Re: [edk2-devel] [PATCH v4] ArmVirt: Allow memory attributes protocol to be disabled

["Gerd Hoffmann" <kraxel@redhat.com>]

On Tue, Dec 12, 2023 at 09:36:00AM +0100, Ard Biesheuvel wrote:
> From: Ard Biesheuvel <ardb@kernel.org>
> 
> Shim's PE loader uses the EFI memory attributes protocol in a way that
> results in an immediate crash when invoking the loaded image, unless the
> base and size of its executable segment are both aligned to 4k.
> 
> If this is not the case, it will strip the memory allocation of its
> executable permissions, but fail to add them back for the executable
> region, resulting in non-executable code. Unfortunately, the PE loader
> does not even bother invoking the protocol in this case (as it notices
> the misalignment), making it very hard for system firmware to work
> around this by attempting to infer the intent of the caller.
> 
> So let's introduce a QEMU command line option to indicate that the
> protocol should not be exposed at all, and a PCD to set the default for
> this option when it is omitted.
> 
>   -fw_cfg opt/org.tianocore/UninstallMemAttrProtocol,string=y

Tested-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Gerd Hoffmann <kraxel@redhat.com>

take care,
  Gerd



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