UefiCpuPkg:Limit PhysicalAddressBits in special case

When creating smm page table, limit maximum
supported physical addresses bits returned by
CalculateMaximumSupportAddress() to 47 if
5-Level Paging is disabled.

This commit is to avoid issue that more than
47-bit physical addresses are requested in smm
page table when 5-level paging is disabled.
4-level paging supports translating 48-bit
linear addresses to 52-bit physical addresses.
Since linear addresses are sign-extended,
linear-address space of 4-level paging is:
[0, 2^47-1] and
[0xffff8000_00000000, 0xffffffff_ffffffff].
So only [0, 2^47-1] linear-address range maps
to the identical physical-address range when
5-Level paging is disabled.

Signed-off-by: Dun Tan <dun.tan@intel.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>
Reviewed-by: Gerd Hoffmann <kraxel@redhat.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>

0 files changed, 0 insertions, 0 deletions