diff mbox series

[v7,3/7] hw/cxl/events: Wire up get/clear event mailbox commands

Message ID 20230522150947.11546-4-Jonathan.Cameron@huawei.com
State Superseded
Headers show
Series QEMU CXL Provide mock CXL events and irq support | expand

Commit Message

Jonathan Cameron May 22, 2023, 3:09 p.m. UTC 
From: Ira Weiny <ira.weiny@intel.com>

CXL testing is benefited from an artificial event log injection
mechanism.

Add an event log infrastructure to insert, get, and clear events from
the various logs available on a device.

Replace the stubbed out CXL Get/Clear Event mailbox commands with
commands that operate on the new infrastructure.

Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
 include/hw/cxl/cxl_device.h |  25 +++++
 include/hw/cxl/cxl_events.h |  55 +++++++++
 hw/cxl/cxl-events.c         | 217 ++++++++++++++++++++++++++++++++++++
 hw/cxl/cxl-mailbox-utils.c  |  40 ++++++-
 hw/mem/cxl_type3.c          |   1 +
 hw/cxl/meson.build          |   1 +
 6 files changed, 337 insertions(+), 2 deletions(-)

Comments

nifan@outlook.com May 22, 2023, 7:50 p.m. UTC | #1 
The 05/22/2023 16:09, Jonathan Cameron wrote:
> From: Ira Weiny <ira.weiny@intel.com>
> 
> CXL testing is benefited from an artificial event log injection
> mechanism.
> 
> Add an event log infrastructure to insert, get, and clear events from
> the various logs available on a device.
> 
> Replace the stubbed out CXL Get/Clear Event mailbox commands with
> commands that operate on the new infrastructure.
> 
> Signed-off-by: Ira Weiny <ira.weiny@intel.com>
> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> ---

Reviewed-by: Fan Ni <fan.ni@samsung.com>

See comments below in cxl_event_insert.

>  include/hw/cxl/cxl_device.h |  25 +++++
>  include/hw/cxl/cxl_events.h |  55 +++++++++
>  hw/cxl/cxl-events.c         | 217 ++++++++++++++++++++++++++++++++++++
>  hw/cxl/cxl-mailbox-utils.c  |  40 ++++++-
>  hw/mem/cxl_type3.c          |   1 +
>  hw/cxl/meson.build          |   1 +
>  6 files changed, 337 insertions(+), 2 deletions(-)
> 
> diff --git a/include/hw/cxl/cxl_device.h b/include/hw/cxl/cxl_device.h
> index 9f8ee85f8a..d3aec1bc0e 100644
> --- a/include/hw/cxl/cxl_device.h
> +++ b/include/hw/cxl/cxl_device.h
> @@ -111,6 +111,20 @@ typedef enum {
>      CXL_MBOX_MAX = 0x17
>  } CXLRetCode;
>  
> +typedef struct CXLEvent {
> +    CXLEventRecordRaw data;
> +    QSIMPLEQ_ENTRY(CXLEvent) node;
> +} CXLEvent;
> +
> +typedef struct CXLEventLog {
> +    uint16_t next_handle;
> +    uint16_t overflow_err_count;
> +    uint64_t first_overflow_timestamp;
> +    uint64_t last_overflow_timestamp;
> +    QemuMutex lock;
> +    QSIMPLEQ_HEAD(, CXLEvent) events;
> +} CXLEventLog;
> +
>  typedef struct cxl_device_state {
>      MemoryRegion device_registers;
>  
> @@ -161,6 +175,8 @@ typedef struct cxl_device_state {
>      uint64_t mem_size;
>      uint64_t pmem_size;
>      uint64_t vmem_size;
> +
> +    CXLEventLog event_logs[CXL_EVENT_TYPE_MAX];
>  } CXLDeviceState;
>  
>  /* Initialize the register block for a device */
> @@ -353,6 +369,15 @@ MemTxResult cxl_type3_write(PCIDevice *d, hwaddr host_addr, uint64_t data,
>  
>  uint64_t cxl_device_get_timestamp(CXLDeviceState *cxlds);
>  
> +void cxl_event_init(CXLDeviceState *cxlds);
> +bool cxl_event_insert(CXLDeviceState *cxlds, CXLEventLogType log_type,
> +                      CXLEventRecordRaw *event);
> +CXLRetCode cxl_event_get_records(CXLDeviceState *cxlds, CXLGetEventPayload *pl,
> +                                 uint8_t log_type, int max_recs,
> +                                 uint16_t *len);
> +CXLRetCode cxl_event_clear_records(CXLDeviceState *cxlds,
> +                                   CXLClearEventPayload *pl);
> +
>  void cxl_set_poison_list_overflowed(CXLType3Dev *ct3d);
>  
>  #endif
> diff --git a/include/hw/cxl/cxl_events.h b/include/hw/cxl/cxl_events.h
> index aeb3b0590e..d4aaa894f1 100644
> --- a/include/hw/cxl/cxl_events.h
> +++ b/include/hw/cxl/cxl_events.h
> @@ -10,6 +10,8 @@
>  #ifndef CXL_EVENTS_H
>  #define CXL_EVENTS_H
>  
> +#include "qemu/uuid.h"
> +
>  /*
>   * CXL rev 3.0 section 8.2.9.2.2; Table 8-49
>   *
> @@ -25,4 +27,57 @@ typedef enum CXLEventLogType {
>      CXL_EVENT_TYPE_MAX
>  } CXLEventLogType;
>  
> +/*
> + * Common Event Record Format
> + * CXL rev 3.0 section 8.2.9.2.1; Table 8-42
> + */
> +#define CXL_EVENT_REC_HDR_RES_LEN 0xf
> +typedef struct CXLEventRecordHdr {
> +    QemuUUID id;
> +    uint8_t length;
> +    uint8_t flags[3];
> +    uint16_t handle;
> +    uint16_t related_handle;
> +    uint64_t timestamp;
> +    uint8_t maint_op_class;
> +    uint8_t reserved[CXL_EVENT_REC_HDR_RES_LEN];
> +} QEMU_PACKED CXLEventRecordHdr;
> +
> +#define CXL_EVENT_RECORD_DATA_LENGTH 0x50
> +typedef struct CXLEventRecordRaw {
> +    CXLEventRecordHdr hdr;
> +    uint8_t data[CXL_EVENT_RECORD_DATA_LENGTH];
> +} QEMU_PACKED CXLEventRecordRaw;
> +#define CXL_EVENT_RECORD_SIZE (sizeof(CXLEventRecordRaw))
> +
> +/*
> + * Get Event Records output payload
> + * CXL rev 3.0 section 8.2.9.2.2; Table 8-50
> + */
> +#define CXL_GET_EVENT_FLAG_OVERFLOW     BIT(0)
> +#define CXL_GET_EVENT_FLAG_MORE_RECORDS BIT(1)
> +typedef struct CXLGetEventPayload {
> +    uint8_t flags;
> +    uint8_t reserved1;
> +    uint16_t overflow_err_count;
> +    uint64_t first_overflow_timestamp;
> +    uint64_t last_overflow_timestamp;
> +    uint16_t record_count;
> +    uint8_t reserved2[0xa];
> +    CXLEventRecordRaw records[];
> +} QEMU_PACKED CXLGetEventPayload;
> +#define CXL_EVENT_PAYLOAD_HDR_SIZE (sizeof(CXLGetEventPayload))
> +
> +/*
> + * Clear Event Records input payload
> + * CXL rev 3.0 section 8.2.9.2.3; Table 8-51
> + */
> +typedef struct CXLClearEventPayload {
> +    uint8_t event_log;      /* CXLEventLogType */
> +    uint8_t clear_flags;
> +    uint8_t nr_recs;
> +    uint8_t reserved[3];
> +    uint16_t handle[];
> +} CXLClearEventPayload;
> +
>  #endif /* CXL_EVENTS_H */
> diff --git a/hw/cxl/cxl-events.c b/hw/cxl/cxl-events.c
> new file mode 100644
> index 0000000000..5da1b76b97
> --- /dev/null
> +++ b/hw/cxl/cxl-events.c
> @@ -0,0 +1,217 @@
> +/*
> + * CXL Event processing
> + *
> + * Copyright(C) 2023 Intel Corporation.
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2. See the
> + * COPYING file in the top-level directory.
> + */
> +
> +#include <stdint.h>
> +
> +#include "qemu/osdep.h"
> +#include "qemu/bswap.h"
> +#include "qemu/typedefs.h"
> +#include "qemu/error-report.h"
> +#include "hw/cxl/cxl.h"
> +#include "hw/cxl/cxl_events.h"
> +
> +/* Artificial limit on the number of events a log can hold */
> +#define CXL_TEST_EVENT_OVERFLOW 8
> +
> +static void reset_overflow(CXLEventLog *log)
> +{
> +    log->overflow_err_count = 0;
> +    log->first_overflow_timestamp = 0;
> +    log->last_overflow_timestamp = 0;
> +}
> +
> +void cxl_event_init(CXLDeviceState *cxlds)
> +{
> +    CXLEventLog *log;
> +    int i;
> +
> +    for (i = 0; i < CXL_EVENT_TYPE_MAX; i++) {
> +        log = &cxlds->event_logs[i];
> +        log->next_handle = 1;
> +        log->overflow_err_count = 0;
> +        log->first_overflow_timestamp = 0;
> +        log->last_overflow_timestamp = 0;
> +        qemu_mutex_init(&log->lock);
> +        QSIMPLEQ_INIT(&log->events);
> +    }
> +}
> +
> +static CXLEvent *cxl_event_get_head(CXLEventLog *log)
> +{
> +    return QSIMPLEQ_FIRST(&log->events);
> +}
> +
> +static CXLEvent *cxl_event_get_next(CXLEvent *entry)
> +{
> +    return QSIMPLEQ_NEXT(entry, node);
> +}
> +
> +static int cxl_event_count(CXLEventLog *log)
> +{
> +    CXLEvent *event;
> +    int rc = 0;
> +
> +    QSIMPLEQ_FOREACH(event, &log->events, node) {
> +        rc++;
> +    }
> +
> +    return rc;
> +}
> +
> +static bool cxl_event_empty(CXLEventLog *log)
> +{
> +    return QSIMPLEQ_EMPTY(&log->events);
> +}
> +
> +static void cxl_event_delete_head(CXLDeviceState *cxlds,
> +                                  CXLEventLogType log_type,
> +                                  CXLEventLog *log)
> +{
> +    CXLEvent *entry = cxl_event_get_head(log);
> +
> +    reset_overflow(log);
> +    QSIMPLEQ_REMOVE_HEAD(&log->events, node);
> +    if (cxl_event_empty(log)) {
> +        cxl_event_set_status(cxlds, log_type, false);
> +    }
> +    g_free(entry);
> +}
> +
> +/*
> + * return true if an interrupt should be generated as a result
> + * of inserting this event.
> + */
> +bool cxl_event_insert(CXLDeviceState *cxlds, CXLEventLogType log_type,
> +                      CXLEventRecordRaw *event)
> +{
> +    uint64_t time;
> +    CXLEventLog *log;
> +    CXLEvent *entry;
> +
> +    if (log_type >= CXL_EVENT_TYPE_MAX) {
> +        return false;
> +    }
> +
> +    time = cxl_device_get_timestamp(cxlds);
> +
> +    log = &cxlds->event_logs[log_type];
> +
> +    QEMU_LOCK_GUARD(&log->lock);
> +
> +    if (cxl_event_count(log) >= CXL_TEST_EVENT_OVERFLOW) {
> +        if (log->overflow_err_count == 0) {
> +            log->first_overflow_timestamp = time;
> +        }
> +        log->overflow_err_count++;
> +        log->last_overflow_timestamp = time;
> +        return false;
> +    }
> +
> +    entry = g_new0(CXLEvent, 1);
> +
> +    memcpy(&entry->data, event, sizeof(*event));
> +
> +    entry->data.hdr.handle = cpu_to_le16(log->next_handle);
> +    log->next_handle++;
> +    /* 0 handle is never valid */
> +    if (log->next_handle == 0) {

next_handle is uint16_t, how can it be 0 after next_handle++?

> +        log->next_handle++;
> +    }
> +    entry->data.hdr.timestamp = cpu_to_le64(time);
> +
> +    QSIMPLEQ_INSERT_TAIL(&log->events, entry, node);
> +    cxl_event_set_status(cxlds, log_type, true);
> +
> +    /* Count went from 0 to 1 */
> +    return cxl_event_count(log) == 1;
> +}
> +
> +CXLRetCode cxl_event_get_records(CXLDeviceState *cxlds, CXLGetEventPayload *pl,
> +                                 uint8_t log_type, int max_recs,
> +                                 uint16_t *len)
> +{
> +    CXLEventLog *log;
> +    CXLEvent *entry;
> +    uint16_t nr;
> +
> +    if (log_type >= CXL_EVENT_TYPE_MAX) {
> +        return CXL_MBOX_INVALID_INPUT;
> +    }
> +
> +    log = &cxlds->event_logs[log_type];
> +
> +    QEMU_LOCK_GUARD(&log->lock);
> +
> +    entry = cxl_event_get_head(log);
> +    for (nr = 0; entry && nr < max_recs; nr++) {
> +        memcpy(&pl->records[nr], &entry->data, CXL_EVENT_RECORD_SIZE);
> +        entry = cxl_event_get_next(entry);
> +    }
> +
> +    if (!cxl_event_empty(log)) {
> +        pl->flags |= CXL_GET_EVENT_FLAG_MORE_RECORDS;
> +    }
> +
> +    if (log->overflow_err_count) {
> +        pl->flags |= CXL_GET_EVENT_FLAG_OVERFLOW;
> +        pl->overflow_err_count = cpu_to_le16(log->overflow_err_count);
> +        pl->first_overflow_timestamp = cpu_to_le64(log->first_overflow_timestamp);
> +        pl->last_overflow_timestamp = cpu_to_le64(log->last_overflow_timestamp);
> +    }
> +
> +    pl->record_count = cpu_to_le16(nr);
> +    *len = CXL_EVENT_PAYLOAD_HDR_SIZE + (CXL_EVENT_RECORD_SIZE * nr);
> +
> +    return CXL_MBOX_SUCCESS;
> +}
> +
> +CXLRetCode cxl_event_clear_records(CXLDeviceState *cxlds, CXLClearEventPayload *pl)
> +{
> +    CXLEventLog *log;
> +    uint8_t log_type;
> +    CXLEvent *entry;
> +    int nr;
> +
> +    log_type = pl->event_log;
> +
> +    if (log_type >= CXL_EVENT_TYPE_MAX) {
> +        return CXL_MBOX_INVALID_INPUT;
> +    }
> +
> +    log = &cxlds->event_logs[log_type];
> +
> +    QEMU_LOCK_GUARD(&log->lock);
> +    /*
> +     * Must itterate the queue twice.
> +     * "The device shall verify the event record handles specified in the input
> +     * payload are in temporal order. If the device detects an older event
> +     * record that will not be cleared when Clear Event Records is executed,
> +     * the device shall return the Invalid Handle return code and shall not
> +     * clear any of the specified event records."
> +     *   -- CXL 3.0 8.2.9.2.3
> +     */
> +    entry = cxl_event_get_head(log);
> +    for (nr = 0; entry && nr < pl->nr_recs; nr++) {
> +        uint16_t handle = pl->handle[nr];
> +
> +        /* NOTE: Both handles are little endian. */
> +        if (handle == 0 || entry->data.hdr.handle != handle) {
> +            return CXL_MBOX_INVALID_INPUT;
> +        }
> +        entry = cxl_event_get_next(entry);
> +    }
> +
> +    entry = cxl_event_get_head(log);
> +    for (nr = 0; entry && nr < pl->nr_recs; nr++) {
> +        cxl_event_delete_head(cxlds, log_type, log);
> +        entry = cxl_event_get_head(log);
> +    }
> +
> +    return CXL_MBOX_SUCCESS;
> +}
> diff --git a/hw/cxl/cxl-mailbox-utils.c b/hw/cxl/cxl-mailbox-utils.c
> index d7e114aaae..3f46538048 100644
> --- a/hw/cxl/cxl-mailbox-utils.c
> +++ b/hw/cxl/cxl-mailbox-utils.c
> @@ -9,6 +9,7 @@
>  
>  #include "qemu/osdep.h"
>  #include "hw/cxl/cxl.h"
> +#include "hw/cxl/cxl_events.h"
>  #include "hw/pci/pci.h"
>  #include "qemu/cutils.h"
>  #include "qemu/log.h"
> @@ -95,11 +96,46 @@ struct cxl_cmd {
>          return CXL_MBOX_SUCCESS;                                          \
>      }
>  
> -DEFINE_MAILBOX_HANDLER_ZEROED(events_get_records, 0x20);
> -DEFINE_MAILBOX_HANDLER_NOP(events_clear_records);
>  DEFINE_MAILBOX_HANDLER_ZEROED(events_get_interrupt_policy, 4);
>  DEFINE_MAILBOX_HANDLER_NOP(events_set_interrupt_policy);
>  
> +static CXLRetCode cmd_events_get_records(struct cxl_cmd *cmd,
> +                                         CXLDeviceState *cxlds,
> +                                         uint16_t *len)
> +{
> +    CXLGetEventPayload *pl;
> +    uint8_t log_type;
> +    int max_recs;
> +
> +    if (cmd->in < sizeof(log_type)) {
> +        return CXL_MBOX_INVALID_INPUT;
> +    }
> +
> +    log_type = *((uint8_t *)cmd->payload);
> +
> +    pl = (CXLGetEventPayload *)cmd->payload;
> +    memset(pl, 0, sizeof(*pl));
> +
> +    max_recs = (cxlds->payload_size - CXL_EVENT_PAYLOAD_HDR_SIZE) /
> +                CXL_EVENT_RECORD_SIZE;
> +    if (max_recs > 0xFFFF) {
> +        max_recs = 0xFFFF;
> +    }
> +
> +    return cxl_event_get_records(cxlds, pl, log_type, max_recs, len);
> +}
> +
> +static CXLRetCode cmd_events_clear_records(struct cxl_cmd *cmd,
> +                                           CXLDeviceState *cxlds,
> +                                           uint16_t *len)
> +{
> +    CXLClearEventPayload *pl;
> +
> +    pl = (CXLClearEventPayload *)cmd->payload;
> +    *len = 0;
> +    return cxl_event_clear_records(cxlds, pl);
> +}
> +
>  /* 8.2.9.2.1 */
>  static CXLRetCode cmd_firmware_update_get_info(struct cxl_cmd *cmd,
>                                                 CXLDeviceState *cxl_dstate,
> diff --git a/hw/mem/cxl_type3.c b/hw/mem/cxl_type3.c
> index d751803188..ec5a384885 100644
> --- a/hw/mem/cxl_type3.c
> +++ b/hw/mem/cxl_type3.c
> @@ -724,6 +724,7 @@ static void ct3_realize(PCIDevice *pci_dev, Error **errp)
>          goto err_release_cdat;
>      }
>  
> +    cxl_event_init(&ct3d->cxl_dstate);
>      return;
>  
>  err_release_cdat:
> diff --git a/hw/cxl/meson.build b/hw/cxl/meson.build
> index cfa95ffd40..71059972d4 100644
> --- a/hw/cxl/meson.build
> +++ b/hw/cxl/meson.build
> @@ -5,6 +5,7 @@ softmmu_ss.add(when: 'CONFIG_CXL',
>                     'cxl-mailbox-utils.c',
>                     'cxl-host.c',
>                     'cxl-cdat.c',
> +                   'cxl-events.c',
>                 ),
>                 if_false: files(
>                     'cxl-host-stubs.c',
> -- 
> 2.39.2
>
Jonathan Cameron May 23, 2023, 10:39 a.m. UTC | #2 
On Mon, 22 May 2023 12:50:34 -0700
Fan Ni <nifan@outlook.com> wrote:

> The 05/22/2023 16:09, Jonathan Cameron wrote:
> > From: Ira Weiny <ira.weiny@intel.com>
> > 
> > CXL testing is benefited from an artificial event log injection
> > mechanism.
> > 
> > Add an event log infrastructure to insert, get, and clear events from
> > the various logs available on a device.
> > 
> > Replace the stubbed out CXL Get/Clear Event mailbox commands with
> > commands that operate on the new infrastructure.
> > 
> > Signed-off-by: Ira Weiny <ira.weiny@intel.com>
> > Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> > ---  
> 
> Reviewed-by: Fan Ni <fan.ni@samsung.com>
> 
> See comments below in cxl_event_insert.

...

> > +    memcpy(&entry->data, event, sizeof(*event));
> > +
> > +    entry->data.hdr.handle = cpu_to_le16(log->next_handle);
> > +    log->next_handle++;
> > +    /* 0 handle is never valid */
> > +    if (log->next_handle == 0) {  
> 
> next_handle is uint16_t, how can it be 0 after next_handle++?

Intent was to deal with wrap around.
We are fine with reusing handles after sufficiently long time that
there can't be a confusion, just not 0 as that has special
meaning when used to 'point' to a related event
(see definition of Related Event Record Handle)

> 
> > +        log->next_handle++;
> > +    }
> > +    entry->data.hdr.timestamp = cpu_to_le64(time);
> > +
> > +    QSIMPLEQ_INSERT_TAIL(&log->events, entry, node);
> > +    cxl_event_set_status(cxlds, log_type, true);
> > +
> > +    /* Count went from 0 to 1 */
> > +    return cxl_event_count(log) == 1;
> > +}
Ira Weiny May 23, 2023, 2:26 p.m. UTC | #3 
Fan Ni wrote:
> The 05/22/2023 16:09, Jonathan Cameron wrote:
> > From: Ira Weiny <ira.weiny@intel.com>
> > 
> > CXL testing is benefited from an artificial event log injection
> > mechanism.
> > 
> > Add an event log infrastructure to insert, get, and clear events from
> > the various logs available on a device.
> > 
> > Replace the stubbed out CXL Get/Clear Event mailbox commands with
> > commands that operate on the new infrastructure.
> > 
> > Signed-off-by: Ira Weiny <ira.weiny@intel.com>
> > Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> > ---
> 
> Reviewed-by: Fan Ni <fan.ni@samsung.com>
> 
> See comments below in cxl_event_insert.
> 

[snip]

> > +
> > +/*
> > + * return true if an interrupt should be generated as a result
> > + * of inserting this event.
> > + */
> > +bool cxl_event_insert(CXLDeviceState *cxlds, CXLEventLogType log_type,
> > +                      CXLEventRecordRaw *event)
> > +{
> > +    uint64_t time;
> > +    CXLEventLog *log;
> > +    CXLEvent *entry;
> > +
> > +    if (log_type >= CXL_EVENT_TYPE_MAX) {
> > +        return false;
> > +    }
> > +
> > +    time = cxl_device_get_timestamp(cxlds);
> > +
> > +    log = &cxlds->event_logs[log_type];
> > +
> > +    QEMU_LOCK_GUARD(&log->lock);
> > +
> > +    if (cxl_event_count(log) >= CXL_TEST_EVENT_OVERFLOW) {
> > +        if (log->overflow_err_count == 0) {
> > +            log->first_overflow_timestamp = time;
> > +        }
> > +        log->overflow_err_count++;
> > +        log->last_overflow_timestamp = time;
> > +        return false;
> > +    }
> > +
> > +    entry = g_new0(CXLEvent, 1);
> > +
> > +    memcpy(&entry->data, event, sizeof(*event));
> > +
> > +    entry->data.hdr.handle = cpu_to_le16(log->next_handle);
> > +    log->next_handle++;
> > +    /* 0 handle is never valid */
> > +    if (log->next_handle == 0) {
> 
> next_handle is uint16_t, how can it be 0 after next_handle++?
> 

If enough events are added and it overflows back to 0.

> > +        log->next_handle++;

This statement then rolls it to 1 to keep it from ever being 0.

Thanks for the review!

Ira
diff mbox series

Patch

diff --git a/include/hw/cxl/cxl_device.h b/include/hw/cxl/cxl_device.h
index 9f8ee85f8a..d3aec1bc0e 100644
--- a/include/hw/cxl/cxl_device.h
+++ b/include/hw/cxl/cxl_device.h
@@ -111,6 +111,20 @@  typedef enum {
     CXL_MBOX_MAX = 0x17
 } CXLRetCode;
 
+typedef struct CXLEvent {
+    CXLEventRecordRaw data;
+    QSIMPLEQ_ENTRY(CXLEvent) node;
+} CXLEvent;
+
+typedef struct CXLEventLog {
+    uint16_t next_handle;
+    uint16_t overflow_err_count;
+    uint64_t first_overflow_timestamp;
+    uint64_t last_overflow_timestamp;
+    QemuMutex lock;
+    QSIMPLEQ_HEAD(, CXLEvent) events;
+} CXLEventLog;
+
 typedef struct cxl_device_state {
     MemoryRegion device_registers;
 
@@ -161,6 +175,8 @@  typedef struct cxl_device_state {
     uint64_t mem_size;
     uint64_t pmem_size;
     uint64_t vmem_size;
+
+    CXLEventLog event_logs[CXL_EVENT_TYPE_MAX];
 } CXLDeviceState;
 
 /* Initialize the register block for a device */
@@ -353,6 +369,15 @@  MemTxResult cxl_type3_write(PCIDevice *d, hwaddr host_addr, uint64_t data,
 
 uint64_t cxl_device_get_timestamp(CXLDeviceState *cxlds);
 
+void cxl_event_init(CXLDeviceState *cxlds);
+bool cxl_event_insert(CXLDeviceState *cxlds, CXLEventLogType log_type,
+                      CXLEventRecordRaw *event);
+CXLRetCode cxl_event_get_records(CXLDeviceState *cxlds, CXLGetEventPayload *pl,
+                                 uint8_t log_type, int max_recs,
+                                 uint16_t *len);
+CXLRetCode cxl_event_clear_records(CXLDeviceState *cxlds,
+                                   CXLClearEventPayload *pl);
+
 void cxl_set_poison_list_overflowed(CXLType3Dev *ct3d);
 
 #endif
diff --git a/include/hw/cxl/cxl_events.h b/include/hw/cxl/cxl_events.h
index aeb3b0590e..d4aaa894f1 100644
--- a/include/hw/cxl/cxl_events.h
+++ b/include/hw/cxl/cxl_events.h
@@ -10,6 +10,8 @@ 
 #ifndef CXL_EVENTS_H
 #define CXL_EVENTS_H
 
+#include "qemu/uuid.h"
+
 /*
  * CXL rev 3.0 section 8.2.9.2.2; Table 8-49
  *
@@ -25,4 +27,57 @@  typedef enum CXLEventLogType {
     CXL_EVENT_TYPE_MAX
 } CXLEventLogType;
 
+/*
+ * Common Event Record Format
+ * CXL rev 3.0 section 8.2.9.2.1; Table 8-42
+ */
+#define CXL_EVENT_REC_HDR_RES_LEN 0xf
+typedef struct CXLEventRecordHdr {
+    QemuUUID id;
+    uint8_t length;
+    uint8_t flags[3];
+    uint16_t handle;
+    uint16_t related_handle;
+    uint64_t timestamp;
+    uint8_t maint_op_class;
+    uint8_t reserved[CXL_EVENT_REC_HDR_RES_LEN];
+} QEMU_PACKED CXLEventRecordHdr;
+
+#define CXL_EVENT_RECORD_DATA_LENGTH 0x50
+typedef struct CXLEventRecordRaw {
+    CXLEventRecordHdr hdr;
+    uint8_t data[CXL_EVENT_RECORD_DATA_LENGTH];
+} QEMU_PACKED CXLEventRecordRaw;
+#define CXL_EVENT_RECORD_SIZE (sizeof(CXLEventRecordRaw))
+
+/*
+ * Get Event Records output payload
+ * CXL rev 3.0 section 8.2.9.2.2; Table 8-50
+ */
+#define CXL_GET_EVENT_FLAG_OVERFLOW     BIT(0)
+#define CXL_GET_EVENT_FLAG_MORE_RECORDS BIT(1)
+typedef struct CXLGetEventPayload {
+    uint8_t flags;
+    uint8_t reserved1;
+    uint16_t overflow_err_count;
+    uint64_t first_overflow_timestamp;
+    uint64_t last_overflow_timestamp;
+    uint16_t record_count;
+    uint8_t reserved2[0xa];
+    CXLEventRecordRaw records[];
+} QEMU_PACKED CXLGetEventPayload;
+#define CXL_EVENT_PAYLOAD_HDR_SIZE (sizeof(CXLGetEventPayload))
+
+/*
+ * Clear Event Records input payload
+ * CXL rev 3.0 section 8.2.9.2.3; Table 8-51
+ */
+typedef struct CXLClearEventPayload {
+    uint8_t event_log;      /* CXLEventLogType */
+    uint8_t clear_flags;
+    uint8_t nr_recs;
+    uint8_t reserved[3];
+    uint16_t handle[];
+} CXLClearEventPayload;
+
 #endif /* CXL_EVENTS_H */
diff --git a/hw/cxl/cxl-events.c b/hw/cxl/cxl-events.c
new file mode 100644
index 0000000000..5da1b76b97
--- /dev/null
+++ b/hw/cxl/cxl-events.c
@@ -0,0 +1,217 @@ 
+/*
+ * CXL Event processing
+ *
+ * Copyright(C) 2023 Intel Corporation.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2. See the
+ * COPYING file in the top-level directory.
+ */
+
+#include <stdint.h>
+
+#include "qemu/osdep.h"
+#include "qemu/bswap.h"
+#include "qemu/typedefs.h"
+#include "qemu/error-report.h"
+#include "hw/cxl/cxl.h"
+#include "hw/cxl/cxl_events.h"
+
+/* Artificial limit on the number of events a log can hold */
+#define CXL_TEST_EVENT_OVERFLOW 8
+
+static void reset_overflow(CXLEventLog *log)
+{
+    log->overflow_err_count = 0;
+    log->first_overflow_timestamp = 0;
+    log->last_overflow_timestamp = 0;
+}
+
+void cxl_event_init(CXLDeviceState *cxlds)
+{
+    CXLEventLog *log;
+    int i;
+
+    for (i = 0; i < CXL_EVENT_TYPE_MAX; i++) {
+        log = &cxlds->event_logs[i];
+        log->next_handle = 1;
+        log->overflow_err_count = 0;
+        log->first_overflow_timestamp = 0;
+        log->last_overflow_timestamp = 0;
+        qemu_mutex_init(&log->lock);
+        QSIMPLEQ_INIT(&log->events);
+    }
+}
+
+static CXLEvent *cxl_event_get_head(CXLEventLog *log)
+{
+    return QSIMPLEQ_FIRST(&log->events);
+}
+
+static CXLEvent *cxl_event_get_next(CXLEvent *entry)
+{
+    return QSIMPLEQ_NEXT(entry, node);
+}
+
+static int cxl_event_count(CXLEventLog *log)
+{
+    CXLEvent *event;
+    int rc = 0;
+
+    QSIMPLEQ_FOREACH(event, &log->events, node) {
+        rc++;
+    }
+
+    return rc;
+}
+
+static bool cxl_event_empty(CXLEventLog *log)
+{
+    return QSIMPLEQ_EMPTY(&log->events);
+}
+
+static void cxl_event_delete_head(CXLDeviceState *cxlds,
+                                  CXLEventLogType log_type,
+                                  CXLEventLog *log)
+{
+    CXLEvent *entry = cxl_event_get_head(log);
+
+    reset_overflow(log);
+    QSIMPLEQ_REMOVE_HEAD(&log->events, node);
+    if (cxl_event_empty(log)) {
+        cxl_event_set_status(cxlds, log_type, false);
+    }
+    g_free(entry);
+}
+
+/*
+ * return true if an interrupt should be generated as a result
+ * of inserting this event.
+ */
+bool cxl_event_insert(CXLDeviceState *cxlds, CXLEventLogType log_type,
+                      CXLEventRecordRaw *event)
+{
+    uint64_t time;
+    CXLEventLog *log;
+    CXLEvent *entry;
+
+    if (log_type >= CXL_EVENT_TYPE_MAX) {
+        return false;
+    }
+
+    time = cxl_device_get_timestamp(cxlds);
+
+    log = &cxlds->event_logs[log_type];
+
+    QEMU_LOCK_GUARD(&log->lock);
+
+    if (cxl_event_count(log) >= CXL_TEST_EVENT_OVERFLOW) {
+        if (log->overflow_err_count == 0) {
+            log->first_overflow_timestamp = time;
+        }
+        log->overflow_err_count++;
+        log->last_overflow_timestamp = time;
+        return false;
+    }
+
+    entry = g_new0(CXLEvent, 1);
+
+    memcpy(&entry->data, event, sizeof(*event));
+
+    entry->data.hdr.handle = cpu_to_le16(log->next_handle);
+    log->next_handle++;
+    /* 0 handle is never valid */
+    if (log->next_handle == 0) {
+        log->next_handle++;
+    }
+    entry->data.hdr.timestamp = cpu_to_le64(time);
+
+    QSIMPLEQ_INSERT_TAIL(&log->events, entry, node);
+    cxl_event_set_status(cxlds, log_type, true);
+
+    /* Count went from 0 to 1 */
+    return cxl_event_count(log) == 1;
+}
+
+CXLRetCode cxl_event_get_records(CXLDeviceState *cxlds, CXLGetEventPayload *pl,
+                                 uint8_t log_type, int max_recs,
+                                 uint16_t *len)
+{
+    CXLEventLog *log;
+    CXLEvent *entry;
+    uint16_t nr;
+
+    if (log_type >= CXL_EVENT_TYPE_MAX) {
+        return CXL_MBOX_INVALID_INPUT;
+    }
+
+    log = &cxlds->event_logs[log_type];
+
+    QEMU_LOCK_GUARD(&log->lock);
+
+    entry = cxl_event_get_head(log);
+    for (nr = 0; entry && nr < max_recs; nr++) {
+        memcpy(&pl->records[nr], &entry->data, CXL_EVENT_RECORD_SIZE);
+        entry = cxl_event_get_next(entry);
+    }
+
+    if (!cxl_event_empty(log)) {
+        pl->flags |= CXL_GET_EVENT_FLAG_MORE_RECORDS;
+    }
+
+    if (log->overflow_err_count) {
+        pl->flags |= CXL_GET_EVENT_FLAG_OVERFLOW;
+        pl->overflow_err_count = cpu_to_le16(log->overflow_err_count);
+        pl->first_overflow_timestamp = cpu_to_le64(log->first_overflow_timestamp);
+        pl->last_overflow_timestamp = cpu_to_le64(log->last_overflow_timestamp);
+    }
+
+    pl->record_count = cpu_to_le16(nr);
+    *len = CXL_EVENT_PAYLOAD_HDR_SIZE + (CXL_EVENT_RECORD_SIZE * nr);
+
+    return CXL_MBOX_SUCCESS;
+}
+
+CXLRetCode cxl_event_clear_records(CXLDeviceState *cxlds, CXLClearEventPayload *pl)
+{
+    CXLEventLog *log;
+    uint8_t log_type;
+    CXLEvent *entry;
+    int nr;
+
+    log_type = pl->event_log;
+
+    if (log_type >= CXL_EVENT_TYPE_MAX) {
+        return CXL_MBOX_INVALID_INPUT;
+    }
+
+    log = &cxlds->event_logs[log_type];
+
+    QEMU_LOCK_GUARD(&log->lock);
+    /*
+     * Must itterate the queue twice.
+     * "The device shall verify the event record handles specified in the input
+     * payload are in temporal order. If the device detects an older event
+     * record that will not be cleared when Clear Event Records is executed,
+     * the device shall return the Invalid Handle return code and shall not
+     * clear any of the specified event records."
+     *   -- CXL 3.0 8.2.9.2.3
+     */
+    entry = cxl_event_get_head(log);
+    for (nr = 0; entry && nr < pl->nr_recs; nr++) {
+        uint16_t handle = pl->handle[nr];
+
+        /* NOTE: Both handles are little endian. */
+        if (handle == 0 || entry->data.hdr.handle != handle) {
+            return CXL_MBOX_INVALID_INPUT;
+        }
+        entry = cxl_event_get_next(entry);
+    }
+
+    entry = cxl_event_get_head(log);
+    for (nr = 0; entry && nr < pl->nr_recs; nr++) {
+        cxl_event_delete_head(cxlds, log_type, log);
+        entry = cxl_event_get_head(log);
+    }
+
+    return CXL_MBOX_SUCCESS;
+}
diff --git a/hw/cxl/cxl-mailbox-utils.c b/hw/cxl/cxl-mailbox-utils.c
index d7e114aaae..3f46538048 100644
--- a/hw/cxl/cxl-mailbox-utils.c
+++ b/hw/cxl/cxl-mailbox-utils.c
@@ -9,6 +9,7 @@ 
 
 #include "qemu/osdep.h"
 #include "hw/cxl/cxl.h"
+#include "hw/cxl/cxl_events.h"
 #include "hw/pci/pci.h"
 #include "qemu/cutils.h"
 #include "qemu/log.h"
@@ -95,11 +96,46 @@  struct cxl_cmd {
         return CXL_MBOX_SUCCESS;                                          \
     }
 
-DEFINE_MAILBOX_HANDLER_ZEROED(events_get_records, 0x20);
-DEFINE_MAILBOX_HANDLER_NOP(events_clear_records);
 DEFINE_MAILBOX_HANDLER_ZEROED(events_get_interrupt_policy, 4);
 DEFINE_MAILBOX_HANDLER_NOP(events_set_interrupt_policy);
 
+static CXLRetCode cmd_events_get_records(struct cxl_cmd *cmd,
+                                         CXLDeviceState *cxlds,
+                                         uint16_t *len)
+{
+    CXLGetEventPayload *pl;
+    uint8_t log_type;
+    int max_recs;
+
+    if (cmd->in < sizeof(log_type)) {
+        return CXL_MBOX_INVALID_INPUT;
+    }
+
+    log_type = *((uint8_t *)cmd->payload);
+
+    pl = (CXLGetEventPayload *)cmd->payload;
+    memset(pl, 0, sizeof(*pl));
+
+    max_recs = (cxlds->payload_size - CXL_EVENT_PAYLOAD_HDR_SIZE) /
+                CXL_EVENT_RECORD_SIZE;
+    if (max_recs > 0xFFFF) {
+        max_recs = 0xFFFF;
+    }
+
+    return cxl_event_get_records(cxlds, pl, log_type, max_recs, len);
+}
+
+static CXLRetCode cmd_events_clear_records(struct cxl_cmd *cmd,
+                                           CXLDeviceState *cxlds,
+                                           uint16_t *len)
+{
+    CXLClearEventPayload *pl;
+
+    pl = (CXLClearEventPayload *)cmd->payload;
+    *len = 0;
+    return cxl_event_clear_records(cxlds, pl);
+}
+
 /* 8.2.9.2.1 */
 static CXLRetCode cmd_firmware_update_get_info(struct cxl_cmd *cmd,
                                                CXLDeviceState *cxl_dstate,
diff --git a/hw/mem/cxl_type3.c b/hw/mem/cxl_type3.c
index d751803188..ec5a384885 100644
--- a/hw/mem/cxl_type3.c
+++ b/hw/mem/cxl_type3.c
@@ -724,6 +724,7 @@  static void ct3_realize(PCIDevice *pci_dev, Error **errp)
         goto err_release_cdat;
     }
 
+    cxl_event_init(&ct3d->cxl_dstate);
     return;
 
 err_release_cdat:
diff --git a/hw/cxl/meson.build b/hw/cxl/meson.build
index cfa95ffd40..71059972d4 100644
--- a/hw/cxl/meson.build
+++ b/hw/cxl/meson.build
@@ -5,6 +5,7 @@  softmmu_ss.add(when: 'CONFIG_CXL',
                    'cxl-mailbox-utils.c',
                    'cxl-host.c',
                    'cxl-cdat.c',
+                   'cxl-events.c',
                ),
                if_false: files(
                    'cxl-host-stubs.c',