KVM: arm64: Factor out setting HCRX_EL2 traps into separate function

Factor out the code for setting a vcpu's HCRX_EL2 traps in to a
separate inline function. This allows us to share the logic with
pKVM when setting the traps in protected mode.

No functional change intended.

Reviewed-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Fuad Tabba <tabba@google.com>
Link: https://lore.kernel.org/r/20250314111832.4137161-2-tabba@google.com
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>

Author: Fuad Tabba

arch/arm64/include/asm/kvm_emulate.h

@@ -649,4 +649,28 @@ static inline bool guest_hyp_sve_traps_enabled(const struct kvm_vcpu *vcpu)
 {
 	return __guest_hyp_cptr_xen_trap_enabled(vcpu, ZEN);
 }
+
+static inline void vcpu_set_hcrx(struct kvm_vcpu *vcpu)
+{
+	struct kvm *kvm = vcpu->kvm;
+
+	if (cpus_have_final_cap(ARM64_HAS_HCX)) {
+		/*
+		 * In general, all HCRX_EL2 bits are gated by a feature.
+		 * The only reason we can set SMPME without checking any
+		 * feature is that its effects are not directly observable
+		 * from the guest.
+		 */
+		vcpu->arch.hcrx_el2 = HCRX_EL2_SMPME;
+
+		if (kvm_has_feat(kvm, ID_AA64ISAR2_EL1, MOPS, IMP))
+			vcpu->arch.hcrx_el2 |= (HCRX_EL2_MSCEn | HCRX_EL2_MCE2);
+
+		if (kvm_has_tcr2(kvm))
+			vcpu->arch.hcrx_el2 |= HCRX_EL2_TCR2En;
+
+		if (kvm_has_fpmr(kvm))
+			vcpu->arch.hcrx_el2 |= HCRX_EL2_EnFPM;
+	}
+}
 #endif /* __ARM64_KVM_EMULATE_H__ */

arch/arm64/kvm/sys_regs.c

@@ -4971,25 +4971,7 @@ void kvm_calculate_traps(struct kvm_vcpu *vcpu)
 	mutex_lock(&kvm->arch.config_lock);
 	vcpu_set_hcr(vcpu);
 	vcpu_set_ich_hcr(vcpu);
-
-	if (cpus_have_final_cap(ARM64_HAS_HCX)) {
-		/*
-		 * In general, all HCRX_EL2 bits are gated by a feature.
-		 * The only reason we can set SMPME without checking any
-		 * feature is that its effects are not directly observable
-		 * from the guest.
-		 */
-		vcpu->arch.hcrx_el2 = HCRX_EL2_SMPME;
-
-		if (kvm_has_feat(kvm, ID_AA64ISAR2_EL1, MOPS, IMP))
-			vcpu->arch.hcrx_el2 |= (HCRX_EL2_MSCEn | HCRX_EL2_MCE2);
-
-		if (kvm_has_tcr2(kvm))
-			vcpu->arch.hcrx_el2 |= HCRX_EL2_TCR2En;
-
-		if (kvm_has_fpmr(kvm))
-			vcpu->arch.hcrx_el2 |= HCRX_EL2_EnFPM;
-	}
+	vcpu_set_hcrx(vcpu);
 
 	if (test_bit(KVM_ARCH_FLAG_FGU_INITIALIZED, &kvm->arch.flags))
 		goto out;