This PCD holds the address mask for page table entries when memory
encryption is enabled on AMD processors supporting the Secure Encrypted
Virtualization (SEV) feature.
The mask is applied when 4GB tables are created (UefiCapsule.c), and when
the tables are expanded on-demand by page-faults above 4GB's (X64Entry.c).
Cc: Feng Tian <feng.tian@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Leo Duran <leo.duran@amd.com>
Reviewed-by: Star Zeng <star.zeng@intel.com>
We are going to reduce reserved memory consumption by page table buffer,
then OS can have more available memory to use.
Take PhysicalAddressBits = 48 and 2MB page granularity as example,
1:1 Virtual to Physical identity mapping page table buffer needs to be
((512 + 1) * 512 + 1) * 4096 = 1075843072 bytes = 0x40201000 bytes.
The code is updated to build 4G page table by default and only use 8 extra
pages to handles > 4G request by page fault.
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Star Zeng <star.zeng@intel.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18069 6f19259b-4bc3-4df7-8a09-765794883524
Leo Duran
Star Zeng
jyao1
li-elvin