Re: [edk2] [PATCH v4 0/7] MdeModulePkg: add support for dispatching foreign arch PE/COFF images

["Michael D Kinney" <michael.d.kinney@intel.com>]

Ard,

Thank you for the update on this patch series.
This design is very clean.  One logic issue for
protocol notifications, but that should be only
require a small update.

Mike

> -----Original Message-----
> From: edk2-devel [mailto:edk2-devel-
> bounces@lists.01.org] On Behalf Of Ard Biesheuvel
> Sent: Sunday, March 31, 2019 8:27 PM
> To: edk2-devel@lists.01.org
> Cc: Ni, Ray <ray.ni@intel.com>; Zimmer, Vincent
> <vincent.zimmer@intel.com>; Dong, Eric
> <eric.dong@intel.com>; Carsey, Jaben
> <jaben.carsey@intel.com>; Richardson, Brian
> <brian.richardson@intel.com>; Gao, Liming
> <liming.gao@intel.com>; Kinney, Michael D
> <michael.d.kinney@intel.com>; Zeng, Star
> <star.zeng@intel.com>
> Subject: [edk2] [PATCH v4 0/7] MdeModulePkg: add
> support for dispatching foreign arch PE/COFF images
> 
> Add the basic plumbing to DXE core, the PCI bus driver
> and the boot manager
> to allow PE/COFF images to be dispatched that target an
> architecture that is
> not native for the platform, but which is supported by
> one of potentially
> several available emulators.
> 
> One implementation of such an emulator can be found
> here:
> https://github.com/ardbiesheuvel/X86EmulatorPkg/tree/up
> stream-v4
> 
> This also allows us to get rid of the special treatment
> of EBC images in
> core code. Instead, the EbcDxe driver is augmented with
> an implementation
> of the EDK2 PE/COFF image emulator protocol so that
> internal knowledge of
> how EBC is implemented (I-cache flushing, thunks) is
> removed from the DXE
> core.
> 
> Changes since v3:
> - Simplify the handling of option ROMs and Driver####
> images, by simply
>   deferring to the LoadImage() boot service to decide
> whether an image
>   can be supported or not - this removes some redundant
> checks from the
>   BDS layer and the PCI bus driver.
> - Move the machine type supported by the emulator into
> the protocol struct,
>   so we can optimize away calls into the emulator for
> each image loaded.
>   Instead, the LoadImage() code will only invoke the
> IsSupported() method for
>   images that are known to have a matching machine
> type.
> 
> Note that I have considered, but ultimately dismissed
> the suggestion to
> register and unregister emulators via a new protocol.
> The main issue is
> that registering and unregistering struct containing
> sets of function
> pointers is awfully similar to managing a protocol
> database, and we already
> have the code to do that in EDK2.
> 
> So instead, I have removed all the code that iterates
> over a handle buffer
> of emu protocols and invokes each one to see if it will
> support the image.
> Instead, this is all done by CoreLoadImage().
> 
> Changes since v2:
> - incorporate feedback from Andrew Fish (delivered in
> person):
>   * pass a device path into the IsImageSupported()
> protocol method so that an
>     implementation can blacklist or whitelist certain
> devices, or implement
>     other policies that depend on the device where the
> driver originated
>   * allow the emulator to supersede the native loading
> of the image - this
>     permits things like X86 on X86 emulators for
> security sandboxing or debug
> 
> Changes since v1:
> - subsume the EBC handling into the EDK2 emulator
> protocol and abstract
>   away from EBC specifics in core code.
> - allow multiple emulator implementations to co-exist
> - incorporate Star's review feedback
> 
> Cc: Vincent Zimmer <vincent.zimmer@intel.com>
> Cc: Brian Richardson <brian.richardson@intel.com>
> Cc: Michael D Kinney <michael.d.kinney@intel.com>
> Cc: Andrew Fish <afish@apple.com>
> Cc: Leif Lindholm <leif.lindholm@linaro.org>
> Cc: Star Zeng <star.zeng@intel.com>
> Cc: Eric Dong <eric.dong@intel.com>
> Cc: Ruiyu Ni <ruiyu.ni@intel.com>
> Cc: Liming Gao <liming.gao@intel.com>
> Cc: Jaben Carsey <jaben.carsey@intel.com>
> Cc: Steven Shi <steven.shi@intel.com>
> 
> Ard Biesheuvel (7):
>   MdeModulePkg: introduce PE/COFF image emulator
> protocol
>   MdeModulePkg/DxeCore: invoke the emulator protocol
> for foreign images
>   MdeModulePkg/PciBusDxe: dispatch option ROMs for
> foreign architectures
>   MdeModulePkg/UefiBootManagerLib: allow foreign
> Driver#### images
>   MdeModulePkg/EbcDxe: implement the PE/COFF emulator
> protocol
>   MdePkg/UefiBaseType.h: treat EBC as a non-native
> machine type
>   MdeModulePkg/DxeCore: remove explicit EBC handling
> 
>  .../Bus/Pci/PciBusDxe/PciOptionRomSupport.c   |   7 -
>  MdeModulePkg/Core/Dxe/DxeMain.h               |   6 +-
>  MdeModulePkg/Core/Dxe/DxeMain.inf             |   2 +-
>  MdeModulePkg/Core/Dxe/Image/Image.c           | 183
> ++++++++++++------
>  .../Include/Protocol/PeCoffImageEmulator.h    | 107
> ++++++++++
>  .../Library/UefiBootManagerLib/BmLoadOption.c |   6 +-
>  MdeModulePkg/MdeModulePkg.dec                 |   4 +
>  MdeModulePkg/Universal/EbcDxe/EbcDebugger.inf |   3 +
>  MdeModulePkg/Universal/EbcDxe/EbcDxe.inf      |   3 +
>  MdeModulePkg/Universal/EbcDxe/EbcInt.c        | 123
> ++++++++++++
>  MdeModulePkg/Universal/EbcDxe/EbcInt.h        |   3 +
>  MdePkg/Include/Uefi/UefiBaseType.h            |   6 +-
>  12 files changed, 381 insertions(+), 72 deletions(-)
>  create mode 100644
> MdeModulePkg/Include/Protocol/PeCoffImageEmulator.h
> 
> --
> 2.17.1
> 
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