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


Ni, Ray
 

Jeff,

Tom from AMD booked the meeting for SEV discussion months ago. I am afraid there is no time for this discussion.

Let's try to resolve it in mails.



Firstly, let me rephase the problem and your proposed solutions here (subjective + verb + objective). Sunny's input is also included. Hope Mike K and others can provide inputs.

Personally, I agree with 2.b. It helps us to gradually migrate the PlatformBootManagerLib to PlatformBootManager protocol. Protocol with Revision field helps to reduce the impact to old platforms with new APIs added.



**Problem:

Platform requires certain BlockIo/SimpleFileSystem/LoadFile instances don't cause Boot#### created. It's a need of platform customization.



**Details:

Boot#### for BlockIo/SimpleFileSystem/LoadFile are created by API EfiBootMangerRefreshAllBootOptions(). There are 2 places that call this API:

1. Platform Boot Manager calls the API (usually in the full configuration boot path)
2. UiApp calls the API when entering "Boot Manager" page and "Boot Maintenance Manager" page.



Platform can change Platform Boot Manager to remove the unneeded Boot#### in case #1.

But platform has no way to remove the Boot#### created in case #2 .



**Potential solutions:

1. Update UiApp
* Define a new PCD and a new event group.

If PCD is TRUE, UiApp signals the event. Event callback creates the Boot####. Otherwise, EfiBootManagerRefreshAllBootOptions() is called.

* Add a new PlatformBootManagerLib API (implemented by platform).

UiApp calls the new API instead of EfiBootManagerRefreshAllBootOption. (need to coordinate rollout with updates to all platforms).

* Add a new protocol (implemented by platform).

UiApp calls the new protocol if it exists otherwise calls EfiBootManagerRefreshAllBootOption.



1. Update EfiBootManagerRefreshAllBootOptions()
* Add a new library class (implemented by platform).

EfiBootManagerRefreshAllBootOption() calls the new library class.

* Add a new PlatformBootManager protocol (implemented by platform).

EfiBootManagerRefreshAllBootOption() calls the new protocol if it exists.

Thanks,
Ray

From: Jeff Brasen <jbrasen@nvidia.com>
Sent: Wednesday, December 11, 2019 4:46 AM
To: Ni, Ray <ray.ni@intel.com>; devel@edk2.groups.io; Laszlo Ersek <lersek@redhat.com>; afish@apple.com; discuss@edk2.groups.io
Cc: Ashish Singhal <ashishsingha@nvidia.com>; Wang, Jian J <jian.j.wang@intel.com>; Wu, Hao A <hao.a.wu@intel.com>; Gao, Zhichao <zhichao.gao@intel.com>; Kinney, Michael D <michael.d.kinney@intel.com>
Subject: Re: [edk2-devel] [PATCH] Support skipping automatic BM enumeration

Can we discuss this at the design meeting this week (12/12)?


Thanks,

Jeff

________________________________
From: Jeff Brasen
Sent: Thursday, November 14, 2019 10:04 AM
To: Ni, Ray <ray.ni@intel.com<mailto:ray.ni@intel.com>>; devel@edk2.groups.io<mailto:devel@edk2.groups.io> <devel@edk2.groups.io<mailto:devel@edk2.groups.io>>; Laszlo Ersek <lersek@redhat.com<mailto:lersek@redhat.com>>; afish@apple.com<mailto:afish@apple.com> <afish@apple.com<mailto:afish@apple.com>>
Cc: Ashish Singhal <ashishsingha@nvidia.com<mailto:ashishsingha@nvidia.com>>; Wang, Jian J <jian.j.wang@intel.com<mailto:jian.j.wang@intel.com>>; Wu, Hao A <hao.a.wu@intel.com<mailto:hao.a.wu@intel.com>>; Gao, Zhichao <zhichao.gao@intel.com<mailto:zhichao.gao@intel.com>>; Kinney, Michael D <michael.d.kinney@intel.com<mailto:michael.d.kinney@intel.com>>
Subject: RE: [edk2-devel] [PATCH] Support skipping automatic BM enumeration


Yes, I think that would be good.



Summarizing everything in this thread



Problem: Platform needs to customize the boot options, this can be done for normal boot but the UiApp calls EfiBootManagerRefreshAllBootOption in a couple places.



Potential solutions:

1 - Define new PCD and event group if PCD is set true then signal event instead of calling EfiBootManagerRefreshAllBootOption in UiApp

2 - Add new function to boot manager library and replace call to EfiBootManagerRefreshAllBootOption in UiApp (need to coordinate rollout with updates to all platform.

3 - Add new protocol with new function, if supported call this otherwise call EfiBootManagerRefreshAllBootOption as is done now

4 - For 2/3 use generic function so we don't need new APIs for future expansion

5 - Update EfiBootManagerRefreshAllBootOption to call platform specific function.



Thanks,
Jeff





From: Ni, Ray <ray.ni@intel.com<mailto:ray.ni@intel.com>>
Sent: Wednesday, November 13, 2019 7:09 PM
To: devel@edk2.groups.io<mailto:devel@edk2.groups.io>; Jeff Brasen <jbrasen@nvidia.com<mailto:jbrasen@nvidia.com>>; Laszlo Ersek <lersek@redhat.com<mailto:lersek@redhat.com>>; afish@apple.com<mailto:afish@apple.com>
Cc: Ashish Singhal <ashishsingha@nvidia.com<mailto:ashishsingha@nvidia.com>>; Wang, Jian J <jian.j.wang@intel.com<mailto:jian.j.wang@intel.com>>; Wu, Hao A <hao.a.wu@intel.com<mailto:hao.a.wu@intel.com>>; Gao, Zhichao <zhichao.gao@intel.com<mailto:zhichao.gao@intel.com>>; Kinney, Michael D <michael.d.kinney@intel.com<mailto:michael.d.kinney@intel.com>>
Subject: RE: [edk2-devel] [PATCH] Support skipping automatic BM enumeration



Jeff,

I think it's a good topic that we could discuss in the open design meeting.

Are you ok to present the problem you have and discuss the potential solutions in that meeting?

https://github.com/tianocore/tianocore.github.io/wiki/Design-Meeting



Thanks,

Ray



From: devel@edk2.groups.io<mailto:devel@edk2.groups.io> <devel@edk2.groups.io<mailto:devel@edk2.groups.io>> On Behalf Of Jeff Brasen
Sent: Thursday, November 14, 2019 2:43 AM
To: Ni, Ray <ray.ni@intel.com<mailto:ray.ni@intel.com>>; devel@edk2.groups.io<mailto:devel@edk2.groups.io>; Laszlo Ersek <lersek@redhat.com<mailto:lersek@redhat.com>>; afish@apple.com<mailto:afish@apple.com>
Cc: Ashish Singhal <ashishsingha@nvidia.com<mailto:ashishsingha@nvidia.com>>; Wang, Jian J <jian.j.wang@intel.com<mailto:jian.j.wang@intel.com>>; Wu, Hao A <hao.a.wu@intel.com<mailto:hao.a.wu@intel.com>>; Gao, Zhichao <zhichao.gao@intel.com<mailto:zhichao.gao@intel.com>>; Kinney, Michael D <michael.d.kinney@intel.com<mailto:michael.d.kinney@intel.com>>
Subject: Re: [edk2-devel] [PATCH] Support skipping automatic BM enumeration



Thinking about this more I think we could do this with a PCD and a new group event without having to define any new function interfaces.



We could change UiApp and BootManagerMenuApp (and any others that are relevant) from



EfiBootManagerRefreshAllBootOption ();



to



if (FeaturePcdGet (PcdEventBasedRefreshAllBootOptionSupport) {

EFI_EVENT Event;

gBS->CreateEventEx ( 0, 0, NULL, NULL, &gEventBasedRefreshGuid, &Event );

gBS->SignalEvent (Event);

gBS->CloseEvent (Event);

} else {

EfiBootManagerRefreshAllBootOption ();

}



Then a platform that wants to do this on its own would just set this pcd and create a group event and do what it needs to do there.



Thanks,

Jeff

________________________________

From: Jeff Brasen <jbrasen@nvidia.com<mailto:jbrasen@nvidia.com>>
Sent: Monday, November 11, 2019 5:00 PM
To: Ni, Ray <ray.ni@intel.com<mailto:ray.ni@intel.com>>; devel@edk2.groups.io<mailto:devel@edk2.groups.io> <devel@edk2.groups.io<mailto:devel@edk2.groups.io>>; Laszlo Ersek <lersek@redhat.com<mailto:lersek@redhat.com>>; afish@apple.com<mailto:afish@apple.com> <afish@apple.com<mailto:afish@apple.com>>
Cc: Ashish Singhal <ashishsingha@nvidia.com<mailto:ashishsingha@nvidia.com>>; Wang, Jian J <jian.j.wang@intel.com<mailto:jian.j.wang@intel.com>>; Wu, Hao A <hao.a.wu@intel.com<mailto:hao.a.wu@intel.com>>; Gao, Zhichao <zhichao.gao@intel.com<mailto:zhichao.gao@intel.com>>; Kinney, Michael D <michael.d.kinney@intel.com<mailto:michael.d.kinney@intel.com>>
Subject: Re: [edk2-devel] [PATCH] Support skipping automatic BM enumeration



I am not sure a PCD would work (unless I am missing something) We do want to do a connect all and re-enumerate in UiApp but we need the platform code to be involved in that process.



Thanks,

Jeff

________________________________

From: Ni, Ray <ray.ni@intel.com<mailto:ray.ni@intel.com>>
Sent: Monday, November 11, 2019 4:58 PM
To: devel@edk2.groups.io<mailto:devel@edk2.groups.io> <devel@edk2.groups.io<mailto:devel@edk2.groups.io>>; Jeff Brasen <jbrasen@nvidia.com<mailto:jbrasen@nvidia.com>>; Laszlo Ersek <lersek@redhat.com<mailto:lersek@redhat.com>>; afish@apple.com<mailto:afish@apple.com> <afish@apple.com<mailto:afish@apple.com>>
Cc: Ashish Singhal <ashishsingha@nvidia.com<mailto:ashishsingha@nvidia.com>>; Wang, Jian J <jian.j.wang@intel.com<mailto:jian.j.wang@intel.com>>; Wu, Hao A <hao.a.wu@intel.com<mailto:hao.a.wu@intel.com>>; Gao, Zhichao <zhichao.gao@intel.com<mailto:zhichao.gao@intel.com>>; Kinney, Michael D <michael.d.kinney@intel.com<mailto:michael.d.kinney@intel.com>>
Subject: RE: [edk2-devel] [PATCH] Support skipping automatic BM enumeration



Jeff,

If adding a PCD to control UiApp can meet the real needs, I prefer to do in that way instead of adding new APIs to PlatformBootManagerLib.



Thanks,

Ray



From: devel@edk2.groups.io<mailto:devel@edk2.groups.io> <devel@edk2.groups.io<mailto:devel@edk2.groups.io>> On Behalf Of Jeff Brasen
Sent: Tuesday, November 12, 2019 6:58 AM
To: Laszlo Ersek <lersek@redhat.com<mailto:lersek@redhat.com>>; Ni, Ray <ray.ni@intel.com<mailto:ray.ni@intel.com>>; devel@edk2.groups.io<mailto:devel@edk2.groups.io>; afish@apple.com<mailto:afish@apple.com>
Cc: Ashish Singhal <ashishsingha@nvidia.com<mailto:ashishsingha@nvidia.com>>; Wang, Jian J <jian.j.wang@intel.com<mailto:jian.j.wang@intel.com>>; Wu, Hao A <hao.a.wu@intel.com<mailto:hao.a.wu@intel.com>>; Gao, Zhichao <zhichao.gao@intel.com<mailto:zhichao.gao@intel.com>>; Kinney, Michael D <michael.d.kinney@intel.com<mailto:michael.d.kinney@intel.com>>
Subject: Re: [edk2-devel] [PATCH] Support skipping automatic BM enumeration



If we are concerned about deploying this and breaking builds we could do this via a new protocol instead. In that case though we would leave the old default behavior in the code to handle platforms that didn't implement the new protocol, so this might not be the cleanest way to deploy this.



We could also look at adding a generic platform boot hook function (either as a library function or protocol) if we wanted to limit the number of disruption on new customization hooks. Something like



EFI_STATUS PlatformBootNotify (CONST EFI_GUID *NotificationType, VOID *ContextData OPTIONAL)



Where Notification type describes where we are that we want platform to potentially handle and ContextData is per type caller allocated data that provides additional in/out data. This has the same issue of leaving the current default behavior in place for unsupported types as well as being a less than specific function to describe.



Thanks,

Jeff



________________________________

From: Laszlo Ersek <lersek@redhat.com<mailto:lersek@redhat.com>>
Sent: Friday, November 8, 2019 9:37 AM
To: Jeff Brasen <jbrasen@nvidia.com<mailto:jbrasen@nvidia.com>>; Ni, Ray <ray.ni@intel.com<mailto:ray.ni@intel.com>>; devel@edk2.groups.io<mailto:devel@edk2.groups.io> <devel@edk2.groups.io<mailto:devel@edk2.groups.io>>; afish@apple.com<mailto:afish@apple.com> <afish@apple.com<mailto:afish@apple.com>>
Cc: Ashish Singhal <ashishsingha@nvidia.com<mailto:ashishsingha@nvidia.com>>; Wang, Jian J <jian.j.wang@intel.com<mailto:jian.j.wang@intel.com>>; Wu, Hao A <hao.a.wu@intel.com<mailto:hao.a.wu@intel.com>>; Gao, Zhichao <zhichao.gao@intel.com<mailto:zhichao.gao@intel.com>>; Kinney, Michael D <michael.d.kinney@intel.com<mailto:michael.d.kinney@intel.com>>
Subject: Re: [edk2-devel] [PATCH] Support skipping automatic BM enumeration



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@intel.com<mailto:ray.ni@intel.com>>
Sent: Thursday, November 7, 2019 12:21 AM
To: devel@edk2.groups.io<mailto:devel@edk2.groups.io>; Jeff Brasen <jbrasen@nvidia.com<mailto:jbrasen@nvidia.com>>; afish@apple.com<mailto:afish@apple.com>
Cc: Ashish Singhal <ashishsingha@nvidia.com<mailto:ashishsingha@nvidia.com>>; Laszlo Ersek <lersek@redhat.com<mailto:lersek@redhat.com>>; Wang, Jian J <jian.j.wang@intel.com<mailto:jian.j.wang@intel.com>>; Wu, Hao A <hao.a.wu@intel.com<mailto:hao.a.wu@intel.com>>; Gao, Zhichao <zhichao.gao@intel.com<mailto:zhichao.gao@intel.com>>; Kinney, Michael D <michael.d.kinney@intel.com<mailto:michael.d.kinney@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@edk2.groups.io<mailto:devel@edk2.groups.io<mailto:devel@edk2.groups.io%3cmailto:devel@edk2.groups.io>> <devel@edk2.groups.io<mailto:devel@edk2.groups.io<mailto:devel@edk2.groups.io%3cmailto:devel@edk2.groups.io>>> On Behalf Of Jeff Brasen
Sent: Thursday, November 7, 2019 3:02 PM
To: Ni, Ray <ray.ni@intel.com<mailto:ray.ni@intel.com<mailto:ray.ni@intel.com%3cmailto:ray.ni@intel.com>>>; afish@apple.com<mailto:afish@apple.com>
Cc: devel@edk2.groups.io<mailto:devel@edk2.groups.io<mailto:devel@edk2.groups.io%3cmailto:devel@edk2.groups.io>>; Ashish Singhal <ashishsingha@nvidia.com<mailto:ashishsingha@nvidia.com<mailto:ashishsingha@nvidia.com%3cmailto:ashishsingha@nvidia.com>>>; Laszlo Ersek <lersek@redhat.com<mailto:lersek@redhat.com<mailto:lersek@redhat.com%3cmailto:lersek@redhat.com>>>; Wang, Jian J <jian.j.wang@intel.com<mailto:jian.j.wang@intel.com<mailto:jian.j.wang@intel.com%3cmailto:jian.j.wang@intel.com>>>; Wu, Hao A <hao.a.wu@intel.com<mailto:hao.a.wu@intel.com<mailto:hao.a.wu@intel.com%3cmailto:hao.a.wu@intel.com>>>; Gao, Zhichao <zhichao.gao@intel.com<mailto:zhichao.gao@intel.com<mailto:zhichao.gao@intel.com%3cmailto:zhichao.gao@intel.com>>>; Kinney, Michael D <michael.d.kinney@intel.com<mailto:michael.d.kinney@intel.com<mailto:michael.d.kinney@intel.com%3cmailto:michael.d.kinney@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@intel.com<mailto:ray.ni@intel.com<mailto:ray.ni@intel.com%3cmailto:ray.ni@intel.com>>>
Sent: Wednesday, November 6, 2019 11:59:31 PM
To: Jeff Brasen <jbrasen@nvidia.com<mailto:jbrasen@nvidia.com<mailto:jbrasen@nvidia.com%3cmailto:jbrasen@nvidia.com>>>; afish@apple.com<mailto:afish@apple.com> <afish@apple.com<mailto:afish@apple.com<mailto:afish@apple.com%3cmailto:afish@apple.com>>>
Cc: devel@edk2.groups.io<mailto:devel@edk2.groups.io<mailto:devel@edk2.groups.io%3cmailto:devel@edk2.groups.io>> <devel@edk2.groups.io<mailto:devel@edk2.groups.io<mailto:devel@edk2.groups.io%3cmailto:devel@edk2.groups.io>>>; Ashish Singhal <ashishsingha@nvidia.com<mailto:ashishsingha@nvidia.com<mailto:ashishsingha@nvidia.com%3cmailto:ashishsingha@nvidia.com>>>; Laszlo Ersek <lersek@redhat.com<mailto:lersek@redhat.com<mailto:lersek@redhat.com%3cmailto:lersek@redhat.com>>>; Wang, Jian J <jian.j.wang@intel.com<mailto:jian.j.wang@intel.com<mailto:jian.j.wang@intel.com%3cmailto:jian.j.wang@intel.com>>>; Wu, Hao A <hao.a.wu@intel.com<mailto:hao.a.wu@intel.com<mailto:hao.a.wu@intel.com%3cmailto:hao.a.wu@intel.com>>>; Gao, Zhichao <zhichao.gao@intel.com<mailto:zhichao.gao@intel.com<mailto:zhichao.gao@intel.com%3cmailto:zhichao.gao@intel.com>>>; Kinney, Michael D <michael.d.kinney@intel.com<mailto:michael.d.kinney@intel.com<mailto:michael.d.kinney@intel.com%3cmailto:michael.d.kinney@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@nvidia.com<mailto:jbrasen@nvidia.com<mailto:jbrasen@nvidia.com%3cmailto:jbrasen@nvidia.com>>>
Sent: Thursday, November 7, 2019 12:13 PM
To: afish@apple.com<mailto:afish@apple.com>; Ni, Ray <ray.ni@intel.com<mailto:ray.ni@intel.com<mailto:ray.ni@intel.com%3cmailto:ray.ni@intel.com>>>
Cc: devel@edk2.groups.io<mailto:devel@edk2.groups.io<mailto:devel@edk2.groups.io%3cmailto:devel@edk2.groups.io>>; Ashish Singhal <ashishsingha@nvidia.com<mailto:ashishsingha@nvidia.com<mailto:ashishsingha@nvidia.com%3cmailto:ashishsingha@nvidia.com>>>; Laszlo Ersek <lersek@redhat.com<mailto:lersek@redhat.com<mailto:lersek@redhat.com%3cmailto:lersek@redhat.com>>>; Wang, Jian J <jian.j.wang@intel.com<mailto:jian.j.wang@intel.com<mailto:jian.j.wang@intel.com%3cmailto:jian.j.wang@intel.com>>>; Wu, Hao A <hao.a.wu@intel.com<mailto:hao.a.wu@intel.com<mailto:hao.a.wu@intel.com%3cmailto:hao.a.wu@intel.com>>>; Gao, Zhichao <zhichao.gao@intel.com<mailto:zhichao.gao@intel.com<mailto:zhichao.gao@intel.com%3cmailto:zhichao.gao@intel.com>>>; Kinney, Michael D <michael.d.kinney@intel.com<mailto:michael.d.kinney@intel.com<mailto:michael.d.kinney@intel.com%3cmailto:michael.d.kinney@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@apple.com<mailto:afish@apple.com> <afish@apple.com<mailto:afish@apple.com<mailto:afish@apple.com%3cmailto:afish@apple.com>>>
Sent: Wednesday, November 6, 2019 9:20 AM
To: Ni, Ray <ray.ni@intel.com<mailto:ray.ni@intel.com<mailto:ray.ni@intel.com%3cmailto:ray.ni@intel.com>>>
Cc: devel@edk2.groups.io<mailto:devel@edk2.groups.io<mailto:devel@edk2.groups.io%3cmailto:devel@edk2.groups.io>>; Jeff Brasen <jbrasen@nvidia.com<mailto:jbrasen@nvidia.com<mailto:jbrasen@nvidia.com%3cmailto:jbrasen@nvidia.com>>>; Ashish Singhal <ashishsingha@nvidia.com<mailto:ashishsingha@nvidia.com<mailto:ashishsingha@nvidia.com%3cmailto:ashishsingha@nvidia.com>>>; Laszlo Ersek <lersek@redhat.com<mailto:lersek@redhat.com<mailto:lersek@redhat.com%3cmailto:lersek@redhat.com>>>; Wang, Jian J <jian.j.wang@intel.com<mailto:jian.j.wang@intel.com<mailto:jian.j.wang@intel.com%3cmailto:jian.j.wang@intel.com>>>; Wu, Hao A <hao.a.wu@intel.com<mailto:hao.a.wu@intel.com<mailto:hao.a.wu@intel.com%3cmailto:hao.a.wu@intel.com>>>; Gao, Zhichao <zhichao.gao@intel.com<mailto:zhichao.gao@intel.com<mailto:zhichao.gao@intel.com%3cmailto:zhichao.gao@intel.com>>>; Mike Kinney <michael.d.kinney@intel.com<mailto:michael.d.kinney@intel.com<mailto:michael.d.kinney@intel.com%3cmailto:michael.d.kinney@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@intel.com<mailto:ray.ni@intel.com<mailto:ray.ni@intel.com%3cmailto:ray.ni@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@apple.com<mailto:afish@apple.com> <afish@apple.com<mailto:afish@apple.com<mailto:afish@apple.com%3cmailto:afish@apple.com>>>
Sent: Wednesday, November 6, 2019 10:47 AM
To: devel@edk2.groups.io<mailto:devel@edk2.groups.io<mailto:devel@edk2.groups.io%3cmailto:devel@edk2.groups.io>>; jbrasen@nvidia.com<mailto:jbrasen@nvidia.com>
Cc: Ashish Singhal <ashishsingha@nvidia.com<mailto:ashishsingha@nvidia.com<mailto:ashishsingha@nvidia.com%3cmailto:ashishsingha@nvidia.com>>>; Laszlo Ersek <lersek@redhat.com<mailto:lersek@redhat.com<mailto:lersek@redhat.com%3cmailto:lersek@redhat.com>>>; Ni, Ray <ray.ni@intel.com<mailto:ray.ni@intel.com<mailto:ray.ni@intel.com%3cmailto:ray.ni@intel.com>>>; Wang, Jian J <jian.j.wang@intel.com<mailto:jian.j.wang@intel.com<mailto:jian.j.wang@intel.com%3cmailto:jian.j.wang@intel.com>>>; Wu, Hao A <hao.a.wu@intel.com<mailto:hao.a.wu@intel.com<mailto:hao.a.wu@intel.com%3cmailto:hao.a.wu@intel.com>>>; Gao, Zhichao <zhichao.gao@intel.com<mailto:zhichao.gao@intel.com<mailto:zhichao.gao@intel.com%3cmailto:zhichao.gao@intel.com>>>; Kinney, Michael D <michael.d.kinney@intel.com<mailto:michael.d.kinney@intel.com<mailto:michael.d.kinney@intel.com%3cmailto:michael.d.kinney@intel.com>>>
Subject: Re: [edk2-devel] [PATCH] Support skipping automatic BM enumeration







On Nov 5, 2019, at 7:34 PM, Jeff Brasen <jbrasen@nvidia.com<mailto:jbrasen@nvidia.com<mailto:jbrasen@nvidia.com%3cmailto:jbrasen@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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