2c7c5d3d39
Make sure we complete the I/O after determining we have a ucall, which is I/O. Also allow the *uc parameter to optionally be NULL. It's quite possible that a test case will only care about the return value, like for example when looping on a check for UCALL_DONE. Signed-off-by: Andrew Jones <drjones@redhat.com> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>