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Fri, 23 Feb 2024 12:23:03 +0000 Received: from lhrpeml500006.china.huawei.com ([7.191.161.198]) by lhrpeml500006.china.huawei.com ([7.191.161.198]) with mapi id 15.01.2507.035; Fri, 23 Feb 2024 12:23:03 +0000 From: Shiju Jose To: Jonathan Cameron CC: "linux-cxl@vger.kernel.org" , "linux-acpi@vger.kernel.org" , "linux-mm@kvack.org" , "dan.j.williams@intel.com" , "dave@stgolabs.net" , "dave.jiang@intel.com" , "alison.schofield@intel.com" , "vishal.l.verma@intel.com" , "ira.weiny@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 , "Zengtao (B)" , "kangkang.shen@futurewei.com" , wanghuiqiang , Linuxarm Subject: RE: [RFC PATCH v6 02/12] cxl/mbox: Add GET_FEATURE mailbox command Thread-Topic: [RFC PATCH v6 02/12] cxl/mbox: Add GET_FEATURE mailbox command Thread-Index: AQHaYAA6Z/8grteajEC0EjChA/BUx7ETG+mAgATIXoA= Date: Fri, 23 Feb 2024 12:23:03 +0000 Message-ID: References: <20240215111455.1462-1-shiju.jose@huawei.com> <20240215111455.1462-3-shiju.jose@huawei.com> <20240220111423.00003eae@Huawei.com> In-Reply-To: <20240220111423.00003eae@Huawei.com> Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.48.145.174] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-Rspam-User: X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 8191118001D X-Stat-Signature: 6nkxejyj9g5nczdgww3uejtmbko59rbt X-HE-Tag: 1708690989-865233 X-HE-Meta: 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Hi Jonathan, Thanks for the comments. I will post the updated version incorporated with your suggestions in the = series. =20 >-----Original Message----- >From: Jonathan Cameron >Sent: 20 February 2024 11:14 >To: Shiju Jose >Cc: linux-cxl@vger.kernel.org; linux-acpi@vger.kernel.org; linux- >mm@kvack.org; dan.j.williams@intel.com; dave@stgolabs.net; >dave.jiang@intel.com; alison.schofield@intel.com; vishal.l.verma@intel.com= ; >ira.weiny@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 ; Zengtao (B) = ; >kangkang.shen@futurewei.com; wanghuiqiang ; >Linuxarm >Subject: Re: [RFC PATCH v6 02/12] cxl/mbox: Add GET_FEATURE mailbox >command > >On Thu, 15 Feb 2024 19:14:44 +0800 > wrote: > >> From: Shiju Jose >> >> Add support for GET_FEATURE mailbox command. >> >> CXL spec 3.1 section 8.2.9.6 describes optional device specific features= . >> The settings of a feature can be retrieved using Get Feature command. >Hi Shiju > >I think this needs to be more complex so that this utility function gets t= he whole >feature, not just a section of it (subject to big enough buffer being avai= lable etc). >We don't want the higher level code to have to deal with the complexity of= small >mailboxes. Sure. > >A few other things inline. > >Jonathan > >> >> Signed-off-by: Shiju Jose >> --- >> drivers/cxl/core/mbox.c | 22 ++++++++++++++++++++++ >> drivers/cxl/cxlmem.h | 23 +++++++++++++++++++++++ >> 2 files changed, 45 insertions(+) >> >> diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c index >> 191f51f3df0e..f43189b6859a 100644 >> --- a/drivers/cxl/core/mbox.c >> +++ b/drivers/cxl/core/mbox.c >> @@ -1313,6 +1313,28 @@ int cxl_get_supported_features(struct >> cxl_memdev_state *mds, } >> EXPORT_SYMBOL_NS_GPL(cxl_get_supported_features, CXL); >> >> +int cxl_get_feature(struct cxl_memdev_state *mds, >> + struct cxl_mbox_get_feat_in *pi, void *feat_out) > >Comments below on this signature. Key is I'd expect this function to deal= with >potential need for multiple requests (small mailbox size compared to the s= ize of >the output data being read). > >To test that we'd probably have to tweak the qemu code to use a smaller >mailbox. >Or fake that in here so that we do multiple smaller reads. Sure. > >> +{ >> + struct cxl_mbox_cmd mbox_cmd; >> + int rc; >> + >> + mbox_cmd =3D (struct cxl_mbox_cmd) { >> + .opcode =3D CXL_MBOX_OP_GET_FEATURE, >> + .size_in =3D sizeof(*pi), >> + .payload_in =3D pi, >> + .size_out =3D le16_to_cpu(pi->count), >> + .payload_out =3D feat_out, >> + .min_out =3D le16_to_cpu(pi->count), > >Are there feature with variable responses sizes? I think there will be. >size_out should be the size of the buffer, but min_out should be the size = of the >particular feature data header - note these will change as we iterate over >multiple messages. Sure. > > >> + }; >> + rc =3D cxl_internal_send_cmd(mds, &mbox_cmd); >> + if (rc < 0) >> + return rc; >> + >> + return 0; >I think this should return the size to the caller, rather than 0 on succes= s. I will change. > >> +} >> +EXPORT_SYMBOL_NS_GPL(cxl_get_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 >> 23e4d98b9bae..eaecc3234cfd 100644 >> --- a/drivers/cxl/cxlmem.h >> +++ b/drivers/cxl/cxlmem.h >> @@ -530,6 +530,7 @@ enum cxl_opcode { >> 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_GET_FEATURE =3D 0x0501, >> CXL_MBOX_OP_IDENTIFY =3D 0x4000, >> CXL_MBOX_OP_GET_PARTITION_INFO =3D 0x4100, >> CXL_MBOX_OP_SET_PARTITION_INFO =3D 0x4101, >> @@ -757,6 +758,26 @@ struct cxl_mbox_get_supp_feats_out { >> struct cxl_mbox_supp_feat_entry feat_entries[]; } __packed; >> >> +/* Get Feature CXL 3.1 Spec 8.2.9.6.2 */ >> +/* >> + * Get Feature input payload >> + * CXL rev 3.1 section 8.2.9.6.2 Table 8-99 */ >> +/* Get Feature : Payload in selection */ > >Naming of enum is good enough that I don't think we need this particular >comment. I will change. > >> +enum cxl_get_feat_selection { >> + CXL_GET_FEAT_SEL_CURRENT_VALUE, >> + CXL_GET_FEAT_SEL_DEFAULT_VALUE, >> + CXL_GET_FEAT_SEL_SAVED_VALUE, >> + CXL_GET_FEAT_SEL_MAX >> +}; >> + >> +struct cxl_mbox_get_feat_in { >> + uuid_t uuid; >> + __le16 offset; >> + __le16 count; >> + u8 selection; >> +} __packed; >> + >> /* Get Poison List CXL 3.0 Spec 8.2.9.8.4.1 */ struct >> cxl_mbox_poison_in { >> __le64 offset; >> @@ -891,6 +912,8 @@ 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_get_feature(struct cxl_memdev_state *mds, >> + struct cxl_mbox_get_feat_in *pi, void *feat_out); > >For this I'd expect us to wrap up the need for multi messages inside this. >So this would then just take the feature index, a size for the output buff= er overall >size, plus min acceptable response size and a selection enum value. Sure. > >int cxl_get_feature(struct cxl_memdev_state *mds, > uuid_t feat, > void *feat_out, size_t feat_out_min_size, > size_t feat_out_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); Thanks, Shiju