Re: [Qemu-devel] [PATCH 6/9] vhost-scsi: new device supporting the tcm_vhost Linux kernel module

[Asias He <asias@redhat.com>]

On Wed, Jun 19, 2013 at 12:55:10PM +0000, Libaiqing wrote:
> Hi paolo,
>   The vhost-scsi device can be used as boot device?
>   I tested with your config + 3.10 rc6 + seabios 1.7.2.2,but failed.
>   Could you give me some advise to debug this problem ? I can provide more information if need.

Boot from vhost-scsi is supposed to work. The seabios you used should be
fine which contains the fixes for vhost-scsi.

Instead of playing with the /sys/kernel/config/target directly, I really
recommend using targetcli utils.

Nab, I think we really should write some docs for people to use
vhost-scsi.

This is how I install and use targetcli in RHEL6. Note you need upstream
kernel and qemu bits for vhost-scsi.

# yum groupinstall  'Development tools'
# yum install python-devel epydoc python-simpleparse

# git clone git://github.com/agrover/rtslib-fb.git
# git clone git://github.com/agrover/targetcli-fb.git
# git clone git://github.com/agrover/configshell-fb.git
# for i in rtslib-fb configshell-fb targetcli-fb; do
  	make -C $i rpm
  	yum localinstall $i/dist/*.noarch.rpm
  done

In targetcli, create a backstore and vhost wwpn, e.g.
# targetcli
/> /backstores/ramdisk create r0 1g
/> /vhost create
/> cd /vhost/naa.500140527cb6616b/tpg1/luns
/> create /backstores/ramdisk/r0

# qemu -device vhost-scsi-pci,wwpn=naa.500140527cb6616b ...

Hope this helps.

> Regards,
> baiqing
> 
> > -----Original Message-----
> > From: qemu-devel-bounces+libaiqing=huawei.com@nongnu.org
> > [mailto:qemu-devel-bounces+libaiqing=huawei.com@nongnu.org] On
> > Behalf Of Paolo Bonzini
> > Sent: Tuesday, May 28, 2013 4:01 PM
> > To: Wenchao Xia
> > Cc: asias@redhat.com; qemu-devel@nongnu.org; nab@linux-iscsi.org;
> > Michael S. Tsirkin
> > Subject: Re: [Qemu-devel] [PATCH 6/9] vhost-scsi: new device supporting the
> > tcm_vhost Linux kernel module
> > 
> > Il 28/05/2013 09:13, Wenchao Xia ha scritto:
> > >> > From: Nicholas Bellinger <nab@linux-iscsi.org>
> > >> >
> > >> > The WWPN specified in configfs is passed to "-device vhost-scsi-pci".
> > >> > The tgpt field of the SET_ENDPOINT ioctl is obsolete now, so it is not
> > >> > available from the QEMU command-line.  Instead, I hardcode it to
> > zero.
> > >> >
> > > Hi, Paolo
> > >   Any document about how to config it correctly in configfs, before
> > > invoking qemu with the WWPN number?
> > 
> > Unfortunately no, but vhost-scsi doesn't have many knobs (unlike
> > iSCSI for example) so it's quite simple.  Here is an example:
> > 
> > cd /sys/kernel/config/target
> > mkdir -p core/fileio_0/fileio
> > echo 'fd_dev_name=/home/pbonzini/test.img,fd_dev_size=5905580032' >
> > core/fileio_0/fileio/control
> > echo 1 > core/fileio_0/fileio/enable
> > mkdir -p vhost/naa.600140554cf3a18e/tpgt_0/lun/lun_0
> > cd vhost/naa.600140554cf3a18e/tpgt_0
> > ln -sf ../../../../../core/fileio_0/fileio/ lun/lun_0/virtual_scsi_port
> > echo naa.60014053226f0388 > nexus
> > 
> > The "nexus" value is the initiator WWN.  naa.600140554cf3a18e is the
> > target WWN that you have to pass to "-device vhost-scsi-pci".
> > 
> > Paolo
> 

-- 
Asias