KVM has never properly virtualized EFER.LMSLE. However, when the "nested" module parameter is set, KVM lets the guest set EFER.LMSLE. Ostensibly, this is so that SLES11 Xen 4.0 will boot as a nested hypervisor. KVM passes EFER.LMSLE to the hardware through the VMCB, so the setting works most of the time, but the KVM instruction emulator completely ignores the bit, so incorrect guest behavior is almost certainly assured. With Zen3, AMD has abandoned EFER.LMSLE. KVM still allows it, though, as long as "nested" is set. However, since the hardware doesn't support it, the next VMRUN after the emulated WRMSR will fail with "invalid VMCB." To clean things up, revert the hack that allowed a KVM guest to set EFER.LMSLE, and enumerate CPUID.80000008H:EDX.EferLmsleUnsupported[bit 20] in KVM_GET_SUPPORTED_CPUID on SVM hosts. Jim Mattson (3): Revert "KVM: SVM: Allow EFER.LMSLE to be set with nested svm" x86/cpufeatures: Introduce X86_FEATURE_NO_LMSLE KVM: SVM: Unconditionally enumerate EferLmsleUnsupported arch/x86/include/asm/cpufeatures.h | 1 + arch/x86/include/asm/msr-index.h | 2 -- arch/x86/kvm/svm/svm.c | 3 ++- 3 files changed, 3 insertions(+), 3 deletions(-) v1 -> v2: Make no attempt to preserve existing behavior [Sean, Borislav] -- 2.37.3.968.ga6b4b080e4-goog
