From nobody Mon Feb 9 17:37:56 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass; 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; dmarc=pass(p=none dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1680546655; cv=none; d=zohomail.com; s=zohoarc; b=YZIC8JQY9zS9IA+whIOgQkzml5Wp3vPnoaLQZthP5Gz11ASGXBOG3mD/ZYXuKNdf64BZqO21BxJpqr4VePxAcUs3JW8iZrnpyMuUmgwl6/shZQcsr6E+TrrNcG9o5NzobKjCJ6S4Tt8xewzZ3jStodisvSDoH78rIqpbHuxTofk= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1680546655; h=Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To; bh=w78ixlnTJkfmit1c5uhGwpfg3e2qbfo6w6b+6TW1iVA=; b=l8A7fcMTeF5jsuf1yXoNcuAspfDfEpV9qMrKrQ61StySqGg70w7oDdqvMKn76qzjoOSCHx5mTPmJDFFR/Abh5blw5GvFHMLMkVfOtbNOXFeFEpukPqklqWeFdVj2E6WhzSbjP1IgitBgiaNXy+gFX2O7ktbRmgi92+RM68dGuDg= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; 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; dmarc=pass header.from= (p=none dis=none) Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1680546655533139.5063867174199; Mon, 3 Apr 2023 11:30:55 -0700 (PDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pjOwz-00017q-R0; Mon, 03 Apr 2023 14:30:41 -0400 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 1pjOwv-00014h-6B for qemu-devel@nongnu.org; Mon, 03 Apr 2023 14:30:39 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pjOwt-0000YW-ME for qemu-devel@nongnu.org; Mon, 03 Apr 2023 14:30:36 -0400 Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-439-74AM9wfyN9eiYjF1jls1ng-1; Mon, 03 Apr 2023 14:30:33 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id EE94B811E7C; Mon, 3 Apr 2023 18:30:31 +0000 (UTC) Received: from localhost (unknown [10.39.192.107]) by smtp.corp.redhat.com (Postfix) with ESMTP id 521171121314; Mon, 3 Apr 2023 18:30:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1680546635; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=w78ixlnTJkfmit1c5uhGwpfg3e2qbfo6w6b+6TW1iVA=; b=NnAqcyCLKjOMKft6xBEN4IomHgt+gmS71mOCo3mNKtuGDyktPFN2ZmX+/Z7dXbSZ/NxJjN rYiTnJRHssxivsuUsL/D7B7b2Uh5AqdkosRHAnGF9cyql8dvEkB7MtKnFUnbVO3OhFRdRO fqGxA+LxXPT325KvyC12Rpgj39WoK0c= X-MC-Unique: 74AM9wfyN9eiYjF1jls1ng-1 From: Stefan Hajnoczi To: qemu-devel@nongnu.org Cc: Paolo Bonzini , Julia Suvorova , Stefan Hajnoczi , Kevin Wolf , Peter Lieven , Coiby Xu , xen-devel@lists.xenproject.org, Richard Henderson , Stefano Garzarella , , Eduardo Habkost , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , Paul Durrant , "Richard W.M. 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Tsirkin" , =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= , Anthony Perard Subject: [PATCH 09/13] hw/xen: do not set is_external=true on evtchn fds Date: Mon, 3 Apr 2023 14:30:00 -0400 Message-Id: <20230403183004.347205-10-stefanha@redhat.com> In-Reply-To: <20230403183004.347205-1-stefanha@redhat.com> References: <20230403183004.347205-1-stefanha@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.1 on 10.11.54.3 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=170.10.129.124; envelope-from=stefanha@redhat.com; helo=us-smtp-delivery-124.mimecast.com 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, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 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-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1680546656545100001 Content-Type: text/plain; charset="utf-8" is_external=3Dtrue suspends fd handlers between aio_disable_external() and aio_enable_external(). The block layer's drain operation uses this mechanism to prevent new I/O from sneaking in between bdrv_drained_begin() and bdrv_drained_end(). The xen-block device actually works fine with is_external=3Dfalse because BlockBackend requests are already queued between bdrv_drained_begin() and bdrv_drained_end(). Since the Xen ring size is finite, request queuing will stop once the ring is full and memory usage is bounded. After bdrv_drained_end() the BlockBackend requests will resume and xen-block's processing will continue. This is part of ongoing work to remove the aio_disable_external() API. Signed-off-by: Stefan Hajnoczi --- hw/xen/xen-bus.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/hw/xen/xen-bus.c b/hw/xen/xen-bus.c index c59850b1de..c4fd26abe1 100644 --- a/hw/xen/xen-bus.c +++ b/hw/xen/xen-bus.c @@ -842,11 +842,11 @@ void xen_device_set_event_channel_context(XenDevice *= xendev, } =20 if (channel->ctx) - aio_set_fd_handler(channel->ctx, qemu_xen_evtchn_fd(channel->xeh),= true, + aio_set_fd_handler(channel->ctx, qemu_xen_evtchn_fd(channel->xeh),= false, NULL, NULL, NULL, NULL, NULL); =20 channel->ctx =3D ctx; - aio_set_fd_handler(channel->ctx, qemu_xen_evtchn_fd(channel->xeh), tru= e, + aio_set_fd_handler(channel->ctx, qemu_xen_evtchn_fd(channel->xeh), fal= se, xen_device_event, NULL, xen_device_poll, NULL, chan= nel); } =20 @@ -920,7 +920,7 @@ void xen_device_unbind_event_channel(XenDevice *xendev, =20 QLIST_REMOVE(channel, list); =20 - aio_set_fd_handler(channel->ctx, qemu_xen_evtchn_fd(channel->xeh), tru= e, + aio_set_fd_handler(channel->ctx, qemu_xen_evtchn_fd(channel->xeh), fal= se, NULL, NULL, NULL, NULL, NULL); =20 if (qemu_xen_evtchn_unbind(channel->xeh, channel->local_port) < 0) { --=20 2.39.2