1.. SPDX-License-Identifier: GPL-2.0 2 3=============== 4ACRN CPUID bits 5=============== 6 7A guest VM running on an ACRN hypervisor can check some of its features using 8CPUID. 9 10ACRN cpuid functions are: 11 12function: 0x40000000 13 14returns:: 15 16 eax = 0x40000010 17 ebx = 0x4e524341 18 ecx = 0x4e524341 19 edx = 0x4e524341 20 21Note that this value in ebx, ecx and edx corresponds to the string 22"ACRNACRNACRN". The value in eax corresponds to the maximum cpuid function 23present in this leaf, and will be updated if more functions are added in the 24future. 25 26function: define ACRN_CPUID_FEATURES (0x40000001) 27 28returns:: 29 30 ebx, ecx, edx 31 eax = an OR'ed group of (1 << flag) 32 33where ``flag`` is defined as below: 34 35================================= =========== ================================ 36flag value meaning 37================================= =========== ================================ 38ACRN_FEATURE_PRIVILEGED_VM 0 guest VM is a privileged VM 39================================= =========== ================================ 40 41function: 0x40000010 42 43returns:: 44 45 ebx, ecx, edx 46 eax = (Virtual) TSC frequency in kHz. 47