Re: [PATCH -qemu] hw/cxl: Support get/set mctp response payload size

[Fan Ni <nifan.cxl@gmail.com>]

On Wed, Oct 09, 2024 at 06:41:57PM -0700, Davidlohr Bueso wrote:
> Add Get/Set Response Message Limit commands.
> 
> Signed-off-by: Davidlohr Bueso <dave@stgolabs.net>

The commit log may include the cxl spec reference. Otherwise,

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


> ---
>  hw/cxl/cxl-mailbox-utils.c | 68 ++++++++++++++++++++++++++++++++++++--
>  1 file changed, 65 insertions(+), 3 deletions(-)
> 
> diff --git a/hw/cxl/cxl-mailbox-utils.c b/hw/cxl/cxl-mailbox-utils.c
> index c2d776bc96eb..98416af794bb 100644
> --- a/hw/cxl/cxl-mailbox-utils.c
> +++ b/hw/cxl/cxl-mailbox-utils.c
> @@ -7,6 +7,8 @@
>   * COPYING file in the top-level directory.
>   */
>  
> +#include <math.h>
> +
>  #include "qemu/osdep.h"
>  #include "hw/pci/msi.h"
>  #include "hw/pci/msix.h"
> @@ -56,6 +58,8 @@ enum {
>      INFOSTAT    = 0x00,
>          #define IS_IDENTIFY   0x1
>          #define BACKGROUND_OPERATION_STATUS    0x2
> +        #define GET_RESPONSE_MSG_LIMIT   0x3
> +        #define SET_RESPONSE_MSG_LIMIT   0x4
>      EVENTS      = 0x01,
>          #define GET_RECORDS   0x0
>          #define CLEAR_RECORDS   0x1
> @@ -393,7 +397,7 @@ static CXLRetCode cmd_infostat_identify(const struct cxl_cmd *cmd,
>          uint16_t pcie_subsys_vid;
>          uint16_t pcie_subsys_id;
>          uint64_t sn;
> -    uint8_t max_message_size;
> +        uint8_t max_message_size;
>          uint8_t component_type;
>      } QEMU_PACKED *is_identify;
>      QEMU_BUILD_BUG_ON(sizeof(*is_identify) != 18);
> @@ -422,12 +426,58 @@ static CXLRetCode cmd_infostat_identify(const struct cxl_cmd *cmd,
>          is_identify->component_type = 0x3; /* Type 3 */
>      }
>  
> -    /* TODO: Allow this to vary across different CCIs */
> -    is_identify->max_message_size = 9; /* 512 bytes - MCTP_CXL_MAILBOX_BYTES */
> +    is_identify->max_message_size = (uint8_t)log2(cci->payload_max);
>      *len_out = sizeof(*is_identify);
>      return CXL_MBOX_SUCCESS;
>  }
>  
> +/* CXL r3.1 section 8.2.9.1.3: Get Response Message Limit (Opcode 0003h) */
> +static CXLRetCode cmd_get_response_msg_limit(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 rsp_limit;
> +    } QEMU_PACKED *get_rsp_msg_limit = (void *)payload_out;
> +    QEMU_BUILD_BUG_ON(sizeof(*get_rsp_msg_limit) != 1);
> +
> +    get_rsp_msg_limit->rsp_limit = (uint8_t)log2(cci->payload_max);
> +
> +    *len_out = sizeof(*get_rsp_msg_limit);
> +    return CXL_MBOX_SUCCESS;
> +}
> +
> +/* CXL r3.1 section 8.2.9.1.4: Set Response Message Limit (Opcode 0004h) */
> +static CXLRetCode cmd_set_response_msg_limit(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 rsp_limit;
> +    } QEMU_PACKED *in = (void *)payload_in;
> +    QEMU_BUILD_BUG_ON(sizeof(*in) != 1);
> +    struct {
> +        uint8_t rsp_limit;
> +    } QEMU_PACKED *out = (void *)payload_out;
> +    QEMU_BUILD_BUG_ON(sizeof(*out) != 1);
> +
> +    if (in->rsp_limit < 8 || in->rsp_limit > 10) {
> +        return CXL_MBOX_INVALID_INPUT;
> +    }
> +
> +    cci->payload_max = 1 << in->rsp_limit;
> +    out->rsp_limit = in->rsp_limit;
> +
> +    *len_out = sizeof(*out);
> +    return CXL_MBOX_SUCCESS;
> +}
> +
>  static void cxl_set_dsp_active_bm(PCIBus *b, PCIDevice *d,
>                                    void *private)
>  {
> @@ -3000,6 +3050,10 @@ void cxl_initialize_mailbox_t3(CXLCCI *cci, DeviceState *d, size_t payload_max)
>  
>  static const struct cxl_cmd cxl_cmd_set_t3_mctp[256][256] = {
>      [INFOSTAT][IS_IDENTIFY] = { "IDENTIFY", cmd_infostat_identify, 0, 0 },
> +    [INFOSTAT][GET_RESPONSE_MSG_LIMIT] = { "GET_RESPONSE_MSG_LIMIT",
> +                                           cmd_get_response_msg_limit, 0, 0 },
> +    [INFOSTAT][SET_RESPONSE_MSG_LIMIT] = { "SET_RESPONSE_MSG_LIMIT",
> +                                           cmd_set_response_msg_limit, 1, 0 },
>      [TIMESTAMP][GET] = { "TIMESTAMP_GET", cmd_timestamp_get, 0, 0 },
>      [LOGS][GET_SUPPORTED] = { "LOGS_GET_SUPPORTED", cmd_logs_get_supported, 0,
>                                0 },
> @@ -3035,6 +3089,10 @@ void cxl_initialize_t3_ld_cci(CXLCCI *cci, DeviceState *d, DeviceState *intf,
>  
>  static const struct cxl_cmd cxl_cmd_set_t3_fm_owned_ld_mctp[256][256] = {
>      [INFOSTAT][IS_IDENTIFY] = { "IDENTIFY", cmd_infostat_identify, 0,  0},
> +    [INFOSTAT][GET_RESPONSE_MSG_LIMIT] = { "GET_RESPONSE_MSG_LIMIT",
> +                                           cmd_get_response_msg_limit, 0, 0 },
> +    [INFOSTAT][SET_RESPONSE_MSG_LIMIT] = { "SET_RESPONSE_MSG_LIMIT",
> +                                           cmd_set_response_msg_limit, 1, 0 },
>      [LOGS][GET_SUPPORTED] = { "LOGS_GET_SUPPORTED", cmd_logs_get_supported, 0,
>                                0 },
>      [LOGS][GET_LOG] = { "LOGS_GET_LOG", cmd_logs_get_log, 0x18, 0 },
> @@ -3055,6 +3113,10 @@ void cxl_initialize_t3_fm_owned_ld_mctpcci(CXLCCI *cci, DeviceState *d,
>  
>  static const struct cxl_cmd cxl_cmd_set_usp_mctp[256][256] = {
>      [INFOSTAT][IS_IDENTIFY] = { "IDENTIFY", cmd_infostat_identify, 0, 0 },
> +    [INFOSTAT][GET_RESPONSE_MSG_LIMIT] = { "GET_RESPONSE_MSG_LIMIT",
> +                                           cmd_get_response_msg_limit, 0, 0 },
> +    [INFOSTAT][SET_RESPONSE_MSG_LIMIT] = { "SET_RESPONSE_MSG_LIMIT",
> +                                           cmd_set_response_msg_limit, 1, 0 },
>      [LOGS][GET_SUPPORTED] = { "LOGS_GET_SUPPORTED", cmd_logs_get_supported,
>                                0, 0 },
>      [LOGS][GET_LOG] = { "LOGS_GET_LOG", cmd_logs_get_log, 0x18, 0 },
> -- 
> 2.46.1
> 

-- 
Fan Ni