From 28b020b5de1e1bee4a44e2536f71fc96c781863c Mon Sep 17 00:00:00 2001
From: Jiewen Yao <jiewen.yao@intel.com>
Date: Sun, 23 Oct 2016 23:21:20 +0800
Subject: [PATCH] UefiCpuPkg/dec: Add PcdCpuSmmStaticPageTable.

If enabled, SMM will not use on-demand paging.
SMM will build static page table for all memory.

The page table size depend on 2 things:
1) The 1G paging capability.
2) The whole system memory/MMIO addressing capability.

A) If the system only supports 2M paging,
When the whole memory/MMIO is 32bit, we only need 1+1+4=6 pages for 4G.
When the whole memory/MMIO is 39bit, we need 1+1+256 pages (~ 1M)
When the whole memory/MMIO is 48bit, we need 1+256+256*256 pages (~ 257M)

B) If the system supports 1G paging.
When the whole memory/MMIO is 32bit, we only need 1+1+4=6 pages for 4G.
(We still generate 2M page for maintenance consideration.)
When the whole memory/MMIO is 39bit, we still need 6 pages.
(We setup 1G paging for >1G.)
When the whole memory/MMIO is 48bit, we need 1+256 pages (~ 1M).

Cc: Jeff Fan <jeff.fan@intel.com>
Cc: Feng Tian <feng.tian@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jiewen Yao <jiewen.yao@intel.com>
Tested-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jeff Fan <jeff.fan@intel.com>
Reviewed-by: Michael D Kinney <michael.d.kinney@intel.com>
---
 UefiCpuPkg/UefiCpuPkg.dec | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/UefiCpuPkg/UefiCpuPkg.dec b/UefiCpuPkg/UefiCpuPkg.dec
index 542704be70..89779c447d 100644
--- a/UefiCpuPkg/UefiCpuPkg.dec
+++ b/UefiCpuPkg/UefiCpuPkg.dec
@@ -206,6 +206,14 @@
   # @Prompt The specified AP target C-state for Mwait.
   gUefiCpuPkgTokenSpaceGuid.PcdCpuApTargetCstate|0|UINT8|0x00000007
 
+  ## Indicates if SMM uses static page table.
+  #  If enabled, SMM will not use on-demand paging. SMM will build static page table for all memory.<BR><BR>
+  #  This flag only impacts X64 build, because SMM alway builds static page table for IA32.
+  #   TRUE  - SMM uses static page table for all memory.<BR>
+  #   FALSE - SMM uses static page table for below 4G memory and use on-demand paging for above 4G memory.<BR>
+  # @Prompt Use static page table for all memory in SMM.
+  gUefiCpuPkgTokenSpaceGuid.PcdCpuSmmStaticPageTable|TRUE|BOOLEAN|0x3213210D
+
 [PcdsDynamic, PcdsDynamicEx]
   ## Contains the pointer to a CPU S3 data buffer of structure ACPI_CPU_DATA.
   # @Prompt The pointer to a CPU S3 data buffer.
-- 
2.39.2