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=-8.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS 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 6BCEAC433E3 for ; Thu, 27 Aug 2020 08:52:09 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 41863206F0 for ; Thu, 27 Aug 2020 08:52:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 41863206F0 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=bugs.launchpad.net Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:43138 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kBDdg-0002yg-Dm for qemu-devel@archiver.kernel.org; Thu, 27 Aug 2020 04:52:08 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:49834) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kBDd1-00029v-98 for qemu-devel@nongnu.org; Thu, 27 Aug 2020 04:51:27 -0400 Received: from indium.canonical.com ([91.189.90.7]:53074) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1kBDcy-0007mX-N1 for qemu-devel@nongnu.org; Thu, 27 Aug 2020 04:51:27 -0400 Received: from loganberry.canonical.com ([91.189.90.37]) by indium.canonical.com with esmtp (Exim 4.86_2 #2 (Debian)) id 1kBDcw-0006e5-Qz for ; Thu, 27 Aug 2020 08:51:22 +0000 Received: from loganberry.canonical.com (localhost [127.0.0.1]) by loganberry.canonical.com (Postfix) with ESMTP id CA4412E80EC for ; Thu, 27 Aug 2020 08:51:22 +0000 (UTC) MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Date: Thu, 27 Aug 2020 08:40:59 -0000 From: Mike Gelfand <1893003@bugs.launchpad.net> To: qemu-devel@nongnu.org X-Launchpad-Notification-Type: bug X-Launchpad-Bug: product=qemu; status=New; importance=Undecided; assignee=None; X-Launchpad-Bug-Tags: linux-user ppc s390x X-Launchpad-Bug-Information-Type: Public X-Launchpad-Bug-Private: no X-Launchpad-Bug-Security-Vulnerability: no X-Launchpad-Bug-Commenters: mike.dld X-Launchpad-Bug-Reporter: Mike Gelfand (mike.dld) X-Launchpad-Bug-Modifier: Mike Gelfand (mike.dld) References: <159842808665.2865.2216413646645324343.malonedeb@chaenomeles.canonical.com> Message-Id: <159851765924.5796.7987398138944264389.malone@gac.canonical.com> Subject: [Bug 1893003] Re: qemu linux-user doesn't translate host/target data for iovec I/O X-Launchpad-Message-Rationale: Subscriber (QEMU) @qemu-devel-ml X-Launchpad-Message-For: qemu-devel-ml Precedence: bulk X-Generated-By: Launchpad (canonical.com); Revision="99c2d833c8d727fd05148486920aca032e908071"; Instance="production" X-Launchpad-Hash: 706958fe38d73a08bb2684d62462af0b00e150fe Received-SPF: none client-ip=91.189.90.7; envelope-from=bounces@canonical.com; helo=indium.canonical.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/08/27 04:51:23 X-ACL-Warn: Detected OS = Linux 3.11 and newer [fuzzy] X-Spam_score_int: -65 X-Spam_score: -6.6 X-Spam_bar: ------ X-Spam_report: (-6.6 / 5.0 requ) BAYES_00=-1.9, HEADER_FROM_DIFFERENT_DOMAINS=0.25, RCVD_IN_DNSWL_HI=-5, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_NONE=0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Bug 1893003 <1893003@bugs.launchpad.net> Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" The attached patch fixes the issue for me, but is incomplete (and not thoroughly tested) as I've only implemented inotify data translation for readv syscall. ** Patch added: "qemu-5.0.0-inotify-readv.patch" https://bugs.launchpad.net/qemu/+bug/1893003/+attachment/5405134/+files/= qemu-5.0.0-inotify-readv.patch -- = You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1893003 Title: qemu linux-user doesn't translate host/target data for iovec I/O Status in QEMU: New Bug description: When using iovec I/O functions (like `readv`), no data translation happens. I'm hitting this issue with libevent upon constructing a bufferevent over an inotify descriptor, and then building for either ppc64 or s390x (both big-endian) on x86_64 (little-endian) and running resulting code with qemu-ppc64 or qemu-s390x on Gentoo using latest QEMU version available (5.0.0-r2). The code in question is in https://github.com/transmission/transmission/blob/master/libtransmission /watchdir-inotify.c (`tr_watchdir_inotify_new`, `tr_watchdir_inotify_on_event`). While `read` syscall is handled properly, `readv` (which libevent is using in my case) doesn't have any logic to call `host_to_target_data_inotify` or any other translation function, leaving inotify data unchanged (with values in little-endian), which then leads to unit test failures. Quoting `do_syscall1` implementation bits for the reference: ---8<---begin--- case TARGET_NR_read: if (arg2 =3D=3D 0 && arg3 =3D=3D 0) { return get_errno(safe_read(arg1, 0, 0)); } else { if (!(p =3D lock_user(VERIFY_WRITE, arg2, arg3, 0))) return -TARGET_EFAULT; ret =3D get_errno(safe_read(arg1, p, arg3)); if (ret >=3D 0 && fd_trans_host_to_target_data(arg1)) { ret =3D fd_trans_host_to_target_data(arg1)(p, ret); } unlock_user(p, arg2, ret); } return ret; ... case TARGET_NR_readv: { struct iovec *vec =3D lock_iovec(VERIFY_WRITE, arg2, arg3, 0); if (vec !=3D NULL) { ret =3D get_errno(safe_readv(arg1, vec, arg3)); unlock_iovec(vec, arg2, arg3, 1); } else { ret =3D -host_to_target_errno(errno); } } return ret; ---8<---end--- To reiterate, the issue is not only with `readv` but with other iovec functions as well. To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1893003/+subscriptions