>-----Original Message-----
>From: Dave Jiang <dave.jiang@xxxxxxxxx>
>Sent: 24 September 2024 00:34
>To: Shiju Jose <shiju.jose@xxxxxxxxxx>; linux-edac@xxxxxxxxxxxxxxx; linux-
>cxl@xxxxxxxxxxxxxxx; linux-acpi@xxxxxxxxxxxxxxx; linux-mm@xxxxxxxxx; linux-
>kernel@xxxxxxxxxxxxxxx
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>vsalve@xxxxxxxxxx; tanxiaofei <tanxiaofei@xxxxxxxxxx>; Zengtao (B)
><prime.zeng@xxxxxxxxxxxxx>; Roberto Sassu <roberto.sassu@xxxxxxxxxx>;
>kangkang.shen@xxxxxxxxxxxxx; wanghuiqiang <wanghuiqiang@xxxxxxxxxx>;
>Linuxarm <linuxarm@xxxxxxxxxx>
>Subject: Re: [PATCH v12 07/17] cxl: Add Get Supported Features command for
>kernel usage
>
>
>
>On 9/11/24 2:04 AM, shiju.jose@xxxxxxxxxx wrote:
>> From: Dave Jiang <dave.jiang@xxxxxxxxx>
>>
>> CXL spec r3.1 8.2.9.6.1 Get Supported Features (Opcode 0500h) The
>> command retrieve the list of supported device-specific features
>> (identified by UUID) and general information about each Feature.
>>
>> The driver will retrieve the feature entries in order to make checks
>> and provide information for the Get Feature and Set Feature command.
>> One of the main piece of information retrieved are the effects a Set
>> Feature command would have for a particular feature.
>>
>> Signed-off-by: Dave Jiang <dave.jiang@xxxxxxxxx>
>> Signed-off-by: Shiju Jose <shiju.jose@xxxxxxxxxx>
>> ---
>> drivers/cxl/core/mbox.c | 175 +++++++++++++++++++++++++++++++++++
>> drivers/cxl/cxlmem.h | 51 ++++++++++
>> drivers/cxl/pci.c | 4 +
>> include/uapi/linux/cxl_mem.h | 1 +
>> 4 files changed, 231 insertions(+)
>>
>> diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c index
>> fa1ee495a4e3..fe965ec5802f 100644
>> --- a/drivers/cxl/core/mbox.c
>> +++ b/drivers/cxl/core/mbox.c
>> @@ -67,6 +67,7 @@ static struct cxl_mem_command
>cxl_mem_commands[CXL_MEM_COMMAND_ID_MAX] = {
>> CXL_CMD(SET_SHUTDOWN_STATE, 0x1, 0, 0),
>> CXL_CMD(GET_SCAN_MEDIA_CAPS, 0x10, 0x4, 0),
>> CXL_CMD(GET_TIMESTAMP, 0, 0x8, 0),
>> + CXL_CMD(GET_SUPPORTED_FEATURES, 0x8, CXL_VARIABLE_PAYLOAD,
>0),
>> };
>>
>> /*
>> @@ -790,6 +791,180 @@ static const uuid_t log_uuid[] = {
>> [VENDOR_DEBUG_UUID] = DEFINE_CXL_VENDOR_DEBUG_UUID, };
>>
>> +static void cxl_free_features(void *features) {
>> + kvfree(features);
>> +}
>> +
>> +static int cxl_get_supported_features_count(struct cxl_dev_state
>> +*cxlds) {
>> + struct cxl_mailbox *cxl_mbox = &cxlds->cxl_mbox;
>> + struct cxl_mbox_get_sup_feats_out mbox_out;
>> + struct cxl_mbox_get_sup_feats_in mbox_in;
>> + struct cxl_mbox_cmd mbox_cmd;
>> + int rc;
>> +
>> + memset(&mbox_in, 0, sizeof(mbox_in));
>> + mbox_in.count = sizeof(mbox_out);
>> + memset(&mbox_out, 0, sizeof(mbox_out));
>> + mbox_cmd = (struct cxl_mbox_cmd) {
>> + .opcode = CXL_MBOX_OP_GET_SUPPORTED_FEATURES,
>> + .size_in = sizeof(mbox_in),
>> + .payload_in = &mbox_in,
>> + .size_out = sizeof(mbox_out),
>> + .payload_out = &mbox_out,
>> + .min_out = sizeof(mbox_out),
>> + };
>> + rc = cxl_internal_send_cmd(cxl_mbox, &mbox_cmd);
>> + if (rc < 0)
>> + return rc;
>> +
>> + cxlds->num_features = le16_to_cpu(mbox_out.supported_feats);
>> + if (!cxlds->num_features)
>> + return -ENOENT;
>> +
>> + return 0;
>> +}
>> +
>> +int cxl_get_supported_features(struct cxl_dev_state *cxlds) {
>> + int remain_feats, max_size, max_feats, start, rc;
>> + struct cxl_mailbox *cxl_mbox = &cxlds->cxl_mbox;
>> + int feat_size = sizeof(struct cxl_feat_entry);
>> + struct cxl_mbox_get_sup_feats_out *mbox_out;
>> + struct cxl_mbox_get_sup_feats_in mbox_in;
>> + int hdr_size = sizeof(*mbox_out);
>> + struct cxl_mbox_cmd mbox_cmd;
>> + struct cxl_mem_command *cmd;
>> + void *ptr;
>> +
>> + /* Get supported features is optional, need to check */
>> + cmd =
>cxl_mem_find_command(CXL_MBOX_OP_GET_SUPPORTED_FEATURES);
>> + if (!cmd)
>> + return -EOPNOTSUPP;
>> + if (!test_bit(cmd->info.id, cxl_mbox->enabled_cmds))
>> + return -EOPNOTSUPP;
>> +
>> + rc = cxl_get_supported_features_count(cxlds);
>> + if (rc)
>> + return rc;
>> +
>> + struct cxl_feat_entry *entries __free(kvfree) =
>> + kvmalloc(cxlds->num_features * feat_size, GFP_KERNEL);
>> +
>> + if (!entries)
>> + return -ENOMEM;
>> +
>> + cxlds->entries = no_free_ptr(entries);
>> + rc = devm_add_action_or_reset(cxl_mbox->host, cxl_free_features,
>> + cxlds->entries);
>> + if (rc)
>> + return rc;
>> +
>> + max_size = cxl_mbox->payload_size - hdr_size;
>> + /* max feat entries that can fit in mailbox max payload size */
>> + max_feats = max_size / feat_size;
>> + ptr = &cxlds->entries[0];
>> +
>> + mbox_out = kvmalloc(cxl_mbox->payload_size, GFP_KERNEL);
>> + if (!mbox_out)
>> + return -ENOMEM;
>> +
>> + start = 0;
>> + remain_feats = cxlds->num_features;
>> + do {
>> + int retrieved, alloc_size, copy_feats;
>> +
>> + if (remain_feats > max_feats) {
>> + alloc_size = sizeof(*mbox_out) + max_feats * feat_size;
>> + remain_feats = remain_feats - max_feats;
>> + copy_feats = max_feats;
>> + } else {
>> + alloc_size = sizeof(*mbox_out) + remain_feats *
>feat_size;
>> + copy_feats = remain_feats;
>> + remain_feats = 0;
>> + }
>> +
>> + memset(&mbox_in, 0, sizeof(mbox_in));
>> + mbox_in.count = alloc_size;
>> + mbox_in.start_idx = start;
>> + memset(mbox_out, 0, alloc_size);
>> + mbox_cmd = (struct cxl_mbox_cmd) {
>> + .opcode = CXL_MBOX_OP_GET_SUPPORTED_FEATURES,
>> + .size_in = sizeof(mbox_in),
>> + .payload_in = &mbox_in,
>> + .size_out = alloc_size,
>> + .payload_out = mbox_out,
>> + .min_out = hdr_size,
>> + };
>> + rc = cxl_internal_send_cmd(cxl_mbox, &mbox_cmd);
>> + if (rc < 0) {
>> + kfree(mbox_out);
>> + return rc;
>> + }
>> + if (mbox_cmd.size_out <= hdr_size) {
>> + rc = -ENXIO;
>> + goto err;
>> + }
>> +
>> + /*
>> + * Make sure retrieved out buffer is multiple of feature
>> + * entries.
>> + */
>> + retrieved = mbox_cmd.size_out - hdr_size;
>> + if (retrieved % feat_size) {
>> + rc = -ENXIO;
>> + goto err;
>> + }
>> +
>> + /*
>> + * If the reported output entries * defined entry size !=
>> + * retrieved output bytes, then the output package is incorrect.
>> + */
>> + if (mbox_out->num_entries * feat_size != retrieved) {
>> + rc = -ENXIO;
>> + goto err;
>> + }
>> +
>> + memcpy(ptr, mbox_out->ents, retrieved);
>> + ptr += retrieved;
>> + /*
>> + * If the number of output entries is less than expected, add the
>> + * remaining entries to the next batch.
>> + */
>> + remain_feats += copy_feats - mbox_out->num_entries;
>> + start += mbox_out->num_entries;
>> + } while (remain_feats);
>> +
>> + kfree(mbox_out);
>> + return 0;
>> +
>> +err:
>> + kfree(mbox_out);
>> + cxlds->num_features = 0;
>> + return rc;
>> +}
>> +EXPORT_SYMBOL_NS_GPL(cxl_get_supported_features, CXL);
>> +
>> +int cxl_get_supported_feature_entry(struct cxl_dev_state *cxlds, const uuid_t
>*feat_uuid,
>> + struct cxl_feat_entry *feat_entry_out) {
>> + struct cxl_feat_entry *feat_entry;
>> + int count;
>> +
>> + /* Check CXL dev supports the feature */
>> + feat_entry = &cxlds->entries[0];
>> + for (count = 0; count < cxlds->num_features; count++, feat_entry++) {
>> + if (uuid_equal(&feat_entry->uuid, feat_uuid)) {
>> + memcpy(feat_entry_out, feat_entry,
>sizeof(*feat_entry_out));
>> + return 0;
>> + }
>> + }
>> +
>> + return -EOPNOTSUPP;
>> +}
>> +EXPORT_SYMBOL_NS_GPL(cxl_get_supported_feature_entry, CXL);
>> +
>> /**
>> * cxl_enumerate_cmds() - Enumerate commands for a device.
>> * @mds: The driver data for the operation diff --git
>> a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h index
>> d7c6ffe2a884..5d149e64c247 100644
>> --- a/drivers/cxl/cxlmem.h
>> +++ b/drivers/cxl/cxlmem.h
>> @@ -389,6 +389,8 @@ 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
>> + * @features: number of supported features
>> + * @entries: list of supported feature entries.
>> */
>> struct cxl_dev_state {
>> struct device *dev;
>> @@ -404,6 +406,8 @@ struct cxl_dev_state {
>> u64 serial;
>> enum cxl_devtype type;
>> struct cxl_mailbox cxl_mbox;
>> + int num_features;
>> + struct cxl_feat_entry *entries;
>
>Hi Shiju,
>Going back and refactoring the fwctl code, I think this needs to stay with
>cxl_mailbox. Otherwise it makes it really hard to verify the feature effects for
>userspace. Preferably I don't think we want to expose 'struct cxl_dev_state' to
>fwctl if we don't need to.
>
>DJ
Hi Dave,
Ok. Revert to stay with struct cxl_mailbox and tested. Changes will be in the next version.
Thanks,
Shiju
>
>> };
>>
>> /**
>> @@ -482,6 +486,7 @@ enum cxl_opcode {
>> CXL_MBOX_OP_GET_LOG_CAPS = 0x0402,
>> CXL_MBOX_OP_CLEAR_LOG = 0x0403,
>> CXL_MBOX_OP_GET_SUP_LOG_SUBLIST = 0x0405,
>> + CXL_MBOX_OP_GET_SUPPORTED_FEATURES = 0x0500,
>> CXL_MBOX_OP_IDENTIFY = 0x4000,
>> CXL_MBOX_OP_GET_PARTITION_INFO = 0x4100,
>> CXL_MBOX_OP_SET_PARTITION_INFO = 0x4101,
>> @@ -765,6 +770,48 @@ enum {
>> CXL_PMEM_SEC_PASS_USER,
>> };
>>
>> +/* Get Supported Features (0x500h) CXL r3.1 8.2.9.6.1 */ struct
>> +cxl_mbox_get_sup_feats_in {
>> + __le32 count;
>> + __le16 start_idx;
>> + u8 reserved[2];
>> +} __packed;
>> +
>> +/* Supported Feature Entry : Payload out attribute flags */
>> +#define CXL_FEAT_ENTRY_FLAG_CHANGABLE BIT(0)
>> +#define CXL_FEAT_ENTRY_FLAG_DEEPEST_RESET_PERSISTENCE_MASK
> GENMASK(3, 1)
>> +#define CXL_FEAT_ENTRY_FLAG_PERSIST_ACROSS_FIRMWARE_UPDATE
> BIT(4)
>> +#define CXL_FEAT_ENTRY_FLAG_SUPPORT_DEFAULT_SELECTION BIT(5)
>> +#define CXL_FEAT_ENTRY_FLAG_SUPPORT_SAVED_SELECTION BIT(6)
>> +
>> +enum cxl_feat_attr_value_persistence {
>> + CXL_FEAT_ATTR_VALUE_PERSISTENCE_NONE,
>> + CXL_FEAT_ATTR_VALUE_PERSISTENCE_CXL_RESET,
>> + CXL_FEAT_ATTR_VALUE_PERSISTENCE_HOT_RESET,
>> + CXL_FEAT_ATTR_VALUE_PERSISTENCE_WARM_RESET,
>> + CXL_FEAT_ATTR_VALUE_PERSISTENCE_COLD_RESET,
>> + CXL_FEAT_ATTR_VALUE_PERSISTENCE_MAX
>> +};
>> +
>> +struct cxl_feat_entry {
>> + uuid_t uuid;
>> + __le16 id;
>> + __le16 get_feat_size;
>> + __le16 set_feat_size;
>> + __le32 attr_flags;
>> + u8 get_feat_ver;
>> + u8 set_feat_ver;
>> + __le16 set_effects;
>> + u8 reserved[18];
>> +} __packed;
>> +
>> +struct cxl_mbox_get_sup_feats_out {
>> + __le16 num_entries;
>> + __le16 supported_feats;
>> + u8 reserved[4];
>> + struct cxl_feat_entry ents[]
>> +__counted_by(le32_to_cpu(supported_feats));
>> +} __packed;
>> +
>> int cxl_internal_send_cmd(struct cxl_mailbox *cxl_mbox,
>> struct cxl_mbox_cmd *cmd);
>> int cxl_dev_state_identify(struct cxl_memdev_state *mds); @@ -824,4
>> +871,8 @@ struct cxl_hdm { struct seq_file; struct dentry
>> *cxl_debugfs_create_dir(const char *dir); void cxl_dpa_debug(struct
>> seq_file *file, struct cxl_dev_state *cxlds);
>> +
>> +int cxl_get_supported_features(struct cxl_dev_state *cxlds); int
>> +cxl_get_supported_feature_entry(struct cxl_dev_state *cxlds, const uuid_t
>*feat_uuid,
>> + struct cxl_feat_entry *feat_entry_out);
>> #endif /* __CXL_MEM_H__ */
>> diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c index
>> 3c73de475bf3..cec88e3a1754 100644
>> --- a/drivers/cxl/pci.c
>> +++ b/drivers/cxl/pci.c
>> @@ -872,6 +872,10 @@ static int cxl_pci_probe(struct pci_dev *pdev, const
>struct pci_device_id *id)
>> if (rc)
>> return rc;
>>
>> + rc = cxl_get_supported_features(cxlds);
>> + if (rc)
>> + dev_dbg(&pdev->dev, "No features enumerated.\n");
>> +
>> rc = cxl_set_timestamp(mds);
>> if (rc)
>> return rc;
>> diff --git a/include/uapi/linux/cxl_mem.h
>> b/include/uapi/linux/cxl_mem.h index c6c0fe27495d..bd2535962f70 100644
>> --- a/include/uapi/linux/cxl_mem.h
>> +++ b/include/uapi/linux/cxl_mem.h
>> @@ -50,6 +50,7 @@
>> ___C(GET_LOG_CAPS, "Get Log Capabilities"), \
>> ___C(CLEAR_LOG, "Clear Log"), \
>> ___C(GET_SUP_LOG_SUBLIST, "Get Supported Logs Sub-List"), \
>> + ___C(GET_SUPPORTED_FEATURES, "Get Supported Features"),
> \
>> ___C(MAX, "invalid / last command")
>>
>> #define ___C(a, b) CXL_MEM_COMMAND_ID_##a
>
