What you should do, instead, is add an isol. VM specific
hv_cc_platform_has() just like amd_cc_platform_has() and handle
the cc_attrs there for your platform, like return false for
CC_ATTR_GUEST_MEM_ENCRYPT and then you won't need to add that hv_* thing
everywhere.
And then fix it up in __set_memory_enc_dec() too.