From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1Np74A-0006OH-9f for qemu-devel@nongnu.org; Tue, 09 Mar 2010 16:34:14 -0500 Received: from [199.232.76.173] (port=53870 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Np749-0006Nz-S6 for qemu-devel@nongnu.org; Tue, 09 Mar 2010 16:34:13 -0500 Received: from Debian-exim by monty-python.gnu.org with spam-scanned (Exim 4.60) (envelope-from ) id 1Np747-0000JD-CX for qemu-devel@nongnu.org; Tue, 09 Mar 2010 16:34:13 -0500 Received: from mail-gx0-f209.google.com ([209.85.217.209]:43741) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1Np747-0000J8-3e for qemu-devel@nongnu.org; Tue, 09 Mar 2010 16:34:11 -0500 Received: by gxk1 with SMTP id 1so2598004gxk.16 for ; Tue, 09 Mar 2010 13:34:10 -0800 (PST) Message-ID: <4B96BECF.2000505@codemonkey.ws> Date: Tue, 09 Mar 2010 15:34:07 -0600 From: Anthony Liguori MIME-Version: 1.0 Subject: Re: [Qemu-devel] virtio block device and sysfs References: <20100306224234.GA1145@torres.zugschlus.de> In-Reply-To: <20100306224234.GA1145@torres.zugschlus.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Marc Haber Cc: john cooper , qemu-devel@nongnu.org On 03/06/2010 04:42 PM, Marc Haber wrote: > Hi, > > I am looking to get in touch with somebody who knows more about the > connection between host configuration, qemu, kvm, and the virtio block > device driver guest side than I know. > > My goal is to have a possibility to give a "speaking" name to any > block device handed into a guest instance by the host. That name > should be visible inside the guest, just as a LV is visible with its > name in the system running the LVM. > > For example I would like to say on the qemu or kvm command line > '-drive file=some-file,label=some-label,if=virtio', and have the > string "some-label" show up somewhere in /sys/block in the guest, much > as /sys/block/sda/device/model shows the hardware vendor and type for > a standard SATA disk. The guest could then handle the information > passed into it by the host with udev rules, allowing fstab constructs > like "mount /dev/virtio/block/by-label/some-label as /usr" > You probably would just want to plumb ,serial=X into the virtio-blk config space and have the driver use it. Then you can do /dev/block/by-id/XXXXX John attempted this and it was reverted because the implementation exhausted the PCI config space. Regards, Anthony Liguori > Since I don't have pretty much clue about kernel programming, I guess > that one would need to have qemu/kvm support for the additional label > to be passed to the emulated/virtualized guest, and a modification to > the guest kernel virtio driver which needs to accept the information > passed by the host and to generate the appropriate entry in /sys. > > Am I correct in my assumption? Can you say who I need to talk to to > get advice about how to implement this (or to have it implemented, if > it's easy enough)? > > Any hints will be appreciated. > > Greetings > Marc > >