Commit c60d36b4d1ee1f69b7cca897d3621dfa951895c2
* UefiCpuPkg/SmmCpu: Block access-out only when static paging is used
updated page fault handler to treat SMM access-out as allowed
address when static paging is not used.
But that commit is not complete because the page table is still
updated in SetUefiMemMapAttributes() for non-SMRAM memory. When SMM
code accesses non-SMRAM memory, page fault is still generated.
This patch skips to update page table for non-SMRAM memory and
page table itself.
Signed-off-by: Ray Ni <ray...@intel.com>
Cc: Eric Dong <eric.d...@intel.com>
Cc: Jiewen Yao <jiewen....@intel.com>
Cc: Jian J Wang <jian.j.w...@intel.com>
---
UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.c | 21 +++++++++++++++------
1 file changed, 15 insertions(+), 6 deletions(-)
diff --git a/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.c
b/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.c
index 69a04dfb23..d7d94c8b6d 100644
--- a/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.c
+++ b/UefiCpuPkg/PiSmmCpuDxeSmm/PiSmmCpuDxeSmm.c
@@ -1121,6 +1121,9 @@ FindSmramInfo (
*SmrrBase = (UINT32)CurrentSmramRange->CpuStart;
*SmrrSize = (UINT32)CurrentSmramRange->PhysicalSize;
+ //
+ // Extend *SmrrBase/*SmrrSize to include adjacent SMRAM ranges
+ //
do {
Found = FALSE;
for (Index = 0; Index < mSmmCpuSmramRangeCount; Index++) {
@@ -1432,14 +1435,20 @@ PerformRemainingTasks (
SetMemMapAttributes ();
//
- // For outside SMRAM, we only map SMM communication buffer or MMIO.
+ // Protect memory outside SMRAM when SMM Static Page Table is enabled.
//
- SetUefiMemMapAttributes ();
+ if (IsStaticPageTableEnabled ()) {
- //
- // Set page table itself to be read-only
- //
- SetPageTableAttributes ();
+ //
+ // For outside SMRAM, we only map SMM communication buffer or MMIO.
+ //
+ SetUefiMemMapAttributes ();
+
+ //
+ // Set page table itself to be read-only
+ //
+ SetPageTableAttributes ();
+ }
//
// Configure SMM Code Access Check feature if available.
--
2.21.0.windows.1
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