Re: [Xen-devel] Xen Dom U kernel

[kishore kumar <bodkekumar@xxxxxxxxx>]

 

Could you please let me know where this break=premount option should be added?

What is the location of the xen block devices. I want to load this module and check giving the above option and see if it works for me. 

Thank You.

 

On Mon, Apr 19, 2010 at 2:29 PM, listmail <listmail@xxxxxxxxxxxx> wrote:

I don't have any issues using my dom0 kernel & initrd to boot pv domU,  config has CONFIG_XEN_BLKDEV_FRONTEND=m as well.

However, thats when passing through file based images & LVM from the dom0 to the domU.  Is this more of an issue when LVM is implemented on the domU itself???  That's what I am seeing here.  Should he be adding a break=premount option to initrd and checking visibility of the LVM root from busybox?


Pasi Kärkkäinen wrote:

On Mon, Apr 19, 2010 at 12:08:35PM -0700, kishore kumar wrote:
 

  I included
  kernel = "/boot/vmlinuz-2.6.32.10"
  ramdisk = "/boot/initrd-2.6.32.10.img" (This is the same as my Dom 0.  As
  I am trying to boot the same Dom 0 as my Dom U without any changes)

   

You cannot use the dom0 initrd/ramdisk for domU!

dom0 initrd contains drivers for the physical hardware, while in the domU initrd
you need to have drivers for the _virtual_ hardware!

In the log below root was not found because the drivers for the xen block devices
are not loaded.

-- Pasi


 

  disk = ['phy:sda2,sda2,w']
  root= "/dev/VolGroup01/LogVol00 ro"

    I see my .config and I have
  CONFIG_XEN_BLKDEV_FRONTEND=m
  CONFIG_XEN_BLKDEV_BACKEND=y
  CONFIG_XEN_BACKEND=y

  Below is the output pasted.  Any help please on what is going wrong here?

  XENBUS: Device with no driver: device/vbd/2050

  XENBUS: Device with no driver: device/vif/0

  XENBUS: Device with no driver: device/console/0

  Magic number: 1:252:3141

  drivers/rtc/hctosys.c: unable to open rtc device (rtc0)

  Initalizing network drop monitor service

  Freeing unused kernel memory: 3392k freed

  Write protecting the kernel read-only data: 6912k

  Red Hat nash version 5.1.19.6 starting

  Mounting proc filesystem

  Mounting sysfs filesystem

  Creating /dev

  Creating initial device nodes

  Setting up hotplug.

  Creating block device nodes.

  Loading ehci-hcd.ko module

  ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver

  insmod used greatest stack depth: 5712 bytes left

  Loading ssb.ko module

  Loading ohci-hcd.ko module

  ohci_hcd: USB 1.1 'Open' Host Controller (OHCI) Driver

  Loading uhci-hcd.ko module

  uhci_hcd: USB Universal Host Controller Interface driver

  Scanning and configuring dmraid supported devices

  Scanning logical volumes

  Reading all physical volumes. This may take a while...

  lvm used greatest stack depth: 5328 bytes left

  Activating logical volumes

  Volume group "VolGroup01" not found

  Trying to resume from /dev/VolGroup01/LogVol01

  Unable to access resume device (/dev/VolGroup01/LogVol01)

  Creating root device.

  Mounting root filesystem.

  mount: could not find filesystem '/dev/root'

  Setting up other filesystems.

  Setting up new root fs

  setuproot: moving /dev failed: No such file or directory

  no fstab.sys, mounting internal defaults

  setuproot: error mounting /proc: No such file or directory

  setuproot: error mounting /sys: No such file or directory

  Switching to new root and running init.

  unmounting old /dev

  unmounting old /proc

  unmounting old /sys

  switchroot: mount failed: No such file or directory

  init used greatest stack depth: 4888 bytes left

  Kernel panic - not syncing: Attempted to kill init!

  Pid: 1, comm: init Not tainted 2.6.32.10 #2

  Call Trace:

  [<ffffffff8105b747>] panic+0xa5/0x167

  [<ffffffff8100ed81>] ? xen_force_evtchn_callback+0xd/0xf

  [<ffffffff81475d48>] ? _write_unlock_irq+0x30/0x3c

  [<ffffffff8108c9f4>] ? trace_hardirqs_on_caller+0x110/0x134

  [<ffffffff8108ca25>] ? trace_hardirqs_on+0xd/0xf

  [<ffffffff81475d4f>] ? _write_unlock_irq+0x37/0x3c

  [<ffffffff8105efa7>] do_exit+0x7e/0x701

  [<ffffffff8105f6c6>] sys_exit_group+0x0/0x1b

  [<ffffffff8105f6dd>] sys_exit_group+0x17/0x1b

  [<ffffffff81012d72>] system_call_fastpath+0x16/0x1b

  On Sat, Apr 17, 2010 at 5:22 AM, Pasi Kärkkäinen <[1]pasik@xxxxxx> wrote:

    On Fri, Apr 16, 2010 at 03:24:53PM -0700, kishore kumar wrote:
    >    I am using my Dom 0 kernel to boot as my Dom U.
    >    I edited /etc/xen/xmexample1 file and modified only below lines
    >
    >    kernel="/boot/vmlinux-2.6.32.10"
    >    memory=512
    >    vcpus=5
    >    root = "/dev/VolGroup01/LogVol00 ro"
    >    Below is the output I pasted after freezing.  Not sure what is
    wrong.  Can
    >    you please help me here??
    >    I doubt if I have provided the correct root option?
    >

    I bet that kernel has xen block frontend driver as a module?

    You don't seem to have ramdisk/initrd image,
    so you simply don't have the driver loaded at all
    to access the root disk in the guest.

    You must create an initrd image that loads the driver module in the
    guest.
    >
    >    VFS: Cannot open root device "VolGroup01/LogVol00" or
    unknown-block(0,0)
    >
    >    Please append a correct "root=" boot option; here are the available
    >    partitions:
    >
    >    Kernel panic - not syncing: VFS: Unable to mount root fs on
    >    unknown-block(0,0)
    >

    Root was not found - this is usually because you don't have the xen
    blockdev frontend driver loaded.
    -- Pasi

References

  Visible links
  1. mailto:pasik@xxxxxx
   

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