Re: [Xen-users] HVM and tap:aio?

["Omer Khalid" <Omer.Khalid@xxxxxxx>]

Hi,

I got exactly the same problem for Xen 3.1.4, HVM-enabled, 64 bit Host, EL4. I have tried all the combinations as hda, sda etc but it didn't work. Using hda does allows qemu to detect the disk though but it fails boot as well. 

The only difference is that rather than tap:io, I am using "phy" as my guest is installed in LVM. The rest of the thread could be followed here:

http://lists.xensource.com/archives/html/xen-users/2008-08/msg00786.html

I am also waiting to get some insight from a Xen expert to resolve this problem.

Thanks,

Omer

On Thu, Aug 28, 2008 at 9:27 PM, - <debaan@xxxxxxxxx> wrote:

Hello,

I'm not able to use tap:aio disk definitions with my HVM domU's.  Is this supposed to work on this version of Xen, or am I doing something wrong? 
I've tried everything I can think of.  file: works, but not tap:aio: , and I understand that file: will cause OOMkiller if using NFS mounts and is deprecated.

Likewise, tap:aio: for cdrom does not allow me to boot off of cdrom; file: does work fine.

Furthermore, any time I use tap:aio, the bochs bios of the hvm domU shows the hard disk size as 0 MBytes.

Any disk definition that I use that has tap:aio: gives the result either (if tap:aio:/xen/foo/foo.img,xvda,w):

Booting from Hard Disk...
Boot from Hard Disk failed: could not read the boot disk

or (if specifying tap:aio:/xen/foo/foo.img,hda,w)

ata0 master: QEMU HARDDISK ATA-7 Hard-Disk (0 MBytes)
Boot from Hard Disk failed: could not read the boot disk

Host: CentOS 5.2 x86_64, kernel 2.6.18-92.1.6.el5xen
Xen version: 3.1.2-92.1.6.el5
xen_caps: xen-3.0-x86_64 xen-3.0-x86_32p hvm-3.0-x86_32 hvm-3.0-x86_32p hvm-3.0-x86_64
selinux: disabled for testing
domU: OS doesn't appear to matter; domU OS won't start loading at all.

disk lines I've tried:
# disk recognized as 0/1 MB, can't install
#disk = [ "tap:aio:/xen/ausmsit05/ausmsit05.raw,ioemu:sda,w", "file:/xen/iso/Win2003r2_std_32bit.iso,hdc:cdrom,r" ]
#disk = [ "tap:aio:/xen/ausmsit05/ausmsit05.raw,sda,w", "file:/xen/iso/Win2003r2_std_32bit.iso,hdc:cdrom,r" ]
#disk = [ "file:/xen/ausmsit05/ausmsit05.raw,hda,w", "file:/xen/iso/Win2003r2_std_32bit.iso,hdc:cdrom,r" ]
#disk = [ "tap:aio:/xen/ausmsit05/ausmsit05.raw,sda1,w", ",hdc:cdrom,r" ]
#disk = [ "tap:aio:/xen/ausmsit05/ausmsit05.raw,xvda,w", ",hdc:cdrom,r" ]
#disk = [ "tap:aio:/xen/ausmsit05/ausmsit05.raw,hda:ioemu,w", ",hdc:cdrom,r" ]
#disk = [ "tap:aio:/xen/ausmsit05/ausmsit05.raw,ioemu:hda,w", ",hdc:cdrom,r" ]
#disk = [ "tap:aio:/xen/ausmsit05/ausmsit05.raw,ioemu:xvda,w", "phy:/dev/scd0,ioemu:xvdc:cdrom,r" ]
# Boot from Hard Disk failed: could not read the boot disk
disk = [ "tap:aio:/xen/ausmsit05/ausmsit05.raw,hda,w", "tap:aio:/xen/iso/win2003r2_std_32bit_disk1of2.iso,hdc:cdrom,r" ]

in the last example, this is the output of xm block-list ausmsit05 --long
(768
    ((backend-id 0)
        (virtual-device 768)
        (device-type disk)
        (state 1)
        (backend /local/domain/0/backend/tap/55/768)
    )
)
(5632
    ((backend-id 0)
        (virtual-device 5632)
        (device-type cdrom)
        (state 1)
        (backend /local/domain/0/backend/tap/55/5632)
    )
)
and this is from xend.log:

[2008-08-28 14:18:09 xend 3692] DEBUG (blkif:24) exception looking up device number for hda: [Errno 2] No such file or directory: '/dev/hda'
[2008-08-28 14:18:09 xend 3692] DEBUG (DevController:110) DevController: writing {'backend-id': '0', 'virtual-device': '768', 'device-type': 'disk', 'state': '1', 'backend': '/local/domain/0/backend/tap/55/768'} to /local/domain/55/device/vbd/768.
[2008-08-28 14:18:09 xend 3692] DEBUG (DevController:112) DevController: writing {'domain': 'ausmsit05', 'frontend': '/local/domain/55/device/vbd/768', 'format': 'raw', 'dev': 'hda', 'state': '1', 'params': 'aio:/xen/ausmsit05/ausmsit05.raw', 'mode': 'w', 'online': '1', 'frontend-id': '55', 'type': 'tap'} to /local/domain/0/backend/tap/55/768.
[2008-08-28 14:18:09 xend 3692] DEBUG (blkif:24) exception looking up device number for hdc: [Errno 2] No such file or directory: '/dev/hdc'
[2008-08-28 14:18:09 xend 3692] DEBUG (DevController:110) DevController: writing {'backend-id': '0', 'virtual-device': '5632', 'device-type': 'cdrom', 'state': '1', 'backend': '/local/domain/0/backend/tap/55/5632'} to /local/domain/55/device/vbd/5632.
[2008-08-28 14:18:09 xend 3692] DEBUG (DevController:112) DevController: writing {'domain': 'ausmsit05', 'frontend': '/local/domain/55/device/vbd/5632', 'format': 'raw', 'dev': 'hdc', 'state': '1', 'params': 'aio:/xen/iso/win2003r2_std_32bit_disk1of2.iso', 'mode': 'r', 'online': '1', 'frontend-id': '55', 'type': 'tap'} to /local/domain/0/backend/tap/55/5632.

Thank you in advance for any help you can offer.

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--
Omer

-------------------------------------------------------
CERN -- European Organization for Nuclear
Research, IT Department, CH-1211,
Geneva 23, Switzerland

Phone: +41 (0) 22 767 2224
Fax: +41 (0) 22 766 8683
E-mail : Omer.Khalid@xxxxxxx
Homepage: http://cern.ch/Omer.Khalid

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