Re: [PATCH] Add support for FMAPI Get Mutliheaded Head info opcode (5501h)

[Alok Rathore <alok.rathore@samsung.com>]

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On 22/05/25 09:48AM, Fan Ni wrote:
>On Thu, May 22, 2025 at 12:01:35PM +0530, Vinayak Holikatti wrote:
>> CXL spec 3.2 section 7.6.7.5.2  describes Get Head Info.
>>
>> Signed-off-by: Vinayak Holikatti <vinayak.kh@samsung.com>
>> ---
>> This patch is generated against Jonathan Cameron's branch cxl-2025-03-20
>>
>>  hw/cxl/cxl-mailbox-utils.c  | 21 +++++++++
>>  hw/cxl/mhsld/mhsld.c        | 92 ++++++++++++++++++++++++++++++++++++-
>>  hw/cxl/mhsld/mhsld.h        | 26 +++++++++++
>>  include/hw/cxl/cxl_device.h |  6 +++
>>  4 files changed, 144 insertions(+), 1 deletion(-)
>>
>> diff --git a/hw/cxl/cxl-mailbox-utils.c b/hw/cxl/cxl-mailbox-utils.c
>> index a02d130926..4f25caecea 100644
>> --- a/hw/cxl/cxl-mailbox-utils.c
>> +++ b/hw/cxl/cxl-mailbox-utils.c
>> @@ -122,6 +122,7 @@ enum {
>>          #define MANAGEMENT_COMMAND     0x0
>>      MHD = 0x55,
>>          #define GET_MHD_INFO 0x0
>> +        #define GET_MHD_HEAD_INFO 0x1
>>  };
>>
>>  /* CCI Message Format CXL r3.1 Figure 7-19 */
>> @@ -267,6 +268,23 @@ static CXLRetCode cmd_mhd_get_info(const struct cxl_cmd *cmd,
>>      return CXL_MBOX_UNSUPPORTED;
>>  }
>>
>> +/*
>> + * CXL r3.2 section 7.6.7.5.2 - Get Multi-Headed Head Info (Opcode 5501h)
>That does not match the section subject of the spec
>Get Head Info (...

Thanks Fan Ni. Will fix in V1 patch.

>> + */
>> +static CXLRetCode cmd_mhd_get_head_info(const struct cxl_cmd *cmd,
>> +                                   uint8_t *payload_in, size_t len_in,
>> +                                   uint8_t *payload_out, size_t *len_out,
>> +                                   CXLCCI *cci)
>The indent here is not right.

Okay. Will fix in V1 patch.

>> +static CXLRetCode cmd_mhd_get_head_info(const struct cxl_cmd *cmd,
>> +                                        uint8_t *payload_in, size_t len_in,
>
>> +{
>> +    CXLType3Dev *ct3d = CXL_TYPE3(cci->d);
>> +    CXLType3Class *cvc = CXL_TYPE3_GET_CLASS(ct3d);
>> +    if (cvc->mhd_get_head_info) {
>> +        return cvc->mhd_get_head_info(cmd, payload_in, len_in, payload_out,
>> +                                 len_out, cci);
>
>indent needs fix.

Okay. Will fix in V1 patch.

>
>> +    }
>> +    return CXL_MBOX_UNSUPPORTED;
>> +}
>> +
>>  static CXLRetCode cmd_events_get_records(const struct cxl_cmd *cmd,
>>                                           uint8_t *payload_in, size_t len_in,
>>                                           uint8_t *payload_out, size_t *len_out,
>> @@ -3429,6 +3447,7 @@ static const struct cxl_cmd cxl_cmd_set[256][256] = {
>>          "MEDIA_AND_POISON_GET_SCAN_MEDIA_RESULTS",
>>          cmd_media_get_scan_media_results, 0, 0 },
>>      [MHD][GET_MHD_INFO] = { "GET_MULTI_HEADED_INFO", cmd_mhd_get_info, 2, 0},
>> +    [MHD][GET_MHD_HEAD_INFO] = { "GET_MULTI_HEADED_INFO", cmd_mhd_get_head_info, 2, 0},
>>  };
>>
>>  static const struct cxl_cmd cxl_cmd_set_dcd[256][256] = {
>> @@ -3761,6 +3780,8 @@ static const struct cxl_cmd cxl_cmd_set_t3_fm_owned_ld_mctp[256][256] = {
>>      [TIMESTAMP][GET] = { "TIMESTAMP_GET", cmd_timestamp_get, 0, 0 },
>>      [TUNNEL][MANAGEMENT_COMMAND] = { "TUNNEL_MANAGEMENT_COMMAND",
>>                                       cmd_tunnel_management_cmd, ~0, 0 },
>> +    [MHD][GET_MHD_INFO] = { "GET_MULTI_HEADED_INFO", cmd_mhd_get_info, 2, 0},
>> +    [MHD][GET_MHD_HEAD_INFO] = { "GET_MULTI_HEADED_INFO", cmd_mhd_get_head_info, 2, 0},
>>  };
>>
>>  void cxl_initialize_t3_fm_owned_ld_mctpcci(CXLCCI *cci, DeviceState *d,
>> diff --git a/hw/cxl/mhsld/mhsld.c b/hw/cxl/mhsld/mhsld.c
>> index 9f633b3bed..981546b5ff 100644
>> --- a/hw/cxl/mhsld/mhsld.c
>> +++ b/hw/cxl/mhsld/mhsld.c
>> @@ -61,9 +61,57 @@ static CXLRetCode cmd_mhd_get_info(const struct cxl_cmd *cmd,
>>      return CXL_MBOX_SUCCESS;
>>  }
>>
>> +/*
>> + * CXL r3.2 section 7.6.7.5.2 - Get Head Info (Opcode 5501h)
>> + *
>> + * This command retrieves the number of heads, number of supported LDs,
>> + * and Head-to-LD mapping of a Multi-Headed device.
>> + */
>> +static CXLRetCode cmd_mhd_get_head_info(const struct cxl_cmd *cmd,
>> +                                        uint8_t *payload_in, size_t len_in,
>> +                                        uint8_t *payload_out, size_t *len_out,
>> +                                        CXLCCI *cci)
>> +{
>> +    CXLMHSLDState *s = CXL_MHSLD(cci->d);
>> +    MHDGetHeadInfoInput *input = (void *)payload_in;
>> +    MHDGetHeadInfoOutput *output = (void *)payload_out;
>> +    int i = 0;
>> +
>> +    if (input->start_head > MHSLD_HEADS) {
>
>Should be ">=" ?

Right. Head index starts from 0, so this condition should be there.

>
>Also, per the spec, we need also check the "number of heads" field, if
>start_head and number of heads together point to a non-exist head, we
>should return invalid input.

Yes. Will add this check in V1 patch.

>
>> +        return CXL_MBOX_INVALID_INPUT;
>> +    }
>> +
>> +    output->nr_heads = MIN((MHSLD_HEADS - input->start_head), input->nr_heads);
>> +    for (i = input->start_head; i < input->start_head + output->nr_heads; i++) {
>> +        output->head_info_list[i].port_number =
>> +                                 s->mhd_state->head_info_blocks[i].port_number;
>> +        output->head_info_list[i].max_link_width =
>> +                              s->mhd_state->head_info_blocks[i].max_link_width;
>> +        output->head_info_list[i].nego_link_width =
>> +                             s->mhd_state->head_info_blocks[i].nego_link_width;
>> +        output->head_info_list[i].supp_link_speeds_vector =
>> +                     s->mhd_state->head_info_blocks[i].supp_link_speeds_vector;
>> +        output->head_info_list[i].max_link_speed =
>> +                              s->mhd_state->head_info_blocks[i].max_link_speed;
>> +        output->head_info_list[i].current_link_speed =
>> +                          s->mhd_state->head_info_blocks[i].current_link_speed;
>> +        output->head_info_list[i].ltssm_state =
>> +                                 s->mhd_state->head_info_blocks[i].ltssm_state;
>> +        output->head_info_list[i].first_nego_lane_num =
>> +                         s->mhd_state->head_info_blocks[i].first_nego_lane_num;
>> +        output->head_info_list[i].link_state_flags =
>> +                            s->mhd_state->head_info_blocks[i].link_state_flags;
>> +    }
>> +
>> +    *len_out = sizeof(*output) + output->nr_heads * sizeof(MHDHeadInfoBlock);
>> +    return CXL_MBOX_SUCCESS;
>> +}
>> +
>>  static const struct cxl_cmd cxl_cmd_set_mhsld[256][256] = {
>>      [MHSLD_MHD][GET_MHD_INFO] = {"GET_MULTI_HEADED_INFO",
>>          cmd_mhd_get_info, 2, 0},
>> +    [MHSLD_MHD][GET_MHD_HEAD_INFO] = {"GET_HEAD_INFO",
>> +        cmd_mhd_get_head_info, 2, 0},
>>  };
>>
>>  static const Property cxl_mhsld_props[] = {
>> @@ -166,6 +214,47 @@ static void cxl_mhsld_state_initialize(CXLMHSLDState *s, size_t dc_size)
>>      s->mhd_state->nr_blocks = dc_size / MHSLD_BLOCK_SZ;
>>  }
>>
>> +
>> +static void cxl_mhsld_init_head_info(CXLMHSLDState *s, PCIDevice *pdev)
>> +{
>> +    uint16_t lnksta = 0;
>> +    uint16_t current_link_speed = 0;
>> +    uint16_t negotiated_link_width = 0;
>> +    uint16_t lnkcap = 0, lnkcap2 = 0;
>> +    uint16_t max_link_width = 0;
>> +    uint16_t max_link_speed = 0;
>> +    uint16_t supported_link_speeds_vector = 0;
>> +
>> +    lnksta = pdev->config_read(pdev,
>> +                               pdev->exp.exp_cap + PCI_EXP_LNKSTA,
>> +                               sizeof(lnksta));
>> +    lnkcap = pdev->config_read(pdev,
>> +                               pdev->exp.exp_cap + PCI_EXP_LNKCAP,
>> +                               sizeof(lnkcap));
>> +    lnkcap2 = pdev->config_read(pdev,
>> +                                pdev->exp.exp_cap + PCI_EXP_LNKCAP2,
>> +                                sizeof(lnkcap2));
>> +    supported_link_speeds_vector = (lnkcap2 & 0xFE) >> 1;
>> +    max_link_width = (lnkcap & PCI_EXP_LNKCAP_MLW) >> 4;
>> +    max_link_speed = lnkcap & PCI_EXP_LNKCAP_SLS;
>> +    current_link_speed = lnksta & PCI_EXP_LNKSTA_CLS;
>> +    negotiated_link_width = (lnksta & PCI_EXP_LNKSTA_NLW) >> 4;
>> +
>> +    s->mhd_state->head_info_blocks[s->mhd_head].port_number = s->mhd_head;
>> +    s->mhd_state->head_info_blocks[s->mhd_head].max_link_width = max_link_width;
>> +    s->mhd_state->head_info_blocks[s->mhd_head].nego_link_width =
>> +                                                          negotiated_link_width;
>> +    s->mhd_state->head_info_blocks[s->mhd_head].supp_link_speeds_vector =
>> +                                                   supported_link_speeds_vector;
>> +    s->mhd_state->head_info_blocks[s->mhd_head].max_link_speed =
>> +                                                                 max_link_speed;
>> +    s->mhd_state->head_info_blocks[s->mhd_head].current_link_speed =
>> +                                                             current_link_speed;
>> +    s->mhd_state->head_info_blocks[s->mhd_head].ltssm_state = 0x7;
>> +    s->mhd_state->head_info_blocks[s->mhd_head].first_nego_lane_num = 0;
>> +    s->mhd_state->head_info_blocks[s->mhd_head].link_state_flags = 0;
>> +}
>> +
>>  /* Returns starting index of region in MHD map. */
>>  static inline size_t cxl_mhsld_find_dc_region_start(PCIDevice *d,
>>                                                      CXLDCRegion *r)
>> @@ -376,7 +465,7 @@ static void cxl_mhsld_realize(PCIDevice *pci_dev, Error **errp)
>>      }
>>
>>      cxl_mhsld_state_initialize(s, dc_size);
>> -
>> +    cxl_mhsld_init_head_info(s, pci_dev);
>>      /* Set the LD ownership for this head to this system */
>>      s->mhd_state->ldmap[s->mhd_head] = s->mhd_head;
>>      return;
>> @@ -428,6 +517,7 @@ static void cxl_mhsld_class_init(ObjectClass *klass, void *data)
>>
>>      CXLType3Class *cvc = CXL_TYPE3_CLASS(klass);
>>      cvc->mhd_get_info = cmd_mhd_get_info;
>> +    cvc->mhd_get_head_info = cmd_mhd_get_head_info;
>>      cvc->mhd_access_valid = cxl_mhsld_access_valid;
>>      cvc->mhd_reserve_extents = cxl_mhsld_reserve_extents;
>>      cvc->mhd_reclaim_extents = cxl_mhsld_reclaim_extents;
>> diff --git a/hw/cxl/mhsld/mhsld.h b/hw/cxl/mhsld/mhsld.h
>> index e7ead1f0d2..c9fbec71ca 100644
>> --- a/hw/cxl/mhsld/mhsld.h
>> +++ b/hw/cxl/mhsld/mhsld.h
>> @@ -23,6 +23,18 @@
>>   */
>>  #define MHSLD_HEADS  (8)
>>
>> +typedef struct MHDHeadInfoBlock {
>> +    uint8_t port_number;
>> +    uint8_t max_link_width;
>> +    uint8_t nego_link_width;
>> +    uint8_t supp_link_speeds_vector;
>> +    uint8_t max_link_speed;
>> +    uint8_t current_link_speed;
>> +    uint8_t ltssm_state;
>> +    uint8_t first_nego_lane_num;
>> +    uint8_t link_state_flags;
>> +} QEMU_PACKED MHDHeadInfoBlock;
>> +
>>  /*
>>   * The shared state cannot have 2 variable sized regions
>>   * so we have to max out the ldmap.
>> @@ -32,6 +44,7 @@ typedef struct MHSLDSharedState {
>>      uint8_t nr_lds;
>>      uint8_t ldmap[MHSLD_HEADS];
>>      uint64_t nr_blocks;
>> +    MHDHeadInfoBlock head_info_blocks[MHSLD_HEADS];
>>      uint8_t blocks[];
>>  } MHSLDSharedState;
>>
>> @@ -52,6 +65,7 @@ struct CXLMHSLDClass {
>>  enum {
>>      MHSLD_MHD = 0x55,
>>          #define GET_MHD_INFO 0x0
>> +        #define GET_MHD_HEAD_INFO 0x1
>>  };
>>
>>  /*
>> @@ -72,4 +86,16 @@ typedef struct MHDGetInfoOutput {
>>      uint16_t resv2;
>>      uint8_t ldmap[];
>>  } QEMU_PACKED MHDGetInfoOutput;
>> +
>> +typedef struct MHDGetHeadInfoInput {
>> +    uint8_t start_head;
>> +    uint8_t nr_heads;
>> +} QEMU_PACKED MHDGetHeadInfoInput;
>> +
>> +typedef struct MHDGetHeadInfoOutput {
>> +    uint8_t nr_heads;
>> +    uint8_t rsvd[3];
>> +    MHDHeadInfoBlock head_info_list[];
>
>s/head_info_list/head_info/

Okay. Will use head_info in V1 patch.

>
>Fan

Thanks Fan Ni for reviewing the patch.

Alok
>
>> +} QEMU_PACKED MHDGetHeadInfoOutput;
>> +
>>  #endif
>> diff --git a/include/hw/cxl/cxl_device.h b/include/hw/cxl/cxl_device.h
>> index ca515cab13..c93c71c45d 100644
>> --- a/include/hw/cxl/cxl_device.h
>> +++ b/include/hw/cxl/cxl_device.h
>> @@ -732,6 +732,12 @@ struct CXLType3Class {
>>                                 uint8_t *payload_out,
>>                                 size_t *len_out,
>>                                 CXLCCI *cci);
>> +    CXLRetCode (*mhd_get_head_info)(const struct cxl_cmd *cmd,
>> +                               uint8_t *payload_in,
>> +                               size_t len_in,
>> +                               uint8_t *payload_out,
>> +                               size_t *len_out,
>> +                               CXLCCI *cci);
>>      bool (*mhd_access_valid)(PCIDevice *d, uint64_t addr, unsigned int size);
>>      bool (*mhd_reserve_extents)(PCIDevice *d,
>>                                  CxlDynamicCapacityExtentList *records,
>> --
>> 2.34.1
>>

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