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OvmfPkg/IoMmuDxe: abort harder on memory encryption mask failures

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Upon a MemEncryptSevClearPageEncMask() failure in Map(), it wouldn't be
difficult to release the bounce buffer that was implicitly allocated for
BusMasterRead[64] and BusMasterWrite[64] operations. However, undoing any
partial memory encryption mask changes -- partial page splitting and PTE
modifications -- is practically impossible. (For example, restoring the
encryption mask on the entire range has no reason to fare any better than
the MemEncryptSevClearPageEncMask() call itself.)

For this reason, keep ASSERT_EFI_ERROR(), but hang in RELEASE builds too,
if MemEncryptSevClearPageEncMask() or MemEncryptSevSetPageEncMask() fails.

Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Tested-by: Brijesh Singh <brijesh.singh@amd.com>
Reviewed-by: Brijesh Singh <brijesh.singh@amd.com>
This commit is contained in:
Laszlo Ersek 2017-08-02 19:35:38 +02:00
parent 58e681406f
commit f1658838c2
1 changed files with 8 additions and 2 deletions
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6
OvmfPkg/IoMmuDxe/AmdSevIoMmu.c
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@ -224,6 +224,9 @@ IoMmuMap (
TRUE TRUE
); );
ASSERT_EFI_ERROR (Status); ASSERT_EFI_ERROR (Status);
if (EFI_ERROR (Status)) {
CpuDeadLoop ();
}
// //
// If this is a read operation from the Bus Master's point of view, // If this is a read operation from the Bus Master's point of view,
@ -366,6 +369,9 @@ IoMmuUnmap (
TRUE TRUE
); );
ASSERT_EFI_ERROR (Status); ASSERT_EFI_ERROR (Status);
if (EFI_ERROR (Status)) {
CpuDeadLoop ();
}
// //
// For BusMasterCommonBuffer[64] operations, copy the stashed data to the // For BusMasterCommonBuffer[64] operations, copy the stashed data to the