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 X-Spam-Level: X-Spam-Status: No, score=-11.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CF7E4C433E1 for ; Fri, 17 Jul 2020 18:06:14 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 9EFEE206F4 for ; Fri, 17 Jul 2020 18:06:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=greensocs.com header.i=@greensocs.com header.b="FP7Kyjx3" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9EFEE206F4 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=greensocs.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:56226 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jwUkP-00051h-PX for qemu-devel@archiver.kernel.org; Fri, 17 Jul 2020 14:06:13 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:33354) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jwUhf-0003be-6a for qemu-devel@nongnu.org; Fri, 17 Jul 2020 14:03:23 -0400 Received: from beetle.greensocs.com ([5.135.226.135]:59244) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jwUhc-0007Ua-Uk for qemu-devel@nongnu.org; Fri, 17 Jul 2020 14:03:22 -0400 Received: from [172.17.10.10] (unknown [172.17.10.10]) by beetle.greensocs.com (Postfix) with ESMTPSA id 1EB282000A; Fri, 17 Jul 2020 18:03:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=greensocs.com; s=mail; t=1595008998; 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=N+8gkbfjc0KHg0vfr8L6V61Tdiud8G8eV8p46iaQA8Y=; b=FP7Kyjx3naw/VaJnMvkMQrsq7rH9Dm489eST0Ymng2KNsyzfVYB16cj2WgI3O8NYHGTUh2 pv1OHQWrwQD/sqRUYPJUHxh9iaV/vqrkvYCJC2ZlQRISEf00uqzR5NQZUcjb/XsNU1CAGR Yrdpw3ao6+PUyHowIALghchAmeh3TW8= Subject: Re: [PATCH] tcg/cpu-exec: precise single-stepping after an interrupt To: Richard Henderson , qemu-devel@nongnu.org References: <20200717163029.2737546-1-richard.henderson@linaro.org> From: Luc Michel Message-ID: Date: Fri, 17 Jul 2020 20:03:43 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20200717163029.2737546-1-richard.henderson@linaro.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=5.135.226.135; envelope-from=luc.michel@greensocs.com; helo=beetle.greensocs.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/17 14:03:19 X-ACL-Warn: Detected OS = Linux 3.11 and newer X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: pbonzini@redhat.com, peter.maydell@linaro.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 7/17/20 6:30 PM, Richard Henderson wrote: > When single-stepping with a debugger attached to QEMU, and when an > interrupt is raised, the debugger misses the first instruction after > the interrupt. > > Buglink: https://bugs.launchpad.net/qemu/+bug/757702 > Signed-off-by: Richard Henderson Reviewed-by: Luc Michel Tested-by: Luc Michel > --- > accel/tcg/cpu-exec.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c > index 6a3d3a3cfc..66d38f9d85 100644 > --- a/accel/tcg/cpu-exec.c > +++ b/accel/tcg/cpu-exec.c > @@ -588,7 +588,13 @@ static inline bool cpu_handle_interrupt(CPUState *cpu, > else { > if (cc->cpu_exec_interrupt(cpu, interrupt_request)) { > replay_interrupt(); > - cpu->exception_index = -1; > + /* > + * After processing the interrupt, ensure an EXCP_DEBUG is > + * raised when single-stepping so that GDB doesn't miss the > + * next instruction. > + */ > + cpu->exception_index = > + (cpu->singlestep_enabled ? EXCP_DEBUG : -1); > *last_tb = NULL; > } > /* The target hook may have updated the 'cpu->interrupt_request'; >