1# Remote BIOS Configuration (RBC) via BMC 2 3Author: Suryakanth Sekar! ssekar 4 5Other contributors: Jia Chunhui Deepak Kodihalli Patrick Williams 6 7Created: 19-Nov-2019 8 9## Problem Description 10 11Current OpenBMC doesn't provide mechanism to configure the BIOS remotely. This 12is needed in data center to maintain several systems under same configuration. 13 14Remote BIOS Configuration provides ability for the user to view and modify BIOS 15setup configuration parameters remotely via a BMC at any Host state. New BIOS 16configuration parameters take effect immediately or next system reboot based on 17the host firmware support model. 18 19## Background and References 20 211. <https://www.dmtf.org/sites/default/files/standards/documents/DSP0247_1.0.0.pdf> 222. <https://redfish.dmtf.org/schemas/v1/Bios.v1_1_0.json> 233. <https://redfish.dmtf.org/schemas/v1/AttributeRegistry.v1_3_2.json> 24 25## Requirements 26 271. Mechanism to configure BIOS settings remotely over network interface. 282. BMC should support the ability to set the value of all BIOS variables to the 29 factory default state. 303. Based on the host firmware support model, BMC should support both Immediate 31 Update or Deferred update. 324. In deferred model, When the system is in S0, S3, S4 or S5 state. BMC will 33 send the updated BIOS variables on next BIOS boot only. It will not initiate 34 a BIOS boot immediately. 355. In immediate model, BMC should send message to the system firmware (BIOS) 36 Whenever settings are changed. 376. BMC should support BIOS attribute registry in redfish schema for BIOS 38 configuration. 397. BMC should provide secure way for updating BIOS setup password settings. 40 Detailed password handling design -TBD(will be resolve using ARM TrustZone) 41 Ex: Updating the BIOS password should be support only before end of post. 428. Remote BIOS configuration daemon should be independent of interface specific 43 data format. 449. BMC should able to take default / current settings from host and store & 45 expose that for out of band updates. 4610. BMC should provide the new values to the host. 47 48## Proposed Design 49 50```text 51+----------------------------------------------------------------------------------------------------------------+ 52| Remote BIOS configuration (RBC) via BMC | 53| | 54| | 55| +-------------+ +-------------+ +--------------------------------+ +-------+ | 56| | | | | | RBC daemon | | | +----------+ | 57| | NET/ Tools +<-LAN->+ LAN-IPMID/ +<Dbus->+ | | | |Web client| | 58| | | | REDFISH | | Provide following Methods | | | | | | 59| +-------------+ +-------------+ | -SetAttribute() | | | +----^-----+ | 60| | -GetAttribute() | | | | | 61| +-------------+ +-------------+ | -VerifyPassword() | | | LAN | 62| | | | | | -ChangePassword() | | | | | 63| | HOST/ BIOS +<-KCS->+ HOST-IPMID +<Dbus->+ | |Redfish| +----V-----+ | 64| | | | | | Properties +<Dbus>+ API | |Redfish & | | 65| +-----+-------+ +-------------+ | -BaseBIOSTable | | +<-->+BMCWeb | | 66| | | -PendingAttributes | | | +----^-----+ | 67| | | -ResetBIOSSettings | | | | | 68| | | -IsPasswordInitDone | | | | | 69| | | | | | +----V-----+ | 70| | | | | | | Redfish | | 71| | | | | | | Host | | 72| | | | | | | Interface| | 73| | +----^-----------------+---------+ +-------+ +----------+ | 74| | | PendingAttributesUpdated | 75| | | | Signal | 76| | | | | 77| | +----V-----------------V---------+ | 78| | | PLDM daemon | | 79| | | Collect the BIOS data & convert| | 80| +---------MCTP----------------------->| into native D-bus format and | | 81| | send to the RBC | | 82| +--------------------------------+ | 83+----------------------------------------------------------------------------------------------------------------+ 84``` 85 86## Intel uses the following logic 87 88BIOS send data in as Proprietary format to the BMC via IPMI interface. There are 89two types of proprietary XML format files in BIOS configuration. Type-0 contain 90full BIOS variables in XML format. (Generated by BIOS) Type-1 contain modified 91BIOS variables in XML format. (Generated by BMC) 92 93BIOS must provide BIOS capability via KCS interface in early boot stage. BIOS 94must send compressed proprietary XML type 0 file via IPMI command to the BMC. 95 96IPMI interface should decompress & validate the received XML Type 0. IPMI 97interface should convert the XML Type 0 into native to D-bus format and send to 98the RBC daemon. 99 100During BDS phase in BIOS. BIOS must get the existing XML info from BMC. If XML 101version/checksum is mismatch or XML Type 0 is not present in BMC, then BIOS must 102send XML type 0 to the BMC. If XML version and XML checksum matched & pending 103BIOS attributes list exist (XML Type 1) in BMC then BIOS must get pending BIOS 104configuration (XML Type 1) from BMC & update in BIOS region and send updated XML 105Type 0 to the BMC in order to intact again and then BIOS reset the system to 106reflect the updated values in BIOS boot. 107 108BIOS have default BIOS settings in BIOS non-volatile memory. BIOS can restore 109the default BIOS configuration based on the flag setting in OEM IPMI command 110issued during BIOS booting. So, restore default BIOS configuration can be done 111by this mechanism. 112 113RBC daemon should preserve the AllBiosTables, PendingAttributes list in 114non-volatile storage. Pending attributes list will be cleared whenever new 115attributes data received. 116 117### Intel logic for BIOS first boot 118 119```text 120 +---------------------------------------------------------------------------------------------------------------------+ 121 | | 122 | +-----------------------+ +----------------------------------------------------------------------------+| 123 | | BIOS | | BMC || 124 | | | | +-------------------------------+ +------------------------------+ || 125 | | | | |IPMI Interface (kcs) | |RBC daemon Manager | || 126 | | | | | -Responsible for send /recv | |-Responsible for handling BIOS| || 127 | | | | | data between BIOS and BMC | | configuration attributes. | || 128 | | | | | | | -AllBaseAttributes | || 129 | | | | | | | -Pending Attributes | || 130 | | | | | | | -FactoryDefaultSetting | || 131 | | | | | | | -BIOSPwdHashData | || 132 | | | | +-------------------------------+ +------------------------------+ || 133 | +-----------------------+ | +-------------------------------+ +-----------------------------+ || 134 | | Set BIOS capability |<---Req-/Res--> | Set the BIOS capability | | | || 135 | | | | | | | | || 136 | |Set BIOS Pwd hash/Seed |<---Req-/Res--> | Forward to the RBC daemon |--dbus-->| Set BIOSPwdHash data. | || 137 | | | | | | | | || 138 | | | | | | | | || 139 | |Check factory settings |<---Req-/Res--> | Get the FactoryDefault prop |<-dbus-- | Send FactoryDefaultSettings | || 140 | |Init the BIOS config | | | | | | || 141 | |Based on value. | | | | | | || 142 | |Get the XML Type0 info |<---Req-/Res--> | Provide the XML Type 0 Info | | | || 143 | |Generate & compress | | | | | | || 144 | |XML type 0 file | | | Validate the XML Type 0 | |Collect the Attributes Info | || 145 | | | | | Unzip the XML Type 0 |--dbus-->| AllBaseAttributes | || 146 | | Send the XML Type 0 |<---Req-/Res--->| Convert into D-bus format | | || 147 | | via SetPayload command| | | and send to the RBC. | | | || 148 | | | | | | | | || 149 | | Continue the BIOS boot| | | | | | || 150 | +-----------------------+ | +-------------------------------+ +-----------------------------+ || 151 | +----------------------------------------------------------------------------+| 152 +---------------------------------------+-----------------------------------------------------------------------------+ 153``` 154 155### Intel logic for BIOS reset 156 157```text 158 +---------------------------------------------------------------------------------------------------------------------+ 159 | | 160 | +-----------------------+ +----------------------------------------------------------------------------+| 161 | | BIOS | | BMC || 162 | | | | +-------------------------------+ +------------------------------+ || 163 | | | | |IPMI Interface (kcs) | |RBC daemon Manager | || 164 | | | | | -Responsible for send /recv | |-Responsible for handling BIOS| || 165 | | | | | data between BIOS and BMC | | configuration attributes. | || 166 | | | | | | | -AllBaseAttributes | || 167 | | | | | | | -Pending Attributes | || 168 | | | | | | | -FactoryDefaultSetting | || 169 | | | | | | | -BIOSPwdHashData | || 170 + | | | +-------------------------------+ +------------------------------+ || 171 | +-----------------------+ | +-------------------------------+ +-----------------------------+ || 172 | |Set BIOS capability |<---Req-/Res--> | Set the BIOS capability | | | || 173 | | | | | | | | || 174 | |Set BIOS Pwd hash/Seed |<---Req-/Res--> | Forward to the RBC daemon |--dbus-->| Set BIOSPwdHash data | || 175 | | | | | | | | || 176 | | | | | | | | || 177 | |Check factory settings |<---Req-/Res--> | Get the FactoryDefault prop |<-dbus-- | Send FactoryDefaultSettings | || 178 | |Init the BIOS config | | | | | | || 179 | |Based on value. | | | | | | || 180 | |Get the XML Type 0 info|<---Req-/Res--> | Provide the XML Type 0 Info | | | || 181 | |Generate & compress | | | | | | || 182 | |XML type 0 file. | | | | |Collect the Attributes Info | || 183 | |Check XML file Chksum. | | | Validate the XML Type 0 |--dbus-->| BaseBIOSTable | || 184 | |If Chksum mismatch |<---Req-/Res--->| Unzip XML Type 0 & convert | | | || 185 | |then send the payload | | | into D-bus format and send to | | | || 186 | |via SetPayload. | | | the RBC | | | || 187 | |Continue the BIOS boot | | | | | | || 188 | +-----------------------+ | +-------------------------------+ +-----------------------------+ || 189 | +----------------------------------------------------------------------------+| 190 +---------------------------------------+-----------------------------------------------------------------------------+ 191``` 192 193### Intel BIOS Reset Logic When BMC Has Pending Settings 194 195```text 196 +---------------------------------------------------------------------------------------------------------------------+ 197 | | 198 | +-----------------------+ +----------------------------------------------------------------------------+| 199 | | BIOS | | BMC || 200 | | | | +-------------------------------+ +------------------------------+ || 201 | | | | | | | | || 202 | | | | |IPMI Interface (kcs) | |RBC daemon Manager | || 203 | | | | | -Responsible for send /recv | |-Responsible for handling BIOS| || 204 | | | | | data between BIOS and BMC | | configuration attributes. | || 205 | | | | | | | -AllBaseAttributes | || 206 | | | | | | | -Pending Attributes | || 207 | | | | | | | -FactoryDefaultSetting | || 208 | | | | | | | -BIOSPwdHashData | || 209 + | | | +-------------------------------+ +------------------------------+ || 210 | +-----------------------+ | +-------------------------------+ +-----------------------------+ || 211 | |Set BIOS capability |<---Req-/Res--> | Set the BIOS capability | | | || 212 | | | | | | | | || 213 | |Set BIOS Pwd hash/Seed |<---Req-/Res--> | Forward to the RBC daemon |---dbus->| Set BIOSPwdHash data | || 214 | | | | | | | | || 215 | | | | | | | | || 216 | |Check factory settings |<---Req-/Res--> | Get the FactoryDefault prop |<--dbus--| Send FactoryDefaultSettings | || 217 | |Init the BIOS config | | | | | | || 218 | |Based on value. | | | | | | || 219 | |Get the XML Type 0 info|<---Req-/Res--> | Provide the XML Type 0 Info | | | || 220 | |Generate & compress | | | | | | || 221 | |XML Type 0 file. | | | | | | || 222 | |Check XML file Chksum. | | | | | | || 223 | |If Chksum match |<---Req-/Res--->| Provide the XML Type 0 | | | || 224 | |then get the XML Type 1| | | | | | || 225 | |via GetPayload. | | | | | | || 226 | |Get the XML Type 1 | | | | | | || 227 | |via GetPayload command.|<---Req-/Res--->| Provide the XML Type 1 | | | || 228 | | | | | | | | || 229 | |Update the new value | | | | | | || 230 | |and new chksum in |<---Req-/Res--->| Get new XML Type 0 & convert |--dbus-->| Collect the Atributes info | || 231 | |BIOS. | | | into native to D-bus format | | AllBaseAttributes | || 232 | |Reset the system. | | | | | | || 233 | +-----------------------+ | +-------------------------------+ +-----------------------------+ || 234 | +----------------------------------------------------------------------------+| 235 +---------------------------------------+-----------------------------------------------------------------------------+ 236``` 237 238## BIOS send the data in BIOS configuration PLDM via MCTP 239 240BIOS should update the BIOS settings via Set BIOS table PLDM command- BIOS 241string table, Attribute name table, Attribute value table via MCTP. 242 243RBC daemon should create pending BIOS attributes list based on the user input 244configuration and send PendingAttributesUpdated signal. 245 246PLDM daemon should register for PendingAttributesUpdated signal & RBC daemon 247should generate signal whenever attribute value changed by SetPendingAttributes, 248set attribute D-bus call. PLDM should Wait for PendingAttributesUpdated signal 249and pull the pending attributes value from RBC daemon. PLDM should delete the 250Pending attributes value table once its not valid or updated in BIOS. RBC should 251clear pending attributes list whenever new attributes data received. 252 253RBC daemon should preserve the AllBaseAttributes, PendingAttributes list in 254non-volatile storage. PLDM daemon should preserve BIOS tables in non-volatile 255storage. RBC and PLDM should restored the data whenever BMC reset. 256 257### BIOS first boot 258 259```text 260 261 +--------------------------------------------------------------------------------------------------------------------+ 262 | +-----------------------+ +---------------------------------------------------------------------------+| 263 | | BIOS | | BMC || 264 | | | | +-------------------------------+ +-----------------------------+|| 265 | | | | |PLDM Interface (MCTP) | |RBC Daemon Manager ||| 266 | | | | | -Responsible for send /recv | |-Responsible for handle BIOS ||| 267 | | | | | data between BIOS and BMC | | configuration attributes. ||| 268 | | | | | | | -AllBaseAttributes ||| 269 | | | | | | | -Pending Attributes ||| 270 | | | | | | | -FactoryDefaultSetting ||| 271 | | | | | | | -BIOSPwdHashData ||| 272 + +-----------------------+ | +-------------------------------+ +-----------------------------+|| 273 | |Get the table info |<---Req-/Res--> | Provide the table information | | ||| 274 | | & Check table Tag | | | | | ||| 275 | |using GetBIOS table | | | | | ||| 276 | | | | | | | ||| 277 | |Set BIOS string table |<---Req-/Res--> | Get the string table | | ||| 278 | | via Set BIOS table | | | | | ||| 279 | |SetBIOSAttribute table |<---Req-/Res--> | Get the attributes table | | ||| 280 | |SetBIOSAttributeValue |<---Req-/Res--> | Get the attributes value table| | ||| 281 | |table via SetBIOStable | | | | | ||| 282 | |table via SetBIOStable | | | | | ||| 283 | |Init the BIOS config | | | Send the attributes data in | | ||| 284 | |Based on value. | | | native to D-bus format |--dbus-->| AllBaseAttributes ||| 285 | |via Set BIOS table | | | by Setting AllBaseAttributes | | ||| 286 | | | | | | | ||| 287 | | Continue the BIOS boot| | | | | ||| 288 | +-----------------------+ | +-------------------------------+ +-----------------------------+|| 289 | +---------------------------------------------------------------------------+| 290 +---------------------------------------+----------------------------------------------------------------------------+ 291``` 292 293### BIOS reset 294 295```text 296 +--------------------------------------------------------------------------------------------------------------------+ 297 | +-----------------------+ +---------------------------------------------------------------------------+| 298 | | BIOS | | BMC || 299 | | | | +-------------------------------+ +-----------------------------+|| 300 | | | | |PLDM Interface (MCTP) | |RBC Daemon Manager ||| 301 | | | | | -Responsible for send /recv | |-Responsible for handle BIOS ||| 302 | | | | | data between BIOS and BMC | | configuration attributes. ||| 303 | | | | | | | -AllBaseAttributes ||| 304 | | | | | | | -Pending Attributes ||| 305 | | | | | | | -FactoryDefaultSetting ||| 306 | | | | | | | -BIOSPwdHashData ||| 307 | +-----------------------+ | +-------------------------------+ +-----------------------------+|| 308 | |Get the table info |<---Req-/Res--> | Provide the table information | | ||| 309 | | & Check table Tag | | | | | ||| 310 | |using GetBIOS table | | | | | ||| 311 | | | | | | | ||| 312 | | Get the Pending table |<---Req-/Res--> | Provide the Pending attributes| | ||| 313 | | using Get BIOS table | | | table | | ||| 314 | | | | | | | ||| 315 | |SetBIOSAttributeValue |<---Req-/Res--> | Get the attributes table | | ||| 316 | |table via SetBIOStable.| | | Delete the Pending attributes | | ||| 317 | |Init the BIOS config | | | table | | ||| 318 | |Based on value. | | | | | ||| 319 | | | | | Send the attributes data in | | ||| 320 | | | | | native to D-bus format by |--dbus-->| AllBaseAttributes ||| 321 | | Reset the BIOS boot | | | setting AllBaseAttributes | | ||| 322 | +-----------------------+ | +-------------------------------+ +-----------------------------+|| 323 | +---------------------------------------------------------------------------+| 324 +---------------------------------------+----------------------------------------------------------------------------+ 325 326``` 327 328### Complete BIOS BMC flow for BIOS configuration in deferred update model 329 330```text 331+----------------------------------------+ +----------------------------------------+ 332| BIOS | | BMC | 333| | | | 334| +----------------------------------+ | | +------------------------------------+ | 335| | Send the BIOS capability Support| |--------KCS-------->| |1.Get the complete atttributes data.| | 336| | Send the compressed BIOS file(or)| |-MCTP/KCS/Redfish-->| |2.Validate and convert into | | 337| | Send PLDM data via MCTP (or) | | | | native to D-bus format. | | 338| | Send the Redfish host interface | | | |3.Expose the D-bus interface | | 339| +----------------------------------+ | | +------------------------------------+ | 340| | | | 341| +----------------------------------+ | | | 342| | Get the file info & config status| <-Get config status-| | 343| | - Any config changed or not | | | | 344| | - File checksum in BMC | | | | 345| | - New attribute values exist | | | | 346| +----------------------------------+ | | | 347| | | +-----------------------------------+ | 348| +----------------------------------+ | | | | | 349| | If new attribute value exist |<-|-----------------------| Send the new value attributes | | 350| | then | | | | (Pending Attributes list) | | 351| | Get & Update the BIOS variables | -| -----+ | | | | 352| | | | | | +-----------------------------------+ | 353| +---------------+------------------+ | | | | 354| | | | | | 355| YES | | | | 356| | | | | +----------------------------------+ | 357| +--------------V------------------+ | | | | | | 358| | Send the updated data to BMC | | | | | Update the BIOS attributes | | 359| | |------------------------->| (BaseBIOSTable) | | 360| +---------------------------------+ | | | +----------------------------------+ | 361| | | | | 362| | | | | 363| +---------------------------------+ | | | | 364| | Reset the BIOS for BIOS conf | | NO | | 365| | update | | | | | 366| +---------------------------------+ | | | | 367| | | | | 368| +----------------------------------+ | | | | 369| | Continue the BIOS boot | <-------+ | | 370| +----------------------------------+ | | | 371+----------------------------------------+ +----------------------------------------+ 372``` 373 374### Complete BIOS BMC flow for BIOS configuration in immediate update model 375 376```text 377+----------------------------------------+ +----------------------------------------+ 378| BIOS | | BMC | 379| | | | 380| +----------------------------------+ | | +------------------------------------+ | 381| | Send the BIOS capability Support| |--------KCS-------->| |1.Get the complete atttributes data | | 382| | Send the compressed BIOS file(or)| |-MCTP/KCS/Redfish-->| |2.Validate and convert into | | 383| | Send PLDM data via MCTP (or) | | | | native to D-bus format. | | 384| | Send the Redfish host interface | | | |3.Expose the D-bus interface | | 385| +----------------------------------+ | | +------------------------------------+ | 386| | | | 387| | | +------------------------------------+ | 388| | | |PLDM can send complete all tables | | 389| | | | & send the native to D-bus format | | 390| | | | by Setting AllBaseAttributes | | 391| | | +------------------------------------+ | 392| | | +------------------------------------+ | 393| | | | If attribute value changed then | | 394| | | | Biosconfig send signal to PLDM. | | 395| | | | PLDM read Pending attributes table | | 396| | | | PLDM send the message to the host | | 397| | | | PLDM send the data to the host | | 398| | | +------------------------------------+ | 399| +----------------------------------+ | | +------------------------------------+ | 400| | Read the new Atributes value |<-|----------------------| Send new Pending attributes table | | 401| | and | | | | | | 402| | Update in the BIOS structure | | | +------------------------------------+ | 403| +---------------+------------------+ | | | 404| | | | | 405| YES | | | 406| | | | +-----------------------------------+ | 407| +--------------V------------------+ | | | Update the BIOS atrributes data. | | 408| | Send the updated data to BMC | | | | Discard the Pending attributes | | 409| | |------------------------>| table | | 410| +---------------------------------+ | | +-----------------------------------+ | 411| | | | 412+----------------------------------------+ +----------------------------------------+ 413``` 414 415RBC should create the Pending Attribute list whenever SetPendingAttributes & 416SetAttribute Method called and raise the PendingAttributesUpdated signal. RBC 417should preserve the Pending Attributes list across the BMC reset and RBC should 418clear the Pending Attributes list whenever new AllBaseBIOSTables received from 419BIOS. 420 421### Redfish interfaces for remote Bios configuration 422 423```text 424 +-----------------------------------------------------------------------------------------------------------+ 425 | +-------------------------+ +----------------------------------------------------------------+| 426 | | RBC Web tool - POSTMAN | | BMC || 427 | | (Please refer the | | +-----------------------+ +---------------------------+ || 428 | | below redfish example | | |Redfish Daemon | |RBC Daemon Manager | || 429 | | for each request) | | |-Responsible for handle| |-Parse Bios Data,convert to| || 430 | | | | |all Redfish request | | required format & return | || 431 | | | | +-----------------------+ +---------------------------+ || 432 | +-------------------------+ | +-----------------------+ +---------------------------+ || 433 | | | | | | | | || 434 | |1.Get Current attributes |<---Req-/Res--> | Read BaseBIOSTable |<-dbus-| BaseBIOSTable | || 435 | | name & value list | | | | | | || 436 | | | | | | | | || 437 | |2.Get Attribute Registry |<---Req-/Res--> | Read BaseBIOSTable |<-dbus-| BaseBIOSTable | || 438 | | | | | | | | || 439 | |3.Change BIOS Password |<---Req-/Res--> | Call RBC D-bus Method |-dbus->| ChangePassword() | || 440 | | | | | | | | || 441 | |4.Reset To default |<---Req-/Res--> | Set ResetBIOSSettings |-dbus->| ResetBiosSettings | || 442 | | settings | | | | | -ResetFlag | || 443 | |5.Update new BIOS setting|<---Req-/Res--->| Call RBC D-bus Method |-dbus->| SetAttribute() | || 444 | | (For single attribute) | | | | | | || 445 | | | | | | | | || 446 | |6.Get Pending attributes |<---Req-/Res--->| Get PendingAttributes |<-dbus-| PendingAttributes | || 447 | | list | | | | | | || 448 | |7.Update new BIOS setting|<---Req-/Res--->| Set PendingAttributes |<-dbus-| PendingAttributes | || 449 | | list | | | | | | || 450 | | For multiple attributes| | | | | | || 451 | +-------------------------+ | +-----------------------+ +---------------------------+ || 452 | +---------------------------------------------------------------+|| 453 +-----------------------------------------+-----------------------------------------------------------------+ 454``` 455 4561. Get Current Attributes name and value list: Get the current BIOS settings 457 attribute name and value pair list. GET Method - 458 `https://<BMC>/redfish/v1/Systems/system/Bios` 459 4602. Get Attribute Registry: Get the detailed information about Bios Attribute 461 like current value, supported value, description, Menupath, Default value. 462 GET Method - `https://<BMC>/redfish/v1/Registries/Bios` 463 4643. Change BIOS password: ACTION - 465 `https://<BMC>/redfish/v1/Systems/system/Bios/Actions/Bios.ChangePassword` 466 4674. Reset To default settings: ACTION - 468 `https://<BMC>/redfish/v1/Systems/system/Bios/Actions/Bios.ResetBios` 469 4705. Update new BIOS settings (single attribute): Use to send the new value for 471 particular attribute or list of attributes. PATCH Method - 472 `https://<BMC>/redfish/v1/Systems/system/Bios/Settings` Ex: Attribute name 473 and new value : `{ "DdrFreqLimit" : 2400 }` 474 4756. Get the new pending value list: Use to get the new pending attributes list. 476 GET Method - `https://<BMC>/redfish/v1/Systems/system/Bios/Settings` - Valid 477 only in deferred model. For immediate update model, It will be empty. Ex: 478 Attribute name and new value : `{ "DdrFreqLimit" : 2400, "QuietBoot", 0x1 }` 479 4807. Update new BIOS settings (multiple attributes): Use to send the new value for 481 particular attribute or list of attributes. PATCH Method - 482 `https://<BMC>/redfish/v1/Systems/system/Bios/Settings` Ex: Attribute name 483 and new value list : `{ "DdrFreqLimit" : 2400, "QuietBoot", 0x1 }` 484 485## Alternatives Considered 486 487Redfish Host specification definition is not completed and ready BIOS support 488also not available. There are 1000+ BIOS variables and storing in 489phosphor-settingsd is not optimal. 490 491## Impacts 492 493BIOS must support and follow RBC BIOS configuration flow. 494 495## Testing 496 497Able to change the BIOS configuration via BMC through LAN Able to change the 498BIOS setup password via BMC Compliance with Redfish will be tested using the 499Redfish Service Validator 500