KVM: arm64: Enforce absence of FEAT_SCTLR2 on SCTLR2_EL{1,2}

Enforce that SCTLR2_EL{1,2} are RES0 when FEAT_SCTLR2 isn't present.

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

Author: Marc Zyngier

arch/arm64/kvm/config.c

@@ -1026,6 +1026,9 @@ static const struct reg_bits_to_feat_map sctlr2_feat_map[] = {
 		   FEAT_CPA2),
 };
 
+static const DECLARE_FEAT_MAP(sctlr2_desc, SCTLR2_EL1,
+			      sctlr2_feat_map, FEAT_SCTLR2);
+
 static const struct reg_bits_to_feat_map tcr2_el2_feat_map[] = {
 	NEEDS_FEAT(TCR2_EL2_FNG1	|
 		   TCR2_EL2_FNG0	|
@@ -1192,8 +1195,7 @@ void __init check_feature_map(void)
 	check_reg_desc(&hdfgwtr2_desc);
 	check_reg_desc(&hcrx_desc);
 	check_reg_desc(&hcr_desc);
-	check_feat_map(sctlr2_feat_map, ARRAY_SIZE(sctlr2_feat_map),
-		       SCTLR2_EL1_RES0, "SCTLR2_EL1");
+	check_reg_desc(&sctlr2_desc);
 	check_feat_map(tcr2_el2_feat_map, ARRAY_SIZE(tcr2_el2_feat_map),
 		       TCR2_EL2_RES0, "TCR2_EL2");
 	check_feat_map(sctlr_el1_feat_map, ARRAY_SIZE(sctlr_el1_feat_map),
@@ -1399,9 +1401,7 @@ void get_reg_fixed_bits(struct kvm *kvm, enum vcpu_sysreg reg, u64 *res0, u64 *r
 		break;
 	case SCTLR2_EL1:
 	case SCTLR2_EL2:
-		*res0 = compute_res0_bits(kvm, sctlr2_feat_map,
-					  ARRAY_SIZE(sctlr2_feat_map), 0, 0);
-		*res0 |= SCTLR2_EL1_RES0;
+		*res0 = compute_reg_res0_bits(kvm, &sctlr2_desc, 0, 0);
 		*res1 = SCTLR2_EL1_RES1;
 		break;
 	case TCR2_EL2: