Re: [PATCH 2/9] cxl-mailbox-utils: 0x5600 - FMAPI Get DCD Info

[Jonathan Cameron <Jonathan.Cameron@huawei.com>]

On Mon, 17 Mar 2025 16:31:29 +0000
anisa.su887@gmail.com wrote:

> From: Anisa Su <anisa.su@samsung.com>
> 
> FM DCD Management command 0x5600 implemented per CXL 3.2 Spec Section 7.6.7.6.1
> 
> Signed-off-by: Anisa Su <anisa.su@samsung.com>
> ---
>  hw/cxl/cxl-mailbox-utils.c | 67 ++++++++++++++++++++++++++++++++++++++
>  hw/cxl/i2c_mctp_cxl.c      |  6 +++-
>  2 files changed, 72 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/cxl/cxl-mailbox-utils.c b/hw/cxl/cxl-mailbox-utils.c
> index 1b62d36101..e9991fd1a7 100644
> --- a/hw/cxl/cxl-mailbox-utils.c
> +++ b/hw/cxl/cxl-mailbox-utils.c
> @@ -122,6 +122,8 @@ enum {
>          #define MANAGEMENT_COMMAND     0x0
>      MHD = 0x55,
>          #define GET_MHD_INFO 0x0
> +    FMAPI_DCD_MGMT = 0x56,
> +        #define GET_DCD_INFO 0x0
>  };
>  
>  /* CCI Message Format CXL r3.1 Figure 7-19 */
> @@ -3341,6 +3343,62 @@ static CXLRetCode cmd_dcd_release_dyn_cap(const struct cxl_cmd *cmd,
>      return CXL_MBOX_SUCCESS;
>  }
>  
> +/*
> + * CXL r3.2 section 7.6.7.6.1: Get DCD Info (Opcode 5600h)
> + */

Single line comment should be fine here.

> +static CXLRetCode cmd_fm_get_dcd_info(const struct cxl_cmd *cmd,
> +                                      uint8_t *payload_in,
> +                                      size_t len_in,
> +                                      uint8_t *payload_out,
> +                                      size_t *len_out,
> +                                      CXLCCI *cci)
> +{
> +    struct {
> +        uint8_t num_hosts;
> +        uint8_t num_regions_supported;
> +        uint8_t rsvd1[2];
> +        uint16_t add_select_policy_bitmask;
> +        uint8_t rsvd2[2];
> +        uint16_t release_select_policy_bitmask;
> +        uint8_t sanitize_on_release_bitmask;
> +        uint8_t rsvd3;
> +        uint64_t total_dynamic_capacity;
> +        uint64_t region_blk_size_bitmasks[8];
> +    } QEMU_PACKED *out;
    } QEMU_PACKED *out = (void *)payload_out;
> +    CXLType3Dev *ct3d = CXL_TYPE3(cci->d);
> +    CXLDCRegion region;
> +    int i;
> +
> +    if (ct3d->dc.num_regions == 0) {
> +        return CXL_MBOX_UNSUPPORTED;
> +    }
> +
> +    out = (void *)payload_out;
Why not just do this at declaration above?
It is harmless to set it then even if we exit earlier
I think.

> +
> +    /* TODO: num hosts set to 1 for now */

Unless this changes later in the set, no need for a todo here.
This simply denotes what we are emulating. Maybe we will make
it more flexible in future, maybe not.

> +    out->num_hosts = 1;
> +    out->num_regions_supported = ct3d->dc.num_regions;
> +    /* TODO: only prescriptive supported for now */

Likewise, not a todo that needs comment. Just a current setting.
As long as we never make it nor support this we are fine for
compatibility etc.  The CXL stuff doesn't support migration anyway
so not problems there.

> +    stw_le_p(&out->add_select_policy_bitmask,
> +             CXL_EXTENT_SELECTION_POLICY_PRESCRIPTIVE);
> +    stw_le_p(&out->release_select_policy_bitmask,
> +             CXL_EXTENT_REMOVAL_POLICY_PRESCRIPTIVE);
> +    /* TODO: sanitize on release bitmask cleared for now */

As with above, not really a todo, more of a choice made for now.

> +    out->sanitize_on_release_bitmask = 0;
> +
> +    stq_le_p(&out->total_dynamic_capacity,
> +             ct3d->dc.total_capacity / CXL_CAPACITY_MULTIPLIER);
> +
> +    for (i = 0; i < ct3d->dc.num_regions; i++) {
> +        region = ct3d->dc.regions[i];
> +        memcpy(&out->region_blk_size_bitmasks[i],
> +                &region.supported_blk_size_bitmask, 8);

sizeof(out->region_blk_size_bitmasks[i]) 

> +    }
> +
> +    *len_out = sizeof(*out);
> +    return CXL_MBOX_SUCCESS;
> +}
> +
>  static const struct cxl_cmd cxl_cmd_set[256][256] = {
>      [INFOSTAT][BACKGROUND_OPERATION_ABORT] = { "BACKGROUND_OPERATION_ABORT",
>          cmd_infostat_bg_op_abort, 0, 0 },
> @@ -3462,6 +3520,11 @@ static const struct cxl_cmd cxl_cmd_set_sw[256][256] = {
>                                       cmd_tunnel_management_cmd, ~0, 0 },
>  };
>  
> +static const struct cxl_cmd cxl_cmd_set_fm_dcd[256][256] = {
> +    [FMAPI_DCD_MGMT][GET_DCD_INFO] = { "GET_DCD_INFO",
> +        cmd_fm_get_dcd_info, 0, 0},
> +};
> +
>  /*
>   * While the command is executing in the background, the device should
>   * update the percentage complete in the Background Command Status Register
> @@ -3764,7 +3827,11 @@ void cxl_initialize_t3_fm_owned_ld_mctpcci(CXLCCI *cci, DeviceState *d,
>                                             DeviceState *intf,
>                                             size_t payload_max)
>  {
> +    CXLType3Dev *ct3d = CXL_TYPE3(d);
>      cxl_copy_cci_commands(cci, cxl_cmd_set_t3_fm_owned_ld_mctp);
> +    if (ct3d->dc.num_regions) {
> +        cxl_copy_cci_commands(cci, cxl_cmd_set_fm_dcd);
> +    }
>      cci->d = d;
>      cci->intf = intf;
>      cxl_init_cci(cci, payload_max);
> diff --git a/hw/cxl/i2c_mctp_cxl.c b/hw/cxl/i2c_mctp_cxl.c
> index 7d2cbc3b75..df95182925 100644
> --- a/hw/cxl/i2c_mctp_cxl.c
> +++ b/hw/cxl/i2c_mctp_cxl.c
> @@ -46,6 +46,9 @@
>  /* Implementation choice - may make this configurable */
>  #define MCTP_CXL_MAILBOX_BYTES 512
>  
> +/* Supported FMAPI Cmds */
> +#define FMAPI_CMD_MAX_OPCODE 0x57
> +
>  typedef struct CXLMCTPMessage {
>      /*
>       * DSP0236 (MCTP Base) Integrity Check + Message Type
> @@ -200,7 +203,8 @@ static void i2c_mctp_cxl_handle_message(MCTPI2CEndpoint *mctp)
>          if (!(msg->message_type == MCTP_MT_CXL_TYPE3 &&
>                msg->command_set < 0x51) &&
>              !(msg->message_type == MCTP_MT_CXL_FMAPI &&
> -              msg->command_set >= 0x51 && msg->command_set < 0x56)) {
> +              msg->command_set >= 0x51 &&
> +              msg->command_set < FMAPI_CMD_MAX_OPCODE)) {

Hmm. There is a visibility problem here we should address but probably not
by introducing a new define.  Maybe we should move the enum from
cxl-mailbox-utils.c in a precursor patch.

Jonathan


>              buf->rc = CXL_MBOX_UNSUPPORTED;
>              st24_le_p(buf->pl_length, len_out);
>              s->len = s->pos;