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From: Shiju Jose <shiju.jose@huawei.com>
To: Davidlohr Bueso <dave@stgolabs.net>
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Subject: RE: [RFC PATCH v5 01/12] cxl/mbox: Add GET_SUPPORTED_FEATURES mailbox
 command
Thread-Topic: [RFC PATCH v5 01/12] cxl/mbox: Add GET_SUPPORTED_FEATURES
 mailbox command
Thread-Index: AQHaRJCaD0DwIp3NPkK9UMNuy7XDp7EBGDoAgADt89A=
Date: Fri, 9 Feb 2024 11:17:01 +0000
Message-ID: <c4e332fde2654c019d34587c5f1d6a9b@huawei.com>
References: <20240111131741.1356-1-shiju.jose@huawei.com>
 <20240111131741.1356-2-shiju.jose@huawei.com>
 <2k3fvg2xlp7ie47cy7finxchmb6sinkut2mp23wfvv73ik3erw@wohmod7labx5>
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Hi Davidlohr,

Thanks for the feedbacks.

>-----Original Message-----
>From: Davidlohr Bueso <dave@stgolabs.net>
>Sent: 08 February 2024 20:52
>To: Shiju Jose <shiju.jose@huawei.com>
>Cc: linux-cxl@vger.kernel.org; linux-acpi@vger.kernel.org; linux-
>mm@kvack.org; Jonathan Cameron <jonathan.cameron@huawei.com>;
>dave.jiang@intel.com; alison.schofield@intel.com; vishal.l.verma@intel.com=
;
>ira.weiny@intel.com; dan.j.williams@intel.com; linux-edac@vger.kernel.org;
>linux-kernel@vger.kernel.org; david@redhat.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; rafael@kernel.org; lenb@kernel.org;
>naoya.horiguchi@nec.com; james.morse@arm.com; jthoughton@google.com;
>somasundaram.a@hpe.com; erdemaktas@google.com; pgonda@google.com;
>duenwen@google.com; mike.malvestuto@intel.com; gthelen@google.com;
>wschwartz@amperecomputing.com; dferguson@amperecomputing.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 v5 01/12] cxl/mbox: Add GET_SUPPORTED_FEATURES
>mailbox command
>
>On Thu, 11 Jan 2024, shiju.jose@huawei.com wrote:
>
>>From: Shiju Jose <shiju.jose@huawei.com>
>>
>>Add support for GET_SUPPORTED_FEATURES mailbox command.
>>
>>CXL spec 3.0 section 8.2.9.6 describes optional device specific features.
>
>For the whole series, might as well make it 3.1 based. Are you aware of an=
y
>major differences (I have not checked) between versions in either this or =
any of
>the two users that use feats?
Sure, I will make 3.1 based.=20
I checked, no differences found  in feature commands b/w versions 3.0 and 3=
1 other than
new users of the features commands are present in v3.1 such as memory spari=
ng features and Advanced Programmable Corrected Volatile Memory Error Thres=
hold Feature Discovery and Configuration.

>
>>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.
>>
>>Signed-off-by: Shiju Jose <shiju.jose@huawei.com>
>>---
>> drivers/cxl/core/mbox.c | 23 ++++++++++++++++
>> drivers/cxl/cxlmem.h    | 59 +++++++++++++++++++++++++++++++++++++++++
>> 2 files changed, 82 insertions(+)
>>
>>diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c index
>>36270dcfb42e..6960ce935e73 100644
>>--- a/drivers/cxl/core/mbox.c
>>+++ b/drivers/cxl/core/mbox.c
>>@@ -1303,6 +1303,29 @@ int cxl_set_timestamp(struct cxl_memdev_state
>>*mds)  }  EXPORT_SYMBOL_NS_GPL(cxl_set_timestamp, CXL);
>>
>>+int cxl_get_supported_features(struct cxl_memdev_state *mds,
>>+						struct
>cxl_mbox_get_supp_feats_in *pi,
>>+						void *feats_out)
>>+{
>>+	struct cxl_mbox_cmd mbox_cmd;
>>+	int rc;
>>+
>>+	mbox_cmd =3D (struct cxl_mbox_cmd) {
>>+		.opcode =3D CXL_MBOX_OP_GET_SUPPORTED_FEATURES,
>>+		.size_in =3D sizeof(*pi),
>>+		.payload_in =3D pi,
>>+		.size_out =3D le32_to_cpu(pi->count),
>>+		.payload_out =3D feats_out,
>>+		.min_out =3D sizeof(struct cxl_mbox_get_supp_feats_out),
>>+	};
>>+	rc =3D cxl_internal_send_cmd(mds, &mbox_cmd);
>>+	if (rc < 0)
>>+		return rc;
>>+
>>+	return 0;
>>+}
>>+EXPORT_SYMBOL_NS_GPL(cxl_get_supported_features, 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..d831dad748f5 100644
>>--- a/drivers/cxl/cxlmem.h
>>+++ b/drivers/cxl/cxlmem.h
>>@@ -506,6 +506,7 @@ enum cxl_opcode {
>>	CXL_MBOX_OP_SET_TIMESTAMP	=3D 0x0301,
>>	CXL_MBOX_OP_GET_SUPPORTED_LOGS	=3D 0x0400,
>>	CXL_MBOX_OP_GET_LOG		=3D 0x0401,
>>+	CXL_MBOX_OP_GET_SUPPORTED_FEATURES	=3D 0x0500,
>>	CXL_MBOX_OP_IDENTIFY		=3D 0x4000,
>>	CXL_MBOX_OP_GET_PARTITION_INFO	=3D 0x4100,
>>	CXL_MBOX_OP_SET_PARTITION_INFO	=3D 0x4101,
>>@@ -740,6 +741,61 @@ 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)
>>+
>>+enum cxl_feat_attrib_value_persistence {
>>+	CXL_FEAT_ATTRIB_VALUE_PERSISTENCE_NONE =3D 0x0,
>>+	CXL_FEAT_ATTRIB_VALUE_PERSISTENCE_CXL_RESET =3D 0x1,
>>+	CXL_FEAT_ATTRIB_VALUE_PERSISTENCE_HOT_RESET =3D 0x2,
>>+	CXL_FEAT_ATTRIB_VALUE_PERSISTENCE_WARM_RESET =3D 0x3,
>>+	CXL_FEAT_ATTRIB_VALUE_PERSISTENCE_COLD_RESET =3D 0x4,
>
>Just leave the enums without explicit values - you are not changing the de=
fault
>counting.
Sure.

>
>>+	CXL_FEAT_ATTRIB_VALUE_PERSISTENCE_MAX
>>+};
>>+
>>+#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;
>
>Nit but rename to 'attr', it is more along the kernel coding style (just c=
ompare a
>git grep of attrb vs attr). Also applies to the whole series.
Sure. I will modify.

>
>Thanks,
>Davidlohr
>
>>+	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 Poison List  CXL 3.0 Spec 8.2.9.8.4.1 */  struct
>>cxl_mbox_poison_in {
>>	__le64 offset;
>>@@ -867,6 +923,9 @@ 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);
>>+int cxl_get_supported_features(struct cxl_memdev_state *mds,
>>+			       struct cxl_mbox_get_supp_feats_in *pi,
>>+			       void *feats_out);
>> 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);
>>--
>>2.34.1
>>

Thank,
Shiju