From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ian Campbell Subject: Re: Hotplugged devices in Xen 4.5 and domain reboot Date: Tue, 1 Dec 2015 15:41:39 +0000 Message-ID: <1448984499.15768.139.camel@citrix.com> References: <20151201140208.GA25722@citrix.com> <20151201152910.GW21588@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20151201152910.GW21588@citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Wei Liu , Iurii Mykhalskyi Cc: Pavlo Suikov , Ian Jackson , Roger Pau =?ISO-8859-1?Q?Monn=E9?= , Andrii Anisov , xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org On Tue, 2015-12-01 at 15:29 +0000, Wei Liu wrote: > On Tue, Dec 01, 2015 at 04:58:55PM +0200, Iurii Mykhalskyi wrote: > > 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" > > > > What happens if you run this in Dom0? I guess DomD doesn't respond to > the request? > > > 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. > > So this is a special use case. This is the first time I know people > actually run xl block-attach in driver domain. Toolstack commands (xl *) should be run in the toolstack domain, not in the driver domain. I don't think it should be expected that the latter work (at least not without a large amount of development work). In general a driver domain would not be expected to have sufficient privilege over e.g. a guest domain's /local/domain/domU/devices to create the f.e. dirs. > There is a daemon "xl devd" in driver domain. We might be able to teach > it to response to Dom0 toostack request. I'm a bit surprised if it > doesn't do that already. Did you forget to start that daemon? That's the entire purpose of that daemon, isn't it? > > Roger, Ian and Ian, any thought? > > Wei.