ARM: KVM: abstract SAS decoding away

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@cs.columbia.edu>

arch/arm/include/asm/kvm_emulate.h

@@ -120,4 +120,20 @@ static inline bool kvm_vcpu_dabt_iss1tw(struct kvm_vcpu *vcpu)
 	return kvm_vcpu_get_hsr(vcpu) & HSR_DABT_S1PTW;
 }
 
+/* Get Access Size from a data abort */
+static inline int kvm_vcpu_dabt_get_as(struct kvm_vcpu *vcpu)
+{
+	switch ((kvm_vcpu_get_hsr(vcpu) >> 22) & 0x3) {
+	case 0:
+		return 1;
+	case 1:
+		return 2;
+	case 2:
+		return 4;
+	default:
+		kvm_err("Hardware is weird: SAS 0b11 is reserved\n");
+		return -EFAULT;
+	}
+}
+
 #endif /* __ARM_KVM_EMULATE_H__ */

arch/arm/kvm/mmio.c

@@ -77,20 +77,9 @@ static int decode_hsr(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
 		return 1;
 	}
 
-	switch ((kvm_vcpu_get_hsr(vcpu) >> 22) & 0x3) {
-	case 0:
-		len = 1;
-		break;
-	case 1:
-		len = 2;
-		break;
-	case 2:
-		len = 4;
-		break;
-	default:
-		kvm_err("Hardware is weird: SAS 0b11 is reserved\n");
-		return -EFAULT;
-	}
+	len = kvm_vcpu_dabt_get_as(vcpu);
+	if (unlikely(len < 0))
+		return len;
 
 	is_write = kvm_vcpu_dabt_iswrite(vcpu);
 	sign_extend = kvm_vcpu_dabt_issext(vcpu);