KVM: arm64: Convert MDCR_EL2 RES0 handling to compute_reg_res0_bits()

While MDCR_EL2 cannot be RES0, convert it to the same infrastructure
anyway, as it make things cleaner.

Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>

Author: Marc Zyngier

arch/arm64/kvm/config.c

@@ -1162,6 +1162,9 @@ static const struct reg_bits_to_feat_map mdcr_el2_feat_map[] = {
 		   FEAT_AA64EL1),
 };
 
+static const DECLARE_FEAT_MAP(mdcr_el2_desc, MDCR_EL2,
+			      mdcr_el2_feat_map, FEAT_AA64EL2);
+
 static void __init check_feat_map(const struct reg_bits_to_feat_map *map,
 				  int map_size, u64 res0, const char *str)
 {
@@ -1204,8 +1207,7 @@ void __init check_feature_map(void)
 	check_reg_desc(&sctlr2_desc);
 	check_reg_desc(&tcr2_el2_desc);
 	check_reg_desc(&sctlr_el1_desc);
-	check_feat_map(mdcr_el2_feat_map, ARRAY_SIZE(mdcr_el2_feat_map),
-		       MDCR_EL2_RES0, "MDCR_EL2");
+	check_reg_desc(&mdcr_el2_desc);
 }
 
 static bool idreg_feat_match(struct kvm *kvm, const struct reg_bits_to_feat_map *map)
@@ -1417,9 +1419,7 @@ void get_reg_fixed_bits(struct kvm *kvm, enum vcpu_sysreg reg, u64 *res0, u64 *r
 		*res1 = SCTLR_EL1_RES1;
 		break;
 	case MDCR_EL2:
-		*res0 = compute_res0_bits(kvm, mdcr_el2_feat_map,
-					  ARRAY_SIZE(mdcr_el2_feat_map), 0, 0);
-		*res0 |= MDCR_EL2_RES0;
+		*res0 = compute_reg_res0_bits(kvm, &mdcr_el2_desc, 0, 0);
 		*res1 = MDCR_EL2_RES1;
 		break;
 	default: