KVM: arm64: Convert HCR_EL2 RES0 handling to compute_reg_res0_bits()

While HCR_EL2 is unlikely to ever be RES0 (at least when NV is on),
but consistency doesn't hurt, and it can be described in the same
way as the other registers.

Convert it over to the new RES0-computing infrastructure.

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

Author: Marc Zyngier

arch/arm64/kvm/config.c

@@ -136,6 +136,7 @@ struct reg_feat_map_desc {
 #define FEAT_AA32EL0		ID_AA64PFR0_EL1, EL0, AARCH32
 #define FEAT_AA32EL1		ID_AA64PFR0_EL1, EL1, AARCH32
 #define FEAT_AA64EL1		ID_AA64PFR0_EL1, EL1, IMP
+#define FEAT_AA64EL2		ID_AA64PFR0_EL1, EL2, IMP
 #define FEAT_AA64EL3		ID_AA64PFR0_EL1, EL3, IMP
 #define FEAT_AIE		ID_AA64MMFR3_EL1, AIE, IMP
 #define FEAT_S2POE		ID_AA64MMFR3_EL1, S2POE, IMP
@@ -1005,6 +1006,9 @@ static const struct reg_bits_to_feat_map hcr_feat_map[] = {
 	NEEDS_FEAT_FIXED(HCR_EL2_E2H, compute_hcr_e2h),
 };
 
+static const DECLARE_FEAT_MAP(hcr_desc, HCR_EL2,
+			      hcr_feat_map, FEAT_AA64EL2);
+
 static const struct reg_bits_to_feat_map sctlr2_feat_map[] = {
 	NEEDS_FEAT(SCTLR2_EL1_NMEA	|
 		   SCTLR2_EL1_EASE,
@@ -1187,8 +1191,7 @@ void __init check_feature_map(void)
 	check_reg_desc(&hdfgrtr2_desc);
 	check_reg_desc(&hdfgwtr2_desc);
 	check_reg_desc(&hcrx_desc);
-	check_feat_map(hcr_feat_map, ARRAY_SIZE(hcr_feat_map),
-		       HCR_EL2_RES0, "HCR_EL2");
+	check_reg_desc(&hcr_desc);
 	check_feat_map(sctlr2_feat_map, ARRAY_SIZE(sctlr2_feat_map),
 		       SCTLR2_EL1_RES0, "SCTLR2_EL1");
 	check_feat_map(tcr2_el2_feat_map, ARRAY_SIZE(tcr2_el2_feat_map),
@@ -1278,15 +1281,13 @@ static u64 compute_reg_res0_bits(struct kvm *kvm,
 	return res0;
 }
 
-static u64 compute_fixed_bits(struct kvm *kvm,
-			      const struct reg_bits_to_feat_map *map,
-			      int map_size,
-			      u64 *fixed_bits,
-			      unsigned long require,
-			      unsigned long exclude)
+static u64 compute_reg_fixed_bits(struct kvm *kvm,
+				  const struct reg_feat_map_desc *r,
+				  u64 *fixed_bits, unsigned long require,
+				  unsigned long exclude)
 {
-	return __compute_fixed_bits(kvm, map, map_size, fixed_bits,
-				    require | FIXED_VALUE, exclude);
+	return __compute_fixed_bits(kvm, r->bit_feat_map, r->bit_feat_map_sz,
+				    fixed_bits, require | FIXED_VALUE, exclude);
 }
 
 void compute_fgu(struct kvm *kvm, enum fgt_group_id fgt)
@@ -1391,12 +1392,9 @@ void get_reg_fixed_bits(struct kvm *kvm, enum vcpu_sysreg reg, u64 *res0, u64 *r
 		*res1 = __HCRX_EL2_RES1;
 		break;
 	case HCR_EL2:
-		mask = compute_fixed_bits(kvm, hcr_feat_map,
-					  ARRAY_SIZE(hcr_feat_map), &fixed,
-					  0, 0);
-		*res0 = compute_res0_bits(kvm, hcr_feat_map,
-					  ARRAY_SIZE(hcr_feat_map), 0, 0);
-		*res0 |= HCR_EL2_RES0 | (mask & ~fixed);
+		mask = compute_reg_fixed_bits(kvm, &hcr_desc, &fixed, 0, 0);
+		*res0 = compute_reg_res0_bits(kvm, &hcr_desc, 0, 0);
+		*res0 |= (mask & ~fixed);
 		*res1 = HCR_EL2_RES1 | (mask & fixed);
 		break;
 	case SCTLR2_EL1: