Re: pvSCSI test

[Juergen Gross <jgross@suse.com>]

On 02/03/2015 07:16 PM, Kristian Hagsted Rasmussen wrote:
>
> Hi Olaf and Juergen
>
>
> I am interested in testing pvSCSI as I have a system were it would be ideal.
> I have tried to apply this patch "http://marc.info/?l=xen-devel&m=139885599019457&w=2" called "libbxl: add support for pvscsi, iteration 1", to my xen-4.5 tree.
> I am using kernel 3.18.4 compiled with xen-scsiback and xen-scsifront compiled into the kernel, for both Dom0 and DomU.
>
>   My Ubuntu domU is running fine, however the scsi disk I want to pass through does not appear.
>
> in my config I have added the line:
> vscsi= ['3:0:0:0,0:0:0:0']
> I have also tried with:
> vscsi= ['/dev/sdb,0:0:0:0']
>
> but no matter which syntax I use I get the following error in dmesg log:
> xen-pvscsi: 3:0:0:0 doesn't exist
>
> I have no errors in the log files for the domU.
>
> Am I missing something in my configuration, perhaps some device hiding like for pci pass through?

The upstream pvscsi backend is using the target infrastructure. Until
the tools are aware of this you'll have to configure the device to
pass to a domain in Dom0 e.g. via a script:

#!/bin/bash
# usage:
# mkpvscsi device
# e.g. mkpvscsi /dev/sr0

DEV=$1

gen_uuid()
{
         cat /proc/sys/kernel/random/uuid | \
	awk '{print "naa.6001405" substr($1,1,8) substr($1,10,1);}'
}

TARG=`gen_uuid`
INIT=`gen_uuid`

NODE=`lsscsi | awk '$(NF) == "'$DEV'"
	{ print substr($1,2,length($1)-4); }'`
NAME=`echo $NODE | sed 's/:/_/g'`

modprobe configfs
mount -t configfs configfs /sys/kernel/config
modprobe xen-scsiback
modprobe target_core_mod
cd /sys/kernel/config/target

mkdir -p core/pscsi_0/$NAME
echo "$DEV" >core/pscsi_0/$NAME/udev_path

mkdir -p xen-pvscsi/$TARG/tpgt_0
echo "$NODE" >xen-pvscsi/$TARG/tpgt_0/param/alias
echo $INIT >xen-pvscsi/$TARG/tpgt_0/nexus
mkdir xen-pvscsi/$TARG/tpgt_0/lun/lun_0

cd xen-pvscsi/$TARG/tpgt_0/lun/lun_0
ln -s ../../../../../../target/core/pscsi_0/$NAME xen-pvscsi_port



-------------

After doing this you can use the xen tools to give the device to a domU.
Please note: this script is untested, I've used a simpler one which
fitted my needs (using targetcli, which isn't available everywhere).
I have tested all single steps of the script above, though.

Happy testing,

Juergen

P.S.: If you are feeling adventurous you can try other target backends
       than pscsi, e.g. iscsi or fileio.