[edk2-devel] [PATCH v2 3/3] IntelSiliconPkg/PlatformVTdInfoSamplePei: Install Null Root Entry Table

[Sheng Wei]

BIOS uses TE with a null root entry table to block VT-d engine access
to block any DMA traffic in pre-memory phase.

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=2867

Change-Id: I6c086c1f26e60f781de79cc37677cc5717c5edec
Cc: Ray Ni <ray.ni at intel.com>
Cc: Rangasai V Chaganty <rangasai.v.chaganty at intel.com>
Signed-off-by: Sheng Wei <w.sheng at intel.com>
---
 .../PlatformVTdInfoSamplePei/PlatformVTdInfoSamplePei.c   | 15 +++++++++++++++
 .../PlatformVTdInfoSamplePei/PlatformVTdInfoSamplePei.inf |  3 ++-
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/Silicon/Intel/IntelSiliconPkg/Feature/VTd/PlatformVTdInfoSamplePei/PlatformVTdInfoSamplePei.c b/Silicon/Intel/IntelSiliconPkg/Feature/VTd/PlatformVTdInfoSamplePei/PlatformVTdInfoSamplePei.c
index 6f6c14f7..465bc2a4 100644
--- a/Silicon/Intel/IntelSiliconPkg/Feature/VTd/PlatformVTdInfoSamplePei/PlatformVTdInfoSamplePei.c
+++ b/Silicon/Intel/IntelSiliconPkg/Feature/VTd/PlatformVTdInfoSamplePei/PlatformVTdInfoSamplePei.c
@@ -164,6 +164,15 @@ EFI_PEI_PPI_DESCRIPTOR mPlatformVTdNoIgdInfoSampleDesc = {
   &mPlatformVTdNoIgdSample
 };
 
+// BIOS uses TE with a null root entry table to block VT-d engine access to block any DMA traffic in pre-memory phase.
+EDKII_VTD_NULL_ROOT_ENTRY_TABLE_PPI mNullRootEntryTable = 0xFED20000;
+
+EFI_PEI_PPI_DESCRIPTOR mPlatformNullRootEntryTableDesc = {
+  (EFI_PEI_PPI_DESCRIPTOR_PPI | EFI_PEI_PPI_DESCRIPTOR_TERMINATE_LIST),
+  &gEdkiiVTdNullRootEntryTableGuid,
+  &mNullRootEntryTable
+};
+
 /**
   Initialize VTd register.
   Initialize the VTd hardware unit which has INCLUDE_PCI_ALL set
@@ -344,6 +353,12 @@ PlatformVTdInfoSampleInitialize (
   if (!EFI_ERROR(Status)) {
     SiliconInitialized = TRUE;
   }
+
+  Status = PeiServicesInstallPpi (&mPlatformNullRootEntryTableDesc);
+  if (EFI_ERROR (Status)) {
+    DEBUG ((DEBUG_ERROR , "Failed to install the NullRootEntryTable ppi - %r\n", Status));
+  }
+
   DEBUG ((DEBUG_INFO, "SiliconInitialized - %x\n", SiliconInitialized));
   if (!SiliconInitialized) {
     Status = PeiServicesNotifyPpi (&mSiliconInitializedNotifyList);
diff --git a/Silicon/Intel/IntelSiliconPkg/Feature/VTd/PlatformVTdInfoSamplePei/PlatformVTdInfoSamplePei.inf b/Silicon/Intel/IntelSiliconPkg/Feature/VTd/PlatformVTdInfoSamplePei/PlatformVTdInfoSamplePei.inf
index dacfdf5e..b35853b6 100644
--- a/Silicon/Intel/IntelSiliconPkg/Feature/VTd/PlatformVTdInfoSamplePei/PlatformVTdInfoSamplePei.inf
+++ b/Silicon/Intel/IntelSiliconPkg/Feature/VTd/PlatformVTdInfoSamplePei/PlatformVTdInfoSamplePei.inf
@@ -38,7 +38,8 @@
   IoLib
 
 [Ppis]
-  gEdkiiVTdInfoPpiGuid         ## PRODUCES
+  gEdkiiVTdInfoPpiGuid              ## PRODUCES
+  gEdkiiVTdNullRootEntryTableGuid   ## PRODUCES
 
 [Depex]
   gEfiPeiMasterBootModePpiGuid
-- 
2.16.2.windows.1


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