Re: efi bootmenu

Re: efi bootmenu

[Masahisa Kojima]

Hi Takahiro,

On Tue, 21 Dec 2021 at 11:47, Takahiro Akashi
<takahiro.akashi@linaro.org> wrote:
>
> On Mon, Dec 20, 2021 at 06:25:05PM +0900, Masahisa Kojima wrote:
> > Hi Heinrich, Ilias, Akashi-san,
> >
> > Ilias and I are now discussing to create efi bootmenu, almost similar
> > to UiApp in EDK2.
>
> Why not discuss this topic openly in ML?

Yes, I included U-Boot ML.(Sorry, I should include from the the beginning.)

>
> How is this feature related to Simon's bootmethod proposal?

If I correctly understand Simon's bootmethod proposal,
the difference is that efi bootmenu only targets to implement
the menu based UI to select/edit/add/delete "Boot####" and "BootOrder".

>
> > Here is some background.
> > ===
> > U-Boot's command line should be completely disabled on secure devices.
> > However since U-Boot doesn't (yet) support EFI runtime SetVariable
> > for all supported devices, disabling the command line is hard, if even possible.
> > If we provide a boot menu, with access to very limited functionality, e.g select
> > a boot option and allow users to add/edit/delete existing options,
> > we can enhance security and provide a usable alternative to the users.
> >
> > In addition, if we can add options for managing EFI keys and enabling
> > disabling secure boot, we can completely get rid of the u-boot cmd line,
> > greatly enhancing platform security
>
> Basically, it will be a good idea.
> Please keep in mind, however, that add/deleting boot options,
> [en|dis]abling secure boot or modifying secure variables should
> belong to some sort of privileged operations.
> I think that we need to have some mechanism to distinguish them
> from other menus. It might be system specific, though.
>
> > ===
> >
> > I am planning to hook the existing "bootefi bootmgr" boot process.
> > In "bootefi bootmgr", the planned process will be as follows.
> >  1) check "BootNext"
>
> What do you mean by "check"?

I meant the existing bootmgr implementation. If "BootNext" is
specified, system boots with "BootNext".

>
> >  2) show efi bootmenu (*NEW*)
> >  3) if user quits efi bootmenu, then boot in accordance with "BootOrder"
> > It means efi bootmenu is native u-boot program.
> >
> > I would like to hear your opinion how this efi bootmenu should be implemented.
> > Is it better to implement as EFI application?
>
> In my personal opinion, we should implement the feature as a separate
> EFI application. One of benefits of UEFI interfaces are the ability
> to expand functionality with driver modules and applications without
> modifying the core.
> (One example is iPXE boot that Heinrich often picks up in his comments.)
>
> If it is an EFI application, it can be easily replaced with others
> per system and we may be able to use secure boot to authorise the app
> itself.

Thank you, I understand the benefit of implementing as EFI App.

>
> But implementing it as an EFI app is not the goal, and I think you can
> start with what you want to do first.
>
> > Note that  I tried to run edk2 UiApp on U-Boot, I found that the
> > following protocol
> > are required and assertion occurs in DEBUG build.
> >   gEfiHiiConfigRoutingProtocolGuid
> >   gEfiHiiFontProtocolGuid
> >   gEfiHiiImageProtocolGuid
> > Probably these protocols can be implemented as dummy stub.
> > If I run UiApp in RELEASE build,  I encounter exception on UiApp,
> > I have not debugged it.
>
> I didn't investigate this failure in details before, but it might be
> related to a (bogus) device path installed into the efi image which
> is to be loaded into and invoked from the main memory.
>
> -Takahiro Akashi
>
> > Regards,
> > Masahisa Kojima

Thanks,
Masahisa Kojima

Re: efi bootmenu

[Simon Glass]

Hi Masahisa,

On Tue, 21 Dec 2021 at 00:37, Masahisa Kojima
<masahisa.kojima@linaro.org> wrote:
>
> Hi Takahiro,
>
> On Tue, 21 Dec 2021 at 11:47, Takahiro Akashi
> <takahiro.akashi@linaro.org> wrote:
> >
> > On Mon, Dec 20, 2021 at 06:25:05PM +0900, Masahisa Kojima wrote:
> > > Hi Heinrich, Ilias, Akashi-san,
> > >
> > > Ilias and I are now discussing to create efi bootmenu, almost similar
> > > to UiApp in EDK2.
> >
> > Why not discuss this topic openly in ML?
>
> Yes, I included U-Boot ML.(Sorry, I should include from the the beginning.)
>
> >
> > How is this feature related to Simon's bootmethod proposal?
>
> If I correctly understand Simon's bootmethod proposal,
> the difference is that efi bootmenu only targets to implement
> the menu based UI to select/edit/add/delete "Boot####" and "BootOrder".

Yes, EFI would be one of the bootmethods. Others would be U-Boot
scripts, Chrome OS, Android, etc. plus people might add custom ones.

Also I am thinking that (perhaps) the bootdev part of the standard
boot thing could be used to provide boot devices for EFI.

If we do have a bootmenu, I wonder if it could be generic, instead of
tied to EFI?

Regards,
Simon


>
> >
> > > Here is some background.
> > > ===
> > > U-Boot's command line should be completely disabled on secure devices.
> > > However since U-Boot doesn't (yet) support EFI runtime SetVariable
> > > for all supported devices, disabling the command line is hard, if even possible.
> > > If we provide a boot menu, with access to very limited functionality, e.g select
> > > a boot option and allow users to add/edit/delete existing options,
> > > we can enhance security and provide a usable alternative to the users.
> > >
> > > In addition, if we can add options for managing EFI keys and enabling
> > > disabling secure boot, we can completely get rid of the u-boot cmd line,
> > > greatly enhancing platform security
> >
> > Basically, it will be a good idea.
> > Please keep in mind, however, that add/deleting boot options,
> > [en|dis]abling secure boot or modifying secure variables should
> > belong to some sort of privileged operations.
> > I think that we need to have some mechanism to distinguish them
> > from other menus. It might be system specific, though.
> >
> > > ===
> > >
> > > I am planning to hook the existing "bootefi bootmgr" boot process.
> > > In "bootefi bootmgr", the planned process will be as follows.
> > >  1) check "BootNext"
> >
> > What do you mean by "check"?
>
> I meant the existing bootmgr implementation. If "BootNext" is
> specified, system boots with "BootNext".
>
> >
> > >  2) show efi bootmenu (*NEW*)
> > >  3) if user quits efi bootmenu, then boot in accordance with "BootOrder"
> > > It means efi bootmenu is native u-boot program.
> > >
> > > I would like to hear your opinion how this efi bootmenu should be implemented.
> > > Is it better to implement as EFI application?
> >
> > In my personal opinion, we should implement the feature as a separate
> > EFI application. One of benefits of UEFI interfaces are the ability
> > to expand functionality with driver modules and applications without
> > modifying the core.
> > (One example is iPXE boot that Heinrich often picks up in his comments.)
> >
> > If it is an EFI application, it can be easily replaced with others
> > per system and we may be able to use secure boot to authorise the app
> > itself.
>
> Thank you, I understand the benefit of implementing as EFI App.
>
> >
> > But implementing it as an EFI app is not the goal, and I think you can
> > start with what you want to do first.
> >
> > > Note that  I tried to run edk2 UiApp on U-Boot, I found that the
> > > following protocol
> > > are required and assertion occurs in DEBUG build.
> > >   gEfiHiiConfigRoutingProtocolGuid
> > >   gEfiHiiFontProtocolGuid
> > >   gEfiHiiImageProtocolGuid
> > > Probably these protocols can be implemented as dummy stub.
> > > If I run UiApp in RELEASE build,  I encounter exception on UiApp,
> > > I have not debugged it.
> >
> > I didn't investigate this failure in details before, but it might be
> > related to a (bogus) device path installed into the efi image which
> > is to be loaded into and invoked from the main memory.
> >
> > -Takahiro Akashi
> >
> > > Regards,
> > > Masahisa Kojima
>
> Thanks,
> Masahisa Kojima

Re: efi bootmenu

[François Ozog]

Le mar. 28 déc. 2021 à 09:32, Simon Glass <sjg@chromium.org> a écrit :

> Hi Masahisa,
>
> On Tue, 21 Dec 2021 at 00:37, Masahisa Kojima
> <masahisa.kojima@linaro.org> wrote:
> >
> > Hi Takahiro,
> >
> > On Tue, 21 Dec 2021 at 11:47, Takahiro Akashi
> > <takahiro.akashi@linaro.org> wrote:
> > >
> > > On Mon, Dec 20, 2021 at 06:25:05PM +0900, Masahisa Kojima wrote:
> > > > Hi Heinrich, Ilias, Akashi-san,
> > > >
> > > > Ilias and I are now discussing to create efi bootmenu, almost similar
> > > > to UiApp in EDK2.
> > >
> > > Why not discuss this topic openly in ML?
> >
> > Yes, I included U-Boot ML.(Sorry, I should include from the the
> beginning.)
> >
> > >
> > > How is this feature related to Simon's bootmethod proposal?
> >
> > If I correctly understand Simon's bootmethod proposal,
> > the difference is that efi bootmenu only targets to implement
> > the menu based UI to select/edit/add/delete "Boot####" and "BootOrder".
>
> Yes, EFI would be one of the bootmethods. Others would be U-Boot
> scripts, Chrome OS, Android, etc. plus people might add custom ones.
>
> Also I am thinking that (perhaps) the bootdev part of the standard
> boot thing could be used to provide boot devices for EFI.
>
> If we do have a bootmenu, I wonder if it could be generic, instead of
> tied to EFI?

EFI BootXXXX specify an array of device paths and boot options. A device
path is quite a unique construct despite its name.
A device path is itself an array of elements, some elements can be a file
path , configuration information, or diverse metadata. An example of
configuration information element is UART baud,stop bits, parity along with
terminal (vt100, ansi…). Another device path element can cover IP address,
transport information (tcp, UDP and port number).
The traditional EFI boot menu is quite crude and does not expose the full
capabilities of BootXXXX (lacks edit of boot options for instance!).

In the long run we will need to leverage all the BootXXXX capabilities and
those are EFI specific while being OS agnostic.
The other U-Boot boot methods (Android , ChromeOS…) are OS specific.
The goals are thus very different and making a generic approach seems quite
compromised. If there is a fully generic framework available in the future,
it may be possible to integrate the EFI boot menu. But at least there is a
need to solve, code first, the EFI complexities to fuel the generic
architecture discussion.

>
>
> Regards,
> Simon
>
>
> >
> > >
> > > > Here is some background.
> > > > ===
> > > > U-Boot's command line should be completely disabled on secure
> devices.
> > > > However since U-Boot doesn't (yet) support EFI runtime SetVariable
> > > > for all supported devices, disabling the command line is hard, if
> even possible.
> > > > If we provide a boot menu, with access to very limited
> functionality, e.g select
> > > > a boot option and allow users to add/edit/delete existing options,
> > > > we can enhance security and provide a usable alternative to the
> users.
> > > >
> > > > In addition, if we can add options for managing EFI keys and enabling
> > > > disabling secure boot, we can completely get rid of the u-boot cmd
> line,
> > > > greatly enhancing platform security
> > >
> > > Basically, it will be a good idea.
> > > Please keep in mind, however, that add/deleting boot options,
> > > [en|dis]abling secure boot or modifying secure variables should
> > > belong to some sort of privileged operations.
> > > I think that we need to have some mechanism to distinguish them
> > > from other menus. It might be system specific, though.
> > >
> > > > ===
> > > >
> > > > I am planning to hook the existing "bootefi bootmgr" boot process.
> > > > In "bootefi bootmgr", the planned process will be as follows.
> > > >  1) check "BootNext"
> > >
> > > What do you mean by "check"?
> >
> > I meant the existing bootmgr implementation. If "BootNext" is
> > specified, system boots with "BootNext".
> >
> > >
> > > >  2) show efi bootmenu (*NEW*)
> > > >  3) if user quits efi bootmenu, then boot in accordance with
> "BootOrder"
> > > > It means efi bootmenu is native u-boot program.
> > > >
> > > > I would like to hear your opinion how this efi bootmenu should be
> implemented.
> > > > Is it better to implement as EFI application?
> > >
> > > In my personal opinion, we should implement the feature as a separate
> > > EFI application. One of benefits of UEFI interfaces are the ability
> > > to expand functionality with driver modules and applications without
> > > modifying the core.
> > > (One example is iPXE boot that Heinrich often picks up in his
> comments.)
> > >
> > > If it is an EFI application, it can be easily replaced with others
> > > per system and we may be able to use secure boot to authorise the app
> > > itself.
> >
> > Thank you, I understand the benefit of implementing as EFI App.
> >
> > >
> > > But implementing it as an EFI app is not the goal, and I think you can
> > > start with what you want to do first.
> > >
> > > > Note that  I tried to run edk2 UiApp on U-Boot, I found that the
> > > > following protocol
> > > > are required and assertion occurs in DEBUG build.
> > > >   gEfiHiiConfigRoutingProtocolGuid
> > > >   gEfiHiiFontProtocolGuid
> > > >   gEfiHiiImageProtocolGuid
> > > > Probably these protocols can be implemented as dummy stub.
> > > > If I run UiApp in RELEASE build,  I encounter exception on UiApp,
> > > > I have not debugged it.
> > >
> > > I didn't investigate this failure in details before, but it might be
> > > related to a (bogus) device path installed into the efi image which
> > > is to be loaded into and invoked from the main memory.
> > >
> > > -Takahiro Akashi
> > >
> > > > Regards,
> > > > Masahisa Kojima
> >
> > Thanks,
> > Masahisa Kojima
>
-- 
François-Frédéric Ozog | *Director Business Development*
T: +33.67221.6485
francois.ozog@linaro.org | Skype: ffozog

Re: efi bootmenu

[Simon Glass]

Hi François,

On Tue, 28 Dec 2021 at 03:15, François Ozog <francois.ozog@linaro.org> wrote:
>
>
>
> Le mar. 28 déc. 2021 à 09:32, Simon Glass <sjg@chromium.org> a écrit :
>>
>> Hi Masahisa,
>>
>> On Tue, 21 Dec 2021 at 00:37, Masahisa Kojima
>> <masahisa.kojima@linaro.org> wrote:
>> >
>> > Hi Takahiro,
>> >
>> > On Tue, 21 Dec 2021 at 11:47, Takahiro Akashi
>> > <takahiro.akashi@linaro.org> wrote:
>> > >
>> > > On Mon, Dec 20, 2021 at 06:25:05PM +0900, Masahisa Kojima wrote:
>> > > > Hi Heinrich, Ilias, Akashi-san,
>> > > >
>> > > > Ilias and I are now discussing to create efi bootmenu, almost similar
>> > > > to UiApp in EDK2.
>> > >
>> > > Why not discuss this topic openly in ML?
>> >
>> > Yes, I included U-Boot ML.(Sorry, I should include from the the beginning.)
>> >
>> > >
>> > > How is this feature related to Simon's bootmethod proposal?
>> >
>> > If I correctly understand Simon's bootmethod proposal,
>> > the difference is that efi bootmenu only targets to implement
>> > the menu based UI to select/edit/add/delete "Boot####" and "BootOrder".
>>
>> Yes, EFI would be one of the bootmethods. Others would be U-Boot
>> scripts, Chrome OS, Android, etc. plus people might add custom ones.
>>
>> Also I am thinking that (perhaps) the bootdev part of the standard
>> boot thing could be used to provide boot devices for EFI.
>>
>> If we do have a bootmenu, I wonder if it could be generic, instead of
>> tied to EFI?
>
> EFI BootXXXX specify an array of device paths and boot options. A device path is quite a unique construct despite its name.
> A device path is itself an array of elements, some elements can be a file path , configuration information, or diverse metadata. An example of configuration information element is UART baud,stop bits, parity along with terminal (vt100, ansi…). Another device path element can cover IP address, transport information (tcp, UDP and port number).
> The traditional EFI boot menu is quite crude and does not expose the full capabilities of BootXXXX (lacks edit of boot options for instance!).
>
> In the long run we will need to leverage all the BootXXXX capabilities and those are EFI specific while being OS agnostic.
> The other U-Boot boot methods (Android , ChromeOS…) are OS specific.
> The goals are thus very different and making a generic approach seems quite compromised. If there is a fully generic framework available in the future, it may be possible to integrate the EFI boot menu. But at least there is a need to solve, code first, the EFI complexities to fuel the generic architecture discussion.

Despite this, the goal of standard boot is to encompass all of this
within U-Boot. I believe that it will be successful, even if the path
at present is a bit unclear.

[..]

Regards,
Simon

Re: efi bootmenu

[François Ozog]

HI Simon

On Wed, 29 Dec 2021 at 14:36, Simon Glass <sjg@chromium.org> wrote:

> Hi François,
>
> On Tue, 28 Dec 2021 at 03:15, François Ozog <francois.ozog@linaro.org>
> wrote:
> >
> >
> >
> > Le mar. 28 déc. 2021 à 09:32, Simon Glass <sjg@chromium.org> a écrit :
> >>
> >> Hi Masahisa,
> >>
> >> On Tue, 21 Dec 2021 at 00:37, Masahisa Kojima
> >> <masahisa.kojima@linaro.org> wrote:
> >> >
> >> > Hi Takahiro,
> >> >
> >> > On Tue, 21 Dec 2021 at 11:47, Takahiro Akashi
> >> > <takahiro.akashi@linaro.org> wrote:
> >> > >
> >> > > On Mon, Dec 20, 2021 at 06:25:05PM +0900, Masahisa Kojima wrote:
> >> > > > Hi Heinrich, Ilias, Akashi-san,
> >> > > >
> >> > > > Ilias and I are now discussing to create efi bootmenu, almost
> similar
> >> > > > to UiApp in EDK2.
> >> > >
> >> > > Why not discuss this topic openly in ML?
> >> >
> >> > Yes, I included U-Boot ML.(Sorry, I should include from the the
> beginning.)
> >> >
> >> > >
> >> > > How is this feature related to Simon's bootmethod proposal?
> >> >
> >> > If I correctly understand Simon's bootmethod proposal,
> >> > the difference is that efi bootmenu only targets to implement
> >> > the menu based UI to select/edit/add/delete "Boot####" and
> "BootOrder".
> >>
> >> Yes, EFI would be one of the bootmethods. Others would be U-Boot
> >> scripts, Chrome OS, Android, etc. plus people might add custom ones.
> >>
> >> Also I am thinking that (perhaps) the bootdev part of the standard
> >> boot thing could be used to provide boot devices for EFI.
> >>
> >> If we do have a bootmenu, I wonder if it could be generic, instead of
> >> tied to EFI?
> >
> > EFI BootXXXX specify an array of device paths and boot options. A device
> path is quite a unique construct despite its name.
> > A device path is itself an array of elements, some elements can be a
> file path , configuration information, or diverse metadata. An example of
> configuration information element is UART baud,stop bits, parity along with
> terminal (vt100, ansi…). Another device path element can cover IP address,
> transport information (tcp, UDP and port number).
> > The traditional EFI boot menu is quite crude and does not expose the
> full capabilities of BootXXXX (lacks edit of boot options for instance!).
> >
> > In the long run we will need to leverage all the BootXXXX capabilities
> and those are EFI specific while being OS agnostic.
> > The other U-Boot boot methods (Android , ChromeOS…) are OS specific.
> > The goals are thus very different and making a generic approach seems
> quite compromised. If there is a fully generic framework available in the
> future, it may be possible to integrate the EFI boot menu. But at least
> there is a need to solve, code first, the EFI complexities to fuel the
> generic architecture discussion.
>
> Despite this, the goal of standard boot is to encompass all of this
> within U-Boot. I believe that it will be successful, even if the path
> at present is a bit unclear.
>
So I would suggest we work bottom up. Starting by making EFI menu work,
then extend it more generic or integrated it in a framework. Starting top
down would require a long architecture process based on not enough known
problems to solve for each environment.

>
> [..]
>
> Regards,
> Simon
>


-- 
François-Frédéric Ozog | *Director Business Development*
T: +33.67221.6485
francois.ozog@linaro.org | Skype: ffozog

Re: efi bootmenu

[Mark Kettenis]

> From: François Ozog <francois.ozog@linaro.org>
> Date: Wed, 29 Dec 2021 14:39:36 +0100
> 
> HI Simon
> 
> On Wed, 29 Dec 2021 at 14:36, Simon Glass <sjg@chromium.org> wrote:
> 
> > Hi François,
> >
> > On Tue, 28 Dec 2021 at 03:15, François Ozog <francois.ozog@linaro.org>
> > wrote:
> > >
> > >
> > >
> > > Le mar. 28 déc. 2021 à 09:32, Simon Glass <sjg@chromium.org> a écrit :
> > >>
> > >> Hi Masahisa,
> > >>
> > >> On Tue, 21 Dec 2021 at 00:37, Masahisa Kojima
> > >> <masahisa.kojima@linaro.org> wrote:
> > >> >
> > >> > Hi Takahiro,
> > >> >
> > >> > On Tue, 21 Dec 2021 at 11:47, Takahiro Akashi
> > >> > <takahiro.akashi@linaro.org> wrote:
> > >> > >
> > >> > > On Mon, Dec 20, 2021 at 06:25:05PM +0900, Masahisa Kojima wrote:
> > >> > > > Hi Heinrich, Ilias, Akashi-san,
> > >> > > >
> > >> > > > Ilias and I are now discussing to create efi bootmenu, almost
> > similar
> > >> > > > to UiApp in EDK2.
> > >> > >
> > >> > > Why not discuss this topic openly in ML?
> > >> >
> > >> > Yes, I included U-Boot ML.(Sorry, I should include from the the
> > beginning.)
> > >> >
> > >> > >
> > >> > > How is this feature related to Simon's bootmethod proposal?
> > >> >
> > >> > If I correctly understand Simon's bootmethod proposal,
> > >> > the difference is that efi bootmenu only targets to implement
> > >> > the menu based UI to select/edit/add/delete "Boot####" and
> > "BootOrder".
> > >>
> > >> Yes, EFI would be one of the bootmethods. Others would be U-Boot
> > >> scripts, Chrome OS, Android, etc. plus people might add custom ones.
> > >>
> > >> Also I am thinking that (perhaps) the bootdev part of the standard
> > >> boot thing could be used to provide boot devices for EFI.
> > >>
> > >> If we do have a bootmenu, I wonder if it could be generic, instead of
> > >> tied to EFI?
> > >
> > > EFI BootXXXX specify an array of device paths and boot options. A device
> > path is quite a unique construct despite its name.
> > > A device path is itself an array of elements, some elements can be a
> > file path , configuration information, or diverse metadata. An example of
> > configuration information element is UART baud,stop bits, parity along with
> > terminal (vt100, ansi…). Another device path element can cover IP address,
> > transport information (tcp, UDP and port number).
> > > The traditional EFI boot menu is quite crude and does not expose the
> > full capabilities of BootXXXX (lacks edit of boot options for instance!).
> > >
> > > In the long run we will need to leverage all the BootXXXX capabilities
> > and those are EFI specific while being OS agnostic.
> > > The other U-Boot boot methods (Android , ChromeOS…) are OS specific.
> > > The goals are thus very different and making a generic approach seems
> > quite compromised. If there is a fully generic framework available in the
> > future, it may be possible to integrate the EFI boot menu. But at least
> > there is a need to solve, code first, the EFI complexities to fuel the
> > generic architecture discussion.
> >
> > Despite this, the goal of standard boot is to encompass all of this
> > within U-Boot. I believe that it will be successful, even if the path
> > at present is a bit unclear.
> >
> So I would suggest we work bottom up. Starting by making EFI menu work,
> then extend it more generic or integrated it in a framework. Starting top
> down would require a long architecture process based on not enough known
> problems to solve for each environment.
> 

Well, whatever you do, please build something that works well with a
serial console.  EDK2 makes assumptions the terminal emulation on the
other side, insists on changing the colors to white on black and
relies on function keys that need escape sequences.  And escape
sequences over serial are always iffy since they depend on timing for
their interpretation.  You can do better for U-Boot.

Also, keep in mind that BootOrder and Boot#### only really work if
there is runtime EFI variable support.  So the boot menu should
include options to select a device to boot from and use the default
(removable media) bootloader from the ESP on that device.  And a way
to make this selection stick!  Pretty much all x86 EFI implementations
provide functionality like that.  I suppose this could be done by
populating the EFI variable store with appropriate Boot#### variables
and manipulating BootOrder.  But that would make it hard to generalize
the boot menu to non-EFI boot flows.

Re: efi bootmenu

[Heinrich Schuchardt]

On 12/29/21 17:04, Mark Kettenis wrote:
>> From: François Ozog <francois.ozog@linaro.org>
>> Date: Wed, 29 Dec 2021 14:39:36 +0100
>>
>> HI Simon
>>
>> On Wed, 29 Dec 2021 at 14:36, Simon Glass <sjg@chromium.org> wrote:
>>
>>> Hi François,
>>>
>>> On Tue, 28 Dec 2021 at 03:15, François Ozog <francois.ozog@linaro.org>
>>> wrote:
>>>>
>>>>
>>>>
>>>> Le mar. 28 déc. 2021 à 09:32, Simon Glass <sjg@chromium.org> a écrit :
>>>>>
>>>>> Hi Masahisa,
>>>>>
>>>>> On Tue, 21 Dec 2021 at 00:37, Masahisa Kojima
>>>>> <masahisa.kojima@linaro.org> wrote:
>>>>>>
>>>>>> Hi Takahiro,
>>>>>>
>>>>>> On Tue, 21 Dec 2021 at 11:47, Takahiro Akashi
>>>>>> <takahiro.akashi@linaro.org> wrote:
>>>>>>>
>>>>>>> On Mon, Dec 20, 2021 at 06:25:05PM +0900, Masahisa Kojima wrote:
>>>>>>>> Hi Heinrich, Ilias, Akashi-san,
>>>>>>>>
>>>>>>>> Ilias and I are now discussing to create efi bootmenu, almost
>>> similar
>>>>>>>> to UiApp in EDK2.
>>>>>>>
>>>>>>> Why not discuss this topic openly in ML?
>>>>>>
>>>>>> Yes, I included U-Boot ML.(Sorry, I should include from the the
>>> beginning.)
>>>>>>
>>>>>>>
>>>>>>> How is this feature related to Simon's bootmethod proposal?
>>>>>>
>>>>>> If I correctly understand Simon's bootmethod proposal,
>>>>>> the difference is that efi bootmenu only targets to implement
>>>>>> the menu based UI to select/edit/add/delete "Boot####" and
>>> "BootOrder".
>>>>>
>>>>> Yes, EFI would be one of the bootmethods. Others would be U-Boot
>>>>> scripts, Chrome OS, Android, etc. plus people might add custom ones.
>>>>>
>>>>> Also I am thinking that (perhaps) the bootdev part of the standard
>>>>> boot thing could be used to provide boot devices for EFI.
>>>>>
>>>>> If we do have a bootmenu, I wonder if it could be generic, instead of
>>>>> tied to EFI?
>>>>
>>>> EFI BootXXXX specify an array of device paths and boot options. A device
>>> path is quite a unique construct despite its name.
>>>> A device path is itself an array of elements, some elements can be a
>>> file path , configuration information, or diverse metadata. An example of
>>> configuration information element is UART baud,stop bits, parity along with
>>> terminal (vt100, ansi…). Another device path element can cover IP address,
>>> transport information (tcp, UDP and port number).
>>>> The traditional EFI boot menu is quite crude and does not expose the
>>> full capabilities of BootXXXX (lacks edit of boot options for instance!).
>>>>
>>>> In the long run we will need to leverage all the BootXXXX capabilities
>>> and those are EFI specific while being OS agnostic.
>>>> The other U-Boot boot methods (Android , ChromeOS…) are OS specific.
>>>> The goals are thus very different and making a generic approach seems
>>> quite compromised. If there is a fully generic framework available in the
>>> future, it may be possible to integrate the EFI boot menu. But at least
>>> there is a need to solve, code first, the EFI complexities to fuel the
>>> generic architecture discussion.
>>>
>>> Despite this, the goal of standard boot is to encompass all of this
>>> within U-Boot. I believe that it will be successful, even if the path
>>> at present is a bit unclear.
>>>
>> So I would suggest we work bottom up. Starting by making EFI menu work,
>> then extend it more generic or integrated it in a framework. Starting top
>> down would require a long architecture process based on not enough known
>> problems to solve for each environment.
>>
>
> Well, whatever you do, please build something that works well with a
> serial console.  EDK2 makes assumptions the terminal emulation on the
> other side, insists on changing the colors to white on black and
> relies on function keys that need escape sequences.  And escape
> sequences over serial are always iffy since they depend on timing for
> their interpretation.  You can do better for U-Boot.

We already use escape sequences for the U-Boot console and you can't
avoid them for navigation keys. What operating system are you using that
that does not provide a serial terminal emulation which understands ECMA-48?

> Also, keep in mind that BootOrder and Boot#### only really work if
> there is runtime EFI variable support.  So the boot menu should
> include options to select a device to boot from and use the default
> (removable media) bootloader from the ESP on that device.  And a way
> to make this selection stick!  Pretty much all x86 EFI implementations
> provide functionality like that.  I suppose this could be done by
> populating the EFI variable store with appropriate Boot#### variables
> and manipulating BootOrder.  But that would make it hard to generalize
> the boot menu to non-EFI boot flows.

We are talking here about an EFI boot menu. Why do you mention non-EFI?

Best regards

Heinrich

Re: efi bootmenu

[AKASHI Takahiro]

On Wed, Dec 29, 2021 at 05:04:17PM +0100, Mark Kettenis wrote:
> > From: François Ozog <francois.ozog@linaro.org>
> > Date: Wed, 29 Dec 2021 14:39:36 +0100
> > 
> > HI Simon
> > 
> > On Wed, 29 Dec 2021 at 14:36, Simon Glass <sjg@chromium.org> wrote:
> > 
> > > Hi François,
> > >
> > > On Tue, 28 Dec 2021 at 03:15, François Ozog <francois.ozog@linaro.org>
> > > wrote:
> > > >
> > > >
> > > >
> > > > Le mar. 28 déc. 2021 à 09:32, Simon Glass <sjg@chromium.org> a écrit :
> > > >>
> > > >> Hi Masahisa,
> > > >>
> > > >> On Tue, 21 Dec 2021 at 00:37, Masahisa Kojima
> > > >> <masahisa.kojima@linaro.org> wrote:
> > > >> >
> > > >> > Hi Takahiro,
> > > >> >
> > > >> > On Tue, 21 Dec 2021 at 11:47, Takahiro Akashi
> > > >> > <takahiro.akashi@linaro.org> wrote:
> > > >> > >
> > > >> > > On Mon, Dec 20, 2021 at 06:25:05PM +0900, Masahisa Kojima wrote:
> > > >> > > > Hi Heinrich, Ilias, Akashi-san,
> > > >> > > >
> > > >> > > > Ilias and I are now discussing to create efi bootmenu, almost
> > > similar
> > > >> > > > to UiApp in EDK2.
> > > >> > >
> > > >> > > Why not discuss this topic openly in ML?
> > > >> >
> > > >> > Yes, I included U-Boot ML.(Sorry, I should include from the the
> > > beginning.)
> > > >> >
> > > >> > >
> > > >> > > How is this feature related to Simon's bootmethod proposal?
> > > >> >
> > > >> > If I correctly understand Simon's bootmethod proposal,
> > > >> > the difference is that efi bootmenu only targets to implement
> > > >> > the menu based UI to select/edit/add/delete "Boot####" and
> > > "BootOrder".
> > > >>
> > > >> Yes, EFI would be one of the bootmethods. Others would be U-Boot
> > > >> scripts, Chrome OS, Android, etc. plus people might add custom ones.
> > > >>
> > > >> Also I am thinking that (perhaps) the bootdev part of the standard
> > > >> boot thing could be used to provide boot devices for EFI.
> > > >>
> > > >> If we do have a bootmenu, I wonder if it could be generic, instead of
> > > >> tied to EFI?
> > > >
> > > > EFI BootXXXX specify an array of device paths and boot options. A device
> > > path is quite a unique construct despite its name.
> > > > A device path is itself an array of elements, some elements can be a
> > > file path , configuration information, or diverse metadata. An example of
> > > configuration information element is UART baud,stop bits, parity along with
> > > terminal (vt100, ansi…). Another device path element can cover IP address,
> > > transport information (tcp, UDP and port number).
> > > > The traditional EFI boot menu is quite crude and does not expose the
> > > full capabilities of BootXXXX (lacks edit of boot options for instance!).
> > > >
> > > > In the long run we will need to leverage all the BootXXXX capabilities
> > > and those are EFI specific while being OS agnostic.
> > > > The other U-Boot boot methods (Android , ChromeOS…) are OS specific.
> > > > The goals are thus very different and making a generic approach seems
> > > quite compromised. If there is a fully generic framework available in the
> > > future, it may be possible to integrate the EFI boot menu. But at least
> > > there is a need to solve, code first, the EFI complexities to fuel the
> > > generic architecture discussion.
> > >
> > > Despite this, the goal of standard boot is to encompass all of this
> > > within U-Boot. I believe that it will be successful, even if the path
> > > at present is a bit unclear.
> > >
> > So I would suggest we work bottom up. Starting by making EFI menu work,
> > then extend it more generic or integrated it in a framework. Starting top
> > down would require a long architecture process based on not enough known
> > problems to solve for each environment.
> > 
> 
> Well, whatever you do, please build something that works well with a
> serial console.  EDK2 makes assumptions the terminal emulation on the
> other side, insists on changing the colors to white on black and
> relies on function keys that need escape sequences.  And escape
> sequences over serial are always iffy since they depend on timing for
> their interpretation.  You can do better for U-Boot.
> 
> Also, keep in mind that BootOrder and Boot#### only really work if
> there is runtime EFI variable support.  So the boot menu should
> include options to select a device to boot from and use the default
> (removable media) bootloader from the ESP on that device.

I think that this issue can/should be addressed in a separate patch
although I have had no progress on my patch[1].

-Takahiro Akashi

[1] https://lists.denx.de/pipermail/u-boot/2021-November/466583.html

> And a way
> to make this selection stick!  Pretty much all x86 EFI implementations
> provide functionality like that.  I suppose this could be done by
> populating the EFI variable store with appropriate Boot#### variables
> and manipulating BootOrder.  But that would make it hard to generalize
> the boot menu to non-EFI boot flows.

Re: efi bootmenu

[Masahisa Kojima]

On Thu, 6 Jan 2022 at 12:02, AKASHI Takahiro <takahiro.akashi@linaro.org> wrote:
>
> On Wed, Dec 29, 2021 at 05:04:17PM +0100, Mark Kettenis wrote:
> > > From: François Ozog <francois.ozog@linaro.org>
> > > Date: Wed, 29 Dec 2021 14:39:36 +0100
> > >
> > > HI Simon
> > >
> > > On Wed, 29 Dec 2021 at 14:36, Simon Glass <sjg@chromium.org> wrote:
> > >
> > > > Hi François,
> > > >
> > > > On Tue, 28 Dec 2021 at 03:15, François Ozog <francois.ozog@linaro.org>
> > > > wrote:
> > > > >
> > > > >
> > > > >
> > > > > Le mar. 28 déc. 2021 à 09:32, Simon Glass <sjg@chromium.org> a écrit :
> > > > >>
> > > > >> Hi Masahisa,
> > > > >>
> > > > >> On Tue, 21 Dec 2021 at 00:37, Masahisa Kojima
> > > > >> <masahisa.kojima@linaro.org> wrote:
> > > > >> >
> > > > >> > Hi Takahiro,
> > > > >> >
> > > > >> > On Tue, 21 Dec 2021 at 11:47, Takahiro Akashi
> > > > >> > <takahiro.akashi@linaro.org> wrote:
> > > > >> > >
> > > > >> > > On Mon, Dec 20, 2021 at 06:25:05PM +0900, Masahisa Kojima wrote:
> > > > >> > > > Hi Heinrich, Ilias, Akashi-san,
> > > > >> > > >
> > > > >> > > > Ilias and I are now discussing to create efi bootmenu, almost
> > > > similar
> > > > >> > > > to UiApp in EDK2.
> > > > >> > >
> > > > >> > > Why not discuss this topic openly in ML?
> > > > >> >
> > > > >> > Yes, I included U-Boot ML.(Sorry, I should include from the the
> > > > beginning.)
> > > > >> >
> > > > >> > >
> > > > >> > > How is this feature related to Simon's bootmethod proposal?
> > > > >> >
> > > > >> > If I correctly understand Simon's bootmethod proposal,
> > > > >> > the difference is that efi bootmenu only targets to implement
> > > > >> > the menu based UI to select/edit/add/delete "Boot####" and
> > > > "BootOrder".
> > > > >>
> > > > >> Yes, EFI would be one of the bootmethods. Others would be U-Boot
> > > > >> scripts, Chrome OS, Android, etc. plus people might add custom ones.
> > > > >>
> > > > >> Also I am thinking that (perhaps) the bootdev part of the standard
> > > > >> boot thing could be used to provide boot devices for EFI.
> > > > >>
> > > > >> If we do have a bootmenu, I wonder if it could be generic, instead of
> > > > >> tied to EFI?
> > > > >
> > > > > EFI BootXXXX specify an array of device paths and boot options. A device
> > > > path is quite a unique construct despite its name.
> > > > > A device path is itself an array of elements, some elements can be a
> > > > file path , configuration information, or diverse metadata. An example of
> > > > configuration information element is UART baud,stop bits, parity along with
> > > > terminal (vt100, ansi…). Another device path element can cover IP address,
> > > > transport information (tcp, UDP and port number).
> > > > > The traditional EFI boot menu is quite crude and does not expose the
> > > > full capabilities of BootXXXX (lacks edit of boot options for instance!).
> > > > >
> > > > > In the long run we will need to leverage all the BootXXXX capabilities
> > > > and those are EFI specific while being OS agnostic.
> > > > > The other U-Boot boot methods (Android , ChromeOS…) are OS specific.
> > > > > The goals are thus very different and making a generic approach seems
> > > > quite compromised. If there is a fully generic framework available in the
> > > > future, it may be possible to integrate the EFI boot menu. But at least
> > > > there is a need to solve, code first, the EFI complexities to fuel the
> > > > generic architecture discussion.
> > > >
> > > > Despite this, the goal of standard boot is to encompass all of this
> > > > within U-Boot. I believe that it will be successful, even if the path
> > > > at present is a bit unclear.
> > > >
> > > So I would suggest we work bottom up. Starting by making EFI menu work,
> > > then extend it more generic or integrated it in a framework. Starting top
> > > down would require a long architecture process based on not enough known
> > > problems to solve for each environment.
> > >
> >
> > Well, whatever you do, please build something that works well with a
> > serial console.  EDK2 makes assumptions the terminal emulation on the
> > other side, insists on changing the colors to white on black and
> > relies on function keys that need escape sequences.  And escape
> > sequences over serial are always iffy since they depend on timing for
> > their interpretation.  You can do better for U-Boot.
> >
> > Also, keep in mind that BootOrder and Boot#### only really work if
> > there is runtime EFI variable support.  So the boot menu should
> > include options to select a device to boot from and use the default
> > (removable media) bootloader from the ESP on that device.
>
> I think that this issue can/should be addressed in a separate patch
> although I have had no progress on my patch[1].
>
> -Takahiro Akashi
>
> [1] https://lists.denx.de/pipermail/u-boot/2021-November/466583.html
>
> > And a way
> > to make this selection stick!  Pretty much all x86 EFI implementations
> > provide functionality like that.  I suppose this could be done by
> > populating the EFI variable store with appropriate Boot#### variables
> > and manipulating BootOrder.  But that would make it hard to generalize
> > the boot menu to non-EFI boot flows.

Thank you very much for the comments.

As discussed here, EFI bootmenu is a start point.
The major purpose is disabling U-Boot CLI, then EFI bootmenu allows to
select to boot with boot####, and update boot####/bootorder/secure boot keys.

I plan to develop EFI bootmenu as a native U-Boot program,
then consider to migrate to the EFI app if there are concrete
use cases or needs in the future.

> Please keep in mind, however, that add/deleting boot options,
> [en|dis]abling secure boot or modifying secure variables should
> belong to some sort of privileged operations.
> I think that we need to have some mechanism to distinguish them
> from other menus. It might be system specific, though.

Probably I need to implement the password authentication to enter the
privileged operations. The password is embedded in the U-Boot config.

Regards,
Masahisa Kojima

Re: efi bootmenu

[Mark Kettenis]

> Date: Wed, 5 Jan 2022 09:52:41 +0100
> From: Heinrich Schuchardt <xypron.glpk@gmx.de>
> 
> On 12/29/21 17:04, Mark Kettenis wrote:
> >> From: François Ozog <francois.ozog@linaro.org>
> >> Date: Wed, 29 Dec 2021 14:39:36 +0100
> >>
> >> HI Simon
> >>
> >> On Wed, 29 Dec 2021 at 14:36, Simon Glass <sjg@chromium.org> wrote:
> >>
> >>> Hi François,
> >>>
> >>> On Tue, 28 Dec 2021 at 03:15, François Ozog <francois.ozog@linaro.org>
> >>> wrote:
> >>>>
> >>>>
> >>>>
> >>>> Le mar. 28 déc. 2021 à 09:32, Simon Glass <sjg@chromium.org> a écrit :
> >>>>>
> >>>>> Hi Masahisa,
> >>>>>
> >>>>> On Tue, 21 Dec 2021 at 00:37, Masahisa Kojima
> >>>>> <masahisa.kojima@linaro.org> wrote:
> >>>>>>
> >>>>>> Hi Takahiro,
> >>>>>>
> >>>>>> On Tue, 21 Dec 2021 at 11:47, Takahiro Akashi
> >>>>>> <takahiro.akashi@linaro.org> wrote:
> >>>>>>>
> >>>>>>> On Mon, Dec 20, 2021 at 06:25:05PM +0900, Masahisa Kojima wrote:
> >>>>>>>> Hi Heinrich, Ilias, Akashi-san,
> >>>>>>>>
> >>>>>>>> Ilias and I are now discussing to create efi bootmenu, almost
> >>> similar
> >>>>>>>> to UiApp in EDK2.
> >>>>>>>
> >>>>>>> Why not discuss this topic openly in ML?
> >>>>>>
> >>>>>> Yes, I included U-Boot ML.(Sorry, I should include from the the
> >>> beginning.)
> >>>>>>
> >>>>>>>
> >>>>>>> How is this feature related to Simon's bootmethod proposal?
> >>>>>>
> >>>>>> If I correctly understand Simon's bootmethod proposal,
> >>>>>> the difference is that efi bootmenu only targets to implement
> >>>>>> the menu based UI to select/edit/add/delete "Boot####" and
> >>> "BootOrder".
> >>>>>
> >>>>> Yes, EFI would be one of the bootmethods. Others would be U-Boot
> >>>>> scripts, Chrome OS, Android, etc. plus people might add custom ones.
> >>>>>
> >>>>> Also I am thinking that (perhaps) the bootdev part of the standard
> >>>>> boot thing could be used to provide boot devices for EFI.
> >>>>>
> >>>>> If we do have a bootmenu, I wonder if it could be generic, instead of
> >>>>> tied to EFI?
> >>>>
> >>>> EFI BootXXXX specify an array of device paths and boot options. A device
> >>> path is quite a unique construct despite its name.
> >>>> A device path is itself an array of elements, some elements can be a
> >>> file path , configuration information, or diverse metadata. An example of
> >>> configuration information element is UART baud,stop bits, parity along with
> >>> terminal (vt100, ansi…). Another device path element can cover IP address,
> >>> transport information (tcp, UDP and port number).
> >>>> The traditional EFI boot menu is quite crude and does not expose the
> >>> full capabilities of BootXXXX (lacks edit of boot options for instance!).
> >>>>
> >>>> In the long run we will need to leverage all the BootXXXX capabilities
> >>> and those are EFI specific while being OS agnostic.
> >>>> The other U-Boot boot methods (Android , ChromeOS…) are OS specific.
> >>>> The goals are thus very different and making a generic approach seems
> >>> quite compromised. If there is a fully generic framework available in the
> >>> future, it may be possible to integrate the EFI boot menu. But at least
> >>> there is a need to solve, code first, the EFI complexities to fuel the
> >>> generic architecture discussion.
> >>>
> >>> Despite this, the goal of standard boot is to encompass all of this
> >>> within U-Boot. I believe that it will be successful, even if the path
> >>> at present is a bit unclear.
> >>>
> >> So I would suggest we work bottom up. Starting by making EFI menu work,
> >> then extend it more generic or integrated it in a framework. Starting top
> >> down would require a long architecture process based on not enough known
> >> problems to solve for each environment.
> >>
> >
> > Well, whatever you do, please build something that works well with a
> > serial console.  EDK2 makes assumptions the terminal emulation on the
> > other side, insists on changing the colors to white on black and
> > relies on function keys that need escape sequences.  And escape
> > sequences over serial are always iffy since they depend on timing for
> > their interpretation.  You can do better for U-Boot.
> 
> We already use escape sequences for the U-Boot console and you can't
> avoid them for navigation keys. What operating system are you using that
> that does not provide a serial terminal emulation which understands ECMA-48?

The OS doesn't matter so much; it's the terminal emulation software
that matters.  On the BSD's (including macOS) people typically use the
cu(1) utility to connect to a serial console.  This utility doesn't do
any terminal emulation itself, but relies on the environment it runs
in.  I typically use xterm(1), but will often use tmux(1) to keep my
serial console sessions alive.  This mostly emulates a classic VT220
environment, which I do believe to be a superset of ECMA-48.

Anyway, I'm bringing this up since my experience with using the
TianoCore EDK2 "TUI" interface is pretty poor.  It assumes that your
terminal has a fixed size of 80x25, while the standard size of an
xterm is 80x24, which means that inside tmux you'll only have 80x23.
But even with the xterm window resized such that I have an 80x25
console the interface sometimes misbehaves and I end up with elements
in the wrong spot.  And the way the interface relies purely on ESC, Fn
and arrow keys is annoying since the escape sequences generated by
these keys sometimes get misinterpreted.  Now this may all be a poor
implementation on the side of EDK2.  But it makes me believe that a
U-Boot should implement a much simpler interface that is more command
line oriented.  Something like printing a menu and letting the user
select an option by typing a single character or number.

> > Also, keep in mind that BootOrder and Boot#### only really work if
> > there is runtime EFI variable support.  So the boot menu should
> > include options to select a device to boot from and use the default
> > (removable media) bootloader from the ESP on that device.  And a way
> > to make this selection stick!  Pretty much all x86 EFI implementations
> > provide functionality like that.  I suppose this could be done by
> > populating the EFI variable store with appropriate Boot#### variables
> > and manipulating BootOrder.  But that would make it hard to generalize
> > the boot menu to non-EFI boot flows.
> 
> We are talking here about an EFI boot menu. Why do you mention non-EFI?

Because Simon did, and I agree with him that U-Boot would be better of
with a way to select a boot device that is independent of the boot
mechanism.  Suppose that as a user I want to install a Linux distro on
my machine.  I copy the installer for that distro to a USB key and I
want to boot it.  But my system is set up to boot from eMMC.  U-Boot
should make it easy to do a one-off boot from USB without burdening
the user with making a choice between EFI and non-EFI boot methods and
just pick the boot method that makes the machine boot from the USB
key.

Cheers,

Mark

Re: efi bootmenu

[Ilias Apalodimas]

Hi Mark,

[...]
>
> > > Also, keep in mind that BootOrder and Boot#### only really work if
> > > there is runtime EFI variable support.  So the boot menu should
> > > include options to select a device to boot from and use the default
> > > (removable media) bootloader from the ESP on that device.  And a way
> > > to make this selection stick!  Pretty much all x86 EFI implementations
> > > provide functionality like that.  I suppose this could be done by
> > > populating the EFI variable store with appropriate Boot#### variables
> > > and manipulating BootOrder.  But that would make it hard to generalize
> > > the boot menu to non-EFI boot flows.
> >
> > We are talking here about an EFI boot menu. Why do you mention non-EFI?
>
> Because Simon did, and I agree with him that U-Boot would be better of
> with a way to select a boot device that is independent of the boot
> mechanism.  Suppose that as a user I want to install a Linux distro on
> my machine.  I copy the installer for that distro to a USB key and I
> want to boot it.  But my system is set up to boot from eMMC.  U-Boot
> should make it easy to do a one-off boot from USB without burdening
> the user with making a choice between EFI and non-EFI boot methods and
> just pick the boot method that makes the machine boot from the USB
> key.

The concept here is fine,  but I think we should agree on how we
implement that.  IMHO Simon's boot series patches is a huge step
forward compared to the distro_bootcmd.  However EFI has it's own boot
manager and logic.  So I see two ways forward:
1.  Simon's bootmethod has an abstract entry called 'EFI' or something
similar.  In that case we just invoke the efi bootmgr.
2.  We merge the efibootmgr code into Simon's patches.

But isn't that orthogonal to the current discussion?  We can just go
implement it for EFI now and then wire it up to whatever Simon does.


Cheers
/Ilias
>
> Cheers,
>
> Mark

Re: efi bootmenu

[Simon Glass]

Hi Ilias,

On Fri, 7 Jan 2022 at 02:20, Ilias Apalodimas
<ilias.apalodimas@linaro.org> wrote:
>
> Hi Mark,
>
> [...]
> >
> > > > Also, keep in mind that BootOrder and Boot#### only really work if
> > > > there is runtime EFI variable support.  So the boot menu should
> > > > include options to select a device to boot from and use the default
> > > > (removable media) bootloader from the ESP on that device.  And a way
> > > > to make this selection stick!  Pretty much all x86 EFI implementations
> > > > provide functionality like that.  I suppose this could be done by
> > > > populating the EFI variable store with appropriate Boot#### variables
> > > > and manipulating BootOrder.  But that would make it hard to generalize
> > > > the boot menu to non-EFI boot flows.
> > >
> > > We are talking here about an EFI boot menu. Why do you mention non-EFI?
> >
> > Because Simon did, and I agree with him that U-Boot would be better of
> > with a way to select a boot device that is independent of the boot
> > mechanism.  Suppose that as a user I want to install a Linux distro on
> > my machine.  I copy the installer for that distro to a USB key and I
> > want to boot it.  But my system is set up to boot from eMMC.  U-Boot
> > should make it easy to do a one-off boot from USB without burdening
> > the user with making a choice between EFI and non-EFI boot methods and
> > just pick the boot method that makes the machine boot from the USB
> > key.
>
> The concept here is fine,  but I think we should agree on how we
> implement that.  IMHO Simon's boot series patches is a huge step
> forward compared to the distro_bootcmd.  However EFI has it's own boot
> manager and logic.  So I see two ways forward:
> 1.  Simon's bootmethod has an abstract entry called 'EFI' or something
> similar.  In that case we just invoke the efi bootmgr.
> 2.  We merge the efibootmgr code into Simon's patches.
>
> But isn't that orthogonal to the current discussion?  We can just go
> implement it for EFI now and then wire it up to whatever Simon does.

Just one tweak here...I think the concept of a boot device (bootdev)
could be useful as a way for EFI to find boot devices, so that U-Boot
and EFI can share this logic / configuration.

Regards,
Simon