From: "Xin Li (Intel)" <[email protected]> Do not virtualize FRED if FRED consistency checks fail.
Either on broken hardware, or when run KVM on top of another hypervisor before the underlying hypervisor implements nested FRED correctly. Suggested-by: Chao Gao <[email protected]> Signed-off-by: Xin Li (Intel) <[email protected]> Signed-off-by: Sohil Mehta <[email protected]> Reviewed-by: Chao Gao <[email protected]> --- v10: - Remove the comment about why not check FRED VM-exit controls in cpu_has_vmx_fred() (Sean). - Remove redundant parentheses (Sean). --- arch/x86/kvm/vmx/capabilities.h | 5 +++++ arch/x86/kvm/vmx/vmx.c | 3 +++ 2 files changed, 8 insertions(+) diff --git a/arch/x86/kvm/vmx/capabilities.h b/arch/x86/kvm/vmx/capabilities.h index 6be818ce27bf..95d22a54f856 100644 --- a/arch/x86/kvm/vmx/capabilities.h +++ b/arch/x86/kvm/vmx/capabilities.h @@ -409,6 +409,11 @@ static inline bool vmx_pebs_supported(void) !enable_mediated_pmu; } +static inline bool cpu_has_vmx_fred(void) +{ + return vmcs_config.vmentry_ctrl & VM_ENTRY_LOAD_IA32_FRED; +} + static inline bool cpu_has_notify_vmexit(void) { return vmcs_config.cpu_based_2nd_exec_ctrl & diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 062631e2dd37..2a2218e0983b 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -8122,6 +8122,9 @@ static __init void vmx_set_cpu_caps(void) kvm_cpu_cap_check_and_set(X86_FEATURE_DTES64); } + if (!cpu_has_vmx_fred()) + kvm_cpu_cap_clear(X86_FEATURE_FRED); + if (!enable_pmu) kvm_cpu_cap_clear(X86_FEATURE_PDCM); kvm_caps.supported_perf_cap = vmx_get_perf_capabilities(); -- 2.43.0
