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UefiCpuPkg/ArmMmuLib: Validate CCA protection attribute bit

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When deriving the CCA protection attribute from the memory descriptor
virtual and physical addresses, assert that the descriptor uses either a
protected mapping or the expected Realm protection bit.

This catches malformed initial MMU descriptors without rejecting valid
protected IPA mappings.

Signed-off-by: Sami Mujawar <sami.mujawar@arm.com>
This commit is contained in:
Sami Mujawar 2026-06-18 18:32:25 +01:00
parent d052e3a149
commit a7a3220c9e
1 changed files with 24 additions and 1 deletions
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25
UefiCpuPkg/Library/ArmMmuLib/AArch64/ArmMmuLibCore.c
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@ -552,7 +552,9 @@ FillTranslationTable (
IN BOOLEAN Lpa2Enabled
)
{
UINT64 CcaProtectionAttribute;
EFI_STATUS Status;
UINT64 CcaProtectionAttribute;
UINT64 CcaProtectionAttributeMask;
//
// The CCA protection attribute corresponds to the (IPA_WIDTH - 1) bit of the
@ -560,6 +562,9 @@ FillTranslationTable (
// in this bit. Derive the attribute by XORing the two addresses.
//
// NOTE: If more than one bit differs, the memory map is misconfigured.
// In case of LPA2 if the CCA protection attribute bit falls in the top
// bits, i.e. 50 & 51; we expect these to be shifted appropriately when
// the memory map is setup.
//
CcaProtectionAttribute = MemoryRegion->VirtualBase ^ MemoryRegion->PhysicalBase;
@ -568,6 +573,24 @@ FillTranslationTable (
//
ASSERT (((CcaProtectionAttribute & (CcaProtectionAttribute - 1)) == 0));
//
// Get the CCA Protection Attribute mask.
//
Status = ArmCcaGetMemoryProtectionAttribute (&CcaProtectionAttributeMask);
if (EFI_ERROR (Status)) {
return Status;
}
//
// The CCA protection attribute is either absent for protected IPA mappings,
// or equal to the expected Realm protection attribute mask for unprotected
// IPA mappings.
//
ASSERT (
(CcaProtectionAttribute == 0) ||
(CcaProtectionAttribute == CcaProtectionAttributeMask)
);
return UpdateRegionMapping (
MemoryRegion->VirtualBase,
MemoryRegion->Length,