From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:47478) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RmQQN-00077q-Ni for qemu-devel@nongnu.org; Sun, 15 Jan 2012 08:47:08 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1RmQQM-00006J-MC for qemu-devel@nongnu.org; Sun, 15 Jan 2012 08:47:07 -0500 Received: from e28smtp09.in.ibm.com ([122.248.162.9]:52077) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RmQQM-00006D-0P for qemu-devel@nongnu.org; Sun, 15 Jan 2012 08:47:06 -0500 Received: from /spool/local by e28smtp09.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Sun, 15 Jan 2012 19:16:58 +0530 Received: from d28av04.in.ibm.com (d28av04.in.ibm.com [9.184.220.66]) by d28relay03.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id q0FDkrvn4640812 for ; Sun, 15 Jan 2012 19:16:54 +0530 Received: from d28av04.in.ibm.com (loopback [127.0.0.1]) by d28av04.in.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id q0FDkrcd011039 for ; Mon, 16 Jan 2012 00:46:53 +1100 Received: from [127.0.0.1] ([9.77.178.250]) by d28av04.in.ibm.com (8.14.4/8.13.1/NCO v10.0 AVin) with ESMTP id q0FDkp6c011014 for ; Mon, 16 Jan 2012 00:46:52 +1100 Message-ID: <4F12D8C8.9040603@linux.vnet.ibm.com> Date: Sun, 15 Jan 2012 21:46:48 +0800 From: Shu Ming MIME-Version: 1.0 References: <4F0EA08B.2090402@linux.vnet.ibm.com> In-Reply-To: <4F0EA08B.2090402@linux.vnet.ibm.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] The reversion of hot adding a storage disk to Linux guest. List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: QEMU Developers No other comments? Anyway, I think we need a way to hot unplug a storage disk from the guest totally exactly liking to remove a disk physically. After that unplugging, linux guest can not bring back the disk by any command. On 2012-1-12 16:57, Shu Ming wrote: > Hi, > I am testing the hot plug of scsi disk to the KVM Linux guest with > the following command. > > [root@kvm-rhel-01 bin]# ./virsh qemu-monitor-command RHEL6.1-C > "pci_add auto storage file=/nfs/images/storage1-qcow2.img,if=scsi" > OK domian 0, bus 0, slot 7, function 0 > [root@kvm-rhel-01 bin]# lspci > ... > 00:05.0 SCSI storage controller: Red Hat, Inc Virtio block device > 00:06.0 RAM memory: Red Hat, Inc Virtio memory balloon > 00:07.0 SCSI storage controller: LSI Logic / Symbios Logic 53c895a > <---new deviced added > > in the KVM guest: > [root@RHEL6 ~]#cat /proc/scsi/scsi > Attached devices: > Host: scsi1 Channel: 00 Id: 00 Lun: 00 > Vendor: QEMU Model: QEMU DVD-ROM Rev: 1.0. > Type: CD-ROM > Host: scsi2 Channel: 00 Id: 00 Lun: 00 > Vendor: QEMU Model: QEMU HARDDISK Rev: 1.0. > Type: Direct-Access ANSI SCSI revision: 05 > <------new scsi disk attached > > The command successfully created a HBA device in the guest and also > a scsi disk was enumerated under the HBA device. My next request is > to hot detach the scsi disk from the HBA device, not necessarily > detach the HBA device. That is to emulate the swapping out of the > scsi disk from a physical machine and to release the image file in the > backend. Because the scsi disk is not PCI device, "pci_del" command > can not be used in this case. Can we have a way to send some commands > to notice the HBA device to offline the scsi disk? By that way, HBA > device can do some cleanup in their driver to fully offline the scsi > disk. > > BTW: In the linux guest, we can do "echo "scsi remove-single-device 2 > 0 0 0" > /proc/scsi/scsi" to disable the disk. But I don't think it > is fully removed, because you can bring it back again by "echo "scsi > add-single-device 2 0 0 0" > /proc/scsi/scsi" > -- Shu Ming IBM China Systems and Technology Laboratory