Re: [PATCH v11 04/14] cxl/mbox: Add GET_SUPPORTED_FEATURES mailbox command

Dave Jiang
2024-08-21T16:50:50Z

On 8/21/24 9:11 AM, Shiju Jose wrote:
> Hi Dave,
>
>> -----Original Message-----
>> From: Dave Jiang <dave.jiang@intel.com>
>> Sent: 20 August 2024 23:46
>> To: Shiju Jose <shiju.jose@huawei.com>; linux-edac@vger.kernel.org; linux-
>> cxl@vger.kernel.org; linux-acpi@vger.kernel.org; linux-mm@kvack.org; linux-
>> kernel@vger.kernel.org
>> Cc: bp@alien8.de; tony.luck@intel.com; rafael@kernel.org; lenb@kernel.org;
>> mchehab@kernel.org; dan.j.williams@intel.com; dave@stgolabs.net; Jonathan
>> Cameron <jonathan.cameron@huawei.com>; alison.schofield@intel.com;
>> vishal.l.verma@intel.com; ira.weiny@intel.com; david@redhat.com;
>> Vilas.Sridharan@amd.com; leo.duran@amd.com; Yazen.Ghannam@amd.com;
>> rientjes@google.com; jiaqiyan@google.com; Jon.Grimm@amd.com;
>> dave.hansen@linux.intel.com; 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;
>> wbs@os.amperecomputing.com; nifan.cxl@gmail.com; jgroves@micron.com;
>> vsalve@micron.com; tanxiaofei <tanxiaofei@huawei.com>; Zengtao (B)
>> <prime.zeng@hisilicon.com>; Roberto Sassu <roberto.sassu@huawei.com>;
>> kangkang.shen@futurewei.com; wanghuiqiang <wanghuiqiang@huawei.com>;
>> Linuxarm <linuxarm@huawei.com>
>> Subject: Re: [PATCH v11 04/14] cxl/mbox: Add GET_SUPPORTED_FEATURES
>> mailbox command
>>
>>
>>
>> On 8/16/24 9:42 AM, shiju.jose@huawei.com wrote:
>>> From: Shiju Jose <shiju.jose@huawei.com>
>>>
>>> Add support for GET_SUPPORTED_FEATURES mailbox command.
>>>
>>> CXL spec 3.1 section 8.2.9.6 describes optional device specific features.
>>> CXL devices support features with changeable attributes.
>>>
>>> CXL spec 3.1 section 8.2.9.6.1 describes Get Supported features command.
>>> 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 | 68
>> +++++++++++++++++++++++++++++++++++++++++
>>> drivers/cxl/cxlmem.h | 63 ++++++++++++++++++++++++++++++++++++++
>>> 2 files changed, 131 insertions(+)
>>>
>>> diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c index
>>> 2626f3fff201..760fa3e1075f 100644
>>> --- a/drivers/cxl/core/mbox.c
>>> +++ b/drivers/cxl/core/mbox.c
>>> @@ -1324,6 +1324,74 @@ 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,
>>> + u32 count, u16 start_index,
>>> + struct cxl_mbox_get_supp_feats_out *feats_out) {
>>> + struct cxl_mbox_get_supp_feats_in pi;
>>> + struct cxl_mbox_cmd mbox_cmd;
>>> + int rc;
>>> +
>>> + pi.count = cpu_to_le32(count);
>>> + pi.start_index = cpu_to_le16(start_index);
>>> +
>>> + mbox_cmd = (struct cxl_mbox_cmd) {
>>> + .opcode = CXL_MBOX_OP_GET_SUPPORTED_FEATURES,
>>> + .size_in = sizeof(pi),
>>> + .payload_in = &pi,
>>> + .size_out = count,
>>> + .payload_out = feats_out,
>>> + .min_out = sizeof(*feats_out),
>>> + };
>>> + rc = 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_get_supported_feature_entry(struct cxl_memdev_state *mds, const
>> uuid_t *feat_uuid,
>>> + struct cxl_mbox_supp_feat_entry
>> *feat_entry_out)
>>
>> Hi Shiju,
>> thoughts on storing all the supported features meta info from
>> GET_SUPPORTED_FEATURES command in the cxl core driver during device
>> enumeration and the CXL EDAC code can just query the core instead of reading
>>from the device? Just looking forward to supporting other read/set features
>> operations in the future and avoiding going through this entire read and find
>> routine for each feature.
> Thanks for the suggestion.
> I saw you have implementation for storing all the supported features meta info from GET_SUPPORTED_FEATURES command here.
> https://patchwork.kernel.org/project/cxl/patch/20240718213446.1750135-5-dave.jiang@intel.com/
> I am fine basing on it if this patch is ready to go?

If you are fine with it then please feel free to incorporate the changes with your code and we'll go through the reviews. Thanks!

>>
>> DJ
>
> Thanks,
> Shiju
>>
>>> +{
>>> + struct cxl_mbox_supp_feat_entry *feat_entry;
>>> + int feat_index, feats_out_size;
>>> + int nentries, count;
>>> + int ret;
>>> +
>>> + feat_index = 0;
>>> + feats_out_size = sizeof(struct cxl_mbox_get_supp_feats_out) +
>>> + sizeof(struct cxl_mbox_supp_feat_entry);
>>> + struct cxl_mbox_get_supp_feats_out *feats_out __free(kfree) =
>>> + kmalloc(feats_out_size, GFP_KERNEL);
>>> + if (!feats_out)
>>> + return -ENOMEM;
>>> +
>>> + while (true) {
>>> + memset(feats_out, 0, feats_out_size);
>>> + ret = cxl_get_supported_features(mds, feats_out_size,
>>> + feat_index, feats_out);
>>> + if (ret)
>>> + return ret;
>>> +
>>> + nentries = feats_out->nr_entries;
>>> + if (!nentries)
>>> + return -EOPNOTSUPP;
>>> +
>>> + /* Check CXL memdev supports the feature */
>>> + feat_entry = feats_out->feat_entries;
>>> + for (count = 0; count < nentries; count++, feat_entry++) {
>>> + if (uuid_equal(&feat_entry->uuid, feat_uuid)) {
>>> + memcpy(feat_entry_out, feat_entry,
>>> + sizeof(*feat_entry_out));
>>> + return 0;
>>> + }
>>> + }
>>> + feat_index += nentries;
>>> + }
>>> +}
>>> +EXPORT_SYMBOL_NS_GPL(cxl_get_supported_feature_entry, 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
>>> af8169ccdbc0..9939c771f642 100644
>>> --- a/drivers/cxl/cxlmem.h
>>> +++ b/drivers/cxl/cxlmem.h
>>> @@ -531,6 +531,7 @@ 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,
>>> @@ -700,6 +701,63 @@ struct cxl_mbox_set_timestamp_in {
>>>
>>> } __packed;
>>>
>>> +/*
>>> + * Get Supported Features CXL 3.1 Spec 8.2.9.6.1 */
>>> +
>>> +/*
>>> + * Get Supported Features input payload
>>> + * CXL rev 3.1 section 8.2.9.6.1 Table 8-95 */ struct
>>> +cxl_mbox_get_supp_feats_in {
>>> + __le32 count;
>>> + __le16 start_index;
>>> + u8 rsvd[2];
>>> +} __packed;
>>> +
>>> +/*
>>> + * Get Supported Features Supported Feature Entry
>>> + * CXL rev 3.1 section 8.2.9.6.1 Table 8-97 */
>>> +/* 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_mbox_supp_feat_entry {
>>> + uuid_t uuid;
>>> + __le16 index;
>>> + __le16 get_size;
>>> + __le16 set_size;
>>> + __le32 attr_flags;
>>> + u8 get_version;
>>> + u8 set_version;
>>> + __le16 set_effects;
>>> + u8 rsvd[18];
>>> +} __packed;
>>> +
>>> +/*
>>> + * Get Supported Features output payload
>>> + * CXL rev 3.1 section 8.2.9.6.1 Table 8-96 */ struct
>>> +cxl_mbox_get_supp_feats_out {
>>> + __le16 nr_entries;
>>> + __le16 nr_supported;
>>> + u8 rsvd[4];
>>> + 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;
>>> @@ -831,6 +889,11 @@ void cxl_event_trace_record(const struct
>> cxl_memdev *cxlmd,
>>> enum cxl_event_type event_type,
>>> const uuid_t *uuid, union cxl_event *evt); int
>>> cxl_set_timestamp(struct cxl_memdev_state *mds);
>>> +int cxl_get_supported_features(struct cxl_memdev_state *mds,
>>> + u32 count, u16 start_index,
>>> + struct cxl_mbox_get_supp_feats_out *feats_out);
>> int
>>> +cxl_get_supported_feature_entry(struct cxl_memdev_state *mds, const
>> uuid_t *feat_uuid,
>>> + struct cxl_mbox_supp_feat_entry
>> *feat_entry_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);
>