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Diffstat (limited to 'Documentation/virt/acrn/cpuid.rst')
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diff --git a/Documentation/virt/acrn/cpuid.rst b/Documentation/virt/acrn/cpuid.rst new file mode 100644 index 000000000000..65fa4b9c1798 --- /dev/null +++ b/Documentation/virt/acrn/cpuid.rst @@ -0,0 +1,46 @@ +.. 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. |