Ard Biesheuvel a4a2258a1f ArmVirtPkg/NorFlashQemuLib: disable NOR flash DT nodes upon discovery ... Our UEFI guest firmware takes ownership of the emulated NOR flash in order to support the variable runtime services, and it does not expect the OS to interfere with the underlying storage directly. So disable the NOR flash DT nodes as we discover them, in a way similar to how we disable the PL031 RTC in the device tree when we attach our RTC runtime driver to it. Note that this also hides the NOR flash bank that carries the UEFI executable code, but this is not intended to be updatable from inside the guest anyway, and if it was, we should use capsule update to do so. Also, the first -pflash argument that defines the backing for this flash bank is often issued with the 'readonly' modifier, in order to prevent any changes whatsoever to be made to the executable firmware image by the guest. This issue has become relevant due to the following Linux changes, which enable the flash driver stack for default build configurations targetting arm64 and 32-bit ARM. ce693fc2a877 ("arm64: defconfig: Enable flash device drivers for QorIQ boards", 2020-03-16). 5f068190cc10 ("ARM: multi_v7_defconfig: Enable support for CFI NOR FLASH", 2019-04-03) Reviewed-by: Laszlo Ersek <lersek@redhat.com> Reviewed-by: Philippe Mathieu-Daude <philmd@redhat.com> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@arm.com>		2020-06-24 16:05:53 +00:00
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NorFlashQemuLib.c	ArmVirtPkg/NorFlashQemuLib: disable NOR flash DT nodes upon discovery	2020-06-24 16:05:53 +00:00
NorFlashQemuLib.inf	ArmVirtPkg: Replace BSD License with BSD+Patent License	2019-04-09 09:10:21 -07:00