SGX_ENCL_PAGE_BEING_RECLAIMED flag is set when the enclave page is beingLGTM.
reclaimed (moved to the backing store). This flag however has two
logical meanings:
1. Don't attempt to load the enclave page (the page is busy).
2. Don't attempt to remove the PCMD page corresponding to this enclave
page (the PCMD page is busy).
To reflect these two meanings, split SGX_ENCL_PAGE_BEING_RECLAIMED into
two flags: SGX_ENCL_PAGE_BUSY and SGX_ENCL_PAGE_PCMD_BUSY. Currently,
both flags are set only when the enclave page is being reclaimed. A
future commit will introduce a new case when the enclave page is being
removed; this new case will set only the SGX_ENCL_PAGE_BUSY flag.