[edk2-devel] [edk2-discuss] PLDM messages via MCTP over KCS

Thu Aug 31 04:59:03 UTC 2023

[AMD Official Use Only - General]

Hi Aladyshev,

> -----Original Message-----
> From: Konstantin Aladyshev <aladyshev22 at gmail.com>
> Sent: Wednesday, August 30, 2023 11:09 PM
> To: Chang, Abner <Abner.Chang at amd.com>
> Cc: discuss at edk2.groups.io; devel at edk2.groups.io
> Subject: Re: [edk2-discuss] PLDM messages via MCTP over KCS
>
> Caution: This message originated from an External Source. Use proper caution
> when opening attachments, clicking links, or responding.
>
>
> Hi!
>
> I've started to implement MCTP over KCS binding for the libmctp
> (https://github.com/openbmc/libmctp) and test it with the current code
> in the ManageabilityPkg.
>
> I was able successfully send the MCTP packet to the BMC, but right now
> I'm having some troubles with receiving the answer back.
>
> I think I've found some bug in the `KcsTransportSendCommand` code.
>
> After it sends data over KCS in expects a responce starting with a
> 'IPMI_KCS_RESPONSE_HEADER'
> https://github.com/tianocore/edk2-
> platforms/blob/14553d31c72afa7289f6a2555b6e91f4f715a05a/Features/
> ManageabilityPkg/Library/ManageabilityTransportKcsLib/Common/KcsComm
> on.c#L476
>
> Isn't it wrong, assuming that the right header in case of MCTP should
> be 'MANAGEABILITY_MCTP_KCS_HEADER' ?
>
> I guess the 'IpmiHelperCheckCompletionCode' check after the data
> receive is also not relevant for the MCTP.

This is something I don’t really sure as I can't verify the response payload because our BMC doesn't have the code to handle MCTP over KCS command. However it is appreciated if community can help to verify this. As I can remember, I can see the return KCS status is 0xC1, the invalid command. Thus I think if we do a MCTP over KCS, the first response is still KCS response header.
This is not what do you see on the BCM it does support MCTP over KCS? If so, then I would like to have your help to correct this code.

>
> Since 'ManageabilityTransportKcsLib' can be used both for IPMI and
> MCTP, how should we deal with this?
If KcsCommon.c, we can have different code path for the given protocol GUID. e.g., if (TransportToken->ManagebilityProtocolSpecification == MCTP).
Then skip reading the KCS_REPOSNSE_HEADER or to read the MCTP_RESPONSE_HEADER (I don see what is the response header for MCTP KCS in spec though, does it mention the KCS response?).

Thanks
Abner

>
> Best regards,
> Konstantin Aladyshev
>
> On Wed, Aug 23, 2023 at 5:18 AM Chang, Abner <Abner.Chang at amd.com>
> wrote:
> >
> > [AMD Official Use Only - General]
> >
> > Please see my answers inline.
> >
> > > -----Original Message-----
> > > From: discuss at edk2.groups.io <discuss at edk2.groups.io> On Behalf Of
> > > Konstantin Aladyshev via groups.io
> > > Sent: Wednesday, August 23, 2023 1:54 AM
> > > To: Chang, Abner <Abner.Chang at amd.com>
> > > Cc: discuss at edk2.groups.io; devel at edk2.groups.io
> > > Subject: Re: [edk2-discuss] PLDM messages via MCTP over KCS
> > >
> > > Caution: This message originated from an External Source. Use proper
> caution
> > > when opening attachments, clicking links, or responding.
> > >
> > >
> > > Thanks for the answer!
> > >
> > > I was a little bit confused about the part, that in the same package I
> > > actually need to provide different library implementations for the
> > > same 'ManageabilityTransportLib', thanks for the clarification!
> > > I think your DSC example should go into the package documentation.
> > Yes, this is a good idea.  I will update it.
> >
> > >
> > > As for me, I'm working with the OpenBMC distribution
> > > (https://github.com/openbmc/openbmc) and my goal is to transfer data
> > > from the BIOS to the BMC via MCTP/PLDM.
> > > Currently there is no solution for the MCTP over KCS binding in Linux,
> > > so I need to add this support:
> > > - either to the MCTP userspace library
> > > (https://github.com/openbmc/libmctp) [old OpenBMC way, but probably
> > > easier]
> > > - or to the MCTP kernel binding
> > > (https://github.com/torvalds/linux/tree/master/drivers/net/mctp)
> > > [modern mctp Linux driver approach]
> > >
> > > Both don't sound like an easy task, so can I ask, what MC (i.e.
> > > management controller) device and firmware do you use on the other
> > > side of the MCTP KCS transmissions?
> >
> > We use OpenBMC as well, but as you mention there are some missing pieces
> to fully support manageability between host and BMC.
> > We don’t have code to handle MCTP IPMI either, the edk2 ManageabilityPkg
> provides the framework while MCTP/PLDM/KCS implementation provides a
> sample other than IPMI/KCS to prove the flexibility of ManageabilityPkg.
> > Actually, MCTP over KCS is not supported in our BMC firmware yet, thus
> BMC just returns the invalid command. However, the transport framework
> has been verified to make sure the implementation works fine as expect.
> > We need help from community to provide more manageability protocols and
> transport interface libraries to this package.
> >
> > >
> > > You've also mentioned PLDM SMBIOS, isn't it covered by the
> > > https://github.com/tianocore/edk2-
> > >
> platforms/blob/master/Features/ManageabilityPkg/Universal/PldmSmbiosTr
> > > ansferDxe/PldmSmbiosTransferDxe.c
> > > ?
> > Ah hah, yes I forget I upstream it.
> >
> > Please just feel free to send patch to make more functionalities to this
> package.
> > Thanks
> > Abner
> >
> > >
> > >
> > > Best regards,
> > > Konstantin Aladyshev
> > >
> > > On Tue, Aug 22, 2023 at 7:26 PM Chang, Abner
> <Abner.Chang at amd.com>
> > > wrote:
> > > >
> > > > [AMD Official Use Only - General]
> > > >
> > > > Hi Aladyshev,
> > > > We use library class to specify the desire transport interface for the
> > > management protocol, such as MCTP, PLDM and IPMI. This way we can
> > > flexibly support any transport interface for the management protocol.
> > > >
> > > > Here is the example of using ManageabilityPkg, which is PLDM over MCTP
> > > over KCS.
> > > >   ManageabilityPkg/Universal/IpmiProtocol/Dxe/IpmiProtocolDxe.inf {
> > > >     <LibraryClasses>
> > > >
> > >
> ManageabilityTransportLib|ManageabilityPkg/Library/ManageabilityTranspor
> > > tKcsLib/Dxe/DxeManageabilityTransportKcs.inf
> > > >   }
> > > >   ManageabilityPkg/Universal/MctpProtocol/Dxe/MctpProtocolDxe.inf {
> > > >     <LibraryClasses>
> > > >
> > >
> ManageabilityTransportLib|ManageabilityPkg/Library/ManageabilityTranspor
> > > tKcsLib/Dxe/DxeManageabilityTransportKcs.inf
> > > >   }
> > > >   ManageabilityPkg/Universal/PldmProtocol/Dxe/PldmProtocolDxe.inf {
> > > >     <LibraryClasses>
> > > >
> > >
> ManageabilityTransportLib|ManageabilityPkg/Library/ManageabilityTranspor
> > > tMctpLib/Dxe/DxeManageabilityTransportMctp.inf
> > > >   }
> > > >
> > > > So you can implement ManageabilityTransport library for either industry
> > > standard or proprietary implementation for the specific management
> > > protocol.
> > > >
> > > > BTW, We do have PLDM SMBIOS over MCTP implementation but not
> > > upstream yet.
> > > >
> > > > Hope this information helps.
> > > > Thanks
> > > > Abner
> > > >
> > > >
> > > > > -----Original Message-----
> > > > > From: discuss at edk2.groups.io <discuss at edk2.groups.io> On Behalf Of
> > > > > Konstantin Aladyshev via groups.io
> > > > > Sent: Tuesday, August 22, 2023 7:00 PM
> > > > > To: discuss <discuss at edk2.groups.io>; devel at edk2.groups.io
> > > > > Subject: [edk2-discuss] PLDM messages via MCTP over KCS
> > > > >
> > > > > Caution: This message originated from an External Source. Use proper
> > > caution
> > > > > when opening attachments, clicking links, or responding.
> > > > >
> > > > >
> > > > > Hi!
> > > > >
> > > > > I'm trying to build `ManageabilityPkg` from the edk2-platforms
> > > > >  repo to issue PLDM messages via MCTP over KCS. Is it possible with
> > > > > the current code? I see all the building blocks, but have trouble
> > > > > putting it all together.
> > > > >
> > > > > The main question that bothers me is what implementation should I set
> > > > > for the `ManageabilityTransportLib`?
> > > > > By default it is set to dummy `BaseManageabilityTransportNull.inf`
> > > > > (https://github.com/tianocore/edk2-
> > > > >
> > >
> platforms/blob/master/Features/ManageabilityPkg/ManageabilityPkg.dsc).
> > > > >
> > > > > On one case to get PLDM via MCTP it looks that I need to set it to
> > > > > `DxeManageabilityTransportMctp.inf`
> > > > > ManageabilityTransportLib| <...>/DxeManageabilityTransportMctp.inf
> > > > > (https://github.com/tianocore/edk2-
> > > > >
> > >
> platforms/blob/master/Features/ManageabilityPkg/Library/ManageabilityTra
> > > > > nsportMctpLib/Dxe/DxeManageabilityTransportMctp.inf)
> > > > >
> > > > > But on the other case if I want MCTP over KCS I need to set it to
> > > > > `DxeManageabilityTransportKcs.inf`
> > > > > ManageabilityTransportLib| <...>/DxeManageabilityTransportKcs.inf
> > > > > (https://github.com/tianocore/edk2-
> > > > >
> > >
> platforms/blob/master/Features/ManageabilityPkg/Library/ManageabilityTra
> > > > > nsportKcsLib/Dxe/DxeManageabilityTransportKcs.inf)
> > > > >
> > > > > What is the right way to resolve this?
> > > > >
> > > > > There are no platforms in the repo that actually implement PLDM/MCTP
> > > > > functionality, so there is no example that I can use as a reference.
> > > > >
> > > > >
> > > > > Best regards,
> > > > > Konstantin Aladyshev
> > > > >
> > > > >
> > > > >
> > > > >
> > > >
> > >
> > >
> > > 
> > >
> >

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