1. A computer program product for facilitating management of storage of a computing environment that supports pageable guests, said computer program product comprising: a non-transitory computer readable storage medium readable by a processor and storing instructions for execution by the processor for performing a method comprising: detecting a storage protection fault in an attempt to access an area of storage that is protected by at least one of a host level of protection and a guest level of protection, wherein the area of storage specifies a first frame of host main storage; determining whether the detected storage protection fault is due to the host level of protection or the guest level of protection, wherein the determining distinguishes between the storage protection fault being caused by host level protection or guest level protection; responsive to the storage protection fault being due to the guest level of protection, performing a first action, the first action indicating storing is not permitted by the guest level of protection; and responsive to the storage protection fault being due to the host level of protection, performing a second action, the second action comprising: responsive to determining that the area of storage is part of a host copy-on-write scheme, assigning a second frame to the area of storage, copying contents of the first frame to the second frame, and permitting guest storing to the area of storage comprising the second frame; and responsive to determining that the area of storage is not part of the host copy-on-write scheme, indicating storing is not permitted by the host level of protection.