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IntelSiliconPkg VTdDxe: Option to force no early access attr request

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REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1272

To have high confidence in usage for platform, add option (BIT2 of
PcdVTdPolicyPropertyMask) to force no IOMMU access attribute request
recording before DMAR table is installed.

Check PcdVTdPolicyPropertyMask BIT2 before RequestAccessAttribute()
and ProcessRequestedAccessAttribute(), then RequestAccessAttribute(),
ProcessRequestedAccessAttribute() and mAccessRequestXXX variables
could be optimized by compiler when PcdVTdPolicyPropertyMask BIT2 = 1.

Test done:
1: Created case that has IOMMU access attribute request before DMAR
   table is installed, ASSERT was triggered after setting
   PcdVTdPolicyPropertyMask BIT2 to 1.

2. Confirmed RequestAccessAttribute(), ProcessRequestedAccessAttribute()
   and mAccessRequestXXX variables were optimized by compiler after
   setting PcdVTdPolicyPropertyMask BIT2 to 1.

Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Rangasai V Chaganty <rangasai.v.chaganty@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Star Zeng <star.zeng@intel.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
This commit is contained in:
Star Zeng
2018-10-17 17:43:28 +08:00
parent 0bc7448ad2
commit 8c09f30010
3 changed files with 15 additions and 1 deletions
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8
IntelSiliconPkg/Feature/VTd/IntelVTdDxe/DmaProtection.c
View File

@@ -515,7 +515,13 @@ SetupVtd (
ParseDmarAcpiTableRmrr ();
ProcessRequestedAccessAttribute ();
if ((PcdGet8 (PcdVTdPolicyPropertyMask) & BIT2) == 0) {
//
// Support IOMMU access attribute request recording before DMAR table is installed.
// Here is to process the requests.
//
ProcessRequestedAccessAttribute ();
}
for (Index = 0; Index < mVtdUnitNumber; Index++) {
DEBUG ((DEBUG_INFO,"VTD Unit %d (Segment: %04x)\n", Index, mVtdUnitInformation[Index].Segment));