From nobody Sun Feb 8 23:19:28 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=fail; 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=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1645454059082353.1381825172821; Mon, 21 Feb 2022 06:34:19 -0800 (PST) Received: from localhost ([::1]:46042 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nM9lb-0007hB-9z for importer@patchew.org; Mon, 21 Feb 2022 09:34:19 -0500 Received: from eggs.gnu.org ([209.51.188.92]:58770) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nM9gy-0004fw-Ul for qemu-devel@nongnu.org; Mon, 21 Feb 2022 09:29:34 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:26086) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nM9gt-0003QQ-8B for qemu-devel@nongnu.org; Mon, 21 Feb 2022 09:29:31 -0500 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-38-zQRqno1XOXSIfz7f5glIKw-1; Mon, 21 Feb 2022 09:29:14 -0500 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id A637A814245; Mon, 21 Feb 2022 14:29:12 +0000 (UTC) Received: from localhost (unknown [10.39.195.91]) by smtp.corp.redhat.com (Postfix) with ESMTP id 432A174EB7; Mon, 21 Feb 2022 14:29:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1645453757; 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: in-reply-to:in-reply-to:references:references; bh=UsXd6i3tDdrBdN2zFs7f1fO4YGsC7zELuTtcVvdruHk=; b=H1lPmqk6tEIDfExQeck3UPTcM021/fUNkKSXuMwdhqbqCWqajUISDqk8JeLgyFNGrYhbAb umTImPVaLkQ5Sc1xDEFEubNwy6m46Dja9/QV6TfMGJA5RUtEaOvsFWQoPJvxGRmfw1Sx5m hpfiUmRU1sI2bJvoRP2cMeX9/xDqcbw= X-MC-Unique: zQRqno1XOXSIfz7f5glIKw-1 From: Stefan Hajnoczi To: qemu-devel@nongnu.org Subject: [PATCH v4 1/4] tls: add macros for coroutine-safe TLS variables Date: Mon, 21 Feb 2022 14:29:04 +0000 Message-Id: <20220221142907.346035-2-stefanha@redhat.com> In-Reply-To: <20220221142907.346035-1-stefanha@redhat.com> References: <20220221142907.346035-1-stefanha@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 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-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=170.10.133.124; envelope-from=stefanha@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -28 X-Spam_score: -2.9 X-Spam_bar: -- X-Spam_report: (-2.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, 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: , Cc: Florian Weimer , Kevin Wolf , qemu-block@nongnu.org, Peter Maydell , Richard Henderson , Stefan Hajnoczi , Paolo Bonzini , Fam Zheng , Serge Guelton Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) X-ZM-MESSAGEID: 1645454061831100001 Content-Type: text/plain; charset="utf-8" Compiler optimizations can cache TLS values across coroutine yield points, resulting in stale values from the previous thread when a coroutine is re-entered by a new thread. Serge Guelton developed an __attribute__((noinline)) wrapper and tested it with clang and gcc. I formatted his idea according to QEMU's coding style and wrote documentation. Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=3D1952483 Suggested-by: Serge Guelton Signed-off-by: Stefan Hajnoczi --- include/qemu/coroutine-tls.h | 159 +++++++++++++++++++++++++++++++++++ 1 file changed, 159 insertions(+) create mode 100644 include/qemu/coroutine-tls.h diff --git a/include/qemu/coroutine-tls.h b/include/qemu/coroutine-tls.h new file mode 100644 index 0000000000..e1f8e78d25 --- /dev/null +++ b/include/qemu/coroutine-tls.h @@ -0,0 +1,159 @@ +/* + * QEMU Thread Local Storage for coroutines + * + * Copyright Red Hat + * + * SPDX-License-Identifier: LGPL-2.1-or-later + * + * This work is licensed under the terms of the GNU LGPL, version 2.1 or l= ater. + * See the COPYING.LIB file in the top-level directory. + * + * It is forbidden to access Thread Local Storage in coroutines because + * compiler optimizations may cause values to be cached across coroutine + * re-entry. Coroutines can run in more than one thread through the course= of + * their life, leading bugs when stale TLS values from the wrong thread are + * used as a result of compiler optimization. + * + * An example is: + * + * ..code-block:: c + * :caption: A coroutine that may see the wrong TLS value + * + * static __thread AioContext *current_aio_context; + * ... + * static void coroutine_fn foo(void) + * { + * aio_notify(current_aio_context); + * qemu_coroutine_yield(); + * aio_notify(current_aio_context); // <-- may be stale after yieldi= ng! + * } + * + * This header provides macros for safely defining variables in Thread Loc= al + * Storage: + * + * ..code-block:: c + * :caption: A coroutine that safely uses TLS + * + * QEMU_DEFINE_STATIC_CO_TLS(AioContext *, current_aio_context) + * ... + * static void coroutine_fn foo(void) + * { + * aio_notify(get_current_aio_context()); + * qemu_coroutine_yield(); + * aio_notify(get_current_aio_context()); // <-- safe + * } + */ + +#ifndef QEMU_COROUTINE_TLS_H +#define QEMU_COROUTINE_TLS_H + +/* + * To stop the compiler from caching TLS values we define accessor functio= ns + * with __attribute__((noinline)) plus asm volatile("") to prevent + * optimizations that override noinline. This is fragile and ultimately ne= eds + * to be solved by a mechanism that is guaranteed to work by the compiler = (e.g. + * stackless coroutines), but for now we use this approach to prevent issu= es. + */ + +/** + * QEMU_DECLARE_CO_TLS: + * @type: the variable's C type + * @var: the variable name + * + * Declare an extern variable in Thread Local Storage from a header file: + * + * .. code-block:: c + * :caption: Declaring an extern variable in Thread Local Storage + * + * QEMU_DECLARE_CO_TLS(int, my_count) + * ... + * int c =3D get_my_count(); + * set_my_count(c + 1); + * *get_ptr_my_count() =3D 0; + * + * This is a coroutine-safe replacement for the __thread keyword and is + * equivalent to the following code: + * + * .. code-block:: c + * :caption: Declaring a TLS variable using __thread + * + * extern __thread int my_count; + * ... + * int c =3D my_count; + * my_count =3D c + 1; + * *(&my_count) =3D 0; + */ +#define QEMU_DECLARE_CO_TLS(type, var) = \ + __attribute__((noinline)) type get_##var(void); = \ + __attribute__((noinline)) void set_##var(type v); = \ + __attribute__((noinline)) type *get_ptr_##var(void); + +/** + * QEMU_DEFINE_CO_TLS: + * @type: the variable's C type + * @var: the variable name + * + * Define a variable in Thread Local Storage that was previously declared = from + * a header file with QEMU_DECLARE_CO_TLS(): + * + * .. code-block:: c + * :caption: Defining a variable in Thread Local Storage + * + * QEMU_DEFINE_CO_TLS(int, my_count) + * + * This is a coroutine-safe replacement for the __thread keyword and is + * equivalent to the following code: + * + * .. code-block:: c + * :caption: Defining a TLS variable using __thread + * + * __thread int my_count; + */ +#define QEMU_DEFINE_CO_TLS(type, var) = \ + static __thread type co_tls_##var; = \ + type get_##var(void) { asm volatile(""); return co_tls_##var; } = \ + void set_##var(type v) { asm volatile(""); co_tls_##var =3D v; } = \ + type *get_ptr_##var(void) = \ + { type *ptr =3D &co_tls_##var; asm volatile("" : "+rm" (ptr)); return = ptr; } + +/** + * QEMU_DEFINE_STATIC_CO_TLS: + * @type: the variable's C type + * @var: the variable name + * + * Define a static variable in Thread Local Storage: + * + * .. code-block:: c + * :caption: Defining a static variable in Thread Local Storage + * + * QEMU_DEFINE_STATIC_CO_TLS(int, my_count) + * ... + * int c =3D get_my_count(); + * set_my_count(c + 1); + * *get_ptr_my_count() =3D 0; + * + * This is a coroutine-safe replacement for the __thread keyword and is + * equivalent to the following code: + * + * .. code-block:: c + * :caption: Defining a static TLS variable using __thread + * + * static __thread int my_count; + * ... + * int c =3D my_count; + * my_count =3D c + 1; + * *(&my_count) =3D 0; + */ +#define QEMU_DEFINE_STATIC_CO_TLS(type, var) = \ + static __thread type co_tls_##var; = \ + static __attribute__((noinline, unused)) = \ + type get_##var(void) = \ + { asm volatile(""); return co_tls_##var; } = \ + static __attribute__((noinline, unused)) = \ + void set_##var(type v) = \ + { asm volatile(""); co_tls_##var =3D v; } = \ + static __attribute__((noinline, unused)) = \ + type *get_ptr_##var(void) = \ + { type *ptr =3D &co_tls_##var; asm volatile("" : "+rm" (ptr)); return = ptr; } + +#endif /* QEMU_COROUTINE_TLS_H */ --=20 2.34.1 From nobody Sun Feb 8 23:19:28 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=fail; 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=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 164545441661070.8574646575139; Mon, 21 Feb 2022 06:40:16 -0800 (PST) Received: from localhost ([::1]:55254 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nM9rL-0005Z8-4p for importer@patchew.org; Mon, 21 Feb 2022 09:40:15 -0500 Received: from eggs.gnu.org ([209.51.188.92]:58816) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nM9h0-0004fz-6N for qemu-devel@nongnu.org; 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a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1645453758; 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: in-reply-to:in-reply-to:references:references; bh=ydAFJulO1fktYGT+VeP4DNbUV9UD3tPDkgP+u0FXbQ0=; b=inwUcmtHGh3nllqzIzXKK++is7ncis5DLql2y6IOpCi/R/BXikggDV2h3UcSGJxVA1CmMq IeU9pFflqYr7scejBreOFuunFrm+Etuh2G4lvs2hwSHdEC6Amrhu86rfM01YwIOtchm2eT /eVjjsgv1t7Z3JiHX+kvN1ipy5hBsrw= X-MC-Unique: sAol9aGzNJ6dVdW-UsKNNw-1 From: Stefan Hajnoczi To: qemu-devel@nongnu.org Subject: [PATCH v4 2/4] util/async: replace __thread with QEMU TLS macros Date: Mon, 21 Feb 2022 14:29:05 +0000 Message-Id: <20220221142907.346035-3-stefanha@redhat.com> In-Reply-To: <20220221142907.346035-1-stefanha@redhat.com> References: <20220221142907.346035-1-stefanha@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Authentication-Results: relay.mimecast.com; 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charset="utf-8" QEMU TLS macros must be used to make TLS variables safe with coroutines. Signed-off-by: Stefan Hajnoczi Reviewed-by: Philippe Mathieu-Daud=C3=A9 --- util/async.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/util/async.c b/util/async.c index 08d25feef5..2ea1172f3e 100644 --- a/util/async.c +++ b/util/async.c @@ -32,6 +32,7 @@ #include "qemu/rcu_queue.h" #include "block/raw-aio.h" #include "qemu/coroutine_int.h" +#include "qemu/coroutine-tls.h" #include "trace.h" =20 /***********************************************************/ @@ -675,12 +676,13 @@ void aio_context_release(AioContext *ctx) qemu_rec_mutex_unlock(&ctx->lock); } =20 -static __thread AioContext *my_aiocontext; +QEMU_DEFINE_STATIC_CO_TLS(AioContext *, my_aiocontext) =20 AioContext *qemu_get_current_aio_context(void) { - if (my_aiocontext) { - return my_aiocontext; + AioContext *ctx =3D get_my_aiocontext(); + if (ctx) { + return ctx; } if (qemu_mutex_iothread_locked()) { /* Possibly in a vCPU thread. */ @@ -691,6 +693,6 @@ AioContext *qemu_get_current_aio_context(void) =20 void qemu_set_current_aio_context(AioContext *ctx) { - assert(!my_aiocontext); - my_aiocontext =3D ctx; + assert(!get_my_aiocontext()); + set_my_aiocontext(ctx); } --=20 2.34.1 From nobody Sun Feb 8 23:19:28 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=fail; 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=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1645454310056485.29120566486677; Mon, 21 Feb 2022 06:38:30 -0800 (PST) Received: from localhost ([::1]:53856 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nM9pd-0004dh-1T for importer@patchew.org; Mon, 21 Feb 2022 09:38:29 -0500 Received: from eggs.gnu.org ([209.51.188.92]:58922) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nM9h7-0004iD-6A for qemu-devel@nongnu.org; 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a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1645453776; 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: in-reply-to:in-reply-to:references:references; bh=uCWbElNmCbRX2GIEYFaMr3geN+BCQusMA1a7CEL68Ow=; b=ON/ICghP7C23RjGUU+jm28KsxrRESDGMJ+weyhIa0KlO7T68UwQFML8havS6BcOgqwuB+T X9IIoYnb2t6pSrCqEMLHl0UtCe2JNIFjjsNn2CoUKBMySYfQat7T+JfzXuOzK/CnuIOi0w qeLhOLwZ+ZzAthh46t7/DhjlwzcB608= X-MC-Unique: FtHvdmbZOOemDhabutsk3w-1 From: Stefan Hajnoczi To: qemu-devel@nongnu.org Subject: [PATCH v4 3/4] rcu: use coroutine TLS macros Date: Mon, 21 Feb 2022 14:29:06 +0000 Message-Id: <20220221142907.346035-4-stefanha@redhat.com> In-Reply-To: <20220221142907.346035-1-stefanha@redhat.com> References: <20220221142907.346035-1-stefanha@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Authentication-Results: relay.mimecast.com; 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charset="utf-8" RCU may be used from coroutines. Standard __thread variables cannot be used by coroutines. Use the coroutine TLS macros instead. Signed-off-by: Stefan Hajnoczi --- include/qemu/rcu.h | 7 ++++--- tests/unit/rcutorture.c | 10 +++++----- tests/unit/test-rcu-list.c | 4 ++-- util/rcu.c | 10 +++++----- 4 files changed, 16 insertions(+), 15 deletions(-) diff --git a/include/qemu/rcu.h b/include/qemu/rcu.h index e69efbd47f..b063c6fde8 100644 --- a/include/qemu/rcu.h +++ b/include/qemu/rcu.h @@ -29,6 +29,7 @@ #include "qemu/atomic.h" #include "qemu/notify.h" #include "qemu/sys_membarrier.h" +#include "qemu/coroutine-tls.h" =20 #ifdef __cplusplus extern "C" { @@ -76,11 +77,11 @@ struct rcu_reader_data { NotifierList force_rcu; }; =20 -extern __thread struct rcu_reader_data rcu_reader; +QEMU_DECLARE_CO_TLS(struct rcu_reader_data, rcu_reader) =20 static inline void rcu_read_lock(void) { - struct rcu_reader_data *p_rcu_reader =3D &rcu_reader; + struct rcu_reader_data *p_rcu_reader =3D get_ptr_rcu_reader(); unsigned ctr; =20 if (p_rcu_reader->depth++ > 0) { @@ -96,7 +97,7 @@ static inline void rcu_read_lock(void) =20 static inline void rcu_read_unlock(void) { - struct rcu_reader_data *p_rcu_reader =3D &rcu_reader; + struct rcu_reader_data *p_rcu_reader =3D get_ptr_rcu_reader(); =20 assert(p_rcu_reader->depth !=3D 0); if (--p_rcu_reader->depth > 0) { diff --git a/tests/unit/rcutorture.c b/tests/unit/rcutorture.c index de6f649058..495a4e6f42 100644 --- a/tests/unit/rcutorture.c +++ b/tests/unit/rcutorture.c @@ -122,7 +122,7 @@ static void *rcu_read_perf_test(void *arg) =20 rcu_register_thread(); =20 - *(struct rcu_reader_data **)arg =3D &rcu_reader; + *(struct rcu_reader_data **)arg =3D get_ptr_rcu_reader(); qatomic_inc(&nthreadsrunning); while (goflag =3D=3D GOFLAG_INIT) { g_usleep(1000); @@ -148,7 +148,7 @@ static void *rcu_update_perf_test(void *arg) =20 rcu_register_thread(); =20 - *(struct rcu_reader_data **)arg =3D &rcu_reader; + *(struct rcu_reader_data **)arg =3D get_ptr_rcu_reader(); qatomic_inc(&nthreadsrunning); while (goflag =3D=3D GOFLAG_INIT) { g_usleep(1000); @@ -253,7 +253,7 @@ static void *rcu_read_stress_test(void *arg) =20 rcu_register_thread(); =20 - *(struct rcu_reader_data **)arg =3D &rcu_reader; + *(struct rcu_reader_data **)arg =3D get_ptr_rcu_reader(); while (goflag =3D=3D GOFLAG_INIT) { g_usleep(1000); } @@ -304,7 +304,7 @@ static void *rcu_update_stress_test(void *arg) struct rcu_stress *cp =3D qatomic_read(&rcu_stress_current); =20 rcu_register_thread(); - *(struct rcu_reader_data **)arg =3D &rcu_reader; + *(struct rcu_reader_data **)arg =3D get_ptr_rcu_reader(); =20 while (goflag =3D=3D GOFLAG_INIT) { g_usleep(1000); @@ -347,7 +347,7 @@ static void *rcu_fake_update_stress_test(void *arg) { rcu_register_thread(); =20 - *(struct rcu_reader_data **)arg =3D &rcu_reader; + *(struct rcu_reader_data **)arg =3D get_ptr_rcu_reader(); while (goflag =3D=3D GOFLAG_INIT) { g_usleep(1000); } diff --git a/tests/unit/test-rcu-list.c b/tests/unit/test-rcu-list.c index 49641e1936..64b81ae058 100644 --- a/tests/unit/test-rcu-list.c +++ b/tests/unit/test-rcu-list.c @@ -171,7 +171,7 @@ static void *rcu_q_reader(void *arg) =20 rcu_register_thread(); =20 - *(struct rcu_reader_data **)arg =3D &rcu_reader; + *(struct rcu_reader_data **)arg =3D get_ptr_rcu_reader(); qatomic_inc(&nthreadsrunning); while (qatomic_read(&goflag) =3D=3D GOFLAG_INIT) { g_usleep(1000); @@ -206,7 +206,7 @@ static void *rcu_q_updater(void *arg) long long n_removed_local =3D 0; struct list_element *el, *prev_el; =20 - *(struct rcu_reader_data **)arg =3D &rcu_reader; + *(struct rcu_reader_data **)arg =3D get_ptr_rcu_reader(); qatomic_inc(&nthreadsrunning); while (qatomic_read(&goflag) =3D=3D GOFLAG_INIT) { g_usleep(1000); diff --git a/util/rcu.c b/util/rcu.c index c91da9f137..b6d6c71cff 100644 --- a/util/rcu.c +++ b/util/rcu.c @@ -65,7 +65,7 @@ static inline int rcu_gp_ongoing(unsigned long *ctr) /* Written to only by each individual reader. Read by both the reader and = the * writers. */ -__thread struct rcu_reader_data rcu_reader; +QEMU_DEFINE_CO_TLS(struct rcu_reader_data, rcu_reader) =20 /* Protected by rcu_registry_lock. */ typedef QLIST_HEAD(, rcu_reader_data) ThreadList; @@ -355,23 +355,23 @@ void drain_call_rcu(void) =20 void rcu_register_thread(void) { - assert(rcu_reader.ctr =3D=3D 0); + assert(get_ptr_rcu_reader()->ctr =3D=3D 0); qemu_mutex_lock(&rcu_registry_lock); - QLIST_INSERT_HEAD(®istry, &rcu_reader, node); + QLIST_INSERT_HEAD(®istry, get_ptr_rcu_reader(), node); qemu_mutex_unlock(&rcu_registry_lock); } =20 void rcu_unregister_thread(void) { qemu_mutex_lock(&rcu_registry_lock); - QLIST_REMOVE(&rcu_reader, node); + QLIST_REMOVE(get_ptr_rcu_reader(), node); qemu_mutex_unlock(&rcu_registry_lock); } =20 void rcu_add_force_rcu_notifier(Notifier *n) { qemu_mutex_lock(&rcu_registry_lock); - notifier_list_add(&rcu_reader.force_rcu, n); + notifier_list_add(&get_ptr_rcu_reader()->force_rcu, n); qemu_mutex_unlock(&rcu_registry_lock); } =20 --=20 2.34.1 From nobody Sun Feb 8 23:19:28 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=fail; 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=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1645454699129274.27716373548105; Mon, 21 Feb 2022 06:44:59 -0800 (PST) Received: from localhost ([::1]:35274 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nM9vt-0002mY-VN for importer@patchew.org; Mon, 21 Feb 2022 09:44:57 -0500 Received: from eggs.gnu.org ([209.51.188.92]:59030) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nM9hQ-0004mg-67 for qemu-devel@nongnu.org; Mon, 21 Feb 2022 09:30:00 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:37813) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nM9hJ-0003UM-MX for qemu-devel@nongnu.org; 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bh=YKyRJlhWijZAQl/G+XAwpjgnydnM+2Dax5jIraia9Kk=; b=cK/DWciQjAbVRrJwDlS8RccYKIiyHuL29bFDSEoXU1IBgESNPFJNzbDxfQfXajBr9S05G0 FQupDTzKuuLGYfZqb6qqtv6h3qtoy34EuszSCzG6Q/XKiU3VCoeT79f3AMQOFxRODTtR7j wNOcvO6C4bGdSL+ojznuEgB8W2ZUfPM= X-MC-Unique: jv3wiu26PkiqiYD9JzyNxQ-1 From: Stefan Hajnoczi To: qemu-devel@nongnu.org Subject: [PATCH v4 4/4] cpus: use coroutine TLS macros for iothread_locked Date: Mon, 21 Feb 2022 14:29:07 +0000 Message-Id: <20220221142907.346035-5-stefanha@redhat.com> In-Reply-To: <20220221142907.346035-1-stefanha@redhat.com> References: <20220221142907.346035-1-stefanha@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 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-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; 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charset="utf-8" qemu_mutex_iothread_locked() may be used from coroutines. Standard __thread variables cannot be used by coroutines. Use the coroutine TLS macros instead. Signed-off-by: Stefan Hajnoczi Reviewed-by: Philippe Mathieu-Daud=C3=A9 --- softmmu/cpus.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/softmmu/cpus.c b/softmmu/cpus.c index 035395ae13..005a5c31ef 100644 --- a/softmmu/cpus.c +++ b/softmmu/cpus.c @@ -473,11 +473,11 @@ bool qemu_in_vcpu_thread(void) return current_cpu && qemu_cpu_is_self(current_cpu); } =20 -static __thread bool iothread_locked =3D false; +QEMU_DEFINE_STATIC_CO_TLS(bool, iothread_locked) =20 bool qemu_mutex_iothread_locked(void) { - return iothread_locked; + return get_iothread_locked(); } =20 /* @@ -490,13 +490,13 @@ void qemu_mutex_lock_iothread_impl(const char *file, = int line) =20 g_assert(!qemu_mutex_iothread_locked()); bql_lock(&qemu_global_mutex, file, line); - iothread_locked =3D true; + set_iothread_locked(true); } =20 void qemu_mutex_unlock_iothread(void) { g_assert(qemu_mutex_iothread_locked()); - iothread_locked =3D false; + set_iothread_locked(false); qemu_mutex_unlock(&qemu_global_mutex); } =20 --=20 2.34.1