From: "Andrew Fish" <afish@apple.com>
To: devel@edk2.groups.io, d.meneses@softi9.pt
Subject: Re: [edk2-devel] How to add a DXE driver to an OVMF image?
Date: Wed, 09 Nov 2022 09:52:06 -0800 [thread overview]
Message-ID: <D9F9A230-4F3A-4470-B3E0-5D837E1154F2@apple.com> (raw)
In-Reply-To: <17126.1667568054194961949@groups.io>
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> On Nov 4, 2022, at 6:20 AM, d.meneses via groups.io <d.meneses=softi9.pt@groups.io> wrote:
>
> Using DebugLib instead to print a message, I was able to confirm that my driver is now running properly:
> cat debug.log | grep Hello
> This works both when adding it in the OVMF build and also when inserted by UEFITool.
>
> The drivers is not being listed by the EFI Shell drivers command.
> This is expected to me as Dxe Drivers are unloaded after they return.
> Nonetheless, the same is happening when I package it as a DXE_RUNTIME_DRIVER.
> What is it that I'm missing?
>
The UEFI Shell drivers command is managing UEFI Driver Model Drivers [1]. A UEFI Driver Model Driver has no depex and publishes an EFI Driver Binding protocol [2]. The idea is the BDS (platform) can now have the policy of what driver gets connected to what device. This is all managed by gBS->ConnectController()/gBS->DisconnectController().
A DXE Driver just publishes an arbitrary protocol.
[1] https://uefi.org/specs/UEFI/2.10/11_Protocols_UEFI_Driver_Model.html
[2] https://github.com/tianocore/edk2/blob/master/MdePkg/Include/Protocol/DriverBinding.h
PS I seem to remember a question about launching an App….
It is possible to customize a generic UEFIs system boot policy via NVRAM variable. You can read up on that here [3].
If you want to change the platform policy in a secure way to do something you likely need to modify the BDS (Boot Device Selection). The design idea around BDS is you could make a system an ATM or a PC just by changing the policy in the BDS, thus the BDS is a place to centralize the platform policy. The easiest way to customize the edk2 BDS is via a custom PlatformBootManagerLib. You can look at the OVMF instance here [4]. You can use this library to add extra policy on top of the NVRAM variables in the UEFI Spec [3]. If you look at the OVMF example this is how the OVMF platform makes the UEFI Shell a default boot option [5].
[3] https://uefi.org/specs/UEFI/2.10/03_Boot_Manager.html#globally-defined-variables
[4] https://github.com/tianocore/edk2/tree/master/OvmfPkg/Library/PlatformBootManagerLib
[5] https://github.com/tianocore/edk2/blob/master/OvmfPkg/Library/PlatformBootManagerLib/BdsPlatform.c#L1717
Sorry if I’m mixing up threads. So much email, and so little time….
> Thank you for your attention,
> Diogo
>
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next prev parent reply other threads:[~2022-11-09 17:52 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-02 11:11 How to add a DXE driver to an OVMF image? d.meneses
2022-11-03 0:58 ` [edk2-devel] " Pedro Falcato
2022-11-03 1:07 ` Andrew Fish
2022-11-03 15:23 ` d.meneses
2022-11-03 16:51 ` Pedro Falcato
2022-11-03 19:11 ` d.meneses
2022-11-03 21:34 ` Andrew Fish
2022-11-03 22:02 ` d.meneses
2022-11-03 22:02 ` Pedro Falcato
2022-11-03 22:12 ` d.meneses
2022-11-04 13:20 ` d.meneses
2022-11-09 17:52 ` Andrew Fish [this message]
2022-11-09 18:29 ` d.meneses
2022-11-09 20:09 ` Andrew Fish
2022-11-10 7:43 ` d.meneses
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