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[Bug 1258631] Re: instances fails to register GPT partition entries on virtio devices


Oh dear, the answer is so simple after one finally realizes what is
going on... The problem here is that the virtio_blk driver has not been
changed to support more than 15 partitions per device. The partition
scanning is looking at the GPT partition table but only at the first 15
elements. Since the other two partitions are 127 and 128, they never get
added if the device is a virtio disk.

So this isn't exactly a bug but a limitation in virtio right now. I am
not sure whether the images could use number 14 and 15 for those two
partitions. Then they should be visible for emulated and virtual
devices... Otherwise this would be some development work which one had
to discuss upstream.

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  instances fails to register GPT partition entries on virtio devices

Status in “linux” package in Ubuntu:
  In Progress
Status in “linux” source package in Raring:
Status in “linux” source package in Saucy:
Status in “linux” source package in Trusty:
  In Progress

Bug description:
  When booting via KVM and using the VirtIO interface, GPT partition
  entries are not shown properly.

  ubuntu@gpt-test-4:~$ sudo parted /dev/vda -s -- print
  Model: Virtio Block Device (virtblk)
  Disk /dev/vda: 10.7GB
  Sector size (logical/physical): 512B/512B
  Partition Table: gpt

  Number  Start   End        Size         File system     Name                          Flags
  127     1049kB  2097kB  1049kB                           BIOS boot partition  bios_grub
  128     2097kB  89.1MB  87.0MB  fat32               EFI System                  boot
      1      89.1MB  10.7GB  10.6GB   ext4                 Linux filesystem

  Booting with "-hda <disk>.img"
  [    2.612975] sr 1:0:0:0: Attached scsi generic sg1 type 5
  [    2.617252] sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
  [    2.644685]  sda: sda1 sda127 sda128
  [    2.664314] sd 0:0:0:0: [sda] Attached SCSI disk

  Booting with "-drive if=virtio,file=<disk>.img" or "-drive if=scsi,file=<disk>.img":
  [    2.411933] brd: module loaded
  [    2.422616] loop: module loaded
  [    2.442178]  vda: vda1
  [    2.455559] scsi0 : ata_piix
  [    2.456868] scsi1 : ata_piix

  ProblemType: Bug
  DistroRelease: Ubuntu 14.04
  Package: udev 204-5ubuntu6
  ProcVersionSignature: Ubuntu 3.12.0-5.13-generic 3.12.2
  Uname: Linux 3.12.0-5-generic x86_64
  ApportVersion: 2.12.7-0ubuntu1
  Architecture: amd64
  Date: Fri Dec  6 18:49:57 2013
  Ec2AMI: ami-00000632
  Ec2AMIManifest: FIXME
  Ec2AvailabilityZone: nova
  Ec2InstanceType: m1.small
  Ec2Kernel: aki-00000548
  Ec2Ramdisk: ari-00000548
   Bus 001 Device 002: ID 0627:0001 Adomax Technology Co., Ltd 
   Bus 001 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
  MachineType: OpenStack Foundation OpenStack Nova
  ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.12.0-5-generic root=LABEL=cloudimg-rootfs console=ttyS0
  SourcePackage: systemd
  UpgradeStatus: No upgrade log present (probably fresh install)
  dmi.bios.date: 01/01/2007
  dmi.bios.vendor: Bochs
  dmi.bios.version: Bochs
  dmi.chassis.type: 1
  dmi.chassis.vendor: Bochs
  dmi.modalias: dmi:bvnBochs:bvrBochs:bd01/01/2007:svnOpenStackFoundation:pnOpenStackNova:pvr2013.1.3:cvnBochs:ct1:cvr:
  dmi.product.name: OpenStack Nova
  dmi.product.version: 2013.1.3
  dmi.sys.vendor: OpenStack Foundation

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