On Wed, Sep 13, 2023, Binbin Wu wrote: > diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h > index e3054e3e46d5..179931b73876 100644 > --- a/arch/x86/include/asm/kvm-x86-ops.h > +++ b/arch/x86/include/asm/kvm-x86-ops.h > @@ -134,6 +134,7 @@ KVM_X86_OP(msr_filter_changed) > KVM_X86_OP(complete_emulated_msr) > KVM_X86_OP(vcpu_deliver_sipi_vector) > KVM_X86_OP_OPTIONAL_RET0(vcpu_get_apicv_inhibit_reasons); > +KVM_X86_OP(get_untagged_addr) This needs to be KVM_X86_OP_OPTIONAL(), otherwise kvm_ops_update() will complain about SVM not implementing the hook. Hooray for useful warns! (I missed this in review).