On Fri, Feb 21, 2025 at 04:33:49PM +0000, Yosry Ahmed wrote: > To properly virtualize IBRS on Intel, an IBPB is executed on emulated > VM-exits to provide separate predictor modes for L1 and L2. > > Similar handling is theoretically needed for AMD, unless IbrsSameMode is > enumerated by the CPU (which should be the case for most/all CPUs > anyway). For correctness and clarity, this series generalizes the > handling to apply for both Intel and AMD as needed. > > I am not sure if this series would land through the kvm-x86 tree or the > tip/x86 tree. Sean, any thoughts about this (or general feedback about this series)? > > Yosry Ahmed (3): > x86/cpufeatures: Define X86_FEATURE_AMD_IBRS_SAME_MODE > KVM: x86: Propagate AMD's IbrsSameMode to the guest > KVM: x86: Generalize IBRS virtualization on emulated VM-exit > > arch/x86/include/asm/cpufeatures.h | 1 + > arch/x86/kvm/cpuid.c | 1 + > arch/x86/kvm/svm/nested.c | 2 ++ > arch/x86/kvm/vmx/nested.c | 11 +---------- > arch/x86/kvm/x86.h | 18 ++++++++++++++++++ > tools/arch/x86/include/asm/cpufeatures.h | 1 + > 6 files changed, 24 insertions(+), 10 deletions(-) > > -- > 2.48.1.601.g30ceb7b040-goog >
