KVM: MIPS: Add callback to check extension

Add an implementation callback for checking presence of KVM extensions.
This allows implementation specific extensions to be provided without
ifdefs in mips.c.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org

arch/mips/kvm/trap_emul.c

@@ -488,6 +488,22 @@ static int kvm_trap_emul_handle_msa_disabled(struct kvm_vcpu *vcpu)
 	return ret;
 }
 
+static int kvm_trap_emul_check_extension(struct kvm *kvm, long ext)
+{
+	int r;
+
+	switch (ext) {
+	case KVM_CAP_MIPS_TE:
+		r = 1;
+		break;
+	default:
+		r = 0;
+		break;
+	}
+
+	return r;
+}
+
 static int kvm_trap_emul_vcpu_init(struct kvm_vcpu *vcpu)
 {
 	struct mm_struct *kern_mm = &vcpu->arch.guest_kernel_mm;
@@ -1238,6 +1254,7 @@ static struct kvm_mips_callbacks kvm_trap_emul_callbacks = {
 	.handle_fpe = kvm_trap_emul_handle_fpe,
 	.handle_msa_disabled = kvm_trap_emul_handle_msa_disabled,
 
+	.check_extension = kvm_trap_emul_check_extension,
 	.vcpu_init = kvm_trap_emul_vcpu_init,
 	.vcpu_uninit = kvm_trap_emul_vcpu_uninit,
 	.vcpu_setup = kvm_trap_emul_vcpu_setup,