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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id B2121C433EF for ; Wed, 1 Dec 2021 17:14:35 +0000 (UTC) Received: from localhost ([::1]:34900 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1msTBi-0000LZ-7r for qemu-devel@archiver.kernel.org; Wed, 01 Dec 2021 12:14:34 -0500 Received: from eggs.gnu.org ([209.51.188.92]:48194) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1msSzV-0000jG-LA for qemu-devel@nongnu.org; Wed, 01 Dec 2021 12:01:57 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:35817) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1msSzQ-0001Lg-Bt for qemu-devel@nongnu.org; Wed, 01 Dec 2021 12:01:55 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1638378111; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=NpyWGZdtxdc207aB8v3Oyrt9gbjXXKLr8XkCrAbvVUg=; b=JQK4mbKDCplV/ySw61yBQ2RMdJQXf2//C9/2Blgzbq/AS35QhqFFC78uI2wabs9oeJHLrY f1BePahJcPPhFmbieILcij+BGO+xeMvRZK0ga6ArHCb0vjel2/qNI8XopLMrMPSBRTv0uG RhCTR+tsvSboAVd2Td038IF3CrJiS0U= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-503-ezO0bCkcPB-P3zGHwVmSVw-1; Wed, 01 Dec 2021 12:01:48 -0500 X-MC-Unique: ezO0bCkcPB-P3zGHwVmSVw-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9D2F910818B9; Wed, 1 Dec 2021 17:01:22 +0000 (UTC) Received: from localhost (unknown [10.39.193.115]) by smtp.corp.redhat.com (Postfix) with ESMTP id 26BF85D9D5; Wed, 1 Dec 2021 17:01:21 +0000 (UTC) From: Stefan Hajnoczi To: qemu-devel@nongnu.org Subject: [RFC v2 0/4] tls: add macros for coroutine-safe TLS variables Date: Wed, 1 Dec 2021 17:01:16 +0000 Message-Id: <20211201170120.286139-1-stefanha@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=stefanha@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable 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: -34 X-Spam_score: -3.5 X-Spam_bar: --- X-Spam_report: (-3.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.716, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=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: , Cc: Kevin Wolf , fweimer@redhat.com, thuth@redhat.com, Daniel Berrange , qemu-block@nongnu.org, Richard Henderson , Stefan Hajnoczi , Paolo Bonzini , Fam Zheng , Warner Losh , sguelton@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" This patch series solves the coroutines TLS problem. Coroutines re-entered = from=0D another thread sometimes see stale TLS values. This happens because compile= rs=0D may cache values across yield points, so a value from the previous thread w= ill=0D be used when the coroutine is re-entered in another thread.=0D =0D Serge Guelton developed a portable technique and Richard Henderson develope= d an=0D inline-friendly architecture-specific technique, see the first patch for=0D details.=0D =0D I have audited all __thread variables in QEMU and converted those that can = be=0D used from coroutines. Most actually look safe to me. This patch does not=0D include a checkpatch.pl rule that requires coroutine-tls.h usage, but perha= ps=0D we should add one for block/ at least?=0D =0D Stefan Hajnoczi (4):=0D tls: add macros for coroutine-safe TLS variables=0D util/async: replace __thread with QEMU TLS macros=0D rcu: use coroutine TLS macros=0D cpus: use coroutine TLS macros for iothread_locked=0D =0D include/qemu/coroutine-tls.h | 202 +++++++++++++++++++++++++++++++++++=0D include/qemu/rcu.h | 7 +-=0D softmmu/cpus.c | 8 +-=0D tests/unit/rcutorture.c | 10 +-=0D tests/unit/test-rcu-list.c | 4 +-=0D util/async.c | 12 ++-=0D util/rcu.c | 10 +-=0D 7 files changed, 229 insertions(+), 24 deletions(-)=0D create mode 100644 include/qemu/coroutine-tls.h=0D =0D --=20=0D 2.33.1=0D =0D