diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c
index 6d9be74bb673..895095dc684e 100644
--- a/arch/x86/kvm/xen.c
+++ b/arch/x86/kvm/xen.c
@@ -1678,15 +1678,14 @@ int kvm_xen_hypercall(struct kvm_vcpu *vcpu)
 	bool handled = false;
 	u8 cpl;
 
-	input = (u64)kvm_register_read(vcpu, VCPU_REGS_RAX);
-
 	/* Hyper-V hypercalls get bit 31 set in EAX */
-	if ((input & 0x80000000) &&
+	if ((kvm_rax_read(vcpu) & 0x80000000) &&
 	    kvm_hv_hypercall_enabled(vcpu))
 		return kvm_hv_hypercall(vcpu);
 
 	longmode = is_64_bit_hypercall(vcpu);
 	if (!longmode) {
+		input = (u32)kvm_rax_read(vcpu);
 		params[0] = (u32)kvm_rbx_read(vcpu);
 		params[1] = (u32)kvm_rcx_read(vcpu);
 		params[2] = (u32)kvm_rdx_read(vcpu);
@@ -1696,6 +1695,7 @@ int kvm_xen_hypercall(struct kvm_vcpu *vcpu)
 	}
 	else {
 #ifdef CONFIG_X86_64
+		input = (u64)kvm_rax_read(vcpu);
 		params[0] = (u64)kvm_rdi_read(vcpu);
 		params[1] = (u64)kvm_rsi_read(vcpu);
 		params[2] = (u64)kvm_rdx_read(vcpu);