Add a per-RAMBlock bitmap (named cgs_bmap) to record if a guest-physical
address is private/shared. The bitmap is allocated only when the guest is
a confidential guest, so it's allocated in the private memory backend.
By default, bits are 0 in the bitmap to indicate all the guest pages are
private pages. When the guest changes a private page to share or shared
page to private later, it exits to QEMU with the KVM_EXIT_MEMORY_FAULT
reason and the cgs_bmap will be updated accordingly.
Signed-off-by: Wei Wang <wei.w.wang@intel.com>
35bb3ae328