Re: [Xen-devel] pvSCSI test

[Juergen Gross <jgross@xxxxxxxx>]

On 02/06/2015 10:32 AM, Kristian Hagsted Rasmussen wrote:
> On Wednesday, February 4, 2015 05:41, Juergen Gross <jgross@xxxxxxxx> wrote:
> > To: Kristian Hagsted Rasmussen; Olaf Hering; xen-devel@xxxxxxxxxxxxxxxxxxx
> > Subject: Re: pvSCSI test
> >
> > 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 $NODE | sed 's/:/_/g'`
> I used targetcli to create the pscsi target, so
> skipped from here
>
> > modprobe configfs
> > mount -t configfs configfs /sys/kernel/config
> > modprobe xen-scsiback
> > modprobe target_core_mod
> to here
>
> > cd /sys/kernel/config/target
> and here to
>
> > mkdir -p core/pscsi_0/$NAME
> > echo "$DEV" >core/pscsi_0/$NAME/udev_path
> to here
>
> > 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.
> Thanks for the script, I had some problems with the symlinking when
> running the script, so tried to make the pscsi in targetcli, and then
> shortening the script to skip all script lines concerning the core dir.
> This made the script working for me, however I still get:
> xen-pvscsi: 3:0:0:0 doesn't exist
> error in dmesg log.
>
> Are you using another patch for the xen-tree than the one I listed above?
I've used xm to get the drivers working, not xl. I wanted to have only
one changed component during tests in order to know which component is
failing. :-)

What are the contents of

/sys/kernel/config/target/xen-pvscsi/$TARG/tpgt_0/param/alias

($TARG replaced by the UUID generated above, of course)?

This should be "3:0:0:0" in your case. That's where the backend is
looking for the match from xenstore.

And the final symlink in the script is required. $NAME can be anything,
but has to match the pscsi name, of course.

Juergen

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