From mboxrd@z Thu Jan  1 00:00:00 1970
From: =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= <roger.pau@citrix.com>
Subject: Re: Hotplugged devices in Xen 4.5 and domain reboot
Date: Tue, 1 Dec 2015 16:56:27 +0100
Message-ID: <565DC32B.7010300@citrix.com>
References: <CAE4oM6w8kh8JCRrduPFcB9bhABpQ9aT7acu5jyP-hQnCUzaOWA@mail.gmail.com>
	<20151201140208.GA25722@citrix.com>
	<CAC+yBMvsKTe0hQzq0ykpsa3VbvVjFYapm7YdO=ufJQxjLB5LsA@mail.gmail.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Return-path: <xen-devel-bounces@lists.xen.org>
In-Reply-To: <CAC+yBMvsKTe0hQzq0ykpsa3VbvVjFYapm7YdO=ufJQxjLB5LsA@mail.gmail.com>
List-Unsubscribe: <http://lists.xen.org/cgi-bin/mailman/options/xen-devel>,
	<mailto:xen-devel-request@lists.xen.org?subject=unsubscribe>
List-Post: <mailto:xen-devel@lists.xen.org>
List-Help: <mailto:xen-devel-request@lists.xen.org?subject=help>
List-Subscribe: <http://lists.xen.org/cgi-bin/mailman/listinfo/xen-devel>,
	<mailto:xen-devel-request@lists.xen.org?subject=subscribe>
Sender: xen-devel-bounces@lists.xen.org
Errors-To: xen-devel-bounces@lists.xen.org
To: Iurii Mykhalskyi <iurii.mykhalskyi@globallogic.com>, Wei Liu <wei.liu2@citrix.com>
Cc: Pavlo Suikov <pavlo.suikov@globallogic.com>, Andrii Anisov <andrii.anisov@globallogic.com>, xen-devel@lists.xen.org
List-Id: xen-devel@lists.xenproject.org

Hello,

El 01/12/15 a les 15.58, Iurii Mykhalskyi ha escrit:
> Our real usb mass-storage device are located at driver domain (DomD). So we
> setup second block-device backend there.
> 
> To hotplug usb mass-storage from DomD we use follow command:
> 
> xl block-attach domU_id phy:/bla-bla,xvda10,w,backend="DomD"

This is not possible by design, you should only be able to execute `xl 
block-attach ...` from the control domain (Dom0). This is due to the 
fact that attaching a new device to a guest requires write permissions 
in the guest xenstore paths, which the driver domain should not have.

> 
> There was no support of attaching block-device in runtime from domain other
> to Domain-0, so we have made some hacks to allow call block-attach command
> from non-dom0 privileged domain.

Do you have either the `xl devd` command running or udev rules 
correctly setup inside of the driver domain?

Does something like the following work? If not, could you paste the 
error when running it with -vvv.

xl block-attach DomU format=raw,vdev=hdc,access=rw,backend=DomD,target=/path/to/dev

Roger.