From: Chao Gao Advertise the LOAD_CET_STATE VM-Entry/Exit control bits in the nested VMX MSRS, as all nested support for CET virtualization, including consistency checks, is in place. Advertise support if and only if KVM supports at least one of IBT or SHSTK. While it's userspace's responsibility to provide a consistent CPU model to the guest, that doesn't mean KVM should set userspace up to fail. Note, the existing {CLEAR,LOAD}_BNDCFGS behavior predates KVM_X86_QUIRK_STUFF_FEATURE_MSRS, i.e. KVM "solved" the inconsistent CPU model problem by overwriting the VMX MSRs provided by userspace. Signed-off-by: Chao Gao Co-developed-by: Sean Christopherson Signed-off-by: Sean Christopherson --- arch/x86/kvm/vmx/nested.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index 024bfb4d3a72..a8a421a8e766 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -7178,13 +7178,17 @@ static void nested_vmx_setup_exit_ctls(struct vmcs_config *vmcs_conf, VM_EXIT_HOST_ADDR_SPACE_SIZE | #endif VM_EXIT_LOAD_IA32_PAT | VM_EXIT_SAVE_IA32_PAT | - VM_EXIT_CLEAR_BNDCFGS; + VM_EXIT_CLEAR_BNDCFGS | VM_EXIT_LOAD_CET_STATE; msrs->exit_ctls_high |= VM_EXIT_ALWAYSON_WITHOUT_TRUE_MSR | VM_EXIT_LOAD_IA32_EFER | VM_EXIT_SAVE_IA32_EFER | VM_EXIT_SAVE_VMX_PREEMPTION_TIMER | VM_EXIT_ACK_INTR_ON_EXIT | VM_EXIT_LOAD_IA32_PERF_GLOBAL_CTRL; + if (!kvm_cpu_cap_has(X86_FEATURE_SHSTK) && + !kvm_cpu_cap_has(X86_FEATURE_IBT)) + msrs->exit_ctls_high &= ~VM_EXIT_LOAD_CET_STATE; + /* We support free control of debug control saving. */ msrs->exit_ctls_low &= ~VM_EXIT_SAVE_DEBUG_CONTROLS; } @@ -7200,11 +7204,16 @@ static void nested_vmx_setup_entry_ctls(struct vmcs_config *vmcs_conf, #ifdef CONFIG_X86_64 VM_ENTRY_IA32E_MODE | #endif - VM_ENTRY_LOAD_IA32_PAT | VM_ENTRY_LOAD_BNDCFGS; + VM_ENTRY_LOAD_IA32_PAT | VM_ENTRY_LOAD_BNDCFGS | + VM_ENTRY_LOAD_CET_STATE; msrs->entry_ctls_high |= (VM_ENTRY_ALWAYSON_WITHOUT_TRUE_MSR | VM_ENTRY_LOAD_IA32_EFER | VM_ENTRY_LOAD_IA32_PERF_GLOBAL_CTRL); + if (!kvm_cpu_cap_has(X86_FEATURE_SHSTK) && + !kvm_cpu_cap_has(X86_FEATURE_IBT)) + msrs->exit_ctls_high &= ~VM_ENTRY_LOAD_CET_STATE; + /* We support free control of debug control loading. */ msrs->entry_ctls_low &= ~VM_ENTRY_LOAD_DEBUG_CONTROLS; } -- 2.51.0.470.ga7dc726c21-goog