From patchwork Thu Jan 26 12:34:23 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pavel Dovgalyuk X-Patchwork-Id: 9539195 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id E6D73604A9 for ; Thu, 26 Jan 2017 12:39:31 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id CFEA727F93 for ; Thu, 26 Jan 2017 12:39:31 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id C49022818E; Thu, 26 Jan 2017 12:39:31 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 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 mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 744592819A for ; Thu, 26 Jan 2017 12:39:31 +0000 (UTC) Received: from localhost ([::1]:38030 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cWjKs-0007Jl-IU for patchwork-qemu-devel@patchwork.kernel.org; Thu, 26 Jan 2017 07:39:30 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49604) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cWjFt-0003E5-4d for qemu-devel@nongnu.org; Thu, 26 Jan 2017 07:34:26 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cWjFs-0004z6-7N for qemu-devel@nongnu.org; Thu, 26 Jan 2017 07:34:21 -0500 Received: from mail.ispras.ru ([83.149.199.45]:42486) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cWjFs-0004yy-1F for qemu-devel@nongnu.org; Thu, 26 Jan 2017 07:34:20 -0500 Received: from [10.10.150.6] (unknown [85.142.117.226]) by mail.ispras.ru (Postfix) with ESMTPSA id 4CD07540068; Thu, 26 Jan 2017 15:34:19 +0300 (MSK) To: qemu-devel@nongnu.org From: Pavel Dovgalyuk Date: Thu, 26 Jan 2017 15:34:23 +0300 Message-ID: <20170126123423.5412.2388.stgit@PASHA-ISP> In-Reply-To: <20170126123411.5412.44769.stgit@PASHA-ISP> References: <20170126123411.5412.44769.stgit@PASHA-ISP> User-Agent: StGit/0.16 MIME-Version: 1.0 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [fuzzy] X-Received-From: 83.149.199.45 Subject: [Qemu-devel] [PATCH v8 2/9] icount: exit cpu loop on expire 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: kwolf@redhat.com, peter.maydell@linaro.org, quintela@redhat.com, jasowang@redhat.com, mst@redhat.com, dovgaluk@ispras.ru, kraxel@redhat.com, pbonzini@redhat.com Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP This patch adds check to break cpu loop when icount expires without setting the TB_EXIT_ICOUNT_EXPIRED flag. It happens when there is no available translated blocks and all instructions were executed. In icount replay mode unnecessary tb_find will be called (which may cause an exception) and execution will be non-deterministic. v8: refactored loop exit code and moved it to separate function Signed-off-by: Pavel Dovgalyuk --- cpu-exec.c | 24 +++++++++++++++++++----- 1 file changed, 19 insertions(+), 5 deletions(-) diff --git a/cpu-exec.c b/cpu-exec.c index fa08c73..f9b8ec8 100644 --- a/cpu-exec.c +++ b/cpu-exec.c @@ -523,9 +523,25 @@ static inline void cpu_handle_interrupt(CPUState *cpu, *last_tb = NULL; } } - if (unlikely(atomic_read(&cpu->exit_request) || replay_has_interrupt())) { +} + + +static void cpu_check_loop_exit(CPUState *cpu) +{ + if (unlikely(atomic_read(&cpu->exit_request) + /* icount has expired, we need to break the execution loop. + This check is needed before tb_find to make execution + deterministic - tb_find may cause an exception + while translating the code from non-mapped page. */ + || (use_icount && ((cpu->icount_extra == 0 + && cpu->icount_decr.u16.low == 0) + || (int32_t)cpu->icount_decr.u32 < 0)))) { atomic_set(&cpu->exit_request, 0); - cpu->exception_index = EXCP_INTERRUPT; + /* If there is an exception that wasn't replayed yet, + don't change exception_index. */ + if (cpu->exception_index == -1) { + cpu->exception_index = EXCP_INTERRUPT; + } cpu_loop_exit(cpu); } } @@ -578,9 +594,6 @@ static inline void cpu_loop_exec_tb(CPUState *cpu, TranslationBlock *tb, cpu_exec_nocache(cpu, insns_left, *last_tb, false); align_clocks(sc, cpu); } - cpu->exception_index = EXCP_INTERRUPT; - *last_tb = NULL; - cpu_loop_exit(cpu); } break; #endif @@ -634,6 +647,7 @@ int cpu_exec(CPUState *cpu) for(;;) { cpu_handle_interrupt(cpu, &last_tb); + cpu_check_loop_exit(cpu); tb = tb_find(cpu, last_tb, tb_exit); cpu_loop_exec_tb(cpu, tb, &last_tb, &tb_exit, &sc); /* Try to align the host and virtual clocks