vpa_pmu_format_group = {
.name = "format",
.attrs = vpa_pmu_format_attr,
};
static const struct attribute_group *vpa_pmu_attr_groups[] = {
&vpa_pmu_events_group,
&vpa_pmu_format_group,
NULL
};
static int vpa_pmu_event_init(struct perf_event *event)
{
if (event->attr.type != event->pmu->type)
return -ENOENT;
/* it does not support event sampling mode */
if (is_sampling_event(event))
return -EOPNOTSUPP;
/* no branch sampling */
if (has_branch_stack(event))
return -EOPNOTSUPP;
/* Invalid event code */
if ((event->attr.config <= 0) || (event->attr.config > 3))
return -EINVAL;
return 0;
}
static unsigned long get_counter_data(struct perf_event *event)
{
unsigned int config = event->attr.config;
u64 data;
switch (config) {
case L1_TO_L2_CS_LAT:
if (event->attach_state & PERF_ATTACH_TASK)
data = kvmhv_get_l1_to_l2_cs_time_vcpu();
else
data = kvmhv_get_l1_to_l2_cs_time();
break;
case L2_TO_L1_CS_LAT:
if (event->attach_state & PERF_ATTACH_TASK)
data = kvmhv_get_l2_to_l1_cs_time_vcpu();
else
data = kvmhv_get_l2_to_l1_cs_time();
break;
case L2_RUNTIME_AGG:
if (event->attach_state & PERF_ATTACH_TASK)
data = kvmhv_get_l2_runtime_agg_vcpu();
else
data = kvmhv_get_l2_runtime_agg();
break;
default:
data = 0;
break;
}
return data;
}
static int vpa_pmu_add(struct perf_event *event, int flags)
{
u64 data;
kvmhv_set_l2_counters_status(smp_processor_id(), true);
data = get_counter_data(event);
local64_set(&event->hw.prev_count, data);
return 0;
}
static void vpa_pmu_read(struct perf_event *event)
{
u64 prev_data, new_data, final_data;
prev_data = local64_read(&event->hw.prev_count);
new_data = get_counter_data(event);
final_data = new_data - prev_data;
local64_add(final_data, &event->count);
}
static void vpa_pmu_del(struct perf_event *event, int flags)
{
vpa_pmu_read(event);
/*
* Disable vpa counter accumulation
*/
kvmhv_set_l2_counters_status(smp_processor_id(), false);
}
static struct pmu vpa_pmu = {
.module = THIS_MODULE,
.task_ctx_nr = perf_sw_context,
.name = "vpa_pmu",
.event_init = vpa_pmu_event_init,
.add = vpa_pmu_add,
.del = vpa_pmu_del,
.read = vpa_pmu_read,
.attr_groups = vpa_pmu_attr_groups,
.capabilities = PERF_PMU_CAP_NO_EXCLUDE | PERF_PMU_CAP_NO_INTERRUPT,
};
static int __init pseries_vpa_pmu_init(void)
{
/*
* List of current Linux on Power platforms and
* this driver is supported only in PowerVM LPAR
* (L1) platform.
*
* Enabled Linux on Power Platforms
* ----------------------------------------
* [X] PowerVM LPAR (L1)
* [ ] KVM Guest On PowerVM KoP(L2)
* [ ] Baremetal(PowerNV)
* [ ] KVM Guest On PowerNV
*/
if (!firmware_has_feature(FW_FEATURE_LPAR) || is_kvm_guest())
return -ENODEV;
perf_pmu_register(&vpa_pmu, vpa_pmu.name, -1);
pr_info("Virtual Processor Area PMU registered.\n");
return 0;
}
static void __exit pseries_vpa_pmu_cleanup(void)
{
perf_pmu_unregister(&vpa_pmu);
pr_info("Virtual Processor Area PMU unregistered.\n");
}
module_init(pseries_vpa_pmu_init);
module_exit(pseries_vpa_pmu_cleanup);
MODULE_DESCRIPTION("Perf Driver for pSeries VPA pmu counter");
MODULE_AUTHOR("Kajol Jain <kjain@linux.ibm.com>");
MODULE_AUTHOR("Madhavan Srinivasan <maddy@linux.ibm.com>");
MODULE_LICENSE("GPL");
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