From nobody Tue Nov 26 11:33:35 2024 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1708530114947490.31005944983235; Wed, 21 Feb 2024 07:41:54 -0800 (PST) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rcod3-0000NL-JR; Wed, 21 Feb 2024 10:35:26 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rcoZI-0000Kv-CL; Wed, 21 Feb 2024 10:31:32 -0500 Received: from isrv.corpit.ru ([86.62.121.231]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rchrq-0002GZ-Tn; Wed, 21 Feb 2024 03:22:16 -0500 Received: from tsrv.corpit.ru (tsrv.tls.msk.ru [192.168.177.2]) by isrv.corpit.ru (Postfix) with ESMTP id 271344F3D1; Wed, 21 Feb 2024 11:21:21 +0300 (MSK) Received: from tls.msk.ru (mjt.wg.tls.msk.ru [192.168.177.130]) by tsrv.corpit.ru (Postfix) with SMTP id E7E69860B0; Wed, 21 Feb 2024 11:20:59 +0300 (MSK) Received: (nullmailer pid 2142044 invoked by uid 1000); Wed, 21 Feb 2024 08:20:58 -0000 From: Michael Tokarev To: qemu-devel@nongnu.org Cc: qemu-stable@nongnu.org, Stefan Hajnoczi , Kevin Wolf , Michael Tokarev Subject: [Stable-8.2.2 19/60] virtio-blk: avoid using ioeventfd state in irqfd conditional Date: Wed, 21 Feb 2024 11:20:07 +0300 Message-Id: <20240221082058.2141850-19-mjt@tls.msk.ru> X-Mailer: git-send-email 2.39.2 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=86.62.121.231; envelope-from=mjt@tls.msk.ru; helo=isrv.corpit.ru X-Spam_score_int: -68 X-Spam_score: -6.9 X-Spam_bar: ------ X-Spam_report: (-6.9 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_HI=-5, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZM-MESSAGEID: 1708530116088100007 Content-Type: text/plain; charset="utf-8" From: Stefan Hajnoczi Requests that complete in an IOThread use irqfd to notify the guest while requests that complete in the main loop thread use the traditional qdev irq code path. The reason for this conditional is that the irq code path requires the BQL: if (s->ioeventfd_started && !s->ioeventfd_disabled) { virtio_notify_irqfd(vdev, req->vq); } else { virtio_notify(vdev, req->vq); } There is a corner case where the conditional invokes the irq code path instead of the irqfd code path: static void virtio_blk_stop_ioeventfd(VirtIODevice *vdev) { ... /* * Set ->ioeventfd_started to false before draining so that host noti= fiers * are not detached/attached anymore. */ s->ioeventfd_started =3D false; /* Wait for virtio_blk_dma_restart_bh() and in flight I/O to complete= */ blk_drain(s->conf.conf.blk); During blk_drain() the conditional produces the wrong result because ioeventfd_started is false. Use qemu_in_iothread() instead of checking the ioeventfd state. Cc: qemu-stable@nongnu.org Buglink: https://issues.redhat.com/browse/RHEL-15394 Signed-off-by: Stefan Hajnoczi Message-ID: <20240122172625.415386-1-stefanha@redhat.com> Reviewed-by: Kevin Wolf Signed-off-by: Kevin Wolf (cherry picked from commit bfa36802d1704fc413c590ebdcc4e5ae0eacf439) Signed-off-by: Michael Tokarev (Mjt: fixup for v8.2.0-809-g3cdaf3dd4a "virtio-blk: rename dataplane to ioeventfd") diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c index a1f8e15522..31aac14581 100644 --- a/hw/block/virtio-blk.c +++ b/hw/block/virtio-blk.c @@ -65,7 +65,7 @@ static void virtio_blk_req_complete(VirtIOBlockReq *req, = unsigned char status) iov_discard_undo(&req->inhdr_undo); iov_discard_undo(&req->outhdr_undo); virtqueue_push(req->vq, &req->elem, req->in_len); - if (s->dataplane_started && !s->dataplane_disabled) { + if (qemu_in_iothread()) { virtio_blk_data_plane_notify(s->dataplane, req->vq); } else { virtio_notify(vdev, req->vq); --=20 2.39.2