-----Original Message-----
From: Gao, Zhichao <zhichao.gao@...>
Sent: Tuesday, August 11, 2020 2:43 PM
To: devel@edk2.groups.io
Cc: Wang, Jian J <jian.j.wang@...>; Wu, Hao A <hao.a.wu@...>; Ni, Ray <ray.ni@...>; Gary Lin
<glin@...>; Andrew Fish <afish@...>
Subject: [PATCH 2/3] MdeModulePkg/PartitionDxe: Remove the check for special MBR

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=2823

Follow the spec definition, the ISO 9660 (and UDF) would be
checked before the MBR. So it is not required to skip such
MBR talbe that contian the entire block device.

Cc: Jian J Wang <jian.j.wang@...>
Cc: Hao A Wu <hao.a.wu@...>
Cc: Ray Ni <ray.ni@...>
Cc: Gary Lin <glin@...>
Cc: Andrew Fish <afish@...>
Signed-off-by: Zhichao Gao <zhichao.gao@...>
---
.../Universal/Disk/PartitionDxe/Mbr.c | 19 -------------------
1 file changed, 19 deletions(-)

diff --git a/MdeModulePkg/Universal/Disk/PartitionDxe/Mbr.c b/MdeModulePkg/Universal/Disk/PartitionDxe/Mbr.c
index 3830af1ea7..822bf03e92 100644
--- a/MdeModulePkg/Universal/Disk/PartitionDxe/Mbr.c
+++ b/MdeModulePkg/Universal/Disk/PartitionDxe/Mbr.c
@@ -55,25 +55,6 @@ PartitionValidMbr (
StartingLBA = UNPACK_UINT32 (Mbr->Partition[Index1].StartingLBA);
SizeInLBA = UNPACK_UINT32 (Mbr->Partition[Index1].SizeInLBA);

- //
- // If the MBR with partition entry covering the ENTIRE disk, i.e. start at LBA0
- // with whole disk size, we treat it as an invalid MBR partition.
- //
- if ((StartingLBA == 0) &&
- (SizeInLBA == (LastLba + 1))) {
- //
- // Refer to the http://manpages.ubuntu.com/manpages/bionic/man8/mkudffs.8.html
- // "WHOLE DISK VS PARTITION"
- // Some linux ISOs may put the MBR table in the first 512 bytes for compatibility reasons with Windows.
- // Linux kernel ignores MBR table if contains partition which starts at sector 0.
- // Skip it because we don't have the partition check for UDF(El Torito compatible).
- // It would continue to do the whole disk check in the UDF routine.
- //
- DEBUG ((DEBUG_INFO, "PartitionValidMbr: MBR table has partition entry covering the ENTIRE disk. Don't treat it as a
valid MBR.\n"));
-
- return FALSE;
- }
-
if (Mbr->Partition[Index1].OSIndicator == 0x00 || SizeInLBA == 0) {
continue;
}
--
2.21.0.windows.1