From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:37144) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gmkSv-0007JO-HN for qemu-devel@nongnu.org; Thu, 24 Jan 2019 14:15:06 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gmkSt-00063A-Af for qemu-devel@nongnu.org; Thu, 24 Jan 2019 14:15:05 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:56776) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gmkSr-00061G-AD for qemu-devel@nongnu.org; Thu, 24 Jan 2019 14:15:01 -0500 Received: from pps.filterd (m0098410.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x0OJDlGx138252 for ; Thu, 24 Jan 2019 14:14:56 -0500 Received: from e34.co.us.ibm.com (e34.co.us.ibm.com [32.97.110.152]) by mx0a-001b2d01.pphosted.com with ESMTP id 2q7j0tmbj7-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Thu, 24 Jan 2019 14:14:56 -0500 Received: from localhost by e34.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 24 Jan 2019 19:14:55 -0000 References: <20190121110354.2247-1-cohuck@redhat.com> <20190121110354.2247-3-cohuck@redhat.com> <20190122193346.4e23e018@oc2783563651> <20190123112112.7822b237.cohuck@redhat.com> <42264dd9-86d7-8994-8c25-bc688067725d@linux.ibm.com> <20190124111934.72e7f0f1.cohuck@redhat.com> From: Eric Farman Date: Thu, 24 Jan 2019 14:14:49 -0500 MIME-Version: 1.0 In-Reply-To: <20190124111934.72e7f0f1.cohuck@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Message-Id: Subject: Re: [Qemu-devel] [PATCH v2 2/5] vfio-ccw: concurrent I/O handling List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Cornelia Huck , Pierre Morel Cc: Halil Pasic , Farhan Ali , linux-s390@vger.kernel.org, kvm@vger.kernel.org, Alex Williamson , qemu-devel@nongnu.org, qemu-s390x@nongnu.org On 01/24/2019 05:19 AM, Cornelia Huck wrote: > On Thu, 24 Jan 2019 11:08:02 +0100 > Pierre Morel wrote: > >> On 23/01/2019 11:21, Cornelia Huck wrote: >>> On Tue, 22 Jan 2019 19:33:46 +0100 >>> Halil Pasic wrote: >>> >>>> On Mon, 21 Jan 2019 12:03:51 +0100 >>>> Cornelia Huck wrote: >>>> >>>>> --- a/drivers/s390/cio/vfio_ccw_private.h >>>>> +++ b/drivers/s390/cio/vfio_ccw_private.h >>>>> @@ -28,6 +28,7 @@ >>>>> * @mdev: pointer to the mediated device >>>>> * @nb: notifier for vfio events >>>>> * @io_region: MMIO region to input/output I/O arguments/results >>>>> + * @io_mutex: protect against concurrent update of I/O structures >>>> >>>> We could be a bit more specific about what does this mutex guard. >>>> Is it only io_region, or cp, irb and the new regions a well? ->state does >>>> not seem to be covered, but should need some sort of synchronisation >>>> too, or? >>> >>> I'm not sure. IIRC Pierre had some ideas about locking in the fsm? >>> >> >> Yes I postponed this work to not collide with your patch series. >> >> Do you think I should provide a new version of the FSM reworking series >> based on the last comment I got? >> >> I would take into account that the asynchronous commands will come with >> your patch series and only provide the framework changes. > > This was more an answer to Halil's concerns around state > synchronization. I would prefer to first get this series (or a > variation) into decent shape, and then address state machine handling > on top of that (when we know more about the transitions involved), just > to avoid confusion. > > Does that sound reasonable? > It does to me.