From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:51165) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hH5Hu-000466-6A for qemu-devel@nongnu.org; Thu, 18 Apr 2019 07:33:08 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hH5Ht-0006Zi-2W for qemu-devel@nongnu.org; Thu, 18 Apr 2019 07:33:06 -0400 Date: Thu, 18 Apr 2019 12:32:49 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Message-ID: <20190418113249.GP13773@redhat.com> Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= References: <20190417115343.30527-1-pbonzini@redhat.com> <20190418104737.GC5242@linux.fritz.box> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20190418104737.GC5242@linux.fritz.box> Subject: Re: [Qemu-devel] [Qemu-block] [PATCH] scsi-generic: prevent guest from exceeding SG_IO limits List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Kevin Wolf Cc: Paolo Bonzini , Stefan Hajnoczi , qemu block , qemu-devel , Stefan Hajnoczi , qemu-stable On Thu, Apr 18, 2019 at 12:47:37PM +0200, Kevin Wolf wrote: > Am 18.04.2019 um 11:48 hat Paolo Bonzini geschrieben: > > On 17/04/19 14:30, Stefan Hajnoczi wrote: > > > On Wed, Apr 17, 2019 at 12:54 PM Paolo Bonzini wrote: > > >> Linux places a limit of UIO_MAXIOV pages on SG_IO ioctls (and if the limit > > >> is exceeded, a confusing ENOMEM error is returned[1]). Prevent the guest > > >> from exceeding these limits, by capping the maximum transfer length to > > >> that value in the block limits VPD page. > > >> > > >> [1] Oh well, at least it was easier to follow the kernel source knowing > > >> it had to end as ENOMEM... > > >> > > >> Cc: qemu-stable@nongnu.org > > >> Cc: qemu-block@nongnu.org > > >> Cc: Stefan Hajnoczi > > >> Signed-off-by: Paolo Bonzini > > >> --- > > >> hw/scsi/scsi-generic.c | 17 +++++++++++++---- > > >> 1 file changed, 13 insertions(+), 4 deletions(-) > > > > > > Reviewed-by: Stefan Hajnoczi > > > > > > > This is acually only an issue with kernels prior to 4.5, so it should be > > fixed downstream instead. > > I don't think that upstream QEMU has kernels > 4.5 as an official > requirement, though? We try to be compatible with quite old libs, so we > should stay compatible with old kernels, too. We've not explicitly stated or checked a min kernel version, but our min kernel is defined implicitly by our targetted build platforms: https://qemu.weilnetz.de/doc/qemu-doc.html#Supported-build-platforms The oldest Linux distro under those rules is RHEL-7 (3.10.0), since Debian Jessie actually updates its kernel version so is already on version 4.5 Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :| From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=FROM_EXCESS_BASE64, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS, URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1C2E6C10F0E for ; Thu, 18 Apr 2019 11:42:43 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id DEC552183E for ; Thu, 18 Apr 2019 11:42:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DEC552183E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([127.0.0.1]:39967 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hH5RC-0002dJ-5Z for qemu-devel@archiver.kernel.org; Thu, 18 Apr 2019 07:42:42 -0400 Received: from eggs.gnu.org ([209.51.188.92]:51165) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hH5Hu-000466-6A for qemu-devel@nongnu.org; Thu, 18 Apr 2019 07:33:08 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hH5Ht-0006Zi-2W for qemu-devel@nongnu.org; Thu, 18 Apr 2019 07:33:06 -0400 Received: from mx1.redhat.com ([209.132.183.28]:48324) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hH5Hq-0006Vq-H4; Thu, 18 Apr 2019 07:33:02 -0400 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 79726306C9FF; Thu, 18 Apr 2019 11:32:56 +0000 (UTC) Received: from redhat.com (ovpn-112-59.ams2.redhat.com [10.36.112.59]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 9602B1001DC8; Thu, 18 Apr 2019 11:32:52 +0000 (UTC) Date: Thu, 18 Apr 2019 12:32:49 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Kevin Wolf Message-ID: <20190418113249.GP13773@redhat.com> References: <20190417115343.30527-1-pbonzini@redhat.com> <20190418104737.GC5242@linux.fritz.box> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline In-Reply-To: <20190418104737.GC5242@linux.fritz.box> User-Agent: Mutt/1.11.3 (2019-02-01) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.43]); Thu, 18 Apr 2019 11:32:56 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [Qemu-block] [PATCH] scsi-generic: prevent guest from exceeding SG_IO limits X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Cc: qemu block , Stefan Hajnoczi , qemu-stable , qemu-devel , Stefan Hajnoczi , Paolo Bonzini Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Message-ID: <20190418113249.-BswL_NFyWSul-7qg92jmMQ61tcbP9xBfC3-qsUBo5g@z> On Thu, Apr 18, 2019 at 12:47:37PM +0200, Kevin Wolf wrote: > Am 18.04.2019 um 11:48 hat Paolo Bonzini geschrieben: > > On 17/04/19 14:30, Stefan Hajnoczi wrote: > > > On Wed, Apr 17, 2019 at 12:54 PM Paolo Bonzini wrote: > > >> Linux places a limit of UIO_MAXIOV pages on SG_IO ioctls (and if the limit > > >> is exceeded, a confusing ENOMEM error is returned[1]). Prevent the guest > > >> from exceeding these limits, by capping the maximum transfer length to > > >> that value in the block limits VPD page. > > >> > > >> [1] Oh well, at least it was easier to follow the kernel source knowing > > >> it had to end as ENOMEM... > > >> > > >> Cc: qemu-stable@nongnu.org > > >> Cc: qemu-block@nongnu.org > > >> Cc: Stefan Hajnoczi > > >> Signed-off-by: Paolo Bonzini > > >> --- > > >> hw/scsi/scsi-generic.c | 17 +++++++++++++---- > > >> 1 file changed, 13 insertions(+), 4 deletions(-) > > > > > > Reviewed-by: Stefan Hajnoczi > > > > > > > This is acually only an issue with kernels prior to 4.5, so it should be > > fixed downstream instead. > > I don't think that upstream QEMU has kernels > 4.5 as an official > requirement, though? We try to be compatible with quite old libs, so we > should stay compatible with old kernels, too. We've not explicitly stated or checked a min kernel version, but our min kernel is defined implicitly by our targetted build platforms: https://qemu.weilnetz.de/doc/qemu-doc.html#Supported-build-platforms The oldest Linux distro under those rules is RHEL-7 (3.10.0), since Debian Jessie actually updates its kernel version so is already on version 4.5 Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|