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Message-ID: <bcae8e21-0afc-9fc6-7f90-07afca412223@linux.intel.com>
Date: Mon, 3 Apr 2023 13:32:06 -0400
From: "Liang, Kan" <kan.liang@...ux.intel.com>
To: Jonathan Cameron <Jonathan.Cameron@...wei.com>,
linux-cxl@...r.kernel.org, peterz@...radead.org
Cc: mingo@...hat.com, acme@...nel.org, mark.rutland@....com,
will@...nel.org, dan.j.williams@...el.com, linuxarm@...wei.com,
linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org,
Davidlohr Bueso <dave@...olabs.net>,
Dave Jiang <dave.jiang@...el.com>
Subject: Re: [PATCH v4 4/5] cxl: CXL Performance Monitoring Unit driver
On 2023-03-30 12:45 p.m., Jonathan Cameron wrote:
> CXL rev 3.0 introduces a standard performance monitoring hardware
> block to CXL. Instances are discovered using CXL Register Locator DVSEC
> entries. Each CXL component may have multiple PMUs.
>
> This initial driver supports on a subset of types of counter.
> It support counters that are either fixed or configurable, but requires
> that they support the ability to freeze and write value whilst frozen.
>
> Development done with QEMU model which will be posted shortly.
>
So the patch series is only tested with QEMU. Is there a real hardware
which supports the CXL PMON?
> Reviewed-by: Dave Jiang <dave.jiang@...el.com>
> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>
>
> ---
> v4:
> - Add defines for masks used for config, config1 etc and reorder
> code so those can be next to the attrs. Note that one of the
> bits was wrong showing the advantage of bring all this info
> into one place.
> - Use enabled counter bitmap rather than pointer array to make the
> fixed counter handling look more like the variable counter handling.
> - Drop PERF_EF_RELOAD handling that did nothing.
> - Simplify code as nothing special to do if the counting is already
> up to date (no harm in setting the already set flag).
> ---
> drivers/cxl/Kconfig | 13 +
> drivers/cxl/Makefile | 1 +
> drivers/cxl/cpmu.c | 940 +++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 954 insertions(+)
>
> diff --git a/drivers/cxl/Kconfig b/drivers/cxl/Kconfig
> index ff4e78117b31..0be514b00b8f 100644
> --- a/drivers/cxl/Kconfig
> +++ b/drivers/cxl/Kconfig
> @@ -139,4 +139,17 @@ config CXL_REGION_INVALIDATION_TEST
> If unsure, or if this kernel is meant for production environments,
> say N.
>
> +config CXL_CPMU
> + tristate "CXL Performance Monitoring Unit"
> + default CXL_BUS
> + depends on PERF_EVENTS
> + help
> + Support performance monitoring as defined in CXL rev 3.0
> + section 13.2: Performance Monitoring. CXL components may have
> + one or more CXL Performance Monitoring Units (CPMUs).
> +
> + Say 'y/m' to enable a driver that will attach to performance
> + monitoring units and provide standard perf based interfaces.
> +
> + If unsure say 'm'.
> endif
> diff --git a/drivers/cxl/Makefile b/drivers/cxl/Makefile
> index db321f48ba52..024bb739554b 100644
> --- a/drivers/cxl/Makefile
> +++ b/drivers/cxl/Makefile
> @@ -5,6 +5,7 @@ obj-$(CONFIG_CXL_MEM) += cxl_mem.o
> obj-$(CONFIG_CXL_ACPI) += cxl_acpi.o
> obj-$(CONFIG_CXL_PMEM) += cxl_pmem.o
> obj-$(CONFIG_CXL_PORT) += cxl_port.o
> +obj-$(CONFIG_CXL_CPMU) += cpmu.o
>
> cxl_mem-y := mem.o
> cxl_pci-y := pci.o
> diff --git a/drivers/cxl/cpmu.c b/drivers/cxl/cpmu.c
> new file mode 100644
> index 000000000000..e6821771a4f6
> --- /dev/null
> +++ b/drivers/cxl/cpmu.c
> @@ -0,0 +1,940 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +
> +/*
> + * Copyright(c) 2023 Huawei
> + *
> + * The CXL 3.0 specification includes a standard Performance Monitoring Unit,
> + * called the CXL PMU, or CPMU. In order to allow a high degree of
> + * implementation flexibility the specification provides a wide range of
> + * options all of which are self describing.
> + *
> + * Details in CXL rev 3.0 section 8.2.7 CPMU Register Interface
> + *
> + * TODO
> + * o Discoverability of counters. Allow perftool to provide summed counters
> + * and vendor defined counters.
> + * o Support free running counters - copy the Intel uncore PMU handling for these.
> + * o CPMUs which do not support freeze.
> + * o Add filter validation in cpmu_event_init() so problems are detected earlier.
> + * o Reject configurations that the hardware is ignoring
> + * (e.g. invert when not invertible)
> + * o Support CPMUs with no interrupts using an HRTIMER.
> + */
> +
> +#include <linux/io-64-nonatomic-lo-hi.h>
> +#include <linux/perf_event.h>
> +#include <linux/bitops.h>
> +#include <linux/device.h>
> +#include <linux/bits.h>
> +#include <linux/list.h>
> +#include <linux/bug.h>
> +#include <linux/pci.h>
> +
> +#include "cpmu.h"
> +#include "cxlpci.h"
> +#include "cxl.h"
> +
> +/* CXL rev 3.0 Table 13-5 Events under CXL Vendor ID */
> +#define CPMU_GID_CLOCK_TICKS 0x00
> +#define CPMU_GID_D2H_REQ 0x0010
> +#define CPMU_GID_D2H_RSP 0x0011
> +#define CPMU_GID_H2D_REQ 0x0012
> +#define CPMU_GID_H2D_RSP 0x0013
> +#define CPMU_GID_CACHE_DATA 0x0014
> +#define CPMU_GID_M2S_REQ 0x0020
> +#define CPMU_GID_M2S_RWD 0x0021
> +#define CPMU_GID_M2S_BIRSP 0x0022
> +#define CPMU_GID_S2M_BISNP 0x0023
> +#define CPMU_GID_S2M_NDR 0x0024
> +#define CPMU_GID_S2M_DRS 0x0025
> +#define CPMU_GID_DDR 0x8000
> +
> +static int cpmu_cpuhp_state_num;
> +
> +struct cpmu_event {
> + u16 vid;
> + u16 gid;
> + u32 msk;
> + union {
> + int counter_idx; /* fixed counters */
> + int event_idx; /* configurable counters */
> + };
> + struct list_head node;
> +};
> +
> +#define CPMU_MAX_COUNTERS 64
> +struct cpmu_info {
> + struct pmu pmu;
> + void __iomem *base;
> + struct perf_event **hw_events;
> + struct list_head events_configurable;
> + struct list_head events_fixed;
> + DECLARE_BITMAP(used_counter_bm, CPMU_MAX_COUNTERS);
> + DECLARE_BITMAP(conf_counter_bm, CPMU_MAX_COUNTERS);
> + u16 counter_width;
> + u8 num_counters;
> + u8 num_event_capabilities;
> + int on_cpu;
> + struct hlist_node node;
> + bool freeze_for_enable;
> + bool filter_hdm;
> + int irq;
> +};
> +
> +#define pmu_to_cpmu_info(_pmu) container_of(_pmu, struct cpmu_info, pmu)
> +
> +/*
> + * All CPMU counters are discoverable via the Event Capabilities Registers.
> + * Each Event Capability register contains a a VID / GroupID.
> + * A counter may then count any combination (by summing) of events in
> + * that group which are in the Supported Events Bitmask.
> + * However, there are some complexities to the scheme.
> + * - Fixed function counters refer to an Event Capabilities register.
> + * That event capability register is not then used for Configurable
> + * counters.
> + */
> +static int cpmu_parse_caps(struct device *dev, struct cpmu_info *info)
> +{
> + DECLARE_BITMAP(fixed_counter_event_cap_bm, 32) = {0};
> + void __iomem *base = info->base;
> + u64 val, eval;
> + int i;
> +
> + val = readq(base + CPMU_CAP_REG);
> + info->freeze_for_enable = FIELD_GET(CPMU_CAP_WRITEABLE_WHEN_FROZEN, val) &
> + FIELD_GET(CPMU_CAP_FREEZE, val);
> + if (!info->freeze_for_enable) {
> + dev_err(dev, "Driver does not support CPMUs that do not support freeze for enable\n");
> + return -ENODEV;
> + }
> +
> + info->num_counters = FIELD_GET(CPMU_CAP_NUM_COUNTERS_MSK, val) + 1;
> + info->counter_width = FIELD_GET(CPMU_CAP_COUNTER_WIDTH_MSK, val);
> + info->num_event_capabilities = FIELD_GET(CPMU_CAP_NUM_EVN_CAP_REG_SUP_MSK, val) + 1;
> +
> + info->filter_hdm = FIELD_GET(CPMU_CAP_FILTERS_SUP_MSK, val) & CPMU_FILTER_HDM;
> + if (FIELD_GET(CPMU_CAP_INT, val))
> + info->irq = FIELD_GET(CPMU_CAP_MSI_N_MSK, val);
> + else
> + info->irq = -1;
> +
> + /* First handle fixed function counters; note if configurable counters found */
> + for (i = 0; i < info->num_counters; i++) {
> + struct cpmu_event *cpmu_ev;
> + u32 events_msk;
> + u8 group_idx;
> +
> + val = readq(base + CPMU_COUNTER_CFG_REG(i));
> +
> + if (FIELD_GET(CPMU_COUNTER_CFG_TYPE_MSK, val) ==
> + CPMU_COUNTER_CFG_TYPE_CONFIGURABLE) {
> + set_bit(i, info->conf_counter_bm);
> + }
> +
> + if (FIELD_GET(CPMU_COUNTER_CFG_TYPE_MSK, val) !=
> + CPMU_COUNTER_CFG_TYPE_FIXED_FUN)
> + continue;
> +
> + /* In this case we know which fields are const */
> + group_idx = FIELD_GET(CPMU_COUNTER_CFG_EVENT_GRP_ID_IDX_MSK, val);
> + events_msk = FIELD_GET(CPMU_COUNTER_CFG_EVENTS_MSK, val);
> + eval = readq(base + CPMU_EVENT_CAP_REG(group_idx));
> + cpmu_ev = devm_kzalloc(dev, sizeof(*cpmu_ev), GFP_KERNEL);
> + if (!cpmu_ev)
> + return -ENOMEM;
> +
> + cpmu_ev->vid = FIELD_GET(CPMU_EVENT_CAP_VENDOR_ID_MSK, eval);
> + cpmu_ev->gid = FIELD_GET(CPMU_EVENT_CAP_GROUP_ID_MSK, eval);
> + /* For a fixed purpose counter use the events mask from the counter CFG */
> + cpmu_ev->msk = events_msk;
> + cpmu_ev->counter_idx = i;
> + /* This list add is never unwound as all entries deleted on remove */
> + list_add(&cpmu_ev->node, &info->events_fixed);
> + /*
> + * Configurable counters must not use an Event Capability registers that
> + * is in use for a Fixed counter
> + */
> + set_bit(group_idx, fixed_counter_event_cap_bm);
> + }
> +
> + if (!bitmap_empty(info->conf_counter_bm, CPMU_MAX_COUNTERS)) {
> + struct cpmu_event *cpmu_ev;
> + int j;
> + /* Walk event capabilities unused by fixed counters */
> + for_each_clear_bit(j, fixed_counter_event_cap_bm,
> + info->num_event_capabilities) {
> + cpmu_ev = devm_kzalloc(dev, sizeof(*cpmu_ev), GFP_KERNEL);
> + if (!cpmu_ev)
> + return -ENOMEM;
> +
> + eval = readq(base + CPMU_EVENT_CAP_REG(j));
> + cpmu_ev->vid = FIELD_GET(CPMU_EVENT_CAP_VENDOR_ID_MSK, eval);
> + cpmu_ev->gid = FIELD_GET(CPMU_EVENT_CAP_GROUP_ID_MSK, eval);
> + cpmu_ev->msk = FIELD_GET(CPMU_EVENT_CAP_SUPPORTED_EVENTS_MSK, eval);
> + cpmu_ev->event_idx = j;
> + list_add(&cpmu_ev->node, &info->events_configurable);
> + }
> + }
> +
> + return 0;
> +}
> +
> +static ssize_t cpmu_format_sysfs_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct dev_ext_attribute *eattr;
> +
> + eattr = container_of(attr, struct dev_ext_attribute, attr);
> +
> + return sysfs_emit(buf, "%s\n", (char *)eattr->var);
> +}
> +
> +#define CPMU_FORMAT_ATTR(_name, _format)\
> + (&((struct dev_ext_attribute[]) { \
> + { \
> + .attr = __ATTR(_name, 0444, \
> + cpmu_format_sysfs_show, NULL), \
> + .var = (void *)_format \
> + } \
> + })[0].attr.attr)
> +
> +enum {
> + cpmu_mask_attr,
> + cpmu_gid_attr,
> + cpmu_vid_attr,
> + cpmu_threshold_attr,
> + cpmu_invert_attr,
> + cpmu_edge_attr,
> + cpmu_hdm_filter_en_attr,
> + cpmu_hdm_attr,
> +};
> +
> +static struct attribute *cpmu_format_attr[] = {
> + [cpmu_mask_attr] = CPMU_FORMAT_ATTR(mask, "config:0-31"),
> + [cpmu_gid_attr] = CPMU_FORMAT_ATTR(gid, "config:32-47"),
> + [cpmu_vid_attr] = CPMU_FORMAT_ATTR(vid, "config:48-63"),
> + [cpmu_threshold_attr] = CPMU_FORMAT_ATTR(threshold, "config1:0-15"),
> + [cpmu_invert_attr] = CPMU_FORMAT_ATTR(invert, "config1:16"),
> + [cpmu_edge_attr] = CPMU_FORMAT_ATTR(edge, "config1:17"),
> + [cpmu_hdm_filter_en_attr] = CPMU_FORMAT_ATTR(hdm_filter_en, "config1:18"),
> + [cpmu_hdm_attr] = CPMU_FORMAT_ATTR(hdm, "config2:0-15"),
> + NULL
> +};
> +
> +#define CPMU_ATTR_CONFIG_MASK_MSK GENMASK_ULL(63, 48)
(31, 0)?
> +#define CPMU_ATTR_CONFIG_GID_MSK GENMASK_ULL(47, 32)
> +#define CPMU_ATTR_CONFIG_VID_MSK GENMASK_ULL(63, 48)
> +#define CPMU_ATTR_CONFIG1_THRESHOLD_MSK GENMASK_ULL(15, 0)
> +#define CPMU_ATTR_CONFIG1_INVERT_MSK BIT(16)
> +#define CPMU_ATTR_CONFIG1_EDGE_MSK BIT(17)
> +#define CPMU_ATTR_CONFIG1_FILTER_EN_MSK BIT(18)
> +#define CPMU_ATTR_CONFIG2_HDM_MSK GENMASK(15, 0)
> +
> +static umode_t cpmu_format_is_visible(struct kobject *kobj, struct attribute *attr, int a)
> +{
> + struct device *dev = kobj_to_dev(kobj);
> + struct cpmu_info *info = dev_get_drvdata(dev);
> +
> + /*
> + * Filter capability at the CPMU level, so hide the attributes if the particular
> + * filter is not supported.
> + */
> + if (attr == cpmu_format_attr[cpmu_hdm_filter_en_attr] ||
> + attr == cpmu_format_attr[cpmu_hdm_attr]) {
> + if (info->filter_hdm)
> + return 0444;
> + else
> + return 0;
> + } else {
> + return 0444;
> + }
> +}
> +
> +static const struct attribute_group cpmu_format_group = {
> + .name = "format",
> + .attrs = cpmu_format_attr,
> + .is_visible = cpmu_format_is_visible,
> +};
> +
> +static u32 cpmu_config_get_mask(struct perf_event *event)
> +{
> + return FIELD_GET(CPMU_ATTR_CONFIG_MASK_MSK, event->attr.config);
> +}
> +
> +static u16 cpmu_config_get_gid(struct perf_event *event)
> +{
> + return FIELD_GET(CPMU_ATTR_CONFIG_GID_MSK, event->attr.config);
> +}
> +
> +static u16 cpmu_config_get_vid(struct perf_event *event)
> +{
> + return FIELD_GET(CPMU_ATTR_CONFIG_VID_MSK, event->attr.config);
> +}
> +
> +static u8 cpmu_config1_get_threshold(struct perf_event *event)
> +{
> + return FIELD_GET(CPMU_ATTR_CONFIG1_THRESHOLD_MSK, event->attr.config1);
> +}
> +
> +static bool cpmu_config1_get_invert(struct perf_event *event)
> +{
> + return FIELD_GET(CPMU_ATTR_CONFIG1_INVERT_MSK, event->attr.config1);
> +}
> +
> +static bool cpmu_config1_get_edge(struct perf_event *event)
> +{
> + return FIELD_GET(CPMU_ATTR_CONFIG1_EDGE_MSK, event->attr.config1);
> +}
> +
> +/*
> + * CPMU specification allows for 8 filters, each with a 16 bit value...
> + * So we need to find 8x16bits to store it in.
> + * As the value used for disable is 0xffff, a separate enable switch
> + * is needed.
> + */
> +
> +static bool cpmu_config1_hdm_filter_en(struct perf_event *event)
> +{
> + return FIELD_GET(CPMU_ATTR_CONFIG1_FILTER_EN_MSK, event->attr.config1);
> +}
> +
> +static u16 cpmu_config2_get_hdm_decoder(struct perf_event *event)
> +{
> + return FIELD_GET(CPMU_ATTR_CONFIG2_HDM_MSK, event->attr.config2);
> +}
> +
> +static ssize_t cpmu_event_sysfs_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct perf_pmu_events_attr *pmu_attr =
> + container_of(attr, struct perf_pmu_events_attr, attr);
> +
> + return sysfs_emit(buf, "config=%#llx\n", pmu_attr->id);
> +}
> +
> +#define CPMU_PMU_EVENT_ATTR(_name, _vid, _gid, _msk) \
> + PMU_EVENT_ATTR_ID(_name, cpmu_event_sysfs_show, \
> + ((u64)(_vid) << 48) | ((u64)(_gid) << 32) | (u64)(_msk))
> +
> +/* For CXL spec defined events */
> +#define CPMU_PMU_EVENT_CXL_ATTR(_name, _gid, _msk) \
> + CPMU_PMU_EVENT_ATTR(_name, PCI_DVSEC_VENDOR_ID_CXL, _gid, _msk)
> +
> +static struct attribute *cpmu_event_attrs[] = {
> + CPMU_PMU_EVENT_CXL_ATTR(clock_ticks, CPMU_GID_CLOCK_TICKS, BIT(0)),
> + /* CXL rev 3.0 Table 3-17 - Device to Host Requests */
> + CPMU_PMU_EVENT_CXL_ATTR(d2h_req_rdcurr, CPMU_GID_D2H_REQ, BIT(1)),
> + CPMU_PMU_EVENT_CXL_ATTR(d2h_req_rdown, CPMU_GID_D2H_REQ, BIT(2)),
> + CPMU_PMU_EVENT_CXL_ATTR(d2h_req_rdshared, CPMU_GID_D2H_REQ, BIT(3)),
> + CPMU_PMU_EVENT_CXL_ATTR(d2h_req_rdany, CPMU_GID_D2H_REQ, BIT(4)),
> + CPMU_PMU_EVENT_CXL_ATTR(d2h_req_rdownnodata, CPMU_GID_D2H_REQ, BIT(5)),
> + CPMU_PMU_EVENT_CXL_ATTR(d2h_req_itomwr, CPMU_GID_D2H_REQ, BIT(6)),
> + CPMU_PMU_EVENT_CXL_ATTR(d2h_req_wrcurr, CPMU_GID_D2H_REQ, BIT(7)),
> + CPMU_PMU_EVENT_CXL_ATTR(d2h_req_clflush, CPMU_GID_D2H_REQ, BIT(8)),
> + CPMU_PMU_EVENT_CXL_ATTR(d2h_req_cleanevict, CPMU_GID_D2H_REQ, BIT(9)),
> + CPMU_PMU_EVENT_CXL_ATTR(d2h_req_dirtyevict, CPMU_GID_D2H_REQ, BIT(10)),
> + CPMU_PMU_EVENT_CXL_ATTR(d2h_req_cleanevictnodata, CPMU_GID_D2H_REQ, BIT(11)),
> + CPMU_PMU_EVENT_CXL_ATTR(d2h_req_wowrinv, CPMU_GID_D2H_REQ, BIT(12)),
> + CPMU_PMU_EVENT_CXL_ATTR(d2h_req_wowrinvf, CPMU_GID_D2H_REQ, BIT(13)),
> + CPMU_PMU_EVENT_CXL_ATTR(d2h_req_wrinv, CPMU_GID_D2H_REQ, BIT(14)),
> + CPMU_PMU_EVENT_CXL_ATTR(d2h_req_cacheflushed, CPMU_GID_D2H_REQ, BIT(16)),
> + /* CXL rev 3.0 Table 3-20 - D2H Repsonse Encodings */
> + CPMU_PMU_EVENT_CXL_ATTR(d2h_rsp_rspihiti, CPMU_GID_D2H_RSP, BIT(4)),
> + CPMU_PMU_EVENT_CXL_ATTR(d2h_rsp_rspvhitv, CPMU_GID_D2H_RSP, BIT(6)),
> + CPMU_PMU_EVENT_CXL_ATTR(d2h_rsp_rspihitse, CPMU_GID_D2H_RSP, BIT(5)),
> + CPMU_PMU_EVENT_CXL_ATTR(d2h_rsp_rspshitse, CPMU_GID_D2H_RSP, BIT(1)),
> + CPMU_PMU_EVENT_CXL_ATTR(d2h_rsp_rspsfwdm, CPMU_GID_D2H_RSP, BIT(7)),
> + CPMU_PMU_EVENT_CXL_ATTR(d2h_rsp_rspifwdm, CPMU_GID_D2H_RSP, BIT(15)),
> + CPMU_PMU_EVENT_CXL_ATTR(d2h_rsp_rspvfwdv, CPMU_GID_D2H_RSP, BIT(22)),
> + /* CXL rev 3.0 Table 3-21 - CXL.cache - Mapping of H2D Requests to D2H Responses */
> + CPMU_PMU_EVENT_CXL_ATTR(h2d_req_snpdata, CPMU_GID_H2D_REQ, BIT(1)),
> + CPMU_PMU_EVENT_CXL_ATTR(h2d_req_snpinv, CPMU_GID_H2D_REQ, BIT(2)),
> + CPMU_PMU_EVENT_CXL_ATTR(h2d_req_snpcur, CPMU_GID_H2D_REQ, BIT(3)),
> + /* CXL rev 3.0 Table 3-22 - H2D Response Opcode Encodings */
> + CPMU_PMU_EVENT_CXL_ATTR(h2d_rsp_writepull, CPMU_GID_H2D_RSP, BIT(1)),
> + CPMU_PMU_EVENT_CXL_ATTR(h2d_rsp_go, CPMU_GID_H2D_RSP, BIT(4)),
> + CPMU_PMU_EVENT_CXL_ATTR(h2d_rsp_gowritepull, CPMU_GID_H2D_RSP, BIT(5)),
> + CPMU_PMU_EVENT_CXL_ATTR(h2d_rsp_extcmp, CPMU_GID_H2D_RSP, BIT(6)),
> + CPMU_PMU_EVENT_CXL_ATTR(h2d_rsp_gowritepulldrop, CPMU_GID_H2D_RSP, BIT(8)),
> + CPMU_PMU_EVENT_CXL_ATTR(h2d_rsp_fastgowritepull, CPMU_GID_H2D_RSP, BIT(13)),
> + CPMU_PMU_EVENT_CXL_ATTR(h2d_rsp_goerrwritepull, CPMU_GID_H2D_RSP, BIT(15)),
> + /* CXL rev 3.0 Table 13-5 directly lists these */
> + CPMU_PMU_EVENT_CXL_ATTR(cachedata_d2h_data, CPMU_GID_CACHE_DATA, BIT(0)),
> + CPMU_PMU_EVENT_CXL_ATTR(cachedata_h2d_data, CPMU_GID_CACHE_DATA, BIT(1)),
> + /* CXL rev 3.0 Table 3-29 M2S Req Memory Opcodes */
> + CPMU_PMU_EVENT_CXL_ATTR(m2s_req_meminv, CPMU_GID_M2S_REQ, BIT(0)),
> + CPMU_PMU_EVENT_CXL_ATTR(m2s_req_memrd, CPMU_GID_M2S_REQ, BIT(1)),
> + CPMU_PMU_EVENT_CXL_ATTR(m2s_req_memrddata, CPMU_GID_M2S_REQ, BIT(2)),
> + CPMU_PMU_EVENT_CXL_ATTR(m2s_req_memrdfwd, CPMU_GID_M2S_REQ, BIT(3)),
> + CPMU_PMU_EVENT_CXL_ATTR(m2s_req_memwrfwd, CPMU_GID_M2S_REQ, BIT(4)),
> + CPMU_PMU_EVENT_CXL_ATTR(m2s_req_memspecrd, CPMU_GID_M2S_REQ, BIT(8)),
> + CPMU_PMU_EVENT_CXL_ATTR(m2s_req_meminvnt, CPMU_GID_M2S_REQ, BIT(9)),
> + CPMU_PMU_EVENT_CXL_ATTR(m2s_req_memcleanevict, CPMU_GID_M2S_REQ, BIT(10)),
> + /* CXL rev 3.0 Table 3-35 M2S RwD Memory Opcodes */
> + CPMU_PMU_EVENT_CXL_ATTR(m2s_rwd_memwr, CPMU_GID_M2S_RWD, BIT(1)),
> + CPMU_PMU_EVENT_CXL_ATTR(m2s_rwd_memwrptl, CPMU_GID_M2S_RWD, BIT(2)),
> + CPMU_PMU_EVENT_CXL_ATTR(m2s_rwd_biconflict, CPMU_GID_M2S_RWD, BIT(4)),
> + /* CXL rev 3.0 Table 3-38 M2S BIRsp Memory Opcodes */
> + CPMU_PMU_EVENT_CXL_ATTR(m2s_birsp_i, CPMU_GID_M2S_BIRSP, BIT(0)),
> + CPMU_PMU_EVENT_CXL_ATTR(m2s_birsp_s, CPMU_GID_M2S_BIRSP, BIT(1)),
> + CPMU_PMU_EVENT_CXL_ATTR(m2s_birsp_e, CPMU_GID_M2S_BIRSP, BIT(2)),
> + CPMU_PMU_EVENT_CXL_ATTR(m2s_birsp_iblk, CPMU_GID_M2S_BIRSP, BIT(4)),
> + CPMU_PMU_EVENT_CXL_ATTR(m2s_birsp_sblk, CPMU_GID_M2S_BIRSP, BIT(5)),
> + CPMU_PMU_EVENT_CXL_ATTR(m2s_birsp_eblk, CPMU_GID_M2S_BIRSP, BIT(6)),
> + /* CXL rev 3.0 Table 3-40 S2M BISnp Opcodes */
> + CPMU_PMU_EVENT_CXL_ATTR(s2m_bisnp_cur, CPMU_GID_S2M_BISNP, BIT(0)),
> + CPMU_PMU_EVENT_CXL_ATTR(s2m_bisnp_data, CPMU_GID_S2M_BISNP, BIT(1)),
> + CPMU_PMU_EVENT_CXL_ATTR(s2m_bisnp_inv, CPMU_GID_S2M_BISNP, BIT(2)),
> + CPMU_PMU_EVENT_CXL_ATTR(s2m_bisnp_curblk, CPMU_GID_S2M_BISNP, BIT(4)),
> + CPMU_PMU_EVENT_CXL_ATTR(s2m_bisnp_datblk, CPMU_GID_S2M_BISNP, BIT(5)),
> + CPMU_PMU_EVENT_CXL_ATTR(s2m_bisnp_invblk, CPMU_GID_S2M_BISNP, BIT(6)),
> + /* CXL rev 3.0 Table 3-43 S2M NDR Opcopdes */
> + CPMU_PMU_EVENT_CXL_ATTR(s2m_ndr_cmp, CPMU_GID_S2M_NDR, BIT(0)),
> + CPMU_PMU_EVENT_CXL_ATTR(s2m_ndr_cmps, CPMU_GID_S2M_NDR, BIT(1)),
> + CPMU_PMU_EVENT_CXL_ATTR(s2m_ndr_cmpe, CPMU_GID_S2M_NDR, BIT(2)),
> + CPMU_PMU_EVENT_CXL_ATTR(s2m_ndr_biconflictack, CPMU_GID_S2M_NDR, BIT(3)),
> + /* CXL rev 3.0 Table 3-46 S2M DRS opcodes */
> + CPMU_PMU_EVENT_CXL_ATTR(s2m_drs_memdata, CPMU_GID_S2M_DRS, BIT(0)),
> + CPMU_PMU_EVENT_CXL_ATTR(s2m_drs_memdatanxm, CPMU_GID_S2M_DRS, BIT(1)),
> + /* CXL rev 3.0 Table 13-5 directly lists these */
> + CPMU_PMU_EVENT_CXL_ATTR(ddr_act, CPMU_GID_DDR, BIT(0)),
> + CPMU_PMU_EVENT_CXL_ATTR(ddr_pre, CPMU_GID_DDR, BIT(1)),
> + CPMU_PMU_EVENT_CXL_ATTR(ddr_casrd, CPMU_GID_DDR, BIT(2)),
> + CPMU_PMU_EVENT_CXL_ATTR(ddr_caswr, CPMU_GID_DDR, BIT(3)),
> + CPMU_PMU_EVENT_CXL_ATTR(ddr_refresh, CPMU_GID_DDR, BIT(4)),
> + CPMU_PMU_EVENT_CXL_ATTR(ddr_selfrefreshent, CPMU_GID_DDR, BIT(5)),
> + CPMU_PMU_EVENT_CXL_ATTR(ddr_rfm, CPMU_GID_DDR, BIT(6)),
> + NULL
> +};
> +
> +static struct cpmu_event *cpmu_find_fixed_counter_event(struct cpmu_info *info,
> + int vid, int gid, int msk)
> +{
> + struct cpmu_event *cpmu_ev;
> +
> + list_for_each_entry(cpmu_ev, &info->events_fixed, node) {
> + if (vid != cpmu_ev->vid || gid != cpmu_ev->gid)
> + continue;
> +
> + /* Precise match for fixed counter */
> + if (msk == cpmu_ev->msk)
> + return cpmu_ev;
> + }
> +
> + return ERR_PTR(-EINVAL);
> +}
> +
> +static struct cpmu_event *cpmu_find_config_counter_event(struct cpmu_info *info,
> + int vid, int gid, int msk)
> +{
> + struct cpmu_event *cpmu_ev;
> +
> + list_for_each_entry(cpmu_ev, &info->events_configurable, node) {
> + if (vid != cpmu_ev->vid || gid != cpmu_ev->gid)
> + continue;
> +
> + /* Request mask must be subset of supported */
> + if (msk & ~cpmu_ev->msk)
> + continue;
> +
> + return cpmu_ev;
> + }
> +
> + return ERR_PTR(-EINVAL);
> +}
> +
> +static umode_t cpmu_event_is_visible(struct kobject *kobj, struct attribute *attr, int a)
> +{
> + struct device_attribute *dev_attr = container_of(attr, struct device_attribute, attr);
> + struct perf_pmu_events_attr *pmu_attr =
> + container_of(dev_attr, struct perf_pmu_events_attr, attr);
> + struct device *dev = kobj_to_dev(kobj);
> + struct cpmu_info *info = dev_get_drvdata(dev);
> + int vid = FIELD_GET(CPMU_ATTR_CONFIG_VID_MSK, pmu_attr->id);
> + int gid = FIELD_GET(CPMU_ATTR_CONFIG_GID_MSK, pmu_attr->id);
> + int msk = FIELD_GET(CPMU_ATTR_CONFIG_MASK_MSK, pmu_attr->id);
> +
> + if (!IS_ERR(cpmu_find_fixed_counter_event(info, vid, gid, msk)))
> + return attr->mode;
> +
> + if (!IS_ERR(cpmu_find_config_counter_event(info, vid, gid, msk)))
> + return attr->mode;
> +
> + return 0;
> +}
> +
> +static const struct attribute_group cpmu_events = {
> + .name = "events",
> + .attrs = cpmu_event_attrs,
> + .is_visible = cpmu_event_is_visible,
> +};
> +
> +static ssize_t cpumask_show(struct device *dev, struct device_attribute *attr,
> + char *buf)
> +{
> + struct cpmu_info *info = dev_get_drvdata(dev);
> +
> + return cpumap_print_to_pagebuf(true, buf, cpumask_of(info->on_cpu));
> +}
> +static DEVICE_ATTR_RO(cpumask);
> +
> +static struct attribute *cpmu_cpumask_attrs[] = {
> + &dev_attr_cpumask.attr,
> + NULL
> +};
> +
> +static const struct attribute_group cpmu_cpumask_group = {
> + .attrs = cpmu_cpumask_attrs,
> +};
> +
> +static const struct attribute_group *cpmu_attr_groups[] = {
> + &cpmu_events,
> + &cpmu_format_group,
> + &cpmu_cpumask_group,
> + NULL
> +};
> +
> +/* If counter_idx == NULL, don't try to allocate a counter. */
> +static int cpmu_get_event_idx(struct perf_event *event, int *counter_idx, int *event_idx)
> +{
> + struct cpmu_info *info = pmu_to_cpmu_info(event->pmu);
> + DECLARE_BITMAP(configurable_and_free, CPMU_MAX_COUNTERS);
> + struct cpmu_event *cpmu_ev;
> + u32 mask;
> + u16 gid, vid;
> + int i;
> +
> + vid = cpmu_config_get_vid(event);
> + gid = cpmu_config_get_gid(event);
> + mask = cpmu_config_get_mask(event);
> +
> + cpmu_ev = cpmu_find_fixed_counter_event(info, vid, gid, mask);
> + if (!IS_ERR(cpmu_ev)) {
> + if (!counter_idx)
> + return 0;
> + if (!test_bit(cpmu_ev->counter_idx, info->used_counter_bm)) {
> + *counter_idx = cpmu_ev->counter_idx;
> + return 0;
> + }
> + /* Fixed counter is in use, but maybe a configurable one? */
> + }
> +
> + cpmu_ev = cpmu_find_config_counter_event(info, vid, gid, mask);
> + if (!IS_ERR(cpmu_ev)) {
> + if (!counter_idx)
> + return 0;
> +
> + bitmap_andnot(configurable_and_free, info->conf_counter_bm,
> + info->used_counter_bm, CPMU_MAX_COUNTERS);
> +
> + i = find_first_bit(configurable_and_free, CPMU_MAX_COUNTERS);
> + if (i == CPMU_MAX_COUNTERS)
> + return -EINVAL;
> +
> + *counter_idx = i;
> + return 0;
> + }
> +
> + return -EINVAL;
> +}
> +
> +static int cpmu_event_init(struct perf_event *event)
> +{
> + struct cpmu_info *info = pmu_to_cpmu_info(event->pmu);
> +
> + event->cpu = info->on_cpu;
> + /* Top level type sanity check - is this a Hardware Event being requested */
> + if (event->attr.type != event->pmu->type)
> + return -ENOENT;
> +
> + if (is_sampling_event(event) || event->attach_state & PERF_ATTACH_TASK)
> + return -EOPNOTSUPP;
> + /* TODO: Validation of any filter */
> +
> + /*
> + * Verify that it is possible to count what was requested. Either must
> + * be a fixed counter that is a precise match or a configurable counter
> + * where this is a subset.
> + */
> + return cpmu_get_event_idx(event, NULL, NULL);
> +}
> +
> +static void cpmu_pmu_enable(struct pmu *pmu)
> +{
> + struct cpmu_info *info = pmu_to_cpmu_info(pmu);
> + void __iomem *base = info->base;
> +
> + /* We don't have a global enable, but we 'might' have a global freeze which we can use */
> + if (info->freeze_for_enable) {
> + /* Can assume frozen at this stage */
> + writeq(0, base + CPMU_FREEZE_REG);
> +
> + return;
> + }
> +}
> +
> +static void cpmu_pmu_disable(struct pmu *pmu)
> +{
> + struct cpmu_info *info = pmu_to_cpmu_info(pmu);
> + void __iomem *base = info->base;
> +
> + if (info->freeze_for_enable) {
> + /*
> + * Whilst bits above number of counters are RsvdZ
> + * they are unlikely to be repurposed given
> + * number of counters is allowed to be 64 leaving
> + * no reserved bits. Hence this is only slightly
> + * naughty.
> + */
> + writeq(GENMASK_ULL(63, 0), base + CPMU_FREEZE_REG);
> + return;
> + }
> +}
> +
> +static void cpmu_event_start(struct perf_event *event, int flags)
> +{
> + struct cpmu_info *info = pmu_to_cpmu_info(event->pmu);
> + struct hw_perf_event *hwc = &event->hw;
> + void __iomem *base = info->base;
> + u64 cfg;
> +
> + if (WARN_ON_ONCE(!(hwc->state & PERF_HES_STOPPED)))
> + return;
> +
> + WARN_ON_ONCE(!(hwc->state & PERF_HES_UPTODATE));
> + hwc->state = 0;
> +
> + /*
> + * Currently only hdm filter control is implemnted, this code will
> + * want generalizing when more filters are added.
> + */
> + if (info->filter_hdm) {
> + if (cpmu_config1_hdm_filter_en(event))
> + cfg = cpmu_config2_get_hdm_decoder(event);
> + else
> + cfg = GENMASK(15, 0); /* No filtering if 0xFFFF_FFFF */
> + writeq(cfg, base + CPMU_FILTER_CFG_REG(hwc->idx, 0));
> + }
> +
> + cfg = readq(base + CPMU_COUNTER_CFG_REG(hwc->idx));
I don't think we need the previous value. Just overwrite it.
> + cfg |= FIELD_PREP(CPMU_COUNTER_CFG_INT_ON_OVRFLW, 1);
> + cfg |= FIELD_PREP(CPMU_COUNTER_CFG_ENABLE, 1);
> + cfg |= FIELD_PREP(CPMU_COUNTER_CFG_EDGE, cpmu_config1_get_edge(event) ? 1 : 0);
> + cfg |= FIELD_PREP(CPMU_COUNTER_CFG_INVERT, cpmu_config1_get_invert(event) ? 1 : 0);
> +
> + /* Fixed purpose counters have next two fields RO */
> + if (test_bit(hwc->idx, info->conf_counter_bm)) {
> + cfg |= FIELD_PREP(CPMU_COUNTER_CFG_EVENT_GRP_ID_IDX_MSK, hwc->event_base);
> + cfg |= FIELD_PREP(CPMU_COUNTER_CFG_EVENTS_MSK, cpmu_config_get_mask(event));
> + }
> + cfg &= ~CPMU_COUNTER_CFG_THRESHOLD_MSK;
> + /*
> + * For events that generate only 1 count per clock the CXL 3.0 spec
> + * states the threshold shall be set to 1 but if set to 0 it will
> + * count the raw value anwyay?
> + * There is no definition of what events will count multiple per cycle
> + * and hence to which non 1 values of threshold can apply.
> + * (CXL 3.0 8.2.7.2.1 Counter Configuration - threshold field definition)
> + */
> + cfg |= FIELD_PREP(CPMU_COUNTER_CFG_THRESHOLD_MSK,
> + cpmu_config1_get_threshold(event));
> + writeq(cfg, base + CPMU_COUNTER_CFG_REG(hwc->idx));
> +
> + local64_set(&hwc->prev_count, 0);
> + writeq(0, base + CPMU_COUNTER_REG(hwc->idx));
The counter is reset twice. The other is in add()->cpmu_reset_counter().
I think you can remove the one in add().
> +
> + perf_event_update_userpage(event);
> +}
> +
> +static u64 cpmu_read_counter(struct perf_event *event)
> +{
> + struct cpmu_info *info = pmu_to_cpmu_info(event->pmu);
> + void __iomem *base = info->base;
> +
> + return readq(base + CPMU_COUNTER_REG(event->hw.idx));
> +}
> +
> +static void __cpmu_read(struct perf_event *event, bool overflow)
> +{
> + struct cpmu_info *info = pmu_to_cpmu_info(event->pmu);
> + struct hw_perf_event *hwc = &event->hw;
> + u64 new_cnt, prev_cnt, delta;
> +
> + do {
> + prev_cnt = local64_read(&hwc->prev_count);
> + new_cnt = cpmu_read_counter(event);
> + } while (local64_cmpxchg(&hwc->prev_count, prev_cnt, new_cnt) != prev_cnt);
> +
> + /*
> + * If we know an overflow occur then take that into account.
> + * Note counter is not reset as that would lose events
> + */
> + delta = (new_cnt - prev_cnt) & GENMASK_ULL(info->counter_width - 1, 0);
> + if (overflow && delta < GENMASK_ULL(info->counter_width - 1, 0))
> + delta += (1UL << info->counter_width);
> +
> + local64_add(delta, &event->count);
> +}
> +
> +static void cpmu_read(struct perf_event *event)
> +{
> + __cpmu_read(event, false);
> +}
> +
> +static void cpmu_event_stop(struct perf_event *event, int flags)
> +{
> + struct cpmu_info *info = pmu_to_cpmu_info(event->pmu);
> + void __iomem *base = info->base;
> + struct hw_perf_event *hwc = &event->hw;
> + u64 cfg;
> +
> + cpmu_read(event);
> + WARN_ON_ONCE(hwc->state & PERF_HES_STOPPED);
> + hwc->state |= PERF_HES_STOPPED;
> +
> + cfg = readq(base + CPMU_COUNTER_CFG_REG(hwc->idx));
> + cfg &= ~(FIELD_PREP(CPMU_COUNTER_CFG_INT_ON_OVRFLW, 1) |
> + FIELD_PREP(CPMU_COUNTER_CFG_ENABLE, 1));
> + writeq(cfg, base + CPMU_COUNTER_CFG_REG(hwc->idx));
> +
> + hwc->state |= PERF_HES_UPTODATE;
> +}
> +
> +/*
> + * Reset ensures no possibility of any information leaking to wrong
> + * counter. Note that all fields written during start()
> + */
> +static void cpmu_reset_counter(struct cpmu_info *info, int idx)
> +{
> + void __iomem *base = info->base;
> +
> + /* Much of this register is read only */
> + writeq(0, base + CPMU_EVENT_CAP_REG(idx));
CPMU_COUNTER_CFG_REG?
I don't think we need to reset the config here, since it will be rewrite
in cpmu_event_start().
> + /* Filters are not per counter, so no reset here */
> + writeq(0, base + CPMU_COUNTER_REG(idx));
> +}
> +
> +static int cpmu_event_add(struct perf_event *event, int flags)
> +{
> + struct cpmu_info *info = pmu_to_cpmu_info(event->pmu);
> + struct hw_perf_event *hwc = &event->hw;
> + int idx, rc;
> + int event_idx = 0;
> +
> + hwc->state = PERF_HES_STOPPED | PERF_HES_UPTODATE;
> +
> + rc = cpmu_get_event_idx(event, &idx, &event_idx);
> + if (rc < 0)
> + return rc;
> +
> + hwc->idx = idx;
> +
> + /* Only set for configurable counters */
> + hwc->event_base = event_idx;
> + info->hw_events[idx] = event;
> + set_bit(idx, info->used_counter_bm);
> +
> + cpmu_reset_counter(info, idx);
> +
> + if (flags & PERF_EF_START)
> + cpmu_event_start(event, PERF_EF_RELOAD);
> +
> + return 0;
> +}
> +
> +static void cpmu_event_del(struct perf_event *event, int flags)
> +{
> + struct cpmu_info *info = pmu_to_cpmu_info(event->pmu);
> + struct hw_perf_event *hwc = &event->hw;
> +
> + cpmu_event_stop(event, PERF_EF_UPDATE);
> + clear_bit(hwc->idx, info->used_counter_bm);
> + info->hw_events[hwc->idx] = NULL;
> + perf_event_update_userpage(event);
> +}
> +
> +static irqreturn_t cpmu_irq(int irq, void *data)
> +{
> + struct cpmu_info *info = data;
> + void __iomem *base = info->base;
> + u64 overflowed;
> + DECLARE_BITMAP(overflowedbm, 64);
> + int i;
> +
> + overflowed = readq(base + CPMU_OVERFLOW_REG);
> +
> + /* Interrupt may be shared, so maybe it isn't ours */
> + if (!overflowed)
> + return IRQ_NONE;
> +
> + bitmap_from_arr64(overflowedbm, &overflowed, 64);
> + for_each_set_bit(i, overflowedbm, info->num_counters) {
> + struct perf_event *event = info->hw_events[i];
> +
> + if (!event) {
> + dev_dbg(info->pmu.dev,
> + "overflow but on non enabled counter %d\n", i);
> + continue;
> + }
> +
> + __cpmu_read(event, true);
> + }
> +
> + writeq(overflowed, base + CPMU_OVERFLOW_REG);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static int cxl_cpmu_probe(struct device *dev)
> +{
> + struct cxl_cpmu *cpmu = to_cxl_cpmu(dev);
> + struct pci_dev *pdev = to_pci_dev(dev->parent);
> + struct cpmu_info *info;
> + char *irq_name;
> + int rc, irq;
> +
> + info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
> + if (!info)
> + return -ENOMEM;
> +
> + INIT_LIST_HEAD(&info->events_fixed);
> + INIT_LIST_HEAD(&info->events_configurable);
> +
> + info->base = cpmu->base;
> +
> + info->on_cpu = -1;
> + rc = cpmu_parse_caps(dev, info);
> + if (rc)
> + return rc;
> +
> + info->hw_events = devm_kcalloc(dev, sizeof(*info->hw_events),
> + info->num_counters, GFP_KERNEL);
> + if (!info->hw_events)
> + return -ENOMEM;
> +
> + info->pmu = (struct pmu) {
> + .name = dev_name(dev),
> + .parent = dev,
I don't see the PMU parent is used anywhere.
Please remove this and drop the Patch 2 from this series.
If there will be other followup patches, please add the PMU parent
support there.
Thanks,
Kan
> + .module = THIS_MODULE,
> + .event_init = cpmu_event_init,
> + .pmu_enable = cpmu_pmu_enable,
> + .pmu_disable = cpmu_pmu_disable,
> + .add = cpmu_event_add,
> + .del = cpmu_event_del,
> + .start = cpmu_event_start,
> + .stop = cpmu_event_stop,
> + .read = cpmu_read,
> + .task_ctx_nr = perf_invalid_context,
> + .attr_groups = cpmu_attr_groups,
> + .capabilities = PERF_PMU_CAP_NO_EXCLUDE,
> + };
> +
> + if (info->irq <= 0)
> + return -EINVAL;
> +
> + rc = pci_irq_vector(pdev, info->irq);
> + if (rc < 0)
> + return rc;
> + irq = rc;
> +
> + irq_name = devm_kasprintf(dev, GFP_KERNEL, "%s_overflow\n", dev_name(dev));
> + if (!irq_name)
> + return -ENOMEM;
> +
> + rc = devm_request_irq(dev, irq, cpmu_irq, IRQF_SHARED, irq_name, info);
> + if (rc)
> + return rc;
> + info->irq = irq;
> +
> + rc = cpuhp_state_add_instance(cpmu_cpuhp_state_num, &info->node);
> + if (rc)
> + return rc;
> +
> + rc = perf_pmu_register(&info->pmu, info->pmu.name, -1);
> + if (rc)
> + return rc;
> +
> + dev_set_drvdata(dev, info);
> +
> + return 0;
> +}
> +
> +static void cxl_cpmu_remove(struct device *dev)
> +{
> + struct cpmu_info *info = dev_get_drvdata(dev);
> +
> + perf_pmu_unregister(&info->pmu);
> + cpuhp_state_remove_instance_nocalls(cpmu_cpuhp_state_num, &info->node);
> +}
> +
> +static struct cxl_driver cxl_cpmu_driver = {
> + .name = "cxl_cpmu",
> + .probe = cxl_cpmu_probe,
> + .remove = cxl_cpmu_remove,
> + .id = CXL_DEVICE_CPMU,
> +};
> +
> +static int cpmu_online_cpu(unsigned int cpu, struct hlist_node *node)
> +{
> + struct cpmu_info *info = hlist_entry_safe(node, struct cpmu_info, node);
> +
> + if (info->on_cpu != -1)
> + return 0;
> +
> + info->on_cpu = cpu;
> + WARN_ON(irq_set_affinity(info->irq, cpumask_of(cpu)));
> +
> + return 0;
> +}
> +
> +static int cpmu_offline_cpu(unsigned int cpu, struct hlist_node *node)
> +{
> + struct cpmu_info *info = hlist_entry_safe(node, struct cpmu_info, node);
> + unsigned int target;
> +
> + if (info->on_cpu != cpu)
> + return 0;
> +
> + info->on_cpu = -1;
> + target = cpumask_first(cpu_online_mask);
> + if (target >= nr_cpu_ids) {
> + dev_err(info->pmu.dev, "Unable to find a suitable CPU\n");
> + return 0;
> + }
> +
> + perf_pmu_migrate_context(&info->pmu, cpu, target);
> + info->on_cpu = target;
> + WARN_ON(irq_set_affinity(info->irq, cpumask_of(target)));
> +
> + return 0;
> +}
> +
> +static __init int cxl_cpmu_init(void)
> +{
> + int rc;
> +
> + rc = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN,
> + "AP_PERF_CPMU_ONLINE",
> + cpmu_online_cpu, cpmu_offline_cpu);
> + if (rc < 0)
> + return rc;
> + cpmu_cpuhp_state_num = rc;
> +
> + rc = cxl_driver_register(&cxl_cpmu_driver);
> + if (rc)
> + cpuhp_remove_multi_state(cpmu_cpuhp_state_num);
> +
> + return rc;
> +}
> +
> +static __exit void cxl_cpmu_exit(void)
> +{
> + cxl_driver_unregister(&cxl_cpmu_driver);
> + cpuhp_remove_multi_state(cpmu_cpuhp_state_num);
> +}
> +
> +MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(CXL);
> +module_init(cxl_cpmu_init);
> +module_exit(cxl_cpmu_exit);
> +MODULE_ALIAS_CXL(CXL_DEVICE_CPMU);
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