From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: Re: vhost: Problem RESET_OWNER processing Date: Sat, 8 Aug 2015 08:37:49 +0200 Message-ID: <55C5A3BD.7080802@siemens.com> References: <55C4BAE6.6040408@siemens.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit To: "Ouyang, Changchun" , "dev@dpdk.org" , "Xie, Huawei" Return-path: Received: from goliath.siemens.de (goliath.siemens.de [192.35.17.28]) by dpdk.org (Postfix) with ESMTP id BB2255698 for ; Sat, 8 Aug 2015 08:37:51 +0200 (CEST) In-Reply-To: List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" On 2015-08-08 02:04, Ouyang, Changchun wrote: > > >> -----Original Message----- >> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Jan Kiszka >> Sent: Friday, August 7, 2015 10:04 PM >> To: dev@dpdk.org; Xie, Huawei >> Subject: [dpdk-dev] vhost: Problem RESET_OWNER processing >> >> Hi, >> >> I was wondering if I'm alone with this: the vhost-switch example crashes on >> client disconnects if the client send a RESET_OWNER message. That's at least >> the case for QEMU and vhost-user mode (I suppose vhost-cuse is legacy > > What's your qemu version? git head, which includes 2.4-rc2. VHOST_USER_RESET_OWNER dates back to QEMU commit 294ce717e, and that is after 2.3. Before that commit, QEMU was happily allowing its vhost servers to corrupt guest memory on reboot or while a virtio device was otherwise deactivated. Jan > >> now). And it really ruins the party when playing with this because every VM >> shutdown or guest reboot triggers. >> >> I was looking deeper in the librte_vhost, and I found that reset_owner() is >> doing cleanup_device and then init_device - but without letting the user >> know. So vhost-switch crashed in its main loop over continuing to use the >> device, namely calling rte_vhost_dequeue_burst (with >> dev->virtqueue[]->avail == NULL). >> >> Do we simply need another hook in the vhost API, similar to the destruction >> notification? >> >> Jan >> >> -- >> Siemens AG, Corporate Technology, CT RTC ITP SES-DE Corporate >> Competence Center Embedded Linux -- Siemens AG, Corporate Technology, CT RTC ITP SES-DE Corporate Competence Center Embedded Linux