VMMs retrieve supported CPUID features via KVM_GET_SUPPORTED_CPUID to construct CPUID information to be passed to KVM_SET_CPUID2. Most CPUID feature bits related to speculative attacks are propagated from host CPUID. But AMD processors have AMD-specific IBRS related bits in CPUID Fn8000_0008_EBX (ref: AMD64 Architecture Programmer's Manual Volume 3: General-Purpose and System Instructions) and some bits are not propagated to guests. Enable propagation of these bits to guests, so that VMMs don't have to enable them explicitly based on host CPUID. Takahiro Itazuri (2): x86/cpufeatures: Add AMD-specific IBRS bits KVM: x86: Propagate AMD-specific IBRS related bits arch/x86/include/asm/cpufeatures.h | 3 +++ arch/x86/kvm/cpuid.c | 5 +++-- 2 files changed, 6 insertions(+), 2 deletions(-) -- 2.38.0
