FAQ

Here are some frequently asked questions about the ACRN project.

What hardware does ACRN support?

ACRN runs on Intel Apollo Lake and Kaby Lake boards, as documented in our Supported Hardware documentation.

Clear Linux* OS fails to boot on my NUC

If you’re following the Getting Started Guides documentation and the NUC fails to boot, here are some options to try:

  • Upgrade your platform to the latest BIOS
  • Verify Secure Boot is disabled in the BIOS settings:
    • Depending on your platform, press for example, F2 while booting to enter the BIOS options menu, and verify “Secure Boot” is not checked in the “Boot Options”
  • Make sure you are using EFI (and not legacy BIOS)

How do I configure ACRN’s memory use?

It’s important that the ACRN Kconfig settings are aligned with the physical memory on your platform. Check the documentation for these option settings for details:

For example, if memory is 32G, setup PLATFORM_RAM_SIZE = 32G

config PLATFORM_RAM_SIZE
      hex "Size of the physical platform RAM"
      default 0x200000000 if PLATFORM_SBL
      default 0x800000000 if PLATFORM_UEFI

Setup SOS_RAM_SIZE = 32G too (The SOS will have the whole resource)

config SOS_RAM_SIZE
      hex "Size of the Service OS (SOS) RAM"
      default 0x200000000 if PLATFORM_SBL
      default 0x800000000 if PLATFORM_UEFI

Setup UOS_RAM_SIZE to what you need, for example, 16G

config UOS_RAM_SIZE
      hex "Size of the User OS (UOS) RAM"
      default 0x100000000 if PLATFORM_SBL
      default 0x400000000 if PLATFORM_UEFI

Setup HV_RAM_SIZE (we will reserve memory for guest EPT paging table), if you setup 32G (default 16G), you must enlarge it with (32G-16G)/2M pages (where pages are 4K). The example below is after HV_RAM_SIZE is changed to 240M

config HV_RAM_SIZE
  hex "Size of the RAM region used by the hypervisor"
  default 0x07800000 if PLATFORM_SBL
  default 0x0f000000 if PLATFORM_UEFI