Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 46 insertions, 0 deletions

diff --git a/Documentation/virt/acrn/cpuid.rst b/Documentation/virt/acrn/cpuid.rst
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+.. 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.