From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46913) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XzPzR-0002pi-5G for qemu-devel@nongnu.org; Fri, 12 Dec 2014 08:10:46 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XzPzH-0003PD-U7 for qemu-devel@nongnu.org; Fri, 12 Dec 2014 08:10:37 -0500 Received: from e06smtp14.uk.ibm.com ([195.75.94.110]:44568) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XzPzH-0003Ot-LT for qemu-devel@nongnu.org; Fri, 12 Dec 2014 08:10:27 -0500 Received: from /spool/local by e06smtp14.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 12 Dec 2014 13:10:24 -0000 Received: from b06cxnps3075.portsmouth.uk.ibm.com (d06relay10.portsmouth.uk.ibm.com [9.149.109.195]) by d06dlp01.portsmouth.uk.ibm.com (Postfix) with ESMTP id 8748917D8056 for ; Fri, 12 Dec 2014 13:10:44 +0000 (GMT) Received: from d06av02.portsmouth.uk.ibm.com (d06av02.portsmouth.uk.ibm.com [9.149.37.228]) by b06cxnps3075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id sBCDAKqP52691014 for ; Fri, 12 Dec 2014 13:10:20 GMT Received: from d06av02.portsmouth.uk.ibm.com (localhost [127.0.0.1]) by d06av02.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id sBCDAGxh026196 for ; Fri, 12 Dec 2014 06:10:18 -0700 Message-ID: <548AE934.2000007@linux.vnet.ibm.com> Date: Fri, 12 Dec 2014 16:10:12 +0300 From: Ekaterina Tumanova MIME-Version: 1.0 References: <1417802181-20834-1-git-send-email-tumanova@linux.vnet.ibm.com> In-Reply-To: <1417802181-20834-1-git-send-email-tumanova@linux.vnet.ibm.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v3 0/5] Geometry and blocksize detection for backing devices. List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Public KVM Mailing List Cc: kwolf@redhat.com, borntraeger@de.ibm.com, armbru@redhat.com, mihajlov@linux.vnet.ibm.com, dahi@linux.vnet.ibm.com, stefanha@redhat.com, cornelia.huck@de.ibm.com, pbonzini@redhat.com On 12/05/2014 08:56 PM, Ekaterina Tumanova wrote: > This 3rd revision of the patch set. > > Proper geometry and blocksize information is vital for support of > DASD/ECKD drives in Linux guests. Otherwise things will fail in > certain cases. > > The existing geometry and blocksize qemu defaults have no sense > for DASD drives (hd_geometry_guess detection and 512 for sizes). > Setting this information manually in XML file is far from user-friendly, > as the admin has to manually look up the properties of the > host disks and then modify the guest definition accordingly. > > Since Linux uses DASDs as normal block devices, we actually > want to use virtio-blk to pass those to KVM guests. > > In order to avoid any change in behavior of other drives, the DASD > special casing was advised. We call ioctl BIODASDINFO2 on the block > device, which will only succeed if the device is really a DASD. > > In order to retrieve the underlying device geometry and blocksizes > a new block-backend functions and underlying driver functions were > introduced (blk_probe_blocksizes anf blk_probe_geometry wrappers > and corresponding bdrv_xxxxxx functions). > > As for now only "host_device" driver received new detection methods. > For "raw" we call childs method as usual. In future one may update > other drivers to add some other detection heuristics. > > If the host_device appears to be a DASD, the driver functions > (hdev_probe_blocksizes and hdev_probe_geometry) will call certain > ioctls in order to detect geometry and blocksizes of the underlying device. > if probing failed bdrv_probe_blocksizes caller will set defaults, > and bdrv_probe_geometry will fail to allow fallback to old detection logic. > > The front-end (BlockConf API) was updated: > 1. a new blkconf_blocksizes function was added. It doesn't > change user-defined blocksize values. If properties are unset, it will > set values, returned by blk_probe_backend. In order to allow this logic, > blocksize properties were initialized with 0. (driver will return 512 if > backing device probing didn't succeed or if driver method is not defined). > 2. hd_geometry guess was changed to firstly try to retrieve values via > blk_probe_geometry and if it fails, fallback to the old logic. > > updates from v2: > - avoid passing structs as a function result in backend part > - fix patch desctiptions > - add the blkconf_blocksizes call to all the users of BlockConf > - do not change geometry and blocksize values set via command-line, to do that: > remove hardcoding 512 in DEFINE_BLOCK_PROPERTIES. set defaults in > blk_probe_blocksizes (now always succeeds) and call it only if property is 0. > - fix cylinders calculation. > - document blk_probe_geometry call as "currently only for DASD". > - anything I forgot :) > > Ekaterina Tumanova (5): > block: add bdrv functions for geometry and blocksize > raw-posix: Factor block size detection out of raw_probe_alignment() > block: Add driver methods to probe blocksizes and geometry > block-backend: Add wrappers for blocksizes and geometry probing > BlockConf: Call backend functions to detect geometry and blocksizes > > block.c | 35 +++++++++++ > block/block-backend.c | 10 +++ > block/raw-posix.c | 135 +++++++++++++++++++++++++++++++++++------ > block/raw_bsd.c | 14 +++++ > hw/block/block.c | 18 ++++++ > hw/block/hd-geometry.c | 12 ++++ > hw/block/nvme.c | 1 + > hw/block/virtio-blk.c | 1 + > hw/core/qdev-properties.c | 3 +- > hw/ide/qdev.c | 1 + > hw/scsi/scsi-disk.c | 1 + > hw/usb/dev-storage.c | 1 + > include/block/block.h | 13 ++++ > include/block/block_int.h | 5 ++ > include/hw/block/block.h | 5 +- > include/sysemu/block-backend.h | 2 + > 16 files changed, 237 insertions(+), 20 deletions(-) > friendly *ping* to maintainers of block layer :) I would rather not send next version without getting your feedback first.