From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60158) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bDq7k-00010G-Vc for qemu-devel@nongnu.org; Fri, 17 Jun 2016 05:31:37 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bDq7f-0006Us-0w for qemu-devel@nongnu.org; Fri, 17 Jun 2016 05:31:35 -0400 Received: from mx2.suse.de ([195.135.220.15]:44762) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bDq7e-0006Ui-On for qemu-devel@nongnu.org; Fri, 17 Jun 2016 05:31:30 -0400 References: <1466154874-6218-1-git-send-email-jgross@suse.com> <5763DE5D02000078000F5FF8@suse.com> From: Juergen Gross Message-ID: <5763C36E.4060002@suse.com> Date: Fri, 17 Jun 2016 11:31:26 +0200 MIME-Version: 1.0 In-Reply-To: <5763DE5D02000078000F5FF8@suse.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [Xen-devel] [PATCH v2] xen: fix qdisk BLKIF_OP_DISCARD for 32/64 word size mix List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jan Beulich Cc: anthony.perard@citrix.com, sstabellini@kernel.org, xen-devel , qemu-devel@nongnu.org, kraxel@redhat.com On 17/06/16 11:26, Jan Beulich wrote: >>>> On 17.06.16 at 11:14, wrote: >> In case the word size of the domU and qemu running the qdisk backend >> differ BLKIF_OP_DISCARD will not work reliably, as the request >> structure in the ring have different layouts for different word size. >> >> Correct this by copying the request structure in case of different >> word size element by element in the BLKIF_OP_DISCARD case, too. >> >> The easiest way to achieve this is to resync hw/block/xen_blkif.h with >> its original source from the Linux kernel. >> >> Signed-off-by: Juergen Gross >> --- >> V2: resync with Linux kernel version of hw/block/xen_blkif.h as >> suggested by Paul Durrant > > Oh, I didn't realize he suggested syncing with the Linux variant. > Why not with the canonical one? I have to admit that I particularly > dislike Linux'es strange union-izng, mainly because of it requiring > this myriad of __attribute__((__packed__)). What would be gained by syncing with the canonical one? The part to be modified is available in the Linux variant only. Juergen