From patchwork Thu May 14 18:26:04 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christian Schoenebeck X-Patchwork-Id: 282721 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=-6.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, 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 15FD3C433E0 for ; Thu, 14 May 2020 19:19:39 +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 D4ECF206DC for ; Thu, 14 May 2020 19:19:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=crudebyte.com header.i=@crudebyte.com header.b="gSZAjMcO" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D4ECF206DC Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=crudebyte.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:57124 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jZJOL-0003ys-U4 for qemu-devel@archiver.kernel.org; Thu, 14 May 2020 15:19:37 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:57622) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from <2cc8d6c4ae9fa8210c48c349b207dfb68cb15290@lizzy.crudebyte.com>) id 1jZJNg-0003Oe-K5 for qemu-devel@nongnu.org; Thu, 14 May 2020 15:18:56 -0400 Received: from lizzy.crudebyte.com ([91.194.90.13]:35467) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from <2cc8d6c4ae9fa8210c48c349b207dfb68cb15290@lizzy.crudebyte.com>) id 1jZJNe-0006PH-J2 for qemu-devel@nongnu.org; Thu, 14 May 2020 15:18:56 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=crudebyte.com; s=lizzy; h=Cc:To:Subject:Date:From:References:In-Reply-To: Message-Id:Content-Type:Content-Transfer-Encoding:MIME-Version:Content-ID: Content-Description; bh=wS4qczauhBOj6sgHwbdGA4ceIYc4fObuVM5GVKolD5s=; b=gSZAj McONRy/opbqxtmuMKE8MymZZmYAj7Kk4gjYOnxwfUmomAQ63jVpgMmb5v2Ga/SBymsHF6u1yIEOMg gE6jLeUZMIYRVSP0TFGVQs0MKlYioU+7JtXp/5ON1HoPE2ZtPjc2KWEnt3M3jYHzSpi0OiwJ1Xk+6 v6e00Oag0o2JFBOUbLFjyB4UZmWyVkEy3mn8q2yVwLbxFXLzIpFjNw0cInyMDhQAw1KqTKzMQIv72 yVSO+QPT+YMlr1qLeK0YhK2/lEr84Nd8IDtPqMlzjPskM5dIk8pEFK8KtMGjhbhyPoj9x69zpYvSy 1Ax43yZde+Jr9uIEtv2wXkNhmvsBQ==; Message-Id: <2cc8d6c4ae9fa8210c48c349b207dfb68cb15290.1589481482.git.qemu_oss@crudebyte.com> In-Reply-To: References: From: Christian Schoenebeck Date: Thu, 14 May 2020 20:26:04 +0200 Subject: [PATCH 1/1] virtio-9pfs: don't truncate response To: qemu-devel@nongnu.org Cc: Greg Kurz , Stefano Stabellini , Anthony Perard , Paul Durrant Received-SPF: none client-ip=91.194.90.13; envelope-from=2cc8d6c4ae9fa8210c48c349b207dfb68cb15290@lizzy.crudebyte.com; helo=lizzy.crudebyte.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/14 14:49:51 X-ACL-Warn: Detected OS = Linux 3.11 and newer X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, URIBL_BLOCKED=0.001 autolearn=_AUTOLEARN X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Commit SHA-1 16724a173049ac29c7b5ade741da93a0f46edff7 introduced truncating the response to the currently available transport buffer size, which was supposed to fix an 9pfs error on Xen boot where transport buffer might still be smaller than required for response. Unfortunately this change broke small reads (with less than 12 bytes). To fix this introduced bug for virtio at least, let's revert this change for the virtio transport. Unlike with Xen, we should never come into this situation with virtio that the available transport buffer would be too small for delivering any response to client. So truncating the buffer is not necessary with virtio in the first place. This bug still needs to be addressed for Xen appropriately though. Fixes: 16724a173049ac29c7b5ade741da93a0f46edff7 (for virtio only) Fixes: https://bugs.launchpad.net/bugs/1877688 (for virtio only) Signed-off-by: Christian Schoenebeck --- hw/9pfs/virtio-9p-device.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/hw/9pfs/virtio-9p-device.c b/hw/9pfs/virtio-9p-device.c index 536447a355..bb6154945a 100644 --- a/hw/9pfs/virtio-9p-device.c +++ b/hw/9pfs/virtio-9p-device.c @@ -154,16 +154,13 @@ static void virtio_init_in_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov, VirtQueueElement *elem = v->elems[pdu->idx]; size_t buf_size = iov_size(elem->in_sg, elem->in_num); - if (buf_size < P9_IOHDRSZ) { + if (buf_size < *size) { VirtIODevice *vdev = VIRTIO_DEVICE(v); virtio_error(vdev, - "VirtFS reply type %d needs %zu bytes, buffer has %zu, less than minimum", + "VirtFS reply type %d needs %zu bytes, buffer has %zu", pdu->id + 1, *size, buf_size); } - if (buf_size < *size) { - *size = buf_size; - } *piov = elem->in_sg; *pniov = elem->in_num;