KVM: arm64: Enforce absence of FEAT_HCX on HCRX_EL2

Add the dependency between the HCRX_EL2 register and FEAT_HCX.

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

Author: Marc Zyngier

arch/arm64/kvm/config.c

@@ -214,6 +214,7 @@ struct reg_feat_map_desc {
 #define FEAT_FGT		ID_AA64MMFR0_EL1, FGT, IMP
 #define FEAT_FGT2		ID_AA64MMFR0_EL1, FGT, FGT2
 #define FEAT_MTPMU		ID_AA64DFR0_EL1, MTPMU, IMP
+#define FEAT_HCX		ID_AA64MMFR1_EL1, HCX, IMP
 
 static bool not_feat_aa64el3(struct kvm *kvm)
 {
@@ -929,6 +930,10 @@ static const struct reg_bits_to_feat_map hcrx_feat_map[] = {
 	NEEDS_FEAT(HCRX_EL2_EnAS0, FEAT_LS64_ACCDATA),
 };
 
+
+static const DECLARE_FEAT_MAP(hcrx_desc, __HCRX_EL2,
+			      hcrx_feat_map, FEAT_HCX);
+
 static const struct reg_bits_to_feat_map hcr_feat_map[] = {
 	NEEDS_FEAT(HCR_EL2_TID0, FEAT_AA32EL0),
 	NEEDS_FEAT_FIXED(HCR_EL2_RW, compute_hcr_rw),
@@ -1181,8 +1186,7 @@ void __init check_feature_map(void)
 	check_reg_desc(&hfgitr2_desc);
 	check_reg_desc(&hdfgrtr2_desc);
 	check_reg_desc(&hdfgwtr2_desc);
-	check_feat_map(hcrx_feat_map, ARRAY_SIZE(hcrx_feat_map),
-		       __HCRX_EL2_RES0, "HCRX_EL2");
+	check_reg_desc(&hcrx_desc);
 	check_feat_map(hcr_feat_map, ARRAY_SIZE(hcr_feat_map),
 		       HCR_EL2_RES0, "HCR_EL2");
 	check_feat_map(sctlr2_feat_map, ARRAY_SIZE(sctlr2_feat_map),
@@ -1383,9 +1387,7 @@ void get_reg_fixed_bits(struct kvm *kvm, enum vcpu_sysreg reg, u64 *res0, u64 *r
 		*res1 = HDFGWTR2_EL2_RES1;
 		break;
 	case HCRX_EL2:
-		*res0 = compute_res0_bits(kvm, hcrx_feat_map,
-					  ARRAY_SIZE(hcrx_feat_map), 0, 0);
-		*res0 |= __HCRX_EL2_RES0;
+		*res0 = compute_reg_res0_bits(kvm, &hcrx_desc, 0, 0);
 		*res1 = __HCRX_EL2_RES1;
 		break;
 	case HCR_EL2: