[PATCH v1 1/1] UefiCpuPkg: PiSmmCpuDxeSmm: Not to Change Bitwidth During Static Paging


Kun Qin
 

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3300

Current implementation of SetStaticPageTable routine in PiSmmCpuDxeSmm
driver will check a global variable mPhysicalAddressBits, and eventually
cap any value larger than 39 at 39.

This global variable is used in ConvertMemoryPageAttributes, which backs
SmmSetMemoryAttributes and SmmClearMemoryAttributes. Thus for a processor
that supports more than 39 bits width, trying to mark page table regions
higher than 39-bit will always return EFI_UNSUPPROTED.

This change replaced the changed bitwidth to a stack based variable.

Cc: Eric Dong <eric.dong@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Rahul Kumar <rahul1.kumar@intel.com>

Signed-off-by: Kun Qin <kuqin12@gmail.com>
---
UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c | 25 +++++++++++---------
1 file changed, 14 insertions(+), 11 deletions(-)

diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c b/UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c
index 6902584b1fbd..0caee8a27abe 100644
--- a/UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c
+++ b/UefiCpuPkg/PiSmmCpuDxeSmm/X64/PageTbl.c
@@ -226,6 +226,7 @@ SetStaticPageTable (
UINTN IndexOfPml4Entries;
UINTN IndexOfPdpEntries;
UINTN IndexOfPageDirectoryEntries;
+ UINT64 PhysicalAddressBits;
UINT64 *PageMapLevel5Entry;
UINT64 *PageMapLevel4Entry;
UINT64 *PageMap;
@@ -237,26 +238,28 @@ SetStaticPageTable (
// IA-32e paging translates 48-bit linear addresses to 52-bit physical addresses
// when 5-Level Paging is disabled.
//
- ASSERT (mPhysicalAddressBits <= 52);
- if (!m5LevelPagingNeeded && mPhysicalAddressBits > 48) {
- mPhysicalAddressBits = 48;
+ PhysicalAddressBits = mPhysicalAddressBits;
+
+ ASSERT (PhysicalAddressBits <= 52);
+ if (!m5LevelPagingNeeded && PhysicalAddressBits > 48) {
+ PhysicalAddressBits = 48;
}

NumberOfPml5EntriesNeeded = 1;
- if (mPhysicalAddressBits > 48) {
- NumberOfPml5EntriesNeeded = (UINTN) LShiftU64 (1, mPhysicalAddressBits - 48);
- mPhysicalAddressBits = 48;
+ if (PhysicalAddressBits > 48) {
+ NumberOfPml5EntriesNeeded = (UINTN) LShiftU64 (1, PhysicalAddressBits - 48);
+ PhysicalAddressBits = 48;
}

NumberOfPml4EntriesNeeded = 1;
- if (mPhysicalAddressBits > 39) {
- NumberOfPml4EntriesNeeded = (UINTN) LShiftU64 (1, mPhysicalAddressBits - 39);
- mPhysicalAddressBits = 39;
+ if (PhysicalAddressBits > 39) {
+ NumberOfPml4EntriesNeeded = (UINTN) LShiftU64 (1, PhysicalAddressBits - 39);
+ PhysicalAddressBits = 39;
}

NumberOfPdpEntriesNeeded = 1;
- ASSERT (mPhysicalAddressBits > 30);
- NumberOfPdpEntriesNeeded = (UINTN) LShiftU64 (1, mPhysicalAddressBits - 30);
+ ASSERT (PhysicalAddressBits > 30);
+ NumberOfPdpEntriesNeeded = (UINTN) LShiftU64 (1, PhysicalAddressBits - 30);

//
// By architecture only one PageMapLevel4 exists - so lets allocate storage for it.
--
2.31.0.windows.1

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