Re: [PATCH 1/2] cxl: Move mailbox related bits to the same context

[Dave Jiang <dave.jiang@intel.com>]

On 8/12/24 11:59 PM, Alejandro Lucero Palau wrote:
> 
> On 7/24/24 23:02, fan wrote:
>> On Wed, Jul 24, 2024 at 11:55:16AM -0700, Dave Jiang wrote:
>>> Create a new 'struct cxl_mailbox' and move all mailbox related bits to
>>> it. This allows isolation of all CXL mailbox data in order to export
>>> some of the calls to external callers and avoid exporting of CXL driver
>>> specific bits such has device states. The allocation of
>>> 'struct cxl_mailbox' is also split out with cxl_mailbox_create() so the
>>> mailbox can be created independently.
>>>
>>> Signed-off-by: Dave Jiang <dave.jiang@intel.com>
>>> ---
>>>   MAINTAINERS                  |   1 +
>>>   drivers/cxl/core/mbox.c      | 105 +++++++++++++++++++++++++++++------
>>>   drivers/cxl/core/memdev.c    |  32 ++++++++---
>>>   drivers/cxl/cxlmem.h         |  20 +++----
>>>   drivers/cxl/pci.c            |  82 ++++++++++++++++++---------
>>>   drivers/cxl/pmem.c           |   7 ++-
>>>   include/linux/cxl/mailbox.h  |  28 ++++++++++
>>>   tools/testing/cxl/test/mem.c |  46 +++++++++++----
>>>   8 files changed, 249 insertions(+), 72 deletions(-)
>>>   create mode 100644 include/linux/cxl/mailbox.h
>> Reviewed-by: Fan Ni <fan.ni@samsung.com>
>>
>>> diff --git a/MAINTAINERS b/MAINTAINERS
>>> index 958e935449e5..c809fa1eb452 100644
>>> --- a/MAINTAINERS
>>> +++ b/MAINTAINERS
>>> @@ -5466,6 +5466,7 @@ S:    Maintained
>>>   F:    drivers/cxl/
>>>   F:    include/linux/einj-cxl.h
>>>   F:    include/linux/cxl-event.h
>>> +F:    include/linux/cxl/
>>>   F:    include/uapi/linux/cxl_mem.h
>>>   F:    tools/testing/cxl/
>>>   diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
>>> index 2626f3fff201..9501d2576ccd 100644
>>> --- a/drivers/cxl/core/mbox.c
>>> +++ b/drivers/cxl/core/mbox.c
>>> @@ -244,16 +244,20 @@ static const char *cxl_mem_opcode_to_name(u16 opcode)
>>>   int cxl_internal_send_cmd(struct cxl_memdev_state *mds,
>>>                 struct cxl_mbox_cmd *mbox_cmd)
>>>   {
>>> +    struct cxl_mailbox *cxl_mbox = mds->cxlds.cxl_mbox;
>>>       size_t out_size, min_out;
>>>       int rc;
>>>   -    if (mbox_cmd->size_in > mds->payload_size ||
>>> -        mbox_cmd->size_out > mds->payload_size)
>>> +    if (!cxl_mbox)
>>> +        return -ENODEV;
>>> +
>>> +    if (mbox_cmd->size_in > cxl_mbox->payload_size ||
>>> +        mbox_cmd->size_out > cxl_mbox->payload_size)
>>>           return -E2BIG;
>>>         out_size = mbox_cmd->size_out;
>>>       min_out = mbox_cmd->min_out;
>>> -    rc = mds->mbox_send(mds, mbox_cmd);
>>> +    rc = cxl_mbox->mbox_send(cxl_mbox, mbox_cmd);
>>>       /*
>>>        * EIO is reserved for a payload size mismatch and mbox_send()
>>>        * may not return this error.
>>> @@ -353,11 +357,15 @@ static int cxl_mbox_cmd_ctor(struct cxl_mbox_cmd *mbox,
>>>                    struct cxl_memdev_state *mds, u16 opcode,
>>>                    size_t in_size, size_t out_size, u64 in_payload)
>>>   {
>>> +    struct cxl_mailbox *cxl_mbox = mds->cxlds.cxl_mbox;
>>>       *mbox = (struct cxl_mbox_cmd) {
>>>           .opcode = opcode,
>>>           .size_in = in_size,
>>>       };
>>>   +    if (!cxl_mbox)
>>> +        return -ENODEV;
>>> +
>>>       if (in_size) {
>>>           mbox->payload_in = vmemdup_user(u64_to_user_ptr(in_payload),
>>>                           in_size);
>>> @@ -374,7 +382,7 @@ static int cxl_mbox_cmd_ctor(struct cxl_mbox_cmd *mbox,
>>>         /* Prepare to handle a full payload for variable sized output */
>>>       if (out_size == CXL_VARIABLE_PAYLOAD)
>>> -        mbox->size_out = mds->payload_size;
>>> +        mbox->size_out = cxl_mbox->payload_size;
>>>       else
>>>           mbox->size_out = out_size;
>>>   @@ -398,6 +406,11 @@ static int cxl_to_mem_cmd_raw(struct cxl_mem_command *mem_cmd,
>>>                     const struct cxl_send_command *send_cmd,
>>>                     struct cxl_memdev_state *mds)
>>>   {
>>> +    struct cxl_mailbox *cxl_mbox = mds->cxlds.cxl_mbox;
>>> +
>>> +    if (!cxl_mbox)
>>> +        return -ENODEV;
>>> +
>>>       if (send_cmd->raw.rsvd)
>>>           return -EINVAL;
>>>   @@ -406,7 +419,7 @@ static int cxl_to_mem_cmd_raw(struct cxl_mem_command *mem_cmd,
>>>        * gets passed along without further checking, so it must be
>>>        * validated here.
>>>        */
>>> -    if (send_cmd->out.size > mds->payload_size)
>>> +    if (send_cmd->out.size > cxl_mbox->payload_size)
>>>           return -EINVAL;
>>>         if (!cxl_mem_raw_command_allowed(send_cmd->raw.opcode))
>>> @@ -494,9 +507,13 @@ static int cxl_validate_cmd_from_user(struct cxl_mbox_cmd *mbox_cmd,
>>>                         struct cxl_memdev_state *mds,
>>>                         const struct cxl_send_command *send_cmd)
>>>   {
>>> +    struct cxl_mailbox *cxl_mbox = mds->cxlds.cxl_mbox;
>>>       struct cxl_mem_command mem_cmd;
>>>       int rc;
>>>   +    if (!cxl_mbox)
>>> +        return -ENODEV;
>>> +
>>>       if (send_cmd->id == 0 || send_cmd->id >= CXL_MEM_COMMAND_ID_MAX)
>>>           return -ENOTTY;
>>>   @@ -505,7 +522,7 @@ static int cxl_validate_cmd_from_user(struct cxl_mbox_cmd *mbox_cmd,
>>>        * supports, but output can be arbitrarily large (simply write out as
>>>        * much data as the hardware provides).
>>>        */
>>> -    if (send_cmd->in.size > mds->payload_size)
>>> +    if (send_cmd->in.size > cxl_mbox->payload_size)
>>>           return -EINVAL;
>>>         /* Sanitize and construct a cxl_mem_command */
>>> @@ -591,9 +608,13 @@ static int handle_mailbox_cmd_from_user(struct cxl_memdev_state *mds,
>>>                       u64 out_payload, s32 *size_out,
>>>                       u32 *retval)
>>>   {
>>> +    struct cxl_mailbox *cxl_mbox = mds->cxlds.cxl_mbox;
>>>       struct device *dev = mds->cxlds.dev;
>>>       int rc;
>>>   +    if (!cxl_mbox)
>>> +        return -ENODEV;
>>> +
>>>       dev_dbg(dev,
>>>           "Submitting %s command for user\n"
>>>           "\topcode: %x\n"
>>> @@ -601,7 +622,7 @@ static int handle_mailbox_cmd_from_user(struct cxl_memdev_state *mds,
>>>           cxl_mem_opcode_to_name(mbox_cmd->opcode),
>>>           mbox_cmd->opcode, mbox_cmd->size_in);
>>>   -    rc = mds->mbox_send(mds, mbox_cmd);
>>> +    rc = cxl_mbox->mbox_send(cxl_mbox, mbox_cmd);
>>>       if (rc)
>>>           goto out;
>>>   @@ -659,11 +680,15 @@ int cxl_send_cmd(struct cxl_memdev *cxlmd, struct cxl_send_command __user *s)
>>>   static int cxl_xfer_log(struct cxl_memdev_state *mds, uuid_t *uuid,
>>>               u32 *size, u8 *out)
>>>   {
>>> +    struct cxl_mailbox *cxl_mbox = mds->cxlds.cxl_mbox;
>>>       u32 remaining = *size;
>>>       u32 offset = 0;
>>>   +    if (!cxl_mbox)
>>> +        return -ENODEV;
>>> +
>>>       while (remaining) {
>>> -        u32 xfer_size = min_t(u32, remaining, mds->payload_size);
>>> +        u32 xfer_size = min_t(u32, remaining, cxl_mbox->payload_size);
>>>           struct cxl_mbox_cmd mbox_cmd;
>>>           struct cxl_mbox_get_log log;
>>>           int rc;
>>> @@ -752,17 +777,21 @@ static void cxl_walk_cel(struct cxl_memdev_state *mds, size_t size, u8 *cel)
>>>     static struct cxl_mbox_get_supported_logs *cxl_get_gsl(struct cxl_memdev_state *mds)
>>>   {
>>> +    struct cxl_mailbox *cxl_mbox = mds->cxlds.cxl_mbox;
>>>       struct cxl_mbox_get_supported_logs *ret;
>>>       struct cxl_mbox_cmd mbox_cmd;
>>>       int rc;
>>>   -    ret = kvmalloc(mds->payload_size, GFP_KERNEL);
>>> +    if (!cxl_mbox)
>>> +        return ERR_PTR(-ENODEV);
>>> +
>>> +    ret = kvmalloc(cxl_mbox->payload_size, GFP_KERNEL);
>>>       if (!ret)
>>>           return ERR_PTR(-ENOMEM);
>>>         mbox_cmd = (struct cxl_mbox_cmd) {
>>>           .opcode = CXL_MBOX_OP_GET_SUPPORTED_LOGS,
>>> -        .size_out = mds->payload_size,
>>> +        .size_out = cxl_mbox->payload_size,
>>>           .payload_out = ret,
>>>           /* At least the record number field must be valid */
>>>           .min_out = 2,
>>> @@ -910,6 +939,7 @@ static int cxl_clear_event_record(struct cxl_memdev_state *mds,
>>>                     enum cxl_event_log_type log,
>>>                     struct cxl_get_event_payload *get_pl)
>>>   {
>>> +    struct cxl_mailbox *cxl_mbox = mds->cxlds.cxl_mbox;
>>>       struct cxl_mbox_clear_event_payload *payload;
>>>       u16 total = le16_to_cpu(get_pl->record_count);
>>>       u8 max_handles = CXL_CLEAR_EVENT_MAX_HANDLES;
>>> @@ -919,9 +949,12 @@ static int cxl_clear_event_record(struct cxl_memdev_state *mds,
>>>       int rc = 0;
>>>       int i;
>>>   +    if (!cxl_mbox)
>>> +        return -ENODEV;
>>> +
>>>       /* Payload size may limit the max handles */
>>> -    if (pl_size > mds->payload_size) {
>>> -        max_handles = (mds->payload_size - sizeof(*payload)) /
>>> +    if (pl_size > cxl_mbox->payload_size) {
>>> +        max_handles = (cxl_mbox->payload_size - sizeof(*payload)) /
>>>                     sizeof(__le16);
>>>           pl_size = struct_size(payload, handles, max_handles);
>>>       }
>>> @@ -979,12 +1012,16 @@ static int cxl_clear_event_record(struct cxl_memdev_state *mds,
>>>   static void cxl_mem_get_records_log(struct cxl_memdev_state *mds,
>>>                       enum cxl_event_log_type type)
>>>   {
>>> +    struct cxl_mailbox *cxl_mbox = mds->cxlds.cxl_mbox;
>>>       struct cxl_memdev *cxlmd = mds->cxlds.cxlmd;
>>>       struct device *dev = mds->cxlds.dev;
>>>       struct cxl_get_event_payload *payload;
>>>       u8 log_type = type;
>>>       u16 nr_rec;
>>>   +    if (!cxl_mbox)
>>> +        return;
>>> +
>>>       mutex_lock(&mds->event.log_lock);
>>>       payload = mds->event.buf;
>>>   @@ -995,7 +1032,7 @@ static void cxl_mem_get_records_log(struct cxl_memdev_state *mds,
>>>               .payload_in = &log_type,
>>>               .size_in = sizeof(log_type),
>>>               .payload_out = payload,
>>> -            .size_out = mds->payload_size,
>>> +            .size_out = cxl_mbox->payload_size,
>>>               .min_out = struct_size(payload, records, 0),
>>>           };
>>>   @@ -1328,11 +1365,15 @@ int cxl_mem_get_poison(struct cxl_memdev *cxlmd, u64 offset, u64 len,
>>>                  struct cxl_region *cxlr)
>>>   {
>>>       struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlmd->cxlds);
>>> +    struct cxl_mailbox *cxl_mbox = mds->cxlds.cxl_mbox;
>>>       struct cxl_mbox_poison_out *po;
>>>       struct cxl_mbox_poison_in pi;
>>>       int nr_records = 0;
>>>       int rc;
>>>   +    if (!cxl_mbox)
>>> +        return -ENODEV;
>>> +
>>>       rc = mutex_lock_interruptible(&mds->poison.lock);
>>>       if (rc)
>>>           return rc;
>>> @@ -1346,7 +1387,7 @@ int cxl_mem_get_poison(struct cxl_memdev *cxlmd, u64 offset, u64 len,
>>>               .opcode = CXL_MBOX_OP_GET_POISON,
>>>               .size_in = sizeof(pi),
>>>               .payload_in = &pi,
>>> -            .size_out = mds->payload_size,
>>> +            .size_out = cxl_mbox->payload_size,
>>>               .payload_out = po,
>>>               .min_out = struct_size(po, record, 0),
>>>           };
>>> @@ -1382,7 +1423,12 @@ static void free_poison_buf(void *buf)
>>>   /* Get Poison List output buffer is protected by mds->poison.lock */
>>>   static int cxl_poison_alloc_buf(struct cxl_memdev_state *mds)
>>>   {
>>> -    mds->poison.list_out = kvmalloc(mds->payload_size, GFP_KERNEL);
>>> +    struct cxl_mailbox *cxl_mbox = mds->cxlds.cxl_mbox;
>>> +
>>> +    if (!cxl_mbox)
>>> +        return -ENODEV;
>>> +
>>> +    mds->poison.list_out = kvmalloc(cxl_mbox->payload_size, GFP_KERNEL);
>>>       if (!mds->poison.list_out)
>>>           return -ENOMEM;
>>>   @@ -1408,6 +1454,34 @@ int cxl_poison_state_init(struct cxl_memdev_state *mds)
>>>   }
>>>   EXPORT_SYMBOL_NS_GPL(cxl_poison_state_init, CXL);
>>>   +static void free_cxl_mailbox(void *cxl_mbox)
>>> +{
>>> +    kfree(cxl_mbox);
>>> +}
>>> +
>>> +struct cxl_mailbox *cxl_mailbox_create(struct device *dev)
>>> +{
>>> +    struct cxl_mailbox *cxl_mbox __free(kfree) =
>>> +        kzalloc(sizeof(*cxl_mbox), GFP_KERNEL);
>>> +    int rc;
>>> +
>>> +    if (!cxl_mbox)
>>> +        return ERR_PTR(-ENOMEM);
>>> +
>>> +    cxl_mbox->host = dev;
>>> +    mutex_init(&cxl_mbox->mbox_mutex);
>>> +    rcuwait_init(&cxl_mbox->mbox_wait);
>>> +
>>> +    rc = devm_add_action_or_reset(dev, free_cxl_mailbox, cxl_mbox);
>>> +    if (rc) {
>>> +        cxl_mbox = NULL;
>>> +        return ERR_PTR(rc);
>>> +    }
>>> +
>>> +    return no_free_ptr(cxl_mbox);
>>> +}
>>> +EXPORT_SYMBOL_NS_GPL(cxl_mailbox_create, CXL);
>>> +
>>>   struct cxl_memdev_state *cxl_memdev_state_create(struct device *dev)
>>>   {
>>>       struct cxl_memdev_state *mds;
>>> @@ -1418,7 +1492,6 @@ struct cxl_memdev_state *cxl_memdev_state_create(struct device *dev)
>>>           return ERR_PTR(-ENOMEM);
>>>       }
>>>   -    mutex_init(&mds->mbox_mutex);
>>>       mutex_init(&mds->event.log_lock);
>>>       mds->cxlds.dev = dev;
>>>       mds->cxlds.reg_map.host = dev;
>>> diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c
>>> index 0277726afd04..7c99f89740a9 100644
>>> --- a/drivers/cxl/core/memdev.c
>>> +++ b/drivers/cxl/core/memdev.c
>>> @@ -56,9 +56,9 @@ static ssize_t payload_max_show(struct device *dev,
>>>       struct cxl_dev_state *cxlds = cxlmd->cxlds;
>>>       struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlds);
>>>   -    if (!mds)
>>> +    if (!mds || !cxlds->cxl_mbox)
>>>           return sysfs_emit(buf, "\n");
>>> -    return sysfs_emit(buf, "%zu\n", mds->payload_size);
>>> +    return sysfs_emit(buf, "%zu\n", cxlds->cxl_mbox->payload_size);
>>>   }
>>>   static DEVICE_ATTR_RO(payload_max);
>>>   @@ -124,15 +124,19 @@ static ssize_t security_state_show(struct device *dev,
>>>   {
>>>       struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
>>>       struct cxl_dev_state *cxlds = cxlmd->cxlds;
>>> +    struct cxl_mailbox *cxl_mbox = cxlds->cxl_mbox;
>>>       struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlds);
>>>       unsigned long state = mds->security.state;
>>>       int rc = 0;
>>>   +    if (!cxl_mbox)
>>> +        return -ENODEV;
>>> +
>>>       /* sync with latest submission state */
>>> -    mutex_lock(&mds->mbox_mutex);
>>> +    mutex_lock(&cxl_mbox->mbox_mutex);
>>>       if (mds->security.sanitize_active)
>>>           rc = sysfs_emit(buf, "sanitize\n");
>>> -    mutex_unlock(&mds->mbox_mutex);
>>> +    mutex_unlock(&cxl_mbox->mbox_mutex);
>>>       if (rc)
>>>           return rc;
>>>   @@ -829,12 +833,16 @@ static enum fw_upload_err cxl_fw_prepare(struct fw_upload *fwl, const u8 *data,
>>>   {
>>>       struct cxl_memdev_state *mds = fwl->dd_handle;
>>>       struct cxl_mbox_transfer_fw *transfer;
>>> +    struct cxl_mailbox *cxl_mbox = mds->cxlds.cxl_mbox;
>>> +
>>> +    if (!cxl_mbox)
>>> +        return FW_UPLOAD_ERR_NONE;
>>>         if (!size)
>>>           return FW_UPLOAD_ERR_INVALID_SIZE;
>>>         mds->fw.oneshot = struct_size(transfer, data, size) <
>>> -                mds->payload_size;
>>> +                cxl_mbox->payload_size;
>>>         if (cxl_mem_get_fw_info(mds))
>>>           return FW_UPLOAD_ERR_HW_ERROR;
>>> @@ -854,6 +862,7 @@ static enum fw_upload_err cxl_fw_write(struct fw_upload *fwl, const u8 *data,
>>>   {
>>>       struct cxl_memdev_state *mds = fwl->dd_handle;
>>>       struct cxl_dev_state *cxlds = &mds->cxlds;
>>> +    struct cxl_mailbox *cxl_mbox = cxlds->cxl_mbox;
>>>       struct cxl_memdev *cxlmd = cxlds->cxlmd;
>>>       struct cxl_mbox_transfer_fw *transfer;
>>>       struct cxl_mbox_cmd mbox_cmd;
>>> @@ -861,6 +870,9 @@ static enum fw_upload_err cxl_fw_write(struct fw_upload *fwl, const u8 *data,
>>>       size_t size_in;
>>>       int rc;
>>>   +    if (!cxl_mbox)
>>> +        return FW_UPLOAD_ERR_NONE;
>>> +
>>>       *written = 0;
>>>         /* Offset has to be aligned to 128B (CXL-3.0 8.2.9.3.2 Table 8-57) */
>>> @@ -877,7 +889,7 @@ static enum fw_upload_err cxl_fw_write(struct fw_upload *fwl, const u8 *data,
>>>        * sizeof(*transfer) is 128.  These constraints imply that @cur_size
>>>        * will always be 128b aligned.
>>>        */
>>> -    cur_size = min_t(size_t, size, mds->payload_size - sizeof(*transfer));
>>> +    cur_size = min_t(size_t, size, cxl_mbox->payload_size - sizeof(*transfer));
>>>         remaining = size - cur_size;
>>>       size_in = struct_size(transfer, data, cur_size);
>>> @@ -1059,16 +1071,20 @@ EXPORT_SYMBOL_NS_GPL(devm_cxl_add_memdev, CXL);
>>>   static void sanitize_teardown_notifier(void *data)
>>>   {
>>>       struct cxl_memdev_state *mds = data;
>>> +    struct cxl_mailbox *cxl_mbox = mds->cxlds.cxl_mbox;
>>>       struct kernfs_node *state;
>>>   +    if (!cxl_mbox)
>>> +        return;
>>> +
>>>       /*
>>>        * Prevent new irq triggered invocations of the workqueue and
>>>        * flush inflight invocations.
>>>        */
>>> -    mutex_lock(&mds->mbox_mutex);
>>> +    mutex_lock(&cxl_mbox->mbox_mutex);
>>>       state = mds->security.sanitize_node;
>>>       mds->security.sanitize_node = NULL;
>>> -    mutex_unlock(&mds->mbox_mutex);
>>> +    mutex_unlock(&cxl_mbox->mbox_mutex);
>>>         cancel_delayed_work_sync(&mds->security.poll_dwork);
>>>       sysfs_put(state);
>>> diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
>>> index af8169ccdbc0..17e83a2cf1be 100644
>>> --- a/drivers/cxl/cxlmem.h
>>> +++ b/drivers/cxl/cxlmem.h
>>> @@ -3,11 +3,13 @@
>>>   #ifndef __CXL_MEM_H__
>>>   #define __CXL_MEM_H__
>>>   #include <uapi/linux/cxl_mem.h>
>>> +#include <linux/pci.h>
>>>   #include <linux/cdev.h>
>>>   #include <linux/uuid.h>
>>>   #include <linux/rcuwait.h>
>>>   #include <linux/cxl-event.h>
>>>   #include <linux/node.h>
>>> +#include <linux/cxl/mailbox.h>
>>>   #include "cxl.h"
>>>     /* CXL 2.0 8.2.8.5.1.1 Memory Device Status Register */
>>> @@ -424,6 +426,7 @@ struct cxl_dpa_perf {
>>>    * @ram_res: Active Volatile memory capacity configuration
>>>    * @serial: PCIe Device Serial Number
>>>    * @type: Generic Memory Class device or Vendor Specific Memory device
>>> + * @cxl_mbox: CXL mailbox context
>>>    */
>>>   struct cxl_dev_state {
>>>       struct device *dev;
>>> @@ -438,8 +441,14 @@ struct cxl_dev_state {
>>>       struct resource ram_res;
>>>       u64 serial;
>>>       enum cxl_devtype type;
>>> +    struct cxl_mailbox *cxl_mbox;
>>>   };
>>>   +static inline struct cxl_dev_state *mbox_to_cxlds(struct cxl_mailbox *cxl_mbox)
>>> +{
>>> +    return dev_get_drvdata(cxl_mbox->host);
>>> +}
>>> +
>>>   /**
>>>    * struct cxl_memdev_state - Generic Type-3 Memory Device Class driver data
>>>    *
>>> @@ -448,11 +457,8 @@ struct cxl_dev_state {
>>>    * the functionality related to that like Identify Memory Device and Get
>>>    * Partition Info
>>>    * @cxlds: Core driver state common across Type-2 and Type-3 devices
>>> - * @payload_size: Size of space for payload
>>> - *                (CXL 2.0 8.2.8.4.3 Mailbox Capabilities Register)
>>>    * @lsa_size: Size of Label Storage Area
>>>    *                (CXL 2.0 8.2.9.5.1.1 Identify Memory Device)
>>> - * @mbox_mutex: Mutex to synchronize mailbox access.
>>>    * @firmware_version: Firmware version for the memory device.
>>>    * @enabled_cmds: Hardware commands found enabled in CEL.
>>>    * @exclusive_cmds: Commands that are kernel-internal only
>>> @@ -470,17 +476,13 @@ struct cxl_dev_state {
>>>    * @poison: poison driver state info
>>>    * @security: security driver state info
>>>    * @fw: firmware upload / activation state
>>> - * @mbox_wait: RCU wait for mbox send completely
>>> - * @mbox_send: @dev specific transport for transmitting mailbox commands
>>>    *
>>>    * See CXL 3.0 8.2.9.8.2 Capacity Configuration and Label Storage for
>>>    * details on capacity parameters.
>>>    */
>>>   struct cxl_memdev_state {
>>>       struct cxl_dev_state cxlds;
>>> -    size_t payload_size;
>>>       size_t lsa_size;
>>> -    struct mutex mbox_mutex; /* Protects device mailbox and firmware */
>>>       char firmware_version[0x10];
>>>       DECLARE_BITMAP(enabled_cmds, CXL_MEM_COMMAND_ID_MAX);
>>>       DECLARE_BITMAP(exclusive_cmds, CXL_MEM_COMMAND_ID_MAX);
>>> @@ -500,10 +502,6 @@ struct cxl_memdev_state {
>>>       struct cxl_poison_state poison;
>>>       struct cxl_security_state security;
>>>       struct cxl_fw_state fw;
>>> -
>>> -    struct rcuwait mbox_wait;
>>> -    int (*mbox_send)(struct cxl_memdev_state *mds,
>>> -             struct cxl_mbox_cmd *cmd);
>>>   };
>>>     static inline struct cxl_memdev_state *
>>> diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
>>> index e53646e9f2fb..bd8ee14a7926 100644
>>> --- a/drivers/cxl/pci.c
>>> +++ b/drivers/cxl/pci.c
>>> @@ -11,6 +11,7 @@
>>>   #include <linux/pci.h>
>>>   #include <linux/aer.h>
>>>   #include <linux/io.h>
>>> +#include <linux/cxl/mailbox.h>
>>>   #include "cxlmem.h"
>>>   #include "cxlpci.h"
>>>   #include "cxl.h"
>>> @@ -124,6 +125,7 @@ static irqreturn_t cxl_pci_mbox_irq(int irq, void *id)
>>>       u16 opcode;
>>>       struct cxl_dev_id *dev_id = id;
>>>       struct cxl_dev_state *cxlds = dev_id->cxlds;
>>> +    struct cxl_mailbox *cxl_mbox = cxlds->cxl_mbox;
>>>       struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlds);
>>>         if (!cxl_mbox_background_complete(cxlds))
>>> @@ -132,13 +134,13 @@ static irqreturn_t cxl_pci_mbox_irq(int irq, void *id)
>>>       reg = readq(cxlds->regs.mbox + CXLDEV_MBOX_BG_CMD_STATUS_OFFSET);
>>>       opcode = FIELD_GET(CXLDEV_MBOX_BG_CMD_COMMAND_OPCODE_MASK, reg);
>>>       if (opcode == CXL_MBOX_OP_SANITIZE) {
>>> -        mutex_lock(&mds->mbox_mutex);
>>> +        mutex_lock(&cxl_mbox->mbox_mutex);
>>>           if (mds->security.sanitize_node)
>>>               mod_delayed_work(system_wq, &mds->security.poll_dwork, 0);
>>> -        mutex_unlock(&mds->mbox_mutex);
>>> +        mutex_unlock(&cxl_mbox->mbox_mutex);
>>>       } else {
>>>           /* short-circuit the wait in __cxl_pci_mbox_send_cmd() */
>>> -        rcuwait_wake_up(&mds->mbox_wait);
>>> +        rcuwait_wake_up(&cxl_mbox->mbox_wait);
>>>       }
>>>         return IRQ_HANDLED;
>>> @@ -152,8 +154,9 @@ static void cxl_mbox_sanitize_work(struct work_struct *work)
>>>       struct cxl_memdev_state *mds =
>>>           container_of(work, typeof(*mds), security.poll_dwork.work);
>>>       struct cxl_dev_state *cxlds = &mds->cxlds;
>>> +    struct cxl_mailbox *cxl_mbox = cxlds->cxl_mbox;
>>>   -    mutex_lock(&mds->mbox_mutex);
>>> +    mutex_lock(&cxl_mbox->mbox_mutex);
>>>       if (cxl_mbox_background_complete(cxlds)) {
>>>           mds->security.poll_tmo_secs = 0;
>>>           if (mds->security.sanitize_node)
>>> @@ -167,7 +170,7 @@ static void cxl_mbox_sanitize_work(struct work_struct *work)
>>>           mds->security.poll_tmo_secs = min(15 * 60, timeout);
>>>           schedule_delayed_work(&mds->security.poll_dwork, timeout * HZ);
>>>       }
>>> -    mutex_unlock(&mds->mbox_mutex);
>>> +    mutex_unlock(&cxl_mbox->mbox_mutex);
>>>   }
>>>     /**
>>> @@ -192,17 +195,18 @@ static void cxl_mbox_sanitize_work(struct work_struct *work)
>>>    * not need to coordinate with each other. The driver only uses the primary
>>>    * mailbox.
>>>    */
>>> -static int __cxl_pci_mbox_send_cmd(struct cxl_memdev_state *mds,
>>> +static int __cxl_pci_mbox_send_cmd(struct cxl_mailbox *cxl_mbox,
>>>                      struct cxl_mbox_cmd *mbox_cmd)
>>>   {
>>> -    struct cxl_dev_state *cxlds = &mds->cxlds;
>>> +    struct cxl_dev_state *cxlds = mbox_to_cxlds(cxl_mbox);
>>> +    struct cxl_memdev_state *mds = to_cxl_memdev_state(cxlds);
>>>       void __iomem *payload = cxlds->regs.mbox + CXLDEV_MBOX_PAYLOAD_OFFSET;
>>>       struct device *dev = cxlds->dev;
>>>       u64 cmd_reg, status_reg;
>>>       size_t out_len;
>>>       int rc;
>>>   -    lockdep_assert_held(&mds->mbox_mutex);
>>> +    lockdep_assert_held(&cxl_mbox->mbox_mutex);
>>>         /*
>>>        * Here are the steps from 8.2.8.4 of the CXL 2.0 spec.
>>> @@ -315,10 +319,10 @@ static int __cxl_pci_mbox_send_cmd(struct cxl_memdev_state *mds,
>>>             timeout = mbox_cmd->poll_interval_ms;
>>>           for (i = 0; i < mbox_cmd->poll_count; i++) {
>>> -            if (rcuwait_wait_event_timeout(&mds->mbox_wait,
>>> -                       cxl_mbox_background_complete(cxlds),
>>> -                       TASK_UNINTERRUPTIBLE,
>>> -                       msecs_to_jiffies(timeout)) > 0)
>>> +            if (rcuwait_wait_event_timeout(&cxl_mbox->mbox_wait,
>>> +                               cxl_mbox_background_complete(cxlds),
>>> +                               TASK_UNINTERRUPTIBLE,
>>> +                               msecs_to_jiffies(timeout)) > 0)
>>>                   break;
>>>           }
>>>   @@ -360,7 +364,7 @@ static int __cxl_pci_mbox_send_cmd(struct cxl_memdev_state *mds,
>>>            */
>>>           size_t n;
>>>   -        n = min3(mbox_cmd->size_out, mds->payload_size, out_len);
>>> +        n = min3(mbox_cmd->size_out, cxl_mbox->payload_size, out_len);
>>>           memcpy_fromio(mbox_cmd->payload_out, payload, n);
>>>           mbox_cmd->size_out = n;
>>>       } else {
>>> @@ -370,14 +374,14 @@ static int __cxl_pci_mbox_send_cmd(struct cxl_memdev_state *mds,
>>>       return 0;
>>>   }
>>>   -static int cxl_pci_mbox_send(struct cxl_memdev_state *mds,
>>> +static int cxl_pci_mbox_send(struct cxl_mailbox *cxl_mbox,
>>>                    struct cxl_mbox_cmd *cmd)
>>>   {
>>>       int rc;
>>>   -    mutex_lock_io(&mds->mbox_mutex);
>>> -    rc = __cxl_pci_mbox_send_cmd(mds, cmd);
>>> -    mutex_unlock(&mds->mbox_mutex);
>>> +    mutex_lock_io(&cxl_mbox->mbox_mutex);
>>> +    rc = __cxl_pci_mbox_send_cmd(cxl_mbox, cmd);
>>> +    mutex_unlock(&cxl_mbox->mbox_mutex);
>>>         return rc;
>>>   }
>>> @@ -385,6 +389,7 @@ static int cxl_pci_mbox_send(struct cxl_memdev_state *mds,
>>>   static int cxl_pci_setup_mailbox(struct cxl_memdev_state *mds, bool irq_avail)
>>>   {
>>>       struct cxl_dev_state *cxlds = &mds->cxlds;
>>> +    struct cxl_mailbox *cxl_mbox = cxlds->cxl_mbox;
>>>       const int cap = readl(cxlds->regs.mbox + CXLDEV_MBOX_CAPS_OFFSET);
>>>       struct device *dev = cxlds->dev;
>>>       unsigned long timeout;
>>> @@ -417,8 +422,8 @@ static int cxl_pci_setup_mailbox(struct cxl_memdev_state *mds, bool irq_avail)
>>>           return -ETIMEDOUT;
>>>       }
>>>   -    mds->mbox_send = cxl_pci_mbox_send;
>>> -    mds->payload_size =
>>> +    cxl_mbox->mbox_send = cxl_pci_mbox_send;
>>> +    cxl_mbox->payload_size =
>>>           1 << FIELD_GET(CXLDEV_MBOX_CAP_PAYLOAD_SIZE_MASK, cap);
>>>         /*
>>> @@ -428,16 +433,15 @@ static int cxl_pci_setup_mailbox(struct cxl_memdev_state *mds, bool irq_avail)
>>>        * there's no point in going forward. If the size is too large, there's
>>>        * no harm is soft limiting it.
>>>        */
>>> -    mds->payload_size = min_t(size_t, mds->payload_size, SZ_1M);
>>> -    if (mds->payload_size < 256) {
>>> +    cxl_mbox->payload_size = min_t(size_t, cxl_mbox->payload_size, SZ_1M);
>>> +    if (cxl_mbox->payload_size < 256) {
>>>           dev_err(dev, "Mailbox is too small (%zub)",
>>> -            mds->payload_size);
>>> +            cxl_mbox->payload_size);
>>>           return -ENXIO;
>>>       }
>>>   -    dev_dbg(dev, "Mailbox payload sized %zu", mds->payload_size);
>>> +    dev_dbg(dev, "Mailbox payload sized %zu", cxl_mbox->payload_size);
>>>   -    rcuwait_init(&mds->mbox_wait);
>>>       INIT_DELAYED_WORK(&mds->security.poll_dwork, cxl_mbox_sanitize_work);
>>>         /* background command interrupts are optional */
>>> @@ -578,9 +582,13 @@ static void free_event_buf(void *buf)
>>>    */
>>>   static int cxl_mem_alloc_event_buf(struct cxl_memdev_state *mds)
>>>   {
>>> +    struct cxl_mailbox *cxl_mbox = mds->cxlds.cxl_mbox;
>>>       struct cxl_get_event_payload *buf;
>>>   -    buf = kvmalloc(mds->payload_size, GFP_KERNEL);
>>> +    if (!cxl_mbox)
>>> +        return -ENODEV;
>>> +
>>> +    buf = kvmalloc(cxl_mbox->payload_size, GFP_KERNEL);
>>>       if (!buf)
>>>           return -ENOMEM;
>>>       mds->event.buf = buf;
>>> @@ -786,6 +794,26 @@ static int cxl_event_config(struct pci_host_bridge *host_bridge,
>>>       return 0;
>>>   }
>>>   +static int cxl_pci_create_mailbox(struct cxl_dev_state *cxlds)
>>> +{
>>> +    struct cxl_mailbox *cxl_mbox;
>>> +
>>> +    /*
>>> +     * Don't bother to allocate the mailbox if the mailbox register isn't
>>> +     * there.
>>> +     */
>>> +    if (!cxlds->reg_map.device_map.mbox.valid)
>>> +        return -ENODEV;
>>> +
>>> +    cxl_mbox = cxl_mailbox_create(cxlds->dev);
>>> +    if (IS_ERR(cxl_mbox))
>>> +        return PTR_ERR(cxl_mbox);
>>> +
>>> +    cxlds->cxl_mbox = cxl_mbox;
>>> +
>>> +    return 0;
>>> +}
>>> +
>>>   static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
>>>   {
>>>       struct pci_host_bridge *host_bridge = pci_find_host_bridge(pdev->bus);
>>> @@ -846,6 +874,10 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
>>>       if (rc)
>>>           dev_dbg(&pdev->dev, "Failed to map RAS capability.\n");
>>>   +    rc = cxl_pci_create_mailbox(cxlds);
>>> +    if (rc)
>>> +        return rc;
>>> +
>>>       rc = cxl_await_media_ready(cxlds);
>>>       if (rc == 0)
>>>           cxlds->media_ready = true;
>>> diff --git a/drivers/cxl/pmem.c b/drivers/cxl/pmem.c
>>> index 2ecdaee63021..12e68b194820 100644
>>> --- a/drivers/cxl/pmem.c
>>> +++ b/drivers/cxl/pmem.c
>>> @@ -102,13 +102,18 @@ static int cxl_pmem_get_config_size(struct cxl_memdev_state *mds,
>>>                       struct nd_cmd_get_config_size *cmd,
>>>                       unsigned int buf_len)
>>>   {
>>> +    struct cxl_mailbox *cxl_mbox = mds->cxlds.cxl_mbox;
>>> +
>>> +    if (!cxl_mbox)
>>> +        return -ENODEV;
>>> +
>>>       if (sizeof(*cmd) > buf_len)
>>>           return -EINVAL;
>>>         *cmd = (struct nd_cmd_get_config_size){
>>>           .config_size = mds->lsa_size,
>>>           .max_xfer =
>>> -            mds->payload_size - sizeof(struct cxl_mbox_set_lsa),
>>> +            cxl_mbox->payload_size - sizeof(struct cxl_mbox_set_lsa),
>>>       };
>>>         return 0;
>>> diff --git a/include/linux/cxl/mailbox.h b/include/linux/cxl/mailbox.h
>>> new file mode 100644
>>> index 000000000000..2b9e4bc1690c
>>> --- /dev/null
>>> +++ b/include/linux/cxl/mailbox.h
>>> @@ -0,0 +1,28 @@
>>> +/* SPDX-License-Identifier: GPL-2.0-only */
>>> +/* Copyright(c) 2024 Intel Corporation. */
>>> +#ifndef __CXL_MBOX_H__
>>> +#define __CXL_MBOX_H__
>>> +
>>> +struct cxl_mbox_cmd;
>>> +
>>> +/**
>>> + * struct cxl_mailbox - context for CXL mailbox operations
>>> + * @host: device that hosts the mailbox
>>> + * @adev: auxiliary device for fw-ctl
> 
> 
> This field does not exist in the defined struct.

Ah yeah copy/paste error when I pulled code from the fwctl code branch. If you end up picking up this code for your type2 work, please feel free to delete that. 

DJ

> 
> This aside:
> 
> Reviewed-by: Alejandro Lucero <alucerop@amd.com>
> 
> 
>>> + * @payload_size: Size of space for payload
>>> + *                (CXL 3.1 8.2.8.4.3 Mailbox Capabilities Register)
>>> + * @mbox_mutex: mutex protects device mailbox and firmware
>>> + * @mbox_wait: rcuwait for mailbox
>>> + * @mbox_send: @dev specific transport for transmitting mailbox commands
>>> + */
>>> +struct cxl_mailbox {
>>> +    struct device *host;
>>> +    size_t payload_size;
>>> +    struct mutex mbox_mutex; /* lock to protect mailbox context */
>>> +    struct rcuwait mbox_wait;
>>> +    int (*mbox_send)(struct cxl_mailbox *cxl_mbox, struct cxl_mbox_cmd *cmd);
>>> +};
>>> +
>>> +struct cxl_mailbox *cxl_mailbox_create(struct device *dev);
>>> +
>>> +#endif
>>> diff --git a/tools/testing/cxl/test/mem.c b/tools/testing/cxl/test/mem.c
>>> index eaf091a3d331..29f1a2df9122 100644
>>> --- a/tools/testing/cxl/test/mem.c
>>> +++ b/tools/testing/cxl/test/mem.c
>>> @@ -8,6 +8,7 @@
>>>   #include <linux/delay.h>
>>>   #include <linux/sizes.h>
>>>   #include <linux/bits.h>
>>> +#include <linux/cxl/mailbox.h>
>>>   #include <asm/unaligned.h>
>>>   #include <crypto/sha2.h>
>>>   #include <cxlmem.h>
>>> @@ -530,6 +531,7 @@ static int mock_gsl(struct cxl_mbox_cmd *cmd)
>>>     static int mock_get_log(struct cxl_memdev_state *mds, struct cxl_mbox_cmd *cmd)
>>>   {
>>> +    struct cxl_mailbox *cxl_mbox = mds->cxlds.cxl_mbox;
>>>       struct cxl_mbox_get_log *gl = cmd->payload_in;
>>>       u32 offset = le32_to_cpu(gl->offset);
>>>       u32 length = le32_to_cpu(gl->length);
>>> @@ -538,7 +540,7 @@ static int mock_get_log(struct cxl_memdev_state *mds, struct cxl_mbox_cmd *cmd)
>>>         if (cmd->size_in < sizeof(*gl))
>>>           return -EINVAL;
>>> -    if (length > mds->payload_size)
>>> +    if (length > cxl_mbox->payload_size)
>>>           return -EINVAL;
>>>       if (offset + length > sizeof(mock_cel))
>>>           return -EINVAL;
>>> @@ -613,12 +615,13 @@ void cxl_mockmem_sanitize_work(struct work_struct *work)
>>>   {
>>>       struct cxl_memdev_state *mds =
>>>           container_of(work, typeof(*mds), security.poll_dwork.work);
>>> +    struct cxl_mailbox *cxl_mbox = mds->cxlds.cxl_mbox;
>>>   -    mutex_lock(&mds->mbox_mutex);
>>> +    mutex_lock(&cxl_mbox->mbox_mutex);
>>>       if (mds->security.sanitize_node)
>>>           sysfs_notify_dirent(mds->security.sanitize_node);
>>>       mds->security.sanitize_active = false;
>>> -    mutex_unlock(&mds->mbox_mutex);
>>> +    mutex_unlock(&cxl_mbox->mbox_mutex);
>>>         dev_dbg(mds->cxlds.dev, "sanitize complete\n");
>>>   }
>>> @@ -627,6 +630,7 @@ static int mock_sanitize(struct cxl_mockmem_data *mdata,
>>>                struct cxl_mbox_cmd *cmd)
>>>   {
>>>       struct cxl_memdev_state *mds = mdata->mds;
>>> +    struct cxl_mailbox *cxl_mbox = mds->cxlds.cxl_mbox;
>>>       int rc = 0;
>>>         if (cmd->size_in != 0)
>>> @@ -644,14 +648,14 @@ static int mock_sanitize(struct cxl_mockmem_data *mdata,
>>>           return -ENXIO;
>>>       }
>>>   -    mutex_lock(&mds->mbox_mutex);
>>> +    mutex_lock(&cxl_mbox->mbox_mutex);
>>>       if (schedule_delayed_work(&mds->security.poll_dwork,
>>>                     msecs_to_jiffies(mdata->sanitize_timeout))) {
>>>           mds->security.sanitize_active = true;
>>>           dev_dbg(mds->cxlds.dev, "sanitize issued\n");
>>>       } else
>>>           rc = -EBUSY;
>>> -    mutex_unlock(&mds->mbox_mutex);
>>> +    mutex_unlock(&cxl_mbox->mbox_mutex);
>>>         return rc;
>>>   }
>>> @@ -1330,12 +1334,13 @@ static int mock_activate_fw(struct cxl_mockmem_data *mdata,
>>>       return -EINVAL;
>>>   }
>>>   -static int cxl_mock_mbox_send(struct cxl_memdev_state *mds,
>>> +static int cxl_mock_mbox_send(struct cxl_mailbox *cxl_mbox,
>>>                     struct cxl_mbox_cmd *cmd)
>>>   {
>>> +    struct device *dev = cxl_mbox->host;
>>> +    struct cxl_mockmem_data *mdata = dev_get_drvdata(dev);
>>> +    struct cxl_memdev_state *mds = mdata->mds;
>>>       struct cxl_dev_state *cxlds = &mds->cxlds;
>>> -    struct device *dev = cxlds->dev;
>>> -    struct cxl_mockmem_data *mdata = dev_get_drvdata(dev);
>>>       int rc = -EIO;
>>>         switch (cmd->opcode) {
>>> @@ -1450,6 +1455,19 @@ static ssize_t event_trigger_store(struct device *dev,
>>>   }
>>>   static DEVICE_ATTR_WO(event_trigger);
>>>   +static int cxl_mock_mailbox_create(struct cxl_dev_state *cxlds)
>>> +{
>>> +    struct cxl_mailbox *cxl_mbox;
>>> +
>>> +    cxl_mbox = cxl_mailbox_create(cxlds->dev);
>>> +    if (IS_ERR(cxl_mbox))
>>> +        return PTR_ERR(cxl_mbox);
>>> +
>>> +    cxlds->cxl_mbox = cxl_mbox;
>>> +
>>> +    return 0;
>>> +}
>>> +
>>>   static int cxl_mock_mem_probe(struct platform_device *pdev)
>>>   {
>>>       struct device *dev = &pdev->dev;
>>> @@ -1457,6 +1475,7 @@ static int cxl_mock_mem_probe(struct platform_device *pdev)
>>>       struct cxl_memdev_state *mds;
>>>       struct cxl_dev_state *cxlds;
>>>       struct cxl_mockmem_data *mdata;
>>> +    struct cxl_mailbox *cxl_mbox;
>>>       int rc;
>>>         mdata = devm_kzalloc(dev, sizeof(*mdata), GFP_KERNEL);
>>> @@ -1484,13 +1503,18 @@ static int cxl_mock_mem_probe(struct platform_device *pdev)
>>>       if (IS_ERR(mds))
>>>           return PTR_ERR(mds);
>>>   +    cxlds = &mds->cxlds;
>>> +    rc = cxl_mock_mailbox_create(cxlds);
>>> +    if (rc)
>>> +        return rc;
>>> +
>>> +    cxl_mbox = mds->cxlds.cxl_mbox;
>>>       mdata->mds = mds;
>>> -    mds->mbox_send = cxl_mock_mbox_send;
>>> -    mds->payload_size = SZ_4K;
>>> +    cxl_mbox->mbox_send = cxl_mock_mbox_send;
>>> +    cxl_mbox->payload_size = SZ_4K;
>>>       mds->event.buf = (struct cxl_get_event_payload *) mdata->event_buf;
>>>       INIT_DELAYED_WORK(&mds->security.poll_dwork, cxl_mockmem_sanitize_work);
>>>   -    cxlds = &mds->cxlds;
>>>       cxlds->serial = pdev->id;
>>>       if (is_rcd(pdev))
>>>           cxlds->rcd = true;
>>> -- 
>>> 2.45.2
>>>