From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wayne Gong Subject: xm block-attach DomID tap:aio:/... Date: Fri, 26 Dec 2008 19:03:57 +0800 Message-ID: <4954BA1D.7070400@oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org Hi folks, I meet a problem when developing windows PV drivers for Xen. Now my drivers can support adding a 'file' type backend media as a VBD device using 'xm block-attach' command. With the same code, 'xm block-attach' a 'tap:aio' type backend media cannot works fine on my PV drivers. But if I add a 'file' type backend media to windows VM and set set it to 'tap:aio' type, it works fine. Since my driver didn't get WHQL digital signature, when adding a new device VM, windows will pops up a 'Find new hardware' dialog to install drivers for it even there is a device object represents for it. When installing driver for new storage class device, windows PnP manager will remove the device object and add a new one represents for the new device. In this progress, I will set device backend state to XenbusStateClosing->XenbusStateClosed ->XenbusStateInitWait and then reinitialize the device. If it's a 'file' type, all these progress works fine, but it's a 'type:aio' type, my drivers cannot get any response from ring buffer for Read/Write scsi command. So does anybody can give me some brief guide on difference between 'file' type and 'tap:aio' type as a backend media for a frontend PV drivers? And I want to confirm that a 'tap:aio' type backend can work well when backend state changed as XenbusStateInitWait->XenbusStateConnected-> XenbusStateClosing->XenbusStateClosed ->XenbusStateInitWait->XenbusStateConnected. I know that a 'file' type backend is Yes, I think 'tap:aio' type is Yes either, just want to conform. James, any suggestion? BTW, I use OVM 2.1.2 based on Xen 3.1 series. Merry Christmas and Happy New Year! Thanks Wayne