File ovmf-OvmfPkg-IncompatiblePciDeviceSupportDxe-Ignore-Optio.patch of Package ovmf.25915
From c477b2783f6d95b62266f4fff9b0c286ac1d7bb8 Mon Sep 17 00:00:00 2001
From: Min Xu <min.m.xu@intel.com>
Date: Tue, 8 Mar 2022 16:07:16 +0800
Subject: [PATCH] OvmfPkg/IncompatiblePciDeviceSupportDxe: Ignore OptionRom in
Td guest
RFC: https://bugzilla.tianocore.org/show_bug.cgi?id=3429
Host VMM may inject OptionRom which is untrusted in Td guest. So PCI
OptionRom needs to be ignored if it is Td guest. According to
"Table 20. ACPI 2.0 & 3.0 QWORD Address Space Descriptor Usage"
PI spec 1.7, type-specific flags can be set to 0 when Address
Translation Offset == 6 to skip device option ROM.
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Erdem Aktas <erdemaktas@google.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Signed-off-by: Min Xu <min.m.xu@intel.com>
---
.../IncompatiblePciDeviceSupport.c | 46 +++++++++++++++++++
1 file changed, 46 insertions(+)
diff --git a/OvmfPkg/IncompatiblePciDeviceSupportDxe/IncompatiblePciDeviceSupport.c b/OvmfPkg/IncompatiblePciDeviceSupportDxe/IncompatiblePciDeviceSupport.c
index f5c03bdf6d..2d385d26ef 100644
--- a/OvmfPkg/IncompatiblePciDeviceSupportDxe/IncompatiblePciDeviceSupport.c
+++ b/OvmfPkg/IncompatiblePciDeviceSupportDxe/IncompatiblePciDeviceSupport.c
@@ -71,6 +71,40 @@ STATIC CONST EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR mMmio64Configuration = {
// use probed BAR size
};
+//
+// mOptionRomConfiguration is present only in Td guest.
+// Host VMM can inject option ROM which is untrusted in Td guest,
+// so PCI option ROM needs to be ignored.
+// According to "Table 20. ACPI 2.0 & 3.0 QWORD Address Space Descriptor Usage"
+// PI spec 1.7, type-specific flags can be set to 0 when
+// Address Translation Offset == 6 to skip device option ROM.
+//
+STATIC CONST EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR mOptionRomConfiguration = {
+ ACPI_ADDRESS_SPACE_DESCRIPTOR, // Desc
+ (UINT16)( // Len
+ sizeof (EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR) -
+ OFFSET_OF (
+ EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR,
+ ResType
+ )
+ ),
+ ACPI_ADDRESS_SPACE_TYPE_MEM, // ResType
+ 0, // GenFlag
+ 0, // Disable option roms SpecificFlag
+ 64, // AddrSpaceGranularity:
+ // aperture selection hint
+ // for BAR allocation
+ MAX_UINT64, // AddrRangeMin
+ MAX_UINT64, // AddrRangeMax:
+ // no special alignment
+ // for affected BARs
+ 6, // AddrTranslationOffset:
+ // hint covers all
+ // eligible BARs
+ 0 // AddrLen:
+ // use probed BAR size
+};
+
STATIC CONST EFI_ACPI_END_TAG_DESCRIPTOR mEndDesc = {
ACPI_END_TAG_DESCRIPTOR, // Desc
0 // Checksum: to be ignored
@@ -227,6 +261,13 @@ CheckDevice (
//
Length = sizeof mMmio64Configuration + sizeof mEndDesc;
+ //
+ // In Td guest OptionRom is not allowed.
+ //
+ if (TdIsEnabled ()) {
+ Length += sizeof mOptionRomConfiguration;
+ }
+
*Configuration = AllocateZeroPool (Length);
if (*Configuration == NULL) {
@@ -245,6 +286,11 @@ CheckDevice (
CopyMem (Ptr, &mMmio64Configuration, sizeof mMmio64Configuration);
Length = sizeof mMmio64Configuration;
+ if (TdIsEnabled ()) {
+ CopyMem (Ptr + Length, &mOptionRomConfiguration, sizeof mOptionRomConfiguration);
+ Length += sizeof mOptionRomConfiguration;
+ }
+
CopyMem (Ptr + Length, &mEndDesc, sizeof mEndDesc);
return EFI_SUCCESS;
--
2.35.3
