Re: [Xen-devel] pvSCSI test

[Juergen Gross <jgross@xxxxxxxx>]

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.

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