Re: [PATCH 03/26] cxl/mem: Read dynamic capacity configuration from the device

[Jørgen Hansen]

On 3/25/24 00:18, ira.weiny@xxxxxxxxx wrote:

> From: Navneet Singh <navneet.singh@xxxxxxxxx>
> 
> Devices can optionally support Dynamic Capacity (DC).  These devices are
> known as Dynamic Capacity Devices (DCD).
> 
> Implement the DC mailbox commands as specified in CXL 3.1 section
> 8.2.9.9.9 (opcodes 48XXh).  Read the DC configuration and store the DC
> region information in the device state.
> 
> Signed-off-by: Navneet Singh <navneet.singh@xxxxxxxxx>
> Co-developed-by: Ira Weiny <ira.weiny@xxxxxxxxx>
> Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx>
> 
> ---
> Changes for v1
> [Jørgen: ensure CXL 2.0 device support by removing dc_event_log_size]
> [iweiny/Jørgen: use get DC config command to signal DCD support]
> [djiang: fix subject]
> [Fan: add additional region configuration checks]
> [Jonathan/djiang: split out region mode changes]
> [Jonathan: fix up comments/kdoc]
> [Jonathan: s/cxl_get_dc_id/cxl_get_dc_config/]
> [Jonathan: use __free() in identify call]
> [Jonathan: remove unneeded formatting changes]
> [Jonathan: s/cxl_mbox_dynamic_capacity/cxl_mbox_get_dc_config_out/]
> [Jonathan: s/cxl_mbox_get_dc_config/cxl_mbox_get_dc_config_in/]
> [iweiny: remove type2 work dependancy/rebase on master]
> [iweiny: fix 0day build issues]
> ---
>   drivers/cxl/core/mbox.c | 184 +++++++++++++++++++++++++++++++++++++++++++++++-
>   drivers/cxl/cxlmem.h    |  49 +++++++++++++
>   drivers/cxl/pci.c       |   4 ++
>   3 files changed, 236 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
> index ed4131c6f50b..14e8a7528a8b 100644
> --- a/drivers/cxl/core/mbox.c
> +++ b/drivers/cxl/core/mbox.c
> @@ -1123,7 +1123,7 @@ int cxl_dev_state_identify(struct cxl_memdev_state *mds)
>          if (rc < 0)
>                  return rc;
> 
> -       mds->total_bytes =
> +       mds->static_cap =
>                  le64_to_cpu(id.total_capacity) * CXL_CAPACITY_MULTIPLIER;
>          mds->volatile_only_bytes =
>                  le64_to_cpu(id.volatile_capacity) * CXL_CAPACITY_MULTIPLIER;
> @@ -1230,6 +1230,175 @@ int cxl_mem_sanitize(struct cxl_memdev *cxlmd, u16 cmd)
>          return rc;
>   }
> 
> +static int cxl_dc_save_region_info(struct cxl_memdev_state *mds, u8 index,
> +                                  struct cxl_dc_region_config *region_config)
> +{
> +       struct cxl_dc_region_info *dcr = &mds->dc_region[index];
> +       struct device *dev = mds->cxlds.dev;
> +
> +       dcr->base = le64_to_cpu(region_config->region_base);
> +       dcr->decode_len = le64_to_cpu(region_config->region_decode_length);
> +       dcr->decode_len *= CXL_CAPACITY_MULTIPLIER;
> +       dcr->len = le64_to_cpu(region_config->region_length);
> +       dcr->blk_size = le64_to_cpu(region_config->region_block_size);
> +       dcr->dsmad_handle = le32_to_cpu(region_config->region_dsmad_handle);
> +       dcr->flags = region_config->flags;
> +       snprintf(dcr->name, CXL_DC_REGION_STRLEN, "dc%d", index);
> +
> +       /* Check regions are in increasing DPA order */
> +       if (index > 0) {
> +               struct cxl_dc_region_info *prev_dcr = &mds->dc_region[index - 1];
> +
> +               if ((prev_dcr->base + prev_dcr->decode_len) > dcr->base) {
> +                       dev_err(dev,
> +                               "DPA ordering violation for DC region %d and %d\n",
> +                               index - 1, index);
> +                       return -EINVAL;
> +               }
> +       }
> +
> +       if (!IS_ALIGNED(dcr->base, SZ_256M) ||
> +           !IS_ALIGNED(dcr->base, dcr->blk_size)) {
> +               dev_err(dev, "DC region %d invalid base %#llx blk size %#llx\n", index,
> +                       dcr->base, dcr->blk_size);
> +               return -EINVAL;
> +       }
> +
> +       if (dcr->decode_len == 0 || dcr->len == 0 || dcr->decode_len < dcr->len ||
> +           !IS_ALIGNED(dcr->len, dcr->blk_size)) {
> +               dev_err(dev, "DC region %d invalid length; decode %#llx len %#llx blk size %#llx\n",
> +                       index, dcr->decode_len, dcr->len, dcr->blk_size);
> +               return -EINVAL;
> +       }
> +
> +       if (dcr->blk_size == 0 || dcr->blk_size % 0x40 ||
> +           !is_power_of_2(dcr->blk_size)) {
> +               dev_err(dev, "DC region %d invalid block size; %#llx\n",
> +                       index, dcr->blk_size);
> +               return -EINVAL;
> +       }
> +
> +       dev_dbg(dev,
> +               "DC region %s DPA: %#llx LEN: %#llx BLKSZ: %#llx\n",
> +               dcr->name, dcr->base, dcr->decode_len, dcr->blk_size);
> +
> +       return 0;
> +}
> +
> +/* Returns the number of regions in dc_resp or -ERRNO */
> +static int cxl_get_dc_config(struct cxl_memdev_state *mds, u8 start_region,
> +                            struct cxl_mbox_get_dc_config_out *dc_resp,
> +                            size_t dc_resp_size)
> +{
> +       struct cxl_mbox_get_dc_config_in get_dc = (struct cxl_mbox_get_dc_config_in) {
> +               .region_count = CXL_MAX_DC_REGION,
> +               .start_region_index = start_region,
> +       };
> +       struct cxl_mbox_cmd mbox_cmd = (struct cxl_mbox_cmd) {
> +               .opcode = CXL_MBOX_OP_GET_DC_CONFIG,
> +               .payload_in = &get_dc,
> +               .size_in = sizeof(get_dc),
> +               .size_out = dc_resp_size,
> +               .payload_out = dc_resp,
> +               .min_out = 1,
> +       };
> +       struct device *dev = mds->cxlds.dev;
> +       int rc;
> +
> +       rc = cxl_internal_send_cmd(mds, &mbox_cmd);
> +       if (rc < 0)
> +               return rc;
> +
> +       rc = dc_resp->avail_region_count - start_region;
> +
> +       /*
> +        * The number of regions in the payload may have been truncated due to
> +        * payload_size limits; if so adjust the returned count to match.
> +        */
> +       if (mbox_cmd.size_out < sizeof(*dc_resp))
> +               rc = CXL_REGIONS_RETURNED(mbox_cmd.size_out);
> +
> +       dev_dbg(dev, "Read %d/%d DC regions\n", rc, dc_resp->avail_region_count);
> +
> +       return rc;
> +}
> +
> +static bool cxl_dcd_supported(struct cxl_memdev_state *mds)
> +{
> +       return test_bit(CXL_DCD_ENABLED_GET_CONFIG, mds->dcd_cmds);
> +}
> +
> +/**
> + * cxl_dev_dynamic_capacity_identify() - Reads the dynamic capacity
> + *                                      information from the device.
> + * @mds: The memory device state
> + *
> + * Read Dynamic Capacity information from the device and populate the state
> + * structures for later use.
> + *
> + * Return: 0 if identify was executed successfully, -ERRNO on error.
> + */
> +int cxl_dev_dynamic_capacity_identify(struct cxl_memdev_state *mds)
> +{
> +       size_t dc_resp_size = mds->payload_size;
> +       struct device *dev = mds->cxlds.dev;
> +       u8 start_region, i;
> +       int rc = 0;
> +
> +       for (i = 0; i < CXL_MAX_DC_REGION; i++)
> +               snprintf(mds->dc_region[i].name, CXL_DC_REGION_STRLEN, "<nil>");
> +
> +       /* Check GET_DC_CONFIG is supported by device */
> +       if (!cxl_dcd_supported(mds)) {
> +               dev_dbg(dev, "DCD not supported\n");
> +               return 0;
> +       }
> +
> +       struct cxl_mbox_get_dc_config_out *dc_resp __free(kfree) =
> +                                       kvmalloc(dc_resp_size, GFP_KERNEL);
> +       if (!dc_resp)
> +               return -ENOMEM;
> +
> +       start_region = 0;
> +       do {
> +               int j;
> +
> +               rc = cxl_get_dc_config(mds, start_region, dc_resp, dc_resp_size);
> +               if (rc < 0) {
> +                       dev_dbg(dev, "Failed to get DC config: %d\n", rc);
> +                       return rc;
> +               }
> +
> +               mds->nr_dc_region += rc;
> +
> +               if (mds->nr_dc_region < 1 || mds->nr_dc_region > CXL_MAX_DC_REGION) {
> +                       dev_err(dev, "Invalid num of dynamic capacity regions %d\n",
> +                               mds->nr_dc_region);
> +                       return -EINVAL;
> +               }
> +
> +               for (i = start_region, j = 0; i < mds->nr_dc_region; i++, j++) {
> +                       rc = cxl_dc_save_region_info(mds, i, &dc_resp->region[j]);
> +                       if (rc) {
> +                               dev_dbg(dev, "Failed to save region info: %d\n", rc);
> +                               return rc;
> +                       }
> +               }
> +
> +               start_region = mds->nr_dc_region;
> +
> +       } while (mds->nr_dc_region < dc_resp->avail_region_count);
> +
> +       mds->dynamic_cap =
> +               mds->dc_region[mds->nr_dc_region - 1].base +
> +               mds->dc_region[mds->nr_dc_region - 1].decode_len -
> +               mds->dc_region[0].base;
> +       dev_dbg(dev, "Total dynamic capacity: %#llx\n", mds->dynamic_cap);
> +
> +       return 0;
> +}
> +EXPORT_SYMBOL_NS_GPL(cxl_dev_dynamic_capacity_identify, CXL);
> +
>   static int add_dpa_res(struct device *dev, struct resource *parent,
>                         struct resource *res, resource_size_t start,
>                         resource_size_t size, const char *type)
> @@ -1260,8 +1429,12 @@ int cxl_mem_create_range_info(struct cxl_memdev_state *mds)
>   {
>          struct cxl_dev_state *cxlds = &mds->cxlds;
>          struct device *dev = cxlds->dev;
> +       size_t untenanted_mem;
>          int rc;
> 
> +       untenanted_mem = mds->dc_region[0].base - mds->static_cap;
> +       mds->total_bytes = mds->static_cap + untenanted_mem + mds->dynamic_cap;
> +
>          if (!cxlds->media_ready) {
>                  cxlds->dpa_res = DEFINE_RES_MEM(0, 0);
>                  cxlds->ram_res = DEFINE_RES_MEM(0, 0);
> @@ -1271,6 +1444,15 @@ int cxl_mem_create_range_info(struct cxl_memdev_state *mds)
> 
>          cxlds->dpa_res = DEFINE_RES_MEM(0, mds->total_bytes);
> 
> +       for (int i = 0; i < mds->nr_dc_region; i++) {
> +               struct cxl_dc_region_info *dcr = &mds->dc_region[i];
> +
> +               rc = add_dpa_res(dev, &cxlds->dpa_res, &cxlds->dc_res[i],
> +                                dcr->base, dcr->decode_len, dcr->name);
> +               if (rc)
> +                       return rc;
> +       }
> +
>          if (mds->partition_align_bytes == 0) {
>                  rc = add_dpa_res(dev, &cxlds->dpa_res, &cxlds->ram_res, 0,
>                                   mds->volatile_only_bytes, "ram");
> diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
> index 79a67cff9143..4624cf612c1e 100644
> --- a/drivers/cxl/cxlmem.h
> +++ b/drivers/cxl/cxlmem.h
> @@ -402,6 +402,7 @@ enum cxl_devtype {
>          CXL_DEVTYPE_CLASSMEM,
>   };
> 
> +#define CXL_MAX_DC_REGION 8
>   /**
>    * struct cxl_dpa_perf - DPA performance property entry
>    * @dpa_range - range for DPA address
> @@ -431,6 +432,8 @@ struct cxl_dpa_perf {
>    * @dpa_res: Overall DPA resource tree for the device
>    * @pmem_res: Active Persistent memory capacity configuration
>    * @ram_res: Active Volatile memory capacity configuration
> + * @dc_res: Active Dynamic Capacity memory configuration for each possible
> + *          region
>    * @serial: PCIe Device Serial Number
>    * @type: Generic Memory Class device or Vendor Specific Memory device
>    */
> @@ -445,10 +448,22 @@ struct cxl_dev_state {
>          struct resource dpa_res;
>          struct resource pmem_res;
>          struct resource ram_res;
> +       struct resource dc_res[CXL_MAX_DC_REGION];
>          u64 serial;
>          enum cxl_devtype type;
>   };
> 
> +#define CXL_DC_REGION_STRLEN 8
> +struct cxl_dc_region_info {
> +       u64 base;
> +       u64 decode_len;
> +       u64 len;
> +       u64 blk_size;
> +       u32 dsmad_handle;
> +       u8 flags;
> +       u8 name[CXL_DC_REGION_STRLEN];
> +};
> +
>   /**
>    * struct cxl_memdev_state - Generic Type-3 Memory Device Class driver data
>    *
> @@ -467,6 +482,8 @@ struct cxl_dev_state {
>    * @enabled_cmds: Hardware commands found enabled in CEL.
>    * @exclusive_cmds: Commands that are kernel-internal only
>    * @total_bytes: sum of all possible capacities
> + * @static_cap: Sum of static RAM and PMEM capacities
> + * @dynamic_cap: Complete DPA range occupied by DC regions

How about naming these total_range, static_cap and dynamic_range to make 
it clear that the DPA range occupied by DC regions isn't necessarily 
usable capacity (as opposed to the static_cap where the spec defines it 
as usable capacity).

Thanks,
Jørgen

>    * @volatile_only_bytes: hard volatile capacity
>    * @persistent_only_bytes: hard persistent capacity
>    * @partition_align_bytes: alignment size for partition-able capacity
> @@ -474,6 +491,8 @@ struct cxl_dev_state {
>    * @active_persistent_bytes: sum of hard + soft persistent
>    * @next_volatile_bytes: volatile capacity change pending device reset
>    * @next_persistent_bytes: persistent capacity change pending device reset
> + * @nr_dc_region: number of DC regions implemented in the memory device
> + * @dc_region: array containing info about the DC regions
>    * @event: event log driver state
>    * @poison: poison driver state info
>    * @security: security driver state info
> @@ -494,7 +513,10 @@ struct cxl_memdev_state {
>          DECLARE_BITMAP(dcd_cmds, CXL_DCD_ENABLED_MAX);
>          DECLARE_BITMAP(enabled_cmds, CXL_MEM_COMMAND_ID_MAX);
>          DECLARE_BITMAP(exclusive_cmds, CXL_MEM_COMMAND_ID_MAX);
> +
>          u64 total_bytes;
> +       u64 static_cap;
> +       u64 dynamic_cap;
>          u64 volatile_only_bytes;
>          u64 persistent_only_bytes;
>          u64 partition_align_bytes;
> @@ -506,6 +528,9 @@ struct cxl_memdev_state {
>          struct cxl_dpa_perf ram_perf;
>          struct cxl_dpa_perf pmem_perf;
> 
> +       u8 nr_dc_region;
> +       struct cxl_dc_region_info dc_region[CXL_MAX_DC_REGION];
> +
>          struct cxl_event_state event;
>          struct cxl_poison_state poison;
>          struct cxl_security_state security;
> @@ -705,6 +730,29 @@ struct cxl_mbox_set_partition_info {
> 
>   #define  CXL_SET_PARTITION_IMMEDIATE_FLAG      BIT(0)
> 
> +struct cxl_mbox_get_dc_config_in {
> +       u8 region_count;
> +       u8 start_region_index;
> +} __packed;
> +
> +/* See CXL 3.0 Table 125 get dynamic capacity config Output Payload */
> +struct cxl_mbox_get_dc_config_out {
> +       u8 avail_region_count;
> +       u8 rsvd[7];
> +       struct cxl_dc_region_config {
> +               __le64 region_base;
> +               __le64 region_decode_length;
> +               __le64 region_length;
> +               __le64 region_block_size;
> +               __le32 region_dsmad_handle;
> +               u8 flags;
> +               u8 rsvd[3];
> +       } __packed region[];
> +} __packed;
> +#define CXL_DYNAMIC_CAPACITY_SANITIZE_ON_RELEASE_FLAG BIT(0)
> +#define CXL_REGIONS_RETURNED(size_out) \
> +       ((size_out - 8) / sizeof(struct cxl_dc_region_config))
> +
>   /* Set Timestamp CXL 3.0 Spec 8.2.9.4.2 */
>   struct cxl_mbox_set_timestamp_in {
>          __le64 timestamp;
> @@ -828,6 +876,7 @@ enum {
>   int cxl_internal_send_cmd(struct cxl_memdev_state *mds,
>                            struct cxl_mbox_cmd *cmd);
>   int cxl_dev_state_identify(struct cxl_memdev_state *mds);
> +int cxl_dev_dynamic_capacity_identify(struct cxl_memdev_state *mds);
>   int cxl_await_media_ready(struct cxl_dev_state *cxlds);
>   int cxl_enumerate_cmds(struct cxl_memdev_state *mds);
>   int cxl_mem_create_range_info(struct cxl_memdev_state *mds);
> diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
> index 2ff361e756d6..216881455364 100644
> --- a/drivers/cxl/pci.c
> +++ b/drivers/cxl/pci.c
> @@ -874,6 +874,10 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
>          if (rc)
>                  return rc;
> 
> +       rc = cxl_dev_dynamic_capacity_identify(mds);
> +       if (rc)
> +               return rc;
> +
>          rc = cxl_mem_create_range_info(mds);
>          if (rc)
>                  return rc;
> 
> --
> 2.44.0
> 
>