.. SPDX-License-Identifier: GPL-2.0

=============== ACRN CPUID bits

A guest VM running on an ACRN hypervisor can check some of its features using CPUID.

ACRN cpuid functions are:

function: 0x40000000

returns::

eax = 0x40000010 ebx = 0x4e524341 ecx = 0x4e524341 edx = 0x4e524341

Note that this value in ebx, ecx and edx corresponds to the string "ACRNACRNACRN". The value in eax corresponds to the maximum cpuid function present in this leaf, and will be updated if more functions are added in the future.

function: define ACRN_CPUID_FEATURES (0x40000001)

returns::

      ebx, ecx, edx
      eax = an OR'ed group of (1 << flag)

where flag is defined as below:

================================= =========== ================================ flag value meaning ================================= =========== ================================ ACRN_FEATURE_PRIVILEGED_VM 0 guest VM is a privileged VM ================================= =========== ================================

function: 0x40000010

returns::

      ebx, ecx, edx
      eax = (Virtual) TSC frequency in kHz.