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 DDE2FC433EF for ; Mon, 6 Dec 2021 14:32:31 +0000 (UTC) Received: from localhost ([::1]:38100 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1muF2c-0001Ve-Td for qemu-devel@archiver.kernel.org; Mon, 06 Dec 2021 09:32:30 -0500 Received: from eggs.gnu.org ([209.51.188.92]:51638) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1muExJ-0007FF-3C for qemu-devel@nongnu.org; Mon, 06 Dec 2021 09:27:01 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:24213) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1muExD-0002wa-Hp for qemu-devel@nongnu.org; Mon, 06 Dec 2021 09:26:59 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1638800814; 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=6wqy6ZwguG5EfvKMwgNkeRXsaXQ8pK9sb30dxDc2SjQ=; b=Th3/F+XCuLRycKxwj4RbJv6eKZhMqiK20tepowJnzsFOmYsPyqkrwuhp+LNHYUB8AN4uEX uX3b43C1vgl4LNjqJ88HcR6pk3O+y5SdqJIDxy994M45bnqO2QRYgBzdgxAcn2PHhg0ikK 2KThHWXhSuYDWxowuEYsqJXbldFhUNk= 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-109-jUA6rcyEMK-_py1JylEu1Q-1; Mon, 06 Dec 2021 09:26:51 -0500 X-MC-Unique: jUA6rcyEMK-_py1JylEu1Q-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id AB1FF9392B; Mon, 6 Dec 2021 14:26:48 +0000 (UTC) Received: from localhost (unknown [10.39.193.226]) by smtp.corp.redhat.com (Postfix) with ESMTP id D62B660C7F; Mon, 6 Dec 2021 14:26:33 +0000 (UTC) From: Stefan Hajnoczi To: qemu-devel@nongnu.org Subject: [RFC v3 0/4] tls: add macros for coroutine-safe TLS variables Date: Mon, 6 Dec 2021 14:26:28 +0000 Message-Id: <20211206142632.116925-1-stefanha@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 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: -33 X-Spam_score: -3.4 X-Spam_bar: --- X-Spam_report: (-3.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.619, 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=unavailable 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: Fam Zheng , fweimer@redhat.com, thuth@redhat.com, Daniel Berrange , qemu-block@nongnu.org, Richard Henderson , Stefan Hajnoczi , Paolo Bonzini , Kevin Wolf , Warner Losh , sguelton@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" v3:=0D - Added __attribute__((weak)) to get_ptr_*() [Florian]=0D - Replace rdfsbase with mov %%fs:0,%0 [Florian]=0D =0D 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 | 205 +++++++++++++++++++++++++++++++++++=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, 232 insertions(+), 24 deletions(-)=0D create mode 100644 include/qemu/coroutine-tls.h=0D =0D --=20=0D 2.33.1=0D =0D