From nobody Sun Nov 2 11:46:58 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (208.118.235.17 [208.118.235.17]) by mx.zohomail.com with SMTPS id 1527743941731323.1028865739744; Wed, 30 May 2018 22:19:01 -0700 (PDT) Received: from localhost ([::1]:42057 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fOFzI-00017T-Nd for importer@patchew.org; Thu, 31 May 2018 01:19:00 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41940) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fOFxI-0008Vl-96 for qemu-devel@nongnu.org; Thu, 31 May 2018 01:16:57 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fOFxH-00067h-Du for qemu-devel@nongnu.org; Thu, 31 May 2018 01:16:56 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:39864 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fOFxH-00067D-9H for qemu-devel@nongnu.org; Thu, 31 May 2018 01:16:55 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id D3CE840267BD; Thu, 31 May 2018 05:16:54 +0000 (UTC) Received: from xz-mi.redhat.com (ovpn-12-18.pek2.redhat.com [10.72.12.18]) by smtp.corp.redhat.com (Postfix) with ESMTP id 3AD2E20A8473; Thu, 31 May 2018 05:16:48 +0000 (UTC) From: Peter Xu To: qemu-devel@nongnu.org Date: Thu, 31 May 2018 13:16:38 +0800 Message-Id: <20180531051641.8473-2-peterx@redhat.com> In-Reply-To: <20180531051641.8473-1-peterx@redhat.com> References: <20180531051641.8473-1-peterx@redhat.com> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.6 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.6]); Thu, 31 May 2018 05:16:54 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.6]); Thu, 31 May 2018 05:16:54 +0000 (UTC) for IP:'10.11.54.6' DOMAIN:'int-mx06.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'peterx@redhat.com' RCPT:'' X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 66.187.233.73 Subject: [Qemu-devel] [RFC v2 1/4] docs: mention shared state protect for OOB 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: , Cc: Kevin Wolf , Peter Maydell , Fam Zheng , Eric Auger , John Snow , peterx@redhat.com, Max Reitz , Christian Borntraeger , "Dr . David Alan Gilbert" , =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= , Markus Armbruster Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Out-Of-Band handlers need to protect shared state if there is any. Mention it in the document. Suggested-by: Markus Armbruster Signed-off-by: Peter Xu --- docs/devel/qapi-code-gen.txt | 3 +++ 1 file changed, 3 insertions(+) diff --git a/docs/devel/qapi-code-gen.txt b/docs/devel/qapi-code-gen.txt index b9b6eabd08..aafc15f100 100644 --- a/docs/devel/qapi-code-gen.txt +++ b/docs/devel/qapi-code-gen.txt @@ -680,6 +680,9 @@ OOB command handlers must satisfy the following conditi= ons: - It does not invoke system calls that may block, - It does not access guest RAM that may block when userfaultfd is enabled for postcopy live migration. +- It needs to protect possilbe shared states, since as long as a + command supports Out-Of-Band it means the handler can be run in + parallel with the same handler running in the other thread. =20 If in doubt, do not implement OOB execution support. =20 --=20 2.17.0