Re: Xen Dom U kernel

[kishore kumar <bodkekumar@gmail.com>]

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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@triad.rr.com> 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@iki.fi>
>>> 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@iki.fi
>>>
>>>
>>
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>>
>>
>
>

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