Patch 1 switches MSR_MISC_FEATURES_ENABLE between host and guest to avoid cpuid faulting and ring3mwait of host leaking to guest. Because cpuid faulting eanbled in host may potentially cause guest boot failure, and kvm doesn't expose ring3mwait to guest yet, it should be leaked to guest. Patch 2 optimizes the switch of MSR_MISC_FEATURES_ENABLES by avoiding WRMSR whenever possible to save cycles. ==changelog== v2->v3: - use msr_misc_features_shadow instead of reading hardware msr, from Sean Christopherson - avoid WRMSR whenever possible, from Sean Christopherson. v1->v2: - move the save/restore of cpuid faulting bit to vmx_prepare_swich_to_guest/vmx_prepare_swich_to_host to avoid every vmentry RDMSR, based on Paolo's comment. Xiaoyao Li (2): kvm/vmx: Switch MSR_MISC_FEATURES_ENABLES between host and guest x86/vmx: optimize MSR_MISC_FEATURES_ENABLES switch arch/x86/include/asm/kvm_host.h | 2 ++ arch/x86/kernel/process.c | 1 + arch/x86/kvm/vmx/vmx.c | 31 +++++++++++++++++++++++++++++++ arch/x86/kvm/x86.c | 15 ++++++++++++--- 4 files changed, 46 insertions(+), 3 deletions(-) -- 2.19.1
