Boot Source Override feature problems

Tue Jun 22 01:59:02 AEST 2021

I've redesigned the boot source override feature.

Now it is stored as:
```
/xyz/openbmc_project/control/host0/boot:
     - Interface: xyz.openbmc_project.Control.Boot.Source
     - Interface: xyz.openbmc_project.Control.Boot.Mode
     - Interface: xyz.openbmc_project.Control.Boot.Type
     - Interface: xyz.openbmc_project.Object.Enable
/xyz/openbmc_project/control/host0/boot/one_time:
     - Interface: xyz.openbmc_project.Object.Enable
```
This would solve all of the problems with the current realization.

I've created several commits under one topic in gerrit to the proposed change.
First the `phosphor-settings-manager` commit itself:
44226: phosphor-settings-manager: redesign boot setting override
feature | https://gerrit.openbmc-project.xyz/c/openbmc/openbmc/+/44226
improvements:
- now there is no doubling interfaces for BootSource/BootMode/BootType
- boot override is clearly disabled by default
- one_time is disabled by default

Then I've posed a changes for phosphor-host-ipmid:
44231: Support new boot override setting design |
https://gerrit.openbmc-project.xyz/c/openbmc/phosphor-host-ipmid/+/44231
improvements:
- code simplification
- now it is possible to set boot flag as invalid, which wasn't possible before
- now it is possible to report boot flag as invalid

And bmcweb:
44272: Support new boot override setting design |
https://gerrit.openbmc-project.xyz/c/openbmc/bmcweb/+/44272
improvements:
- significant code simplification!
- no there is no weird interdependency between BootSource/BootMode/BootType
- all the boot parameters now can be set independently

And finally I've created a commit for a
44225: Support all parameter combinations in Redfish boot tests |
https://gerrit.openbmc-project.xyz/c/openbmc/openbmc-test-automation/+/44225
improvements:
- you can see that now `Disabled` state is not decoded as weird
`Options apply to all future boots`, but as `Boot Flag Invalid`
- now it is possible to add all of the combination of tests

Best regards,
Konstantin Aladyshev

On Fri, Jun 11, 2021 at 3:17 PM Deepak Kodihalli
<deepak.kodihalli.83 at gmail.com> wrote:
>
> Hi!
>
> On Thu, May 27, 2021 at 2:21 AM Konstantin Aladyshev
> <aladyshev22 at gmail.com> wrote:
> >
> > Hello!
> > I've merged almost all of my patchsets for the EFI/Legacy support in
> > the Boot Override feature (only bmcweb patchset is left
> > https://gerrit.openbmc-project.xyz/c/openbmc/bmcweb/+/40970) and I
> > want to return to the discussion about the current implementation of
> > the Boot Override feature in OpenBMC.
> >
> > First, here are implementation details from IPMI and Redfish specs for
> > this feature:
> >
> > IPMI specification (Document Revision 1.1 October 1, 2013)
> > ```
> > IPMI:
> > 1b - enabled/disabled
> > 1b - one-time/permanent
> > 1b - EFI/Legacy
> > 4b - BDS (boot device selector)
> >   0000b = No override
> >   0001b = Force PXE
> >   0010b = Force boot from default Hard-drive
> >   0011b = Force boot from default Hard-drive, request Safe Mode
> >   0100b = Force boot from default Diagnostic Partition
> >   0101b = Force boot from default CD/DVD
> >   0110b = Force boot into BIOS Setup
> >   0111b = Force boot from remotely connected (redirected)
> > Floppy/primary removable media
> >   1001b = Force boot from primary remote media
> >   1000b = Force boot from remotely connected (redirected) CD/DVD
> >   1010b = reserved
> >   1011b = Force boot from remotely connected (redirected) Hard Drive
> >   1100-1110b = Reserved
> >   1111b = Force boot from Floppy/primary removable media
> > ```
> > Redfish specification (DSP2046 2021.1 Redfish Resource and Schema
> > Guide 18 May 2021)
> > ```
> > BootSourceOverrideEnabled - Continuous/Disabled/Once
> > BootSourceOverrideMode - Legacy/UEFI
> > BootSourceOverrideTarget -
> >   BiosSetup = Boot to the BIOS setup utility.
> >   Cd = Boot from the CD or DVD.
> >   Diags = Boot to the manufacturer's diagnostics program.
> >   Floppy = Boot from the floppy disk drive.
> >   Hdd = Boot from a hard drive.
> >   None = Boot from the normal boot device.
> >   Pxe = Boot from the Pre-Boot EXecution (PXE) environment.
> >   RemoteDrive (v1.2+) = Boot from a remote drive, such as an iSCSI target.
> >   SDCard (v1.1+) = Boot from an SD card.
> >   UefiBootNext (v1.5+) = Boot to the UEFI device that the BootNext
> > property specifies.
> >   UefiHttp (v1.1+) = Boot from a UEFI HTTP network location.
> >   UefiShell = Boot to the UEFI Shell.
> >   UefiTarget = Boot to the UEFI device specified in the
> > UefiTargetBootSourceOverride property.
> >   Usb = Boot from a system BIOS-specified USB device.
> >   Utilities = Boot to the manufacturer's utilities program or programs
> > ```
> >
> > In the OpenBMC the current Dbus interfaces for the Boot Override feature are:
> > ```
> > /xyz/openbmc_project/control/host0/boot:
> >     - Interface: xyz.openbmc_project.Control.Boot.Source
> >     - Interface: xyz.openbmc_project.Control.Boot.Mode
> >     - Interface: xyz.openbmc_project.Control.Boot.Type
> > /xyz/openbmc_project/control/host0/boot/one_time:
> >     - Interface: xyz.openbmc_project.Control.Boot.Source
> >     - Interface: xyz.openbmc_project.Control.Boot.Mode
> >     - Interface: xyz.openbmc_project.Control.Boot.Type
> >     - Interface: xyz.openbmc_project.Object.Enable
> > ```
> > It works this way:
> > - when `xyz.openbmc_project.Object.Enable` property under
> > `/xyz/openbmc_project/control/host0/boot/one_time` is set to `true` we
> > use Boot.Source/Mode/Type under
> > `/xyz/openbmc_project/control/host0/boot/one_time` for the override
> > feature.
> > - when `xyz.openbmc_project.Object.Enable` property under
> > `/xyz/openbmc_project/control/host0/boot/one_time` is set to `false`
> > we use Boot.Source/Mode/Type under
> > `/xyz/openbmc_project/control/host0/boot` for the override feature.
> >
> > I don't really get why we split Override Source to `Boot.Source` and
> > `Boot.Mode`, but this is the question for another time.
> >
> > Right now I want to discuss the main problem with this approach... it
> > is that OVERRIDE IS ALWAYS ENABLED. This
> > `xyz.openbmc_project.Object.Enable` property only indicates if we
> > should use permanent or one-time override.
> >
> > I guess no one have noticed it since but by default override target
> > (`Boot.Source`) is set to something like "None". So no one have
> > experienced any difficulties. Override is enabled, but it says boot
> > default.
> >
> > Proof that IPMI valid flag is always enabled:
> > ```uint1_t validFlag = 1;```
> > https://github.com/openbmc/phosphor-host-ipmid/blob/e76a61a2f7c19ed07e2bfe98533d82bc23692fc1/chassishandler.cpp#L1861
> >
> > `bmcweb` deals with this issue a little bit different (hello
> > inconsistency!), it performs weird logic to decide if it should set
> > `BootSourceOverrideEnabled` to `Disabled`.
> > https://github.com/openbmc/bmcweb/blob/master/redfish-core/lib/systems.hpp#L951
> > Which would get even weirder when support for EFI/Legacy selector
> > would be merged:
> > https://gerrit.openbmc-project.xyz/c/openbmc/bmcweb/+/40970/10/redfish-core/lib/systems.hpp#929
> >
> > So as you can see, the current approach is kinda buggy, ipmid always
> > reports override as valid, bmcweb reports override as disabled when
> > you write `BootSourceOverrideTarget = None`.
> >
> > This all is already a problem, but when we add Legacy/EFI selector
> > support, things are getting really messy.
> > ipmid can no longer always say that override is valid, since it would
> > be overriding boot either to EFI or Legacy.
> > bmcweb now can report that override is disabled only when
> > `BootSourceOverrideTarget = None` and `BootSourceOverrideMode = EFI`.
> > Weird, yeah? We write that we want override to `None/EFI`, but read
> > that override is `Disabled`. Weird and obviously wrong.
> >
> > How to overcome all of this?
> > To be honest I don't see any use in splitting Boot Override feature in
> > two Dbus objects under `/xyz/openbmc_project/control/host0/boot` and
> > `/xyz/openbmc_project/control/host0/boot/one_time`, since we don't
> > need to fallback to permanent override after one-time override.
> >
> > So I think the problem can be solved if we would have something like
> > this on Dbus to represent Boot Override feature:
> > ```
> > /xyz/openbmc_project/control/host0/boot:
> >     - Interface: xyz.openbmc_project.Control.Boot.Source
> >     - Interface: xyz.openbmc_project.Control.Boot.Mode
> >     - Interface: xyz.openbmc_project.Control.Boot.Type
> >     - Interface: xyz.openbmc_project.Control.Boot.Permanent # true/false
> >     - Interface: xyz.openbmc_project.Object.Enable
> > ```
> > I don't know if we can reuse any of the current interfaces for the
> > `xyz.openbmc_project.Control.Boot.Permanent` feature, but I think
> > something like these interfaces are what we need. With
> > `Boot.Permanent` we can drop `one-time` object, and with
> > `Object.Enable` we can solve all the aforementioned problems.
>
> Sorry for the late response! I think this works. The two different
> D-Bus objects were trying to achieve the same thing (as Boot.Permanent
> true/false), but as you noted they probably both needed an
> Object.Enable interface. Boot.Permanent does seem simpler.
>
> Thanks,
> Deepak