RE: [RFC PATCH 1/6] cxl/mbox: Add GET_SUPPORTED_FEATURES, GET_FEATURE and SET_FEATURE mailbox commands

[Shiju Jose <shiju.jose@huawei.com>]

Hi Dave,

Thanks for the feedbacks.

>-----Original Message-----
>From: Dave Jiang <dave.jiang@intel.com>
>Sent: 15 November 2023 18:21
>To: Shiju Jose <shiju.jose@huawei.com>; linux-cxl@vger.kernel.org
>Cc: Jonathan Cameron <jonathan.cameron@huawei.com>;
>Vilas.Sridharan@amd.com; leo.duran@amd.com; Yazen.Ghannam@amd.com;
>rientjes@google.com; jiaqiyan@google.com; tony.luck@intel.com;
>Jon.Grimm@amd.com; dave.hansen@linux.intel.com; linux-
>acpi@vger.kernel.org; linux-mm@kvack.org; linux-kernel@vger.kernel.org;
>rafael@kernel.org; lenb@kernel.org; naoya.horiguchi@nec.com;
>james.morse@arm.com; david@redhat.com; jthoughton@google.com;
>somasundaram.a@hpe.com; erdemaktas@google.com;
>"pgonda@pgonda"@google.com; duenwen@google.com;
>mike.malvestuto@intel.com; gthelen@google.com; tanxiaofei
><tanxiaofei@huawei.com>; Zengtao (B) <prime.zeng@hisilicon.com>;
>kangkang.shen@futurewei.com; wanghuiqiang <wanghuiqiang@huawei.com>;
>Linuxarm <linuxarm@huawei.com>
>Subject: Re: [RFC PATCH 1/6] cxl/mbox: Add GET_SUPPORTED_FEATURES,
>GET_FEATURE and SET_FEATURE mailbox commands
>
>
>
>On 11/14/23 05:56, shiju.jose@huawei.com wrote:
>> From: Shiju Jose <shiju.jose@huawei.com>
>>
>> Add support for GET_SUPPORTED_FEATURES, GET_FEATURE and
>SET_FEATURE
>> mailbox commands.
>>
>> CXL spec 3.0 section 8.2.9.6 describes optional device specific features.
>> CXL devices supports features with changeable attributes.
>> Get Supported Features retrieves the list of supported device specific
>> features. The settings of a feature can be retrieved using Get Feature
>> and optionally modified using Set Feature.
>
>Maybe split this patch out into 3 for each of the individual commands you are
>enabling. That'll make git bisect easier for debugging.
Sure. I will do this.

>
>A few nits but the rest LGTM.
>
>>
>> Signed-off-by: Shiju Jose <shiju.jose@huawei.com>
>> ---
>>  drivers/cxl/core/mbox.c      | 74 ++++++++++++++++++++++++++++
>>  drivers/cxl/cxlmem.h         | 95 ++++++++++++++++++++++++++++++++++++
>>  include/uapi/linux/cxl_mem.h |  3 ++
>>  3 files changed, 172 insertions(+)
>>
>> diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c index
>> 36270dcfb42e..2a6d8ab927bd 100644
>> --- a/drivers/cxl/core/mbox.c
>> +++ b/drivers/cxl/core/mbox.c
>> @@ -63,6 +63,9 @@ static struct cxl_mem_command
>cxl_mem_commands[CXL_MEM_COMMAND_ID_MAX] = {
>>  	CXL_CMD(GET_SHUTDOWN_STATE, 0, 0x1, 0),
>>  	CXL_CMD(SET_SHUTDOWN_STATE, 0x1, 0, 0),
>>  	CXL_CMD(GET_SCAN_MEDIA_CAPS, 0x10, 0x4, 0),
>> +	CXL_CMD(GET_SUPPORTED_FEATURES, 0x8, CXL_VARIABLE_PAYLOAD,
>0),
>> +	CXL_CMD(GET_FEATURE, 0x15, CXL_VARIABLE_PAYLOAD, 0),
>> +	CXL_CMD(SET_FEATURE, CXL_VARIABLE_PAYLOAD, 0, 0),
>>  };
>>
>>  /*
>> @@ -1303,6 +1306,77 @@ int cxl_set_timestamp(struct cxl_memdev_state
>> *mds)  }  EXPORT_SYMBOL_NS_GPL(cxl_set_timestamp, CXL);
>>
>> +struct cxl_mbox_get_supp_feats_out *cxl_get_supported_features(struct
>cxl_memdev_state *mds,
>> +						struct
>cxl_mbox_get_supp_feats_in *pi) {
>> +	int rc;
>> +	struct cxl_mbox_cmd mbox_cmd;
>> +	struct cxl_mbox_get_supp_feats_out *feats_out;
>
>reverse xmas tree declarations
Sure. Will change.

>
>> +
>> +	feats_out = kvmalloc(pi->count, GFP_KERNEL);
>> +	if (!feats_out)
>> +		return ERR_PTR(-ENOMEM);
>> +
>> +	mbox_cmd = (struct cxl_mbox_cmd) {
>> +		.opcode = CXL_MBOX_OP_GET_SUPPORTED_FEATURES,
>> +		.size_in = sizeof(*pi),
>> +		.payload_in = pi,
>> +		.size_out = pi->count,
>> +		.payload_out = feats_out,
>> +		.min_out = sizeof(struct cxl_mbox_get_supp_feats_out),
>> +	};
>> +	rc = cxl_internal_send_cmd(mds, &mbox_cmd);
>> +	if (rc < 0) {
>> +		kvfree(feats_out);
>> +		return ERR_PTR(rc);
>> +	}
>> +
>> +	return feats_out;
>> +}
>> +EXPORT_SYMBOL_NS_GPL(cxl_get_supported_features, CXL);
>> +
>> +void *cxl_get_feature(struct cxl_memdev_state *mds, struct
>> +cxl_mbox_get_feat_in *pi) {
>> +	int rc;
>> +	void *feat_out;
>> +	struct cxl_mbox_cmd mbox_cmd;
>
>reverse xmas tree declarations
Will change.

>
>
>> +
>> +	feat_out = kvmalloc(pi->count, GFP_KERNEL);
>> +	if (!feat_out)
>> +		return ERR_PTR(-ENOMEM);
>> +
>> +	mbox_cmd = (struct cxl_mbox_cmd) {
>> +		.opcode = CXL_MBOX_OP_GET_FEATURE,
>> +		.size_in = sizeof(*pi),
>> +		.payload_in = pi,
>> +		.size_out = pi->count,
>> +		.payload_out = feat_out,
>> +		.min_out = pi->count,
>> +	};
>> +	rc = cxl_internal_send_cmd(mds, &mbox_cmd);
>> +	if (rc < 0) {
>> +		kvfree(feat_out);
>> +		return ERR_PTR(rc);
>> +	}
>> +
>> +	return feat_out;
>> +}
>> +EXPORT_SYMBOL_NS_GPL(cxl_get_feature, CXL);
>> +
>> +int cxl_set_feature(struct cxl_memdev_state *mds, void *feat_in,
>> +size_t size) {
>> +	struct cxl_mbox_cmd mbox_cmd;
>> +
>> +	mbox_cmd = (struct cxl_mbox_cmd) {
>> +		.opcode = CXL_MBOX_OP_SET_FEATURE,
>> +		.size_in = size,
>> +		.payload_in = feat_in,
>> +	};
>> +
>> +	return cxl_internal_send_cmd(mds, &mbox_cmd); }
>> +EXPORT_SYMBOL_NS_GPL(cxl_set_feature, CXL);
>> +
>>  int cxl_mem_get_poison(struct cxl_memdev *cxlmd, u64 offset, u64 len,
>>  		       struct cxl_region *cxlr)
>>  {
>> diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h index
>> a2fcbca253f3..fdac686560d4 100644
>> --- a/drivers/cxl/cxlmem.h
>> +++ b/drivers/cxl/cxlmem.h
>> @@ -506,6 +506,9 @@ enum cxl_opcode {
>>  	CXL_MBOX_OP_SET_TIMESTAMP	= 0x0301,
>>  	CXL_MBOX_OP_GET_SUPPORTED_LOGS	= 0x0400,
>>  	CXL_MBOX_OP_GET_LOG		= 0x0401,
>> +	CXL_MBOX_OP_GET_SUPPORTED_FEATURES	= 0x0500,
>> +	CXL_MBOX_OP_GET_FEATURE		= 0x0501,
>> +	CXL_MBOX_OP_SET_FEATURE		= 0x0502,
>>  	CXL_MBOX_OP_IDENTIFY		= 0x4000,
>>  	CXL_MBOX_OP_GET_PARTITION_INFO	= 0x4100,
>>  	CXL_MBOX_OP_SET_PARTITION_INFO	= 0x4101,
>> @@ -740,6 +743,94 @@ struct cxl_mbox_set_timestamp_in {
>>
>>  } __packed;
>>
>> +/* Get Supported Features CXL 3.0 Spec 8.2.9.6.1 */
>> +/*
>> + * Get Supported Features input payload
>> + * CXL rev 3.0 section 8.2.9.6.1; Table 8-75  */ struct
>> +cxl_mbox_get_supp_feats_in {
>> +	__le32 count;
>> +	__le16 start_index;
>> +	u16 reserved;
>> +} __packed;
>> +
>> +/*
>> + * Get Supported Features Supported Feature Entry
>> + * CXL rev 3.0 section 8.2.9.6.1; Table 8-77  */
>> +/* 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_DEEPEST_RESET_PERSISTENCE_NONE
>	0x0
>> +#define CXL_FEAT_ENTRY_FLAG_DEEPEST_RESET_PERSISTENCE_CXL_RESET
>	0x1
>> +#define CXL_FEAT_ENTRY_FLAG_DEEPEST_RESET_PERSISTENCE_HOT_RESET
>	0x2
>> +#define
>CXL_FEAT_ENTRY_FLAG_DEEPEST_RESET_PERSISTENCE_WARM_RESET	0x3
>> +#define
>CXL_FEAT_ENTRY_FLAG_DEEPEST_RESET_PERSISTENCE_COLD_RESET	0x4
>
>I think you can declare the flags as enums?
Sure. Will check.

>
>> +#define CXL_FEAT_ENTRY_FLAG_PERSISTENCE_ACROSS_FW_UPDATE_MASK
>	BIT(4)
>> +#define
>CXL_FEAT_ENTRY_FLAG_PERSISTENCE_DEFAULT_SEL_SUPPORT_MASK	BIT(5)
>> +#define CXL_FEAT_ENTRY_FLAG_PERSISTENCE_SAVED_SEL_SUPPORT_MASK
>	BIT(6)
>> +
>> +struct cxl_mbox_supp_feat_entry {
>> +	uuid_t uuid;
>> +	__le16 feat_index;
>> +	__le16 get_feat_size;
>> +	__le16 set_feat_size;
>> +	__le32 attrb_flags;
>> +	u8 get_feat_version;
>> +	u8 set_feat_version;
>> +	__le16 set_feat_effects;
>> +	u8 rsvd[18];
>> +}  __packed;
>> +
>> +/*
>> + * Get Supported Features output payload
>> + * CXL rev 3.0 section 8.2.9.6.1; Table 8-76  */ struct
>> +cxl_mbox_get_supp_feats_out {
>> +	__le16 entries;
>> +	__le16 nsuppfeats_dev;
>> +	u32 reserved;
>> +	struct cxl_mbox_supp_feat_entry feat_entries[]; } __packed;
>> +
>> +/* Get Feature CXL 3.0 Spec 8.2.9.6.2 */
>> +/*
>> + * Get Feature input payload
>> + * CXL rev 3.0 section 8.2.9.6.2; Table 8-79  */
>> +/* Get Feature : Payload in selection */
>> +#define CXL_GET_FEAT_CURRENT_VALUE	0x00
>> +#define CXL_GET_FEAT_DEFAULT_VALUE	0x01
>> +#define CXL_GET_FEAT_SAVED_VALUE	0x02
>> +
>> +struct cxl_mbox_get_feat_in {
>> +	uuid_t uuid;
>> +	__le16 offset;
>> +	__le16 count;
>> +	u8 selection;
>> +}  __packed;
>> +
>> +/* Set Feature CXL 3.0 Spec 8.2.9.6.3 */
>> +/*
>> + * Set Feature input payload
>> + * CXL rev 3.0 section 8.2.9.6.3; Table 8-81  */
>> +/* Set Feature : Payload in flags */
>> +#define CXL_SET_FEAT_FLAG_ACTION_MASK	GENMASK(2, 0)
>> +#define CXL_SET_FEAT_FLAG_ACTION_FULL_DATA_TRANSFER	0x0
>> +#define CXL_SET_FEAT_FLAG_ACTION_INITIATE_DATA_TRANSFER	0x1
>> +#define CXL_SET_FEAT_FLAG_ACTION_CONTINUE_DATA_TRANSFER	0x2
>> +#define CXL_SET_FEAT_FLAG_ACTION_FINISH_DATA_TRANSFER	0x3
>> +#define CXL_SET_FEAT_FLAG_ACTION_ABORT_DATA_TRANSFER	0x4
>> +#define CXL_SET_FEAT_FLAG_MOD_VALUE_SAVED_ACROSS_RESET	BIT(3)
>> +struct cxl_mbox_set_feat_in {
>> +	uuid_t uuid;
>> +	__le32 flags;
>> +	__le16 offset;
>> +	u8 version;
>> +	u8 rsvd[9];
>> +}  __packed;
>> +
>>  /* Get Poison List  CXL 3.0 Spec 8.2.9.8.4.1 */  struct
>> cxl_mbox_poison_in {
>>  	__le64 offset;
>> @@ -867,6 +958,10 @@ void clear_exclusive_cxl_commands(struct
>cxl_memdev_state *mds,
>>  				  unsigned long *cmds);
>>  void cxl_mem_get_event_records(struct cxl_memdev_state *mds, u32
>> status);  int cxl_set_timestamp(struct cxl_memdev_state *mds);
>> +struct cxl_mbox_get_supp_feats_out *cxl_get_supported_features(struct
>cxl_memdev_state *mds,
>> +						struct
>cxl_mbox_get_supp_feats_in *pi); void
>> +*cxl_get_feature(struct cxl_memdev_state *mds, struct
>> +cxl_mbox_get_feat_in *pi); int cxl_set_feature(struct
>> +cxl_memdev_state *mds, void *feat_in, size_t size);
>>  int cxl_poison_state_init(struct cxl_memdev_state *mds);  int
>> cxl_mem_get_poison(struct cxl_memdev *cxlmd, u64 offset, u64 len,
>>  		       struct cxl_region *cxlr);
>> diff --git a/include/uapi/linux/cxl_mem.h
>> b/include/uapi/linux/cxl_mem.h index 14bc6e742148..8c89d323cc41 100644
>> --- a/include/uapi/linux/cxl_mem.h
>> +++ b/include/uapi/linux/cxl_mem.h
>> @@ -46,6 +46,9 @@
>>  	___C(GET_SCAN_MEDIA_CAPS, "Get Scan Media Capabilities"),         \
>>  	___DEPRECATED(SCAN_MEDIA, "Scan Media"),                          \
>>  	___DEPRECATED(GET_SCAN_MEDIA, "Get Scan Media Results"),          \
>> +	___C(GET_SUPPORTED_FEATURES, "Get Supported Features"),           \
>> +	___C(GET_FEATURE, "Get Feature"),                                 \
>> +	___C(SET_FEATURE, "Set Feature"),                                 \
>>  	___C(MAX, "invalid / last command")
>>
>>  #define ___C(a, b) CXL_MEM_COMMAND_ID_##a

Thanks,
Shiju