Re: [OE-core] [RFC PATCH] uki.bbclass: add multi-profile UKI support

["Pavel Löbl" <pavel@loebl.cz>]

On Fri, Apr 03, 2026 at 08:47:17AM +0100, Paul Barker wrote:
> On Thu, 2026-04-02 at 22:25 +0200, Pavel L�bl wrote:
> > Allow generating multi-profile UKI [1]. This is quite usefull for
> > dual slot A/B deploymets with secureboot active.
> > 
> > Currently only .cmdline sections are supported. But can be easily
> > extended with others.
> > 
> > [1] https://uapi-group.org/specifications/specs/unified_kernel_image/#multi-profile-ukis
> > 
> > Signed-off-by: Pavel L�bl <pavel@loebl.cz>
> > ---
> >  meta/classes-recipe/uki.bbclass | 48 +++++++++++++++++++++++++++++----
> >  1 file changed, 43 insertions(+), 5 deletions(-)
> > 
> > diff --git a/meta/classes-recipe/uki.bbclass b/meta/classes-recipe/uki.bbclass
> > index d16f3c95561e..c2d21304c793 100644
> > --- a/meta/classes-recipe/uki.bbclass
> > +++ b/meta/classes-recipe/uki.bbclass
> > @@ -59,6 +59,17 @@
> >  #   - see efi-uki-bootdisk.wks.in how to create ESP partition which hosts systemd-boot,
> >  #     config file(s) for systemd-boot and the UKI binaries.
> >  #
> > +#   - to generate multi-profile UKI (currently only supports .cmdline section)
> > +#
> > +#     UKI_PROFILE[0] = "TITLE=Recovery boot"
> > +#     UKI_PROFILE_CMDLINE[0] = "rootwait recovery"
> > +#
> > +#     UKI_PROFILE[1] = "TITLE=Boot from slot A"
> > +#     UKI_PROFILE_CMDLINE[1] = "rootwait root=LABEL=root_a"
> > +#
> > +#     UKI_PROFILE[2] = "TITLE=Boot from slot B"
> > +#     UKI_PROFILE_CMDLINE[2] = "rootwait root=LABEL=root_b"
> > +#
> 
> Hi Pavel, thanks for the RFC.
> 
> To make things easier to debug and to follow existing conventions, I'd
> suggest:
> 
>     UKI_PROFILES = "slot_a slot_b recovery"
> 
>     UKI_PROFILES[recovery] = "TITLE=Recovery boot"
>     UKI_PROFILE_CMDLINE[recovery] = "rootwait recovery"
> 
>     UKI_PROFILES[slot_a] = "TITLE=Boot from slot A"
>     UKI_PROFILE_CMDLINE[slot_a] = "rootwait root=LABEL=root_a"
> 
>     UKI_PROFILES[slot_b] = "TITLE=Boot from slot B"
>     UKI_PROFILE_CMDLINE[slot_b] = "rootwait root=LABEL=root_b"
> 
Hi Paul,

the idea was to use the same indexes as firmware will be passing to
stub. As multi-profile UKI only supports numerical ones (actually
it's just the order in which they appear in PE32 binary).

In your example user would have to pass @0 from firmware to select
slot_a, @1 for slot_b and @2 for recovery.

I have no issues with that, just wanted to make that clear.

Regards,
Pavel
> 
> Best regards,
> 
> -- 
> Paul Barker
>