[ipxe-devel] Bug in UEFI Sanboot with iso9660

[Vish Ishaya Abrams]

Hello

With current master, after installing windows 2K12 onto an iscsi drive and trying to sanboot in UEFI mode it fails. I tracked the issue down to the iso9660 detection code. It appears that a windows 2K12 install appears as an iso9660 installation in addition to having a GPT:

# isoinfo -d -i /dev/sdb8
CD-ROM is in ISO 9660 format
System id:
Volume id: IR3_SSS_X64FREE_EN-US_DV9
Volume set id: IR3_SSS_X64FREE_EN-US_DV9
Publisher id: MICROSOFT CORPORATION
Data preparer id: MICROSOFT CORPORATION, ONE MICROSOFT WAY, REDMOND WA 98052, (425) 882-8080
Application id: CDIMAGE 2.53 (01/01/2005 TM)
Copyright File id:
Abstract File id:
Bibliographic File id:
Volume set size is: 1
Volume set sequence number is: 1
Logical block size is: 2048
Volume size is: 2217916
El Torito VD version 1 found, boot catalog is in sector 22
NO Joliet present
NO Rock Ridge present
Eltorito validation header:
    Hid 1
    Arch 0 (x86)
    ID 'Microsoft Corporation'
    Key 55 AA
    Eltorito defaultboot header:
        Bootid 88 (bootable)
        Boot media 0 (No Emulation Boot)
        Load segment 0
        Sys type 0
        Nsect 8
        Bootoff 876 2166

# fdisk --list /dev/sdb8

Disk /dev/sdb8: 18.6 GiB, 20004052992 bytes, 39070416 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: 8071B2D8-D75D-49E3-B3DD-B0401535345E

Device        Start      End  Sectors  Size Type
/dev/sdb8p1    2048   616447   614400  300M Windows recovery environment
/dev/sdb8p2  616448   819199   202752   99M EFI System
/dev/sdb8p3  819200  1081343   262144  128M Microsoft reserved
/dev/sdb8p4 1081344 39069695 37988352 18.1G Microsoft basic data

# file -s /dev/sdb8
/dev/sdb8: DOS/MBR boot sector MS-MBR Windows 7 english at offset 0x163 "Invalid partition table" at offset 0x17b "Error loading operating system" at offset 0x19a "Missing operating system" ISO 9660 CD-ROM filesystem data 'IR3_SSS_X64FREE_EN-US_DV9' (bootable); partition 1 : ID=0xee, start-CHS (0x0,0,2), end-CHS (0x3ff,255,63), startsector 1, 4294967295 sectors

the efi_block code detects this as an iso_9660 filesystem and sets a blksize_shift of 2 and it does not successfully read the EFI filesystem. If I comment out the blksize_shift setting, it boots just fine. I also tested booting a couple of actual iso filesystems which detected a blksize_shift of 2. Both the ubuntu installer iso and the windows installer iso boot just fine with the blksize_shift commented out.

This leads me to believe that the blksize_shift code is not necessary in uefi mode. I have commented it out in my build, but I'm not sure if there are some other odd iso images which require this setting. If so, then we need a way to detect the above case where we have an iso9660 that also has an EFI GPT and we can disable setting the blksize_shift in that case.

Any thoughts?
Vish