[edk2-devel] [PATCH] Support skipping automatic BM enumeration

Fri Nov 8 16:37:59 UTC 2019

On 11/07/19 18:46, Jeff Brasen wrote:
> Fixing UiApp seems reasonable, I do think we would want a hook to the platform library in here as the enumeration that occurs in the UiApp is intended to do a full enumeration of the system and there may be platform specifics to how that occurs.

Fully agreed -- entering UiApp should expose everything bootable in the
system, unless (perhaps) PlatformBootManagerLib specifically thinks
otherwise.

Of course, then we arrive (again) at the problem that a call in
UefiBootManagerLib, to a *new* PlatformBootManagerLib API, will break
tens of out-of-tree platforms. :)

I think that can be prevented, as follows; but it will take quite some time:

- introduce the new function declaration in "PlatformBootManagerLib.h",
- modify all platforms (in tree and out of tree) to implement (define)
the new function,
- call the new function from UefiBootManagerLib

For some history / background on this kind of problem, I suggest reading
through:

  https://bugzilla.tianocore.org/show_bug.cgi?id=982

Thanks,
Laszlo

> From: Ni, Ray <ray.ni at intel.com>
> Sent: Thursday, November 7, 2019 12:21 AM
> To: devel at edk2.groups.io; Jeff Brasen <jbrasen at nvidia.com>; afish at apple.com
> Cc: Ashish Singhal <ashishsingha at nvidia.com>; Laszlo Ersek <lersek at redhat.com>; Wang, Jian J <jian.j.wang at intel.com>; Wu, Hao A <hao.a.wu at intel.com>; Gao, Zhichao <zhichao.gao at intel.com>; Kinney, Michael D <michael.d.kinney at intel.com>
> Subject: RE: [edk2-devel] [PATCH] Support skipping automatic BM enumeration
> 
> I treat the issue in this way:
> 
>   1.  Platform Boot Manager library does a good job. It doesn't always call RefreshAll() API to auto-create the boot options
>   2.  But UiApp doesn't. It constantly call RefreshAll().
> 
> Do you think that we can fix UiApp instead? For example, introducing a PCD to control the boot option refresh behavior?
> 
> Thanks,
> Ray
> 
> From: devel at edk2.groups.io<mailto:devel at edk2.groups.io> <devel at edk2.groups.io<mailto:devel at edk2.groups.io>> On Behalf Of Jeff Brasen
> Sent: Thursday, November 7, 2019 3:02 PM
> To: Ni, Ray <ray.ni at intel.com<mailto:ray.ni at intel.com>>; afish at apple.com<mailto:afish at apple.com>
> Cc: devel at edk2.groups.io<mailto:devel at edk2.groups.io>; Ashish Singhal <ashishsingha at nvidia.com<mailto:ashishsingha at nvidia.com>>; Laszlo Ersek <lersek at redhat.com<mailto:lersek at redhat.com>>; Wang, Jian J <jian.j.wang at intel.com<mailto:jian.j.wang at intel.com>>; Wu, Hao A <hao.a.wu at intel.com<mailto:hao.a.wu at intel.com>>; Gao, Zhichao <zhichao.gao at intel.com<mailto:zhichao.gao at intel.com>>; Kinney, Michael D <michael.d.kinney at intel.com<mailto:michael.d.kinney at intel.com>>
> Subject: Re: [edk2-devel] [PATCH] Support skipping automatic BM enumeration
> 
> The issue is there are some auto created options we do not want on our platform.
> Get Outlook for Android<https://aka.ms/ghei36>
> 
> ________________________________
> From: Ni, Ray <ray.ni at intel.com<mailto:ray.ni at intel.com>>
> Sent: Wednesday, November 6, 2019 11:59:31 PM
> To: Jeff Brasen <jbrasen at nvidia.com<mailto:jbrasen at nvidia.com>>; afish at apple.com<mailto:afish at apple.com> <afish at apple.com<mailto:afish at apple.com>>
> Cc: devel at edk2.groups.io<mailto:devel at edk2.groups.io> <devel at edk2.groups.io<mailto:devel at edk2.groups.io>>; Ashish Singhal <ashishsingha at nvidia.com<mailto:ashishsingha at nvidia.com>>; Laszlo Ersek <lersek at redhat.com<mailto:lersek at redhat.com>>; Wang, Jian J <jian.j.wang at intel.com<mailto:jian.j.wang at intel.com>>; Wu, Hao A <hao.a.wu at intel.com<mailto:hao.a.wu at intel.com>>; Gao, Zhichao <zhichao.gao at intel.com<mailto:zhichao.gao at intel.com>>; Kinney, Michael D <michael.d.kinney at intel.com<mailto:michael.d.kinney at intel.com>>
> Subject: RE: [edk2-devel] [PATCH] Support skipping automatic BM enumeration
> 
> 
> Jeff,
> 
> RefreshAllBootOption() only modifies/creates the auto-created boot options. For the boot options created by platform boot manager library, they stay with no one touches. And all auto-created boot options are appended in the end of boot option list (through BootOrder).
> 
> 
> 
> From: Jeff Brasen <jbrasen at nvidia.com<mailto:jbrasen at nvidia.com>>
> Sent: Thursday, November 7, 2019 12:13 PM
> To: afish at apple.com<mailto:afish at apple.com>; Ni, Ray <ray.ni at intel.com<mailto:ray.ni at intel.com>>
> Cc: devel at edk2.groups.io<mailto:devel at edk2.groups.io>; Ashish Singhal <ashishsingha at nvidia.com<mailto:ashishsingha at nvidia.com>>; Laszlo Ersek <lersek at redhat.com<mailto:lersek at redhat.com>>; Wang, Jian J <jian.j.wang at intel.com<mailto:jian.j.wang at intel.com>>; Wu, Hao A <hao.a.wu at intel.com<mailto:hao.a.wu at intel.com>>; Gao, Zhichao <zhichao.gao at intel.com<mailto:zhichao.gao at intel.com>>; Kinney, Michael D <michael.d.kinney at intel.com<mailto:michael.d.kinney at intel.com>>
> Subject: RE: [edk2-devel] [PATCH] Support skipping automatic BM enumeration
> 
> 
> 
> As the suggestions below made sense, we updated our platform boot manager library to behave in this manner and for normal boots everything works well. However the UiApp and boot maintenance applications in EDK2 also call EfiBootManagerRefreshAllBootOption() when ever a user goes into the menu which will re-create the skipped boot options with no place for the platform code to intervene.
> 
> 
> 
> What about a solution where we add a new Platform library function that allows for override of the behavior of BmEnumerateBootOptions? For example, either a function or protocol that takes the same parameters as this function and only if it returns NULL then we continue to the default enumeration code.  Or a function call inserted at the end that would modify the load option array after the system does the standard enumeration.
> 
> 
> 
> -Jeff
> 
> 
> 
> From: afish at apple.com<mailto:afish at apple.com> <afish at apple.com<mailto:afish at apple.com>>
> Sent: Wednesday, November 6, 2019 9:20 AM
> To: Ni, Ray <ray.ni at intel.com<mailto:ray.ni at intel.com>>
> Cc: devel at edk2.groups.io<mailto:devel at edk2.groups.io>; Jeff Brasen <jbrasen at nvidia.com<mailto:jbrasen at nvidia.com>>; Ashish Singhal <ashishsingha at nvidia.com<mailto:ashishsingha at nvidia.com>>; Laszlo Ersek <lersek at redhat.com<mailto:lersek at redhat.com>>; Wang, Jian J <jian.j.wang at intel.com<mailto:jian.j.wang at intel.com>>; Wu, Hao A <hao.a.wu at intel.com<mailto:hao.a.wu at intel.com>>; Gao, Zhichao <zhichao.gao at intel.com<mailto:zhichao.gao at intel.com>>; Mike Kinney <michael.d.kinney at intel.com<mailto:michael.d.kinney at intel.com>>
> Subject: Re: [edk2-devel] [PATCH] Support skipping automatic BM enumeration
> 
> 
> 
> Ray,
> 
> 
> 
> Is there an obvious hook point we could point Jeff and Ashish at?
> 
> 
> 
> Long term it would be a good idea to have a Wiki page to give some guidance on how to customize the BDS.
> 
> 
> 
> Thanks,
> 
> 
> 
> Andrew Fish
> 
> 
> 
> On Nov 5, 2019, at 9:20 PM, Ni, Ray <ray.ni at intel.com<mailto:ray.ni at intel.com>> wrote:
> 
> 
> 
> Andrew,
> 
> I agree with your opinion.
> 
> It's expected that Platform Boot Manager lib calls EfiBootManagerRefreshAllBootOption() only in full configuration boot path.
> 
> The full configuration boot path is chosen when hardware changes happen. So it's not expected EfiBootManagerRefresh...() be
> called in every boot.
> 
> So you could:
> 
>   1.  Delete the auto-created option pointing to LoadFile instance
>   2.  Create your own one with customized description.
> 
> 
> 
> 
> 
> From: afish at apple.com<mailto:afish at apple.com> <afish at apple.com<mailto:afish at apple.com>>
> Sent: Wednesday, November 6, 2019 10:47 AM
> To: devel at edk2.groups.io<mailto:devel at edk2.groups.io>; jbrasen at nvidia.com<mailto:jbrasen at nvidia.com>
> Cc: Ashish Singhal <ashishsingha at nvidia.com<mailto:ashishsingha at nvidia.com>>; Laszlo Ersek <lersek at redhat.com<mailto:lersek at redhat.com>>; Ni, Ray <ray.ni at intel.com<mailto:ray.ni at intel.com>>; Wang, Jian J <jian.j.wang at intel.com<mailto:jian.j.wang at intel.com>>; Wu, Hao A <hao.a.wu at intel.com<mailto:hao.a.wu at intel.com>>; Gao, Zhichao <zhichao.gao at intel.com<mailto:zhichao.gao at intel.com>>; Kinney, Michael D <michael.d.kinney at intel.com<mailto:michael.d.kinney at intel.com>>
> Subject: Re: [edk2-devel] [PATCH] Support skipping automatic BM enumeration
> 
> 
> 
> 
> 
> 
> 
> On Nov 5, 2019, at 7:34 PM, Jeff Brasen <jbrasen at nvidia.com<mailto:jbrasen at nvidia.com>> wrote:
> 
> 
> 
> Wouldn't having a variable that we create and delete on every boot put unnecessary stress on the SPI-NOR that the variable store lives on?
> What about the alternative approach where we allow the platform code to modify the attributes of the auto created variable to disable it with hidden/!active but still match for detection purposes so that it doesn't delete and recreate the modified variable each boot? That way all the logic on what to disable can still be in the platform code and all the existing logic in the boot manager can stay basically the same?
> 
> What changes every boot that forces the variable to need to get modified?
> 
> I would assume the NOR driver is smart enough to not update a variable that is not changing.
> 
> The custom BDS could could only create the variable for this device if it does not exist.
> 
> [JB] The current flow with no changes in the boot manager would be as follows
> 
> 
> 
>   1.  Scan for instance of the boot option in the variables
>   2.  It will not be found, so create a new boot option store it to a variable and update BootOrder
>   3.  Platform code runs creates the options for the boot option it wants and writes those to variable store
>   4.  Delete/disable the boot option in the variable store
> 
> 
> 
> When you reboot it won't find the variable so 1/2/4 will re-occur
> 
> 
> 
> The code that does this (1/2) is EfiBootManagerRefreshAllBootOption in BmBoot.c
> 
> 
> 
> If you modify the variable to disable it with hidden/not active it would delete that and create a new one as well as the code wouldn't recognize that is the same boot option.
> 
> 
> 
> If however we modify EfiBootManagerFindLoadOption to not compare the attributes (at least allow for differences in active and hidden) then the when it refreshes every thing it would see the match and not delete/create a new variable in the store and thus we wouldn't have changes every boot.
> 
> 
> 
> 
> 
> Jeff,
> 
> 
> 
> Sorry if I'm a little off on the sequence of things as the platform I work on day to day has a custom BDS and does not use this library..... I though the patch changed BmEnumerateBootOptions(), so that is going to change how EfiBootManagerRefreshAllBootOption() works. I'd also point out the patch as given is invalid as it changed the behavior of the public library API for EfiBootManagerRefreshAllBootOption() [1] so for the patch to be valid it would need to change the comments to reflect the new behavior. This is kind of what Laszlo's technical debt comment was about.
> 
> 
> 
> I think Laszlo advocated having the BDS platform specific code make sure the boot variables are in the correct state. That should happen before the Boot Manager code runs, and it is  not clear to me why the Boot Manager could would need to run if you have a valid EFI nvram variable to boot from.
> 
> 
> 
> I think the question is how is your use case different than the boot variable that Windows installs? If it works kind of the same way then the answer is to have the BDS platform specific code write the boot variable.
> 
> 
> 
> 
> 
> [1]
> 
> /**
> 
>   The function creates boot options for all possible bootable medias in the following order:
> 
>   1. Removable BlockIo            - The boot option only points to the removable media
> 
>                                     device, like USB key, DVD, Floppy etc.
> 
>   2. Fixed BlockIo                - The boot option only points to a Fixed blockIo device,
> 
>                                     like HardDisk.
> 
>   3. Non-BlockIo SimpleFileSystem - The boot option points to a device supporting
> 
>                                     SimpleFileSystem Protocol, but not supporting BlockIo
> 
>                                     protocol.
> 
>   4. LoadFile                     - The boot option points to the media supporting
> 
>                                     LoadFile protocol.
> 
>   Reference: UEFI Spec chapter 3.3 Boot Option Variables Default Boot Behavior
> 
> 
> 
>   The function won't delete the boot option not added by itself.
> 
> **/
> 
> VOID
> 
> EFIAPI
> 
> EfiBootManagerRefreshAllBootOption (
> 
>   VOID
> 
>   );
> 
> 
> 
> Thanks,
> 
> 
> 
> Andrew Fish
> 
> 
> 
> Thanks,
> 
> Andrew Fish
> 
> Thanks,
> 
> Jeff
> 
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> 
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