/*
* Hypervisor supplied "24x7" performance counter support
*
* Author: Cody P Schafer <cody@linux.vnet.ibm.com>
* Copyright 2014 IBM Corporation.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#define pr_fmt(fmt) "hv-24x7: " fmt
#include <linux/perf_event.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <asm/firmware.h>
#include <asm/hvcall.h>
#include <asm/io.h>
#include "hv-24x7.h"
#include "hv-24x7-catalog.h"
#include "hv-common.h"
/*
* TODO: Merging events:
* - Think of the hcall as an interface to a 4d array of counters:
* - x = domains
* - y = indexes in the domain (core, chip, vcpu, node, etc)
* - z = offset into the counter space
* - w = lpars (guest vms, "logical partitions")
* - A single request is: x,y,y_last,z,z_last,w,w_last
* - this means we can retrieve a rectangle of counters in y,z for a single x.
*
* - Things to consider (ignoring w):
* - input cost_per_request = 16
* - output cost_per_result(ys,zs) = 8 + 8 * ys + ys * zs
* - limited number of requests per hcall (must fit into 4K bytes)
* - 4k = 16 [buffer header] - 16 [request size] * request_count
* - 255 requests per hcall
* - sometimes it will be more efficient to read extra data and discard
*/
/*
* Example usage:
* perf stat -e 'hv_24x7/domain=2,offset=8,starting_index=0,lpar=0xffffffff/'
*/
/* u3 0-6, one of HV_24X7_PERF_DOMAIN */
EVENT_DEFINE_RANGE_FORMAT(domain, config, 0, 3);
/* u16 */
EVENT_DEFINE_RANGE_FORMAT(starting_index, config, 16, 31);
/* u32, see "data_offset" */
EVENT_DEFINE_RANGE_FORMAT(offset, config, 32, 63);
/* u16 */
EVENT_DEFINE_RANGE_FORMAT(lpar, config1, 0, 15);
EVENT_DEFINE_RANGE(reserved1, config, 4, 15);
EVENT_DEFINE_RANGE(reserved2, config1, 16, 63);
EVENT_DEFINE_RANGE(reserved3, config2, 0, 63);
static struct attribute *format_attrs[] = {
&format_attr_domain.attr,
&format_attr_offset.attr,
&format_attr_starting_index.attr,
&format_attr_lpar.attr,
NULL,
};
static struct attribute_group format_group = {
.name = "format",
.attrs = format_attrs,
};
static struct kmem_cache *hv_page_cache;
/*
* read_offset_data - copy data from one buffer to another while treating the
* source buffer as a small view on the total avaliable
* source data.
*
* @dest: buffer to copy into
* @dest_len: length of @dest in bytes
* @requested_offset: the offset within the source data we want. Must be > 0
* @src: buffer to copy data from
* @src_len: length of @src in bytes
* @source_offset: the offset in the sorce data that (src,src_len) refers to.
* Must be > 0
*
* returns the number of bytes copied.
*
* The following ascii art shows the various buffer possitioning we need to
* handle, assigns some arbitrary varibles to points on the buffer, and then
* shows how we fiddle with those values to get things we care about (copy
* start in src and copy len)
*
* s = @src buffer
* d = @dest buffer
* '.' areas in d are written to.
*
* u
* x w v z
* d |.........|
* s |----------------------|
*
* u
* x w z v
* d |........------|
* s |------------------|
*
* x w u,z,v
* d |........|
* s |------------------|
*
* x,w u,v,z
* d |..................|
* s |------------------|
*
* x u
* w v z
* d |........|
* s |------------------|
*
* x z w v
* d |------|
* s |------|
*
* x = source_offset
* w = requested_offset
* z = source_offset + src_len
* v = requested_offset + dest_len
*
* w_offset_in_s = w - x = requested_offset - source_offset
* z_offset_in_s = z - x = src_len
* v_offset_in_s = v - x = request_offset + dest_len - src_len
*/
static ssize_t read_offset_data(void *dest, size_t dest_len,
loff_t requested_offset, void *src,
size_t src_len, loff_t source_offset)
{
size_t w_offset_in_s = requested_offset - source_offset;
size_t z_offset_in_s = src_len;
size_t v_offset_in_s = requested_offset + dest_len - src_len;
size_t u_offset_in_s = min(z_offset_in_s, v_offset_in_s);
size_t copy_len = u_offset_in_s - w_offset_in_s;
if (requested_offset < 0 || source_offset < 0)
return -EINVAL;
if (z_offset_in_s <= w_offset_in_s)
return 0;
memcpy(dest, src + w_offset_in_s, copy_len);
return copy_len;
}
static unsigned long h_get_24x7_catalog_page_(unsigned long phys_4096,
unsigned long version,
unsigned long index)
{
pr_devel("h_get_24x7_catalog_page(0x%lx, %lu, %lu)",
phys_4096,
version,
index);
WARN_ON(!IS_ALIGNED(phys_4096, 4096));
return plpar_hcall_norets(H_GET_24X7_CATALOG_PAGE,
phys_4096,
version,
index);
}
static unsigned long h_get_24x7_catalog_page(char page[],
u64 version, u32 index)
{
return h_get_24x7_catalog_page_(virt_to_phys(page),
version, index);
}
static ssize_t catalog_read(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr, char *buf,
loff_t offset, size_t count)
{
unsigned long hret;
ssize_t ret = 0;
size_t catalog_len = 0, catalog_page_len = 0, page_count = 0;
loff_t page_offset = 0;
uint64_t catalog_version_num = 0;
void *page = kmem_cache_alloc(hv_page_cache, GFP_USER);
struct hv_24x7_catalog_page_0 *page_0 = page;
if (!page)
return -ENOMEM;
hret = h_get_24x7_catalog_page(page, 0, 0);
if (hret) {
ret = -EIO;
goto e_free;
}
catalog_version_num = be64_to_cpu(page_0->version);
catalog_page_len = be32_to_cpu(page_0->length);
catalog_len = catalog_page_len * 4096;
page_offset = offset / 4096;
page_count = count / 4096;
if (page_offset >= catalog_page_len)
goto e_free;
if (page_offset != 0) {
hret = h_get_24x7_catalog_page(page, catalog_version_num,
page_offset);
if (hret) {
ret = -EIO;
goto e_free;
}
}
ret = read_offset_data(buf, count, offset,
page, 4096, page_offset * 4096);
e_free:
if (hret)
pr_err("h_get_24x7_catalog_page(ver=%lld, page=%lld) failed:"
" rc=%ld\n",
catalog_version_num, page_offset, hret);
kmem_cache_free(hv_page_cache, page);
pr_devel("catalog_read: offset=%lld(%lld) count=%zu(%zu) catalog_len=%zu(%zu) => %zd\n",
offset, page_offset, count, page_count, catalog_len,
catalog_page_len, ret);
return ret;
}
#define PAGE_0_ATTR(_name, _fmt, _expr) \
static ssize_t _name##_show(struct device *dev, \
struct device_attribute *dev_attr, \
char *buf) \
{ \
unsigned long hret; \
ssize_t ret = 0; \
void *page = kmem_cache_alloc(hv_page_cache, GFP_USER); \
struct hv_24x7_catalog_page_0 *page_0 = page; \
if (!page) \
return -ENOMEM; \
hret = h_get_24x7_catalog_page(page, 0, 0); \
if (hret) { \
ret = -EIO; \
goto e_free; \
} \
ret = sprintf(buf, _fmt, _expr); \
e_free: \
kfree(page); \
return ret; \
} \
static DEVICE_ATTR_RO(_name)
PAGE_0_ATTR(catalog_version, "%lld\n",
(unsigned long long)be64_to_cpu(page_0->version));
PAGE_0_ATTR(catalog_len, "%lld\n",
(unsigned long long)be32_to_cpu(page_0->length) * 4096);
static BIN_ATTR_RO(catalog, 0/* real length varies */);
static struct bin_attribute *if_bin_attrs[] = {
&bin_attr_catalog,
NULL,
};
static struct attribute *if_attrs[] = {
&dev_attr_catalog_len.attr,
&dev_attr_catalog_version.attr,
NULL,
};
static struct attribute_group if_group = {
.name = "interface",
.bin_attrs = if_bin_attrs,
.attrs = if_attrs,
};
static const struct attribute_group *attr_groups[] = {
&format_group,
&if_group,
NULL,
};
static bool is_physical_domain(int domain)
{
return domain == HV_24X7_PERF_DOMAIN_PHYSICAL_CHIP ||
domain == HV_24X7_PERF_DOMAIN_PHYSICAL_CORE;
}
static unsigned long single_24x7_request(u8 domain, u32 offset, u16 ix,
u16 lpar, u64 *res,
bool success_expected)
{
unsigned long ret;
/*
* request_buffer and result_buffer are not required to be 4k aligned,
* but are not allowed to cross any 4k boundary. Aligning them to 4k is
* the simplest way to ensure that.
*/
struct reqb {
struct hv_24x7_request_buffer buf;
struct hv_24x7_request req;
} __packed __aligned(4096) request_buffer = {
.buf = {
.interface_version = HV_24X7_IF_VERSION_CURRENT,
.num_requests = 1,
},
.req = {
.performance_domain = domain,
.data_size = cpu_to_be16(8),
.data_offset = cpu_to_be32(offset),
.starting_lpar_ix = cpu_to_be16(lpar),
.max_num_lpars = cpu_to_be16(1),
.starting_ix = cpu_to_be16(ix),
.max_ix = cpu_to_be16(1),
}
};
struct resb {
struct hv_24x7_data_result_buffer buf;
struct hv_24x7_result res;
struct hv_24x7_result_element elem;
__be64 result;
} __packed __aligned(4096) result_buffer = {};
ret = plpar_hcall_norets(H_GET_24X7_DATA,
virt_to_phys(&request_buffer), sizeof(request_buffer),
virt_to_phys(&result_buffer), sizeof(result_buffer));
if (ret) {
if (success_expected)
pr_err_ratelimited("hcall failed: %d %#x %#x %d => 0x%lx (%ld) detail=0x%x failing ix=%x\n",
domain, offset, ix, lpar,
ret, ret,
result_buffer.buf.detailed_rc,
result_buffer.buf.failing_request_ix);
return ret;
}
*res = be64_to_cpu(result_buffer.result);
return ret;
}
static unsigned long event_24x7_request(struct perf_event *event, u64 *res,
bool success_expected)
{
return single_24x7_request(event_get_domain(event),
event_get_offset(event),
event_get_starting_index(event),
event_get_lpar(event),
res,
success_expected);
}
static int h_24x7_event_init(struct perf_event *event)
{
struct hv_perf_caps caps;
unsigned domain;
unsigned long hret;
u64 ct;
/* Not our event */
if (event->attr.type != event->pmu->type)
return -ENOENT;
/* Unused areas must be 0 */
if (event_get_reserved1(event) ||
event_get_reserved2(event) ||
event_get_reserved3(event)) {
pr_devel("reserved set when forbidden 0x%llx(0x%llx) 0x%llx(0x%llx) 0x%llx(0x%llx)\n",
event->attr.config,
event_get_reserved1(event),
event->attr.config1,
event_get_reserved2(event),
event->attr.config2,
event_get_reserved3(event));
return -EINVAL;
}
/* unsupported modes and filters */
if (event->attr.exclude_user ||
event->attr.exclude_kernel ||
event->attr.exclude_hv ||
event->attr.exclude_idle ||
event->attr.exclude_host ||
event->attr.exclude_guest)
return -EINVAL;
/* no branch sampling */
if (has_branch_stack(event))
return -EOPNOTSUPP;
/* offset must be 8 byte aligned */
if (event_get_offset(event) % 8) {
pr_devel("bad alignment\n");
return -EINVAL;
}
/* Domains above 6 are invalid */
domain = event_get_domain(event);
if (domain > 6) {
pr_devel("invalid domain %d\n", domain);
return -EINVAL;
}
hret = hv_perf_caps_get(&caps);
if (hret) {
pr_devel("could not get capabilities: rc=%ld\n", hret);
return -EIO;
}
/* PHYSICAL domains & other lpars require extra capabilities */
if (!caps.collect_privileged && (is_physical_domain(domain) ||
(event_get_lpar(event) != event_get_lpar_max()))) {
pr_devel("hv permisions disallow: is_physical_domain:%d, lpar=0x%llx\n",
is_physical_domain(domain),
event_get_lpar(event));
return -EACCES;
}
/* see if the event complains */
if (event_24x7_request(event, &ct, false)) {
pr_devel("test hcall failed\n");
return -EIO;
}
return 0;
}
static u64 h_24x7_get_value(struct perf_event *event)
{
unsigned long ret;
u64 ct;
ret = event_24x7_request(event, &ct, true);
if (ret)
/* We checked this in event init, shouldn't fail here... */
return 0;
return ct;
}
static void h_24x7_event_update(struct perf_event *event)
{
s64 prev;
u64 now;
now = h_24x7_get_value(event);
prev = local64_xchg(&event->hw.prev_count, now);
local64_add(now - prev, &event->count);
}
static void h_24x7_event_start(struct perf_event *event, int flags)
{
if (flags & PERF_EF_RELOAD)
local64_set(&event->hw.prev_count, h_24x7_get_value(event));
}
static void h_24x7_event_stop(struct perf_event *event, int flags)
{
h_24x7_event_update(event);
}
static int h_24x7_event_add(struct perf_event *event, int flags)
{
if (flags & PERF_EF_START)
h_24x7_event_start(event, flags);
return 0;
}
static int h_24x7_event_idx(struct perf_event *event)
{
return 0;
}
static struct pmu h_24x7_pmu = {
.task_ctx_nr = perf_invalid_context,
.name = "hv_24x7",
.attr_groups = attr_groups,
.event_init = h_24x7_event_init,
.add = h_24x7_event_add,
.del = h_24x7_event_stop,
.start = h_24x7_event_start,
.stop = h_24x7_event_stop,
.read = h_24x7_event_update,
.event_idx = h_24x7_event_idx,
};
static int hv_24x7_init(void)
{
int r;
unsigned long hret;
struct hv_perf_caps caps;
if (!firmware_has_feature(FW_FEATURE_LPAR)) {
pr_debug("not a virtualized system, not enabling\n");
return -ENODEV;
}
hret = hv_perf_caps_get(&caps);
if (hret) {
pr_debug("could not obtain capabilities, not enabling, rc=%ld\n",
hret);
return -ENODEV;
}
hv_page_cache = kmem_cache_create("hv-page-4096", 4096, 4096, 0, NULL);
if (!hv_page_cache)
return -ENOMEM;
/* sampling not supported */
h_24x7_pmu.capabilities |= PERF_PMU_CAP_NO_INTERRUPT;
r = perf_pmu_register(&h_24x7_pmu, h_24x7_pmu.name, -1);
if (r)
return r;
return 0;
}
device_initcall(hv_24x7_init);
