Messages in this thread | | | Subject | Re: [PATCH v2 1/7] hyperv: Detect Nested virtualization support for SVM | From | Vineeth Pillai <> | Date | Fri, 16 Apr 2021 12:10:26 -0400 |
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> It may make sense to expand this a bit as it is probably unclear how the > change is related to SVM. > > Something like: > > HYPERV_CPUID_NESTED_FEATURES CPUID leaf can be present on both Intel and > AMD Hyper-V guests. Previously, the code was using > HV_X64_ENLIGHTENED_VMCS_RECOMMENDED feature bit to determine the > availability of nested features leaf and this complies to TLFS: > "Recommend a nested hypervisor using the enlightened VMCS interface. > Also indicates that additional nested enlightenments may be available > (see leaf 0x4000000A)". Enlightened VMCS, however, is an Intel only > feature so the detection method doesn't work for AMD. Use > HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS.EAX CPUID information ("The > maximum input value for hypervisor CPUID information.") instead, this > works for both AMD and Intel. Thanks for the input. Will update the commit message in next revision.
Thanks, Vineeth
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