ArmVirtQemu: Allow EFI memory attributes protocol to be disabled

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.

Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Tested-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Gerd Hoffmann <kraxel@redhat.com>
Link: https://gitlab.com/qemu-project/qemu/-/issues/1990
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

0 files changed, 0 insertions, 0 deletions