FW: Exposing BIOS attributes to a remote management console

Sekar, Suryakanth suryakanth.sekar at linux.intel.com
Mon Feb 10 21:49:04 AEDT 2020

Hi Deepak,

OOB BIOS high level config design doc is in progress. I will send for 
review soon.

Yes, we need to support all interface -IPMI/ MCTP/ Redfish Host interface.

If BIOS is not booted at all. BMC wont have any attribute info. It will 
be empty in BMC side.

BIOS must provide BIOS OOB capability via KCS interface in early boot stage.
Like supported proprietary BIOS attribute file format or PLDM support 
via MCTP  or
Redfish BIOS attribute registry format to the BMC.

BIOS must send the master BIOS attributes file(Intel properitary - XML 
type 0)
via KCS interface or all attributes details via Bios configuration PLDM 
via MCTP or
Redfish host interface during first boot.

BIOS must collect the new attribute values from BMC and update the same 

BIOS must send the updated master attributes file to the BMC and once 
its updated in BIOS

and reset the system to reflect the BIOS configuration.

OOB daemon in BMC  must maintain and collect the  attribute registry 
file from MCTP/ IPMI/ Redfish interface.

Convert the proprietary XML format/ PLDM data  into BIOS attribute 
Registry format &
must support the below following dbus method.


Validate the BIOS input data or User attribute value.

MCTP / Redfish host interface / IPMI must communicate with OOB daemon in 
BMC via D bus



> ---------- Forwarded message ----------
> From: Deepak Kodihalli <dkodihal at linux.vnet.ibm.com 
> <mailto:dkodihal at linux.vnet.ibm.com>>
> Date: Feb 8, 2020 1:59 PM
> Subject: Exposing BIOS attributes to a remote management console
> To: openbmc at lists.ozlabs.org <mailto:openbmc at lists.ozlabs.org>
> Cc:
> Hi,
> To enable remote updates (via a remote management console that talks to
> the BMC) to the host firmware's BIOS settings table on IBM systems,
> we're thinking of the following flow:
> a) The host firmware sends down a BIOS settings table to the BMC using
> PLDM [1].
> b) The BMC uses phosphor-settingsd [2] as the backend to store BIOS
> attributes on D-Bus.
> c) Bmcweb implements the Redfish BIOS schema [3] to enable remote
> reads/writes on the BIOS attributes.
> However, c) is a problem because one needs to write YAML files [4] for
> the BMC to determine what D-Bus objects to make corresponding to the
> BIOS attributes. This requires a unique D-Bus interface *per* BIOS
> attribute. This means the BMC must have prior knowledge about the BIOS
> attributes.
> I don't think that's the right way to go about this for two reasons. One
> - this creates a lockstep dependency on the host firmware when the BIOS
> settings table needs to be updated, and two - I think the OpenBMC
> implementation of this must be able to receive (via PLDM/IPMI/other
> standard in-band means) a set of BIOS attributes from different BIOS
> firmware stacks dynamically and expose them for out of band updates,
> without having prior/build-time knowledge of those attributes. So I
> think this calls for a different kind of D-Bus interface/infrastructure
> than what the phosphor-settingsd app relies on. Something that enables
> the BMC to add to D-Bus a BIOS attribute dynamically, knowing it's name,
> type and default value.
> Any thoughts on this flow? I'm also curious to know if the Redfish BIOS
> schema/attribute registry model requires the BMC to have prior knowledge
> about the system BIOS attributes to update the registry. This wasn't
> obvious to me from a quick read of the schema.
> Thanks,
> Deepak
> [1]
> https://www.dmtf.org/sites/default/files/standards/documents/DSP0247_1.0.0.pdf
> [2] https://github.com/openbmc/phosphor-settingsd
> [3] https://redfish.dmtf.org/schemas/v1/Bios.v1_1_0.json
> [4]
> https://github.com/openbmc/openbmc/blob/master/meta-phosphor/recipes-phosphor/settings/phosphor-settings-defaults/defaults.yaml
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