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| -rw-r--r-- | docs/system/arm/virt.rst | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/docs/system/arm/virt.rst b/docs/system/arm/virt.rst index 7c4c80180c..c245c52b7a 100644 --- a/docs/system/arm/virt.rst +++ b/docs/system/arm/virt.rst @@ -96,7 +96,13 @@ mte highmem Set ``on``/``off`` to enable/disable placing devices and RAM in physical address space above 32 bits. The default is ``on`` for machine types - later than ``virt-2.12``. + later than ``virt-2.12`` when the CPU supports an address space + bigger than 32 bits (i.e. 64-bit CPUs, and 32-bit CPUs with the + Large Physical Address Extension (LPAE) feature). If you want to + boot a 32-bit kernel which does not have ``CONFIG_LPAE`` enabled on + a CPU type which implements LPAE, you will need to manually set + this to ``off``; otherwise some devices, such as the PCI controller, + will not be accessible. compact-highmem Set ``on``/``off`` to enable/disable the compact layout for high memory regions. |