From patchwork Thu Sep 22 10:13:13 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Alex_Benn=C3=A9e?= X-Patchwork-Id: 673302 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3sft985Ms8z9t2C for ; Thu, 22 Sep 2016 20:32:28 +1000 (AEST) Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=linaro.org header.i=@linaro.org header.b=kvgwIqw8; dkim-atps=neutral Received: from localhost ([::1]:36971 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bn1Io-00080g-8F for incoming@patchwork.ozlabs.org; Thu, 22 Sep 2016 06:32:26 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50900) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bn11U-00083z-Tv for qemu-devel@nongnu.org; Thu, 22 Sep 2016 06:14:33 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bn11P-0006nq-Rf for qemu-devel@nongnu.org; Thu, 22 Sep 2016 06:14:31 -0400 Received: from mail-wm0-f43.google.com ([74.125.82.43]:36699) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bn11P-0006ni-Lw for qemu-devel@nongnu.org; Thu, 22 Sep 2016 06:14:27 -0400 Received: by mail-wm0-f43.google.com with SMTP id w84so243501831wmg.1 for ; Thu, 22 Sep 2016 03:14:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=fzPOoTRZU2qskq53y7N0VCOBmEO8Ax0q2x2+5nLcnK0=; b=kvgwIqw8R6+4IkG1TJd6mWhD2Agi8xhR6cZApelDRdvTYZCf9xCY+CImAnfw005g68 epjq+mTm+qAl3fXe7nM8ovDmB9eYoWFySHuPcrWqi6GWCRXdrQOfa5szo7sD8dTDRhit tWh9mcafCYkzT5w/UBOLNOoqr9iJkxesfBOyE= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=fzPOoTRZU2qskq53y7N0VCOBmEO8Ax0q2x2+5nLcnK0=; b=IS8gvCgtiPuwQlTNaIsPZVQbv6qFdU54ZFOCPeM/puMxwVooc6afCrlY5J5ypprIxU sUMln1XdSIFzJ8zxaYUBP+t44vw3HAABMZNIbb5uA4UCw3T5MbGQr+74PgTlXlCdlAio ANjymhrxSGL+vTmmTxT55AtLKMBRStd5SPPH5h5EVwwU2gKvlwbzvfFxGzJHCRl792ug mGi0AlzTvOPFX/LH+Wt4Hc9F4fijkkh0kACqHSSkIHA3XypnhN2nLnRqay41tWwVJh5z 2xKFtjaXO+RLuCbEzEyJs58LoQ40R4jLc0kYt/xACIX460ruc+emqEfzFB3yyFphyetQ dLrg== X-Gm-Message-State: AE9vXwOfjAMJP4CoEt3rmRWl3u68aX6hYzOUkeoOA1nedJZ3H/IG+Cqv6eOpL+2uPftQsEFE X-Received: by 10.28.215.67 with SMTP id o64mr1626111wmg.98.1474539207023; Thu, 22 Sep 2016 03:13:27 -0700 (PDT) Received: from zen.linaro.local ([81.128.185.34]) by smtp.gmail.com with ESMTPSA id o5sm1718722wmg.16.2016.09.22.03.13.24 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 22 Sep 2016 03:13:25 -0700 (PDT) Received: from zen.linaroharston (localhost [127.0.0.1]) by zen.linaro.local (Postfix) with ESMTP id E03233E02AD; Thu, 22 Sep 2016 11:13:22 +0100 (BST) From: =?UTF-8?q?Alex=20Benn=C3=A9e?= To: qemu-devel@nongnu.org, pbonzini@redhat.com, cota@braap.org, stefanha@redhat.com, kwolf@redhat.com Date: Thu, 22 Sep 2016 11:13:13 +0100 Message-Id: <20160922101316.13064-7-alex.bennee@linaro.org> X-Mailer: git-send-email 2.9.3 In-Reply-To: <20160922101316.13064-1-alex.bennee@linaro.org> References: <20160922101316.13064-1-alex.bennee@linaro.org> MIME-Version: 1.0 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 74.125.82.43 Subject: [Qemu-devel] [PATCH v2 6/9] cpu: atomically modify cpu->exit_request 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: mttcg@listserver.greensocs.com, peter.maydell@linaro.org, claudio.fontana@huawei.com, nikunj@linux.vnet.ibm.com, Peter Crosthwaite , jan.kiszka@siemens.com, mark.burton@greensocs.com, a.rigo@virtualopensystems.com, serge.fdrv@gmail.com, bobby.prani@gmail.com, rth@twiddle.net, =?UTF-8?q?Alex=20Benn=C3=A9e?= , fred.konrad@greensocs.com Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" ThreadSanitizer picks up potential races although we already use barriers to ensure things are in the correct order when processing exit requests. For now we just use the relaxed atomic_set/atomic_read semantics to reassure tsan that we can't tear the value. Signed-off-by: Alex Bennée --- cpu-exec.c | 8 ++++---- qom/cpu.c | 4 ++-- 2 files changed, 6 insertions(+), 6 deletions(-) diff --git a/cpu-exec.c b/cpu-exec.c index 9f4bd0b..113d8dc 100644 --- a/cpu-exec.c +++ b/cpu-exec.c @@ -192,7 +192,7 @@ static inline tcg_target_ulong cpu_tb_exec(CPUState *cpu, TranslationBlock *itb) /* We were asked to stop executing TBs (probably a pending * interrupt. We've now stopped, so clear the flag. */ - cpu->tcg_exit_req = 0; + atomic_set(&cpu->tcg_exit_req, 0); } return ret; } @@ -497,8 +497,8 @@ static inline void cpu_handle_interrupt(CPUState *cpu, *last_tb = NULL; } } - if (unlikely(cpu->exit_request || replay_has_interrupt())) { - cpu->exit_request = 0; + if (unlikely(atomic_read(&cpu->exit_request) || replay_has_interrupt())) { + atomic_set(&cpu->exit_request, 0); cpu->exception_index = EXCP_INTERRUPT; cpu_loop_exit(cpu); } @@ -510,7 +510,7 @@ static inline void cpu_loop_exec_tb(CPUState *cpu, TranslationBlock *tb, { uintptr_t ret; - if (unlikely(cpu->exit_request)) { + if (unlikely(atomic_read(&cpu->exit_request))) { return; } diff --git a/qom/cpu.c b/qom/cpu.c index f783b5a..adc8c11 100644 --- a/qom/cpu.c +++ b/qom/cpu.c @@ -119,10 +119,10 @@ void cpu_reset_interrupt(CPUState *cpu, int mask) void cpu_exit(CPUState *cpu) { - cpu->exit_request = 1; + atomic_set(&cpu->exit_request, 1); /* Ensure cpu_exec will see the exit request after TCG has exited. */ smp_wmb(); - cpu->tcg_exit_req = 1; + atomic_set(&cpu->tcg_exit_req, 1); } int cpu_write_elf32_qemunote(WriteCoreDumpFunction f, CPUState *cpu,