Remove EFER.LME and EFER.LMA from EFER reserved bits only if long mode is actually supported. KVM does check long-mode support before allowing the bits for guest writes and userspace writes through KVM_SET_SREGS* (in __kvm_valid_efer()), but userspace writes through KVM_SET_MSRS only check reserved bits. In practice, this doesn't really matter. The true motiviation is getting rid of the #ifdeffery when initializing efer_reserved_bits. Cc: stable@vger.kernel.org Signed-off-by: Yosry Ahmed --- arch/x86/kvm/msrs.c | 10 +--------- arch/x86/kvm/x86.c | 3 +++ 2 files changed, 4 insertions(+), 9 deletions(-) diff --git a/arch/x86/kvm/msrs.c b/arch/x86/kvm/msrs.c index c230b18d87e38..67481429ad6b8 100644 --- a/arch/x86/kvm/msrs.c +++ b/arch/x86/kvm/msrs.c @@ -19,16 +19,8 @@ bool __read_mostly report_ignored_msrs = true; module_param(report_ignored_msrs, bool, 0644); EXPORT_SYMBOL_FOR_KVM_INTERNAL(report_ignored_msrs); -/* EFER defaults: - * - enable syscall per default because its emulated by KVM - * - enable LME and LMA per default on 64 bit KVM - */ -#ifdef CONFIG_X86_64 -static -u64 __read_mostly efer_reserved_bits = ~((u64)(EFER_SCE | EFER_LME | EFER_LMA)); -#else +/* Enable syscall by default because its emulated by KVM */ static u64 __read_mostly efer_reserved_bits = ~((u64)EFER_SCE); -#endif #define MAX_IO_MSRS 256 diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index ca01a2f2ec466..f68424a985cda 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -6913,6 +6913,9 @@ EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_setup_xss_caps); static void kvm_setup_efer_caps(void) { + if (kvm_cpu_cap_has(X86_FEATURE_LM)) + kvm_enable_efer_bits(EFER_LME | EFER_LMA); + if (kvm_cpu_cap_has(X86_FEATURE_NX)) kvm_enable_efer_bits(EFER_NX); -- 2.55.0.141.g00534a21ce-goog