Re: [RFC PATCH 1/9] cxl/mem: Implement Get Event Records command

From: Dave Jiang
Date: Wed Aug 17 2022 - 18:54:23 EST


On 8/12/2022 10:32 PM, ira.weiny@xxxxxxxxx wrote:
From: Ira Weiny <ira.weiny@xxxxxxxxx>

Event records are defined for CXL devices. Each record is reported in
one event log. Devices are required to support the storage of at least
one event record in each event log type.

Devices track event log overflow by incrementing a counter and tracking
the time of the first and last overflow event seen.

Software queries events via the Get Event Record mailbox command; CXL
v3.0 section 8.2.9.2.2.

Issue the Get Event Record mailbox command on driver load. Trace each
record found, as well as any overflow conditions. Only 1 event is
requested for each query. Optimization of multiple record queries is
deferred.

This patch traces a raw event record only and leaves the specific event
record types to subsequent patches.

NOTE: checkpatch is not completely happy with the tracing part of this
patch but AFAICT it is correct. I'm open to suggestions if I've done
something wrong.

Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx>
---
MAINTAINERS | 1 +
drivers/cxl/core/mbox.c | 60 ++++++++++++++
drivers/cxl/cxlmem.h | 66 ++++++++++++++++
include/trace/events/cxl-events.h | 127 ++++++++++++++++++++++++++++++
include/uapi/linux/cxl_mem.h | 1 +
5 files changed, 255 insertions(+)
create mode 100644 include/trace/events/cxl-events.h

diff --git a/MAINTAINERS b/MAINTAINERS
index 54fa6e2059de..1cb9cec31009 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -5014,6 +5014,7 @@ M: Dan Williams <dan.j.williams@xxxxxxxxx>
L: linux-cxl@xxxxxxxxxxxxxxx
S: Maintained
F: drivers/cxl/
+F: include/trace/events/cxl*.h
F: include/uapi/linux/cxl_mem.h
CONEXANT ACCESSRUNNER USB DRIVER
diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
index 16176b9278b4..2cceed8608dc 100644
--- a/drivers/cxl/core/mbox.c
+++ b/drivers/cxl/core/mbox.c
@@ -7,6 +7,9 @@
#include <cxlmem.h>
#include <cxl.h>
+#define CREATE_TRACE_POINTS
+#include <trace/events/cxl-events.h>
+
#include "core.h"
static bool cxl_raw_allow_all;
@@ -48,6 +51,7 @@ static struct cxl_mem_command cxl_mem_commands[CXL_MEM_COMMAND_ID_MAX] = {
CXL_CMD(RAW, CXL_VARIABLE_PAYLOAD, CXL_VARIABLE_PAYLOAD, 0),
#endif
CXL_CMD(GET_SUPPORTED_LOGS, 0, CXL_VARIABLE_PAYLOAD, CXL_CMD_FLAG_FORCE_ENABLE),
+ CXL_CMD(GET_EVENT_RECORD, 1, CXL_VARIABLE_PAYLOAD, 0),
CXL_CMD(GET_FW_INFO, 0, 0x50, 0),
CXL_CMD(GET_PARTITION_INFO, 0, 0x20, 0),
CXL_CMD(GET_LSA, 0x8, CXL_VARIABLE_PAYLOAD, 0),
@@ -704,6 +708,62 @@ int cxl_enumerate_cmds(struct cxl_dev_state *cxlds)
}
EXPORT_SYMBOL_NS_GPL(cxl_enumerate_cmds, CXL);
+static int cxl_mem_get_records_log(struct cxl_dev_state *cxlds,
+ enum cxl_event_log_type type)
+{
+ struct cxl_get_event_payload payload;
+
+ do {
+ u8 log_type = type;
+ u16 record_count;
+ int rc;
+
+ rc = cxl_mbox_send_cmd(cxlds, CXL_MBOX_OP_GET_EVENT_RECORD,
+ &log_type, sizeof(log_type),
+ &payload, sizeof(payload));
+ if (rc)
+ return rc;
+
+ record_count = le16_to_cpu(payload.record_count);
+ if (record_count > 0)
+ trace_cxl_event(dev_name(cxlds->dev), type,
+ &payload.record);
+
+ if (payload.flags & CXL_GET_EVENT_FLAG_OVERFLOW)
+ trace_cxl_event_overflow(dev_name(cxlds->dev), type,
+ &payload);
+
+ } while (payload.flags & CXL_GET_EVENT_FLAG_MORE_RECORDS);
+
+ return 0;
+}
+
+/**
+ * cxl_mem_get_event_records - Get Event Records from the device
+ * @cxlds: The device data for the operation
+ *
+ * Retrieve all event records available on the device and report them as trace
+ * events.
+ *
+ * See CXL v3.0 @8.2.9.2.2 Get Event Records
+ */
+void cxl_mem_get_event_records(struct cxl_dev_state *cxlds)
+{
+ struct device *dev = cxlds->dev;
+ enum cxl_event_log_type log_type;
+
+ for (log_type = CXL_EVENT_TYPE_INFO;
+ log_type < CXL_EVENT_TYPE_MAX; log_type++) {
+ int rc;
+
+ rc = cxl_mem_get_records_log(cxlds, log_type);
+ if (rc)
+ dev_err(dev, "Failed to query %s Event Logs : %d",
+ cxl_event_log_type_str(log_type), rc);
+ }
+}
+EXPORT_SYMBOL_NS_GPL(cxl_mem_get_event_records, CXL);
+
/**
* cxl_mem_get_partition_info - Get partition info
* @cxlds: The device data for the operation
diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
index 88e3a8e54b6a..f83634f3bc8d 100644
--- a/drivers/cxl/cxlmem.h
+++ b/drivers/cxl/cxlmem.h
@@ -4,6 +4,7 @@
#define __CXL_MEM_H__
#include <uapi/linux/cxl_mem.h>
#include <linux/cdev.h>
+#include <linux/uuid.h>
#include "cxl.h"
/* CXL 2.0 8.2.8.5.1.1 Memory Device Status Register */
@@ -253,6 +254,7 @@ struct cxl_dev_state {
enum cxl_opcode {
CXL_MBOX_OP_INVALID = 0x0000,
CXL_MBOX_OP_RAW = CXL_MBOX_OP_INVALID,
+ CXL_MBOX_OP_GET_EVENT_RECORD = 0x0100,
CXL_MBOX_OP_GET_FW_INFO = 0x0200,
CXL_MBOX_OP_ACTIVATE_FW = 0x0202,
CXL_MBOX_OP_GET_SUPPORTED_LOGS = 0x0400,
@@ -322,6 +324,69 @@ struct cxl_mbox_identify {
u8 qos_telemetry_caps;
} __packed;
+/*
+ * Common Event Record Format
+ * CXL v3.0 section 8.2.9.2.1; Table 8-42
+ */
+struct cxl_event_record_hdr {
+ uuid_t id;
+ __le32 flags_length;
+ __le16 handle;
+ __le16 related_handle;
+ __le64 timestamp;
+ __le64 reserved1;
+ __le64 reserved2;
+} __packed;
+
+#define EVENT_RECORD_DATA_LENGTH 0x50
+struct cxl_event_record_raw {
+ struct cxl_event_record_hdr hdr;
+ u8 data[EVENT_RECORD_DATA_LENGTH];
+} __packed;
+
+/*
+ * Get Event Records output payload
+ * CXL v3.0 section 8.2.9.2.2; Table 8-50
+ *
+ * Space given for 1 record
+ */
+#define CXL_GET_EVENT_FLAG_OVERFLOW BIT(0)
+#define CXL_GET_EVENT_FLAG_MORE_RECORDS BIT(1)
+struct cxl_get_event_payload {
+ u8 flags;
+ u8 reserved1;
+ __le16 overflow_err_count;
+ __le64 first_overflow_timestamp;
+ __le64 last_overflow_timestamp;
+ __le16 record_count;
+ u8 reserved2[0xa];
+ struct cxl_event_record_raw record;
+} __packed;
+
+enum cxl_event_log_type {
+ CXL_EVENT_TYPE_INFO = 0x00,
+ CXL_EVENT_TYPE_WARN,
+ CXL_EVENT_TYPE_FAIL,
+ CXL_EVENT_TYPE_FATAL,
+ CXL_EVENT_TYPE_MAX
+};
+static inline char *cxl_event_log_type_str(enum cxl_event_log_type type)
+{
+ switch (type) {
+ case CXL_EVENT_TYPE_INFO:
+ return "Informational";
+ case CXL_EVENT_TYPE_WARN:
+ return "Warning";
+ case CXL_EVENT_TYPE_FAIL:
+ return "Failure";
+ case CXL_EVENT_TYPE_FATAL:
+ return "Fatal";
+ default:
+ break;
+ }
+ return "<unknown>";
+}
+
struct cxl_mbox_get_partition_info {
__le64 active_volatile_cap;
__le64 active_persistent_cap;
@@ -381,6 +446,7 @@ int cxl_mem_create_range_info(struct cxl_dev_state *cxlds);
struct cxl_dev_state *cxl_dev_state_create(struct device *dev);
void set_exclusive_cxl_commands(struct cxl_dev_state *cxlds, unsigned long *cmds);
void clear_exclusive_cxl_commands(struct cxl_dev_state *cxlds, unsigned long *cmds);
+void cxl_mem_get_event_records(struct cxl_dev_state *cxlds);
#ifdef CONFIG_CXL_SUSPEND
void cxl_mem_active_inc(void);
void cxl_mem_active_dec(void);
diff --git a/include/trace/events/cxl-events.h b/include/trace/events/cxl-events.h
new file mode 100644
index 000000000000..f4baeae66cf3
--- /dev/null
+++ b/include/trace/events/cxl-events.h
@@ -0,0 +1,127 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM cxl_events
+
+#if !defined(_CXL_TRACE_EVENTS_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _CXL_TRACE_EVENTS_H
+
+#include <linux/tracepoint.h>
+
+#define EVENT_LOGS \
+ EM(CXL_EVENT_TYPE_INFO, "Info") \
+ EM(CXL_EVENT_TYPE_WARN, "Warning") \
+ EM(CXL_EVENT_TYPE_FAIL, "Failure") \
+ EM(CXL_EVENT_TYPE_FATAL, "Fatal") \
+ EMe(CXL_EVENT_TYPE_MAX, "<undefined>")
+
+/*
+ * First define the enums in the above macros to be exported to userspace via
+ * TRACE_DEFINE_ENUM().
+ */
+#undef EM
+#undef EMe
+#define EM(a, b) TRACE_DEFINE_ENUM(a);
+#define EMe(a, b) TRACE_DEFINE_ENUM(a);
+
+EVENT_LOGS
+#define show_log_type(type) __print_symbolic(type, EVENT_LOGS)
+
+/*
+ * Now redefine the EM and EMe macros to map the enums to the strings that will
+ * be printed in the output
+ */
+#undef EM
+#undef EMe
+#define EM(a, b) {a, b},
+#define EMe(a, b) {a, b}
+
+TRACE_EVENT(cxl_event_overflow,

Kind of a general comment for the event names. Maybe just "overflow" instead of "cxl_event_overflow" since it shows up in sysfs under the cxl_events directory and becomes redundant?

- Dave

+
+ TP_PROTO(const char *dev_name, enum cxl_event_log_type log,
+ struct cxl_get_event_payload *payload),
+
+ TP_ARGS(dev_name, log, payload),
+
+ TP_STRUCT__entry(
+ __string(dev_name, dev_name)
+ __field(int, log)
+ __field(u16, count)
+ __field(u64, first)
+ __field(u64, last)
+ ),
+
+ TP_fast_assign(
+ __assign_str(dev_name, dev_name);
+ __entry->log = log;
+ __entry->count = le16_to_cpu(payload->overflow_err_count);
+ __entry->first = le64_to_cpu(payload->first_overflow_timestamp);
+ __entry->last = le64_to_cpu(payload->last_overflow_timestamp);
+ ),
+
+ TP_printk("%s: EVENT LOG %s OVERFLOW %u records from %llu to %llu",
+ __get_str(dev_name), show_log_type(__entry->log),
+ __entry->count, __entry->first, __entry->last)
+
+);
+
+/*
+ * Common Event Record Format
+ * CXL v2.0 section 8.2.9.1.1; Table 153
+ */
+#define CXL_EVENT_RECORD_FLAG_PERMANENT BIT(2)
+#define CXL_EVENT_RECORD_FLAG_MAINT_NEEDED BIT(3)
+#define CXL_EVENT_RECORD_FLAG_PERF_DEGRADED BIT(4)
+#define CXL_EVENT_RECORD_FLAG_HW_REPLACE BIT(5)
+#define show_hdr_flags(flags) __print_flags(flags, " | ", \
+ { CXL_EVENT_RECORD_FLAG_PERMANENT, "Permanent Condition" }, \
+ { CXL_EVENT_RECORD_FLAG_MAINT_NEEDED, "Maintanance Needed" }, \
+ { CXL_EVENT_RECORD_FLAG_PERF_DEGRADED, "Performance Degraded" }, \
+ { CXL_EVENT_RECORD_FLAG_HW_REPLACE, "Hardware Replacement Needed" } \
+)
+
+TRACE_EVENT(cxl_event,
+
+ TP_PROTO(const char *dev_name, enum cxl_event_log_type log,
+ struct cxl_event_record_raw *rec),
+
+ TP_ARGS(dev_name, log, rec),
+
+ TP_STRUCT__entry(
+ __string(dev_name, dev_name)
+ __field(int, log)
+ __array(u8, id, UUID_SIZE)
+ __field(u32, flags)
+ __field(u16, handle)
+ __field(u16, related_handle)
+ __field(u64, timestamp)
+ __array(u8, data, EVENT_RECORD_DATA_LENGTH)
+ __field(u8, length)
+ ),
+
+ TP_fast_assign(
+ __assign_str(dev_name, dev_name);
+ memcpy(__entry->id, &rec->hdr.id, UUID_SIZE);
+ __entry->log = log;
+ __entry->flags = le32_to_cpu(rec->hdr.flags_length) >> 8;
+ __entry->length = le32_to_cpu(rec->hdr.flags_length) & 0xFF;
+ __entry->handle = le16_to_cpu(rec->hdr.handle);
+ __entry->related_handle = le16_to_cpu(rec->hdr.related_handle);
+ __entry->timestamp = le64_to_cpu(rec->hdr.timestamp);
+ memcpy(__entry->data, &rec->data, EVENT_RECORD_DATA_LENGTH);
+ ),
+
+ TP_printk("%s: %s time=%llu id=%pUl handle=%x related_handle=%x hdr_flags='%s' " \
+ ": %s",
+ __get_str(dev_name), show_log_type(__entry->log),
+ __entry->timestamp, __entry->id, __entry->handle,
+ __entry->related_handle, show_hdr_flags(__entry->flags),
+ __print_hex(__entry->data, EVENT_RECORD_DATA_LENGTH)
+ )
+);
+
+#endif /* _CXL_TRACE_EVENTS_H */
+
+/* This part must be outside protection */
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_FILE cxl-events
+#include <trace/define_trace.h>
diff --git a/include/uapi/linux/cxl_mem.h b/include/uapi/linux/cxl_mem.h
index c71021a2a9ed..70459be5bdd4 100644
--- a/include/uapi/linux/cxl_mem.h
+++ b/include/uapi/linux/cxl_mem.h
@@ -24,6 +24,7 @@
___C(IDENTIFY, "Identify Command"), \
___C(RAW, "Raw device command"), \
___C(GET_SUPPORTED_LOGS, "Get Supported Logs"), \
+ ___C(GET_EVENT_RECORD, "Get Event Record"), \
___C(GET_FW_INFO, "Get FW Info"), \
___C(GET_PARTITION_INFO, "Get Partition Information"), \
___C(GET_LSA, "Get Label Storage Area"), \