kvm: arm64: handle single-step of userspace mmio instructions

The system state of KVM when using userspace emulation is not complete
until we return into KVM_RUN. To handle mmio related updates we wait
until they have been committed and then schedule our KVM_EXIT_DEBUG.

The kvm_arm_handle_step_debug() helper tells us if we need to return
and sets up the exit_reason for us.
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>

virt/kvm/arm/arm.c

@@ -628,6 +628,9 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *run)
 		ret = kvm_handle_mmio_return(vcpu, vcpu->run);
 		if (ret)
 			return ret;
+		if (kvm_arm_handle_step_debug(vcpu, vcpu->run))
+			return 0;
+
 	}
 
 	if (run->immediate_exit)