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Thu, 30 Jul 2020 18:11:25 GMT Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by userp3030.oracle.com with ESMTP id 32hu5x53fh-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 30 Jul 2020 18:11:25 +0000 Received: from abhmp0002.oracle.com (abhmp0002.oracle.com [141.146.116.8]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 06UIBNn6026930; Thu, 30 Jul 2020 18:11:23 GMT Received: from [10.39.200.60] (/10.39.200.60) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Thu, 30 Jul 2020 11:11:22 -0700 Subject: Re: [PATCH V1 12/32] vl: pause option To: Eric Blake , qemu-devel@nongnu.org References: <1596122076-341293-1-git-send-email-steven.sistare@oracle.com> <1596122076-341293-13-git-send-email-steven.sistare@oracle.com> <1dea1698-f8be-519d-e00c-d163b08dca65@redhat.com> From: Steven Sistare Organization: Oracle Corporation Message-ID: <36036b5f-4e63-4287-a8e6-499732f54689@oracle.com> Date: Thu, 30 Jul 2020 14:11:19 -0400 User-Agent: Mozilla/5.0 (Windows NT 10.0; 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envelope-from=steven.sistare@oracle.com; helo=aserp2120.oracle.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/30 14:11:27 X-ACL-Warn: Detected OS = Linux 3.1-3.10 [fuzzy] X-Spam_score_int: -63 X-Spam_score: -6.4 X-Spam_bar: ------ X-Spam_report: (-6.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H2=-1, SPF_HELO_PASS=-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: "Daniel P. Berrange" , Juan Quintela , =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= , "Michael S. Tsirkin" , "Dr. David Alan Gilbert" , Markus Armbruster , Alex Williamson , Stefan Hajnoczi , Paolo Bonzini , =?UTF-8?Q?Marc-Andr=c3=a9_Lureau?= , =?UTF-8?Q?Alex_Benn=c3=a9e?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 7/30/2020 12:20 PM, Eric Blake wrote: > On 7/30/20 10:14 AM, Steve Sistare wrote: >> Provide the -pause command-line parameter and the QEMU_PAUSE environment >> variable to briefly pause QEMU in main and allow a developer to attach gdb. >> Useful when the developer does not invoke QEMU directly, such as when using >> libvirt. > > How would you set this option with libvirt? Add -pause in the qemu args in the xml. > It feels like you are trying to reinvent something that is already well-documented: > > https://www.berrange.com/posts/2011/10/12/debugging-early-startup-of-kvm-with-gdb-when-launched-by-libvirtd/ Too many steps to reach BINGO for my taste. Easier is better. Also, in our shop we start qemu in other ways, such as via services. These new hooks helped me and my colleagues, and I hope others may also find them useful, but if not then we drop them. >> Usage: >>    qemu -pause >>    or >>    export QEMU_PAUSE= >> >> Signed-off-by: Steve Sistare >> --- >>   qemu-options.hx |  9 +++++++++ >>   softmmu/vl.c    | 15 ++++++++++++++- >>   2 files changed, 23 insertions(+), 1 deletion(-) > >> @@ -3204,6 +3211,12 @@ void qemu_init(int argc, char **argv, char **envp) >>               case QEMU_OPTION_gdb: >>                   add_device_config(DEV_GDB, optarg); >>                   break; >> +            case QEMU_OPTION_pause: >> +                seconds = atoi(optarg); > > atoi() cannot detect overflow.  You should never use it in robust parsing of untrusted input. OK. - Steve