From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751075AbeECO0i (ORCPT ); Thu, 3 May 2018 10:26:38 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:60980 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751236AbeECO0g (ORCPT ); Thu, 3 May 2018 10:26:36 -0400 Subject: Re: [PATCH 04/10] vfio: ccw: replace IO_REQ event with SSCH_REQ event To: Dong Jia Shi , Cornelia Huck Cc: pasic@linux.vnet.ibm.com, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org References: <1524149293-12658-1-git-send-email-pmorel@linux.vnet.ibm.com> <1524149293-12658-5-git-send-email-pmorel@linux.vnet.ibm.com> <20180426073053.GZ12194@bjsdjshi@linux.vnet.ibm.com> <20180426074806.GB12194@bjsdjshi@linux.vnet.ibm.com> <20180430173305.632faa80.cohuck@redhat.com> <20180502074622.GV5428@bjsdjshi@linux.vnet.ibm.com> From: Pierre Morel Date: Thu, 3 May 2018 16:26:29 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <20180502074622.GV5428@bjsdjshi@linux.vnet.ibm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-TM-AS-GCONF: 00 x-cbid: 18050314-0012-0000-0000-000005D19525 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18050314-0013-0000-0000-0000194EBCB8 Message-Id: <5816643d-5406-06b9-0727-fdcd771aba63@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-05-03_07:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1805030126 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/05/2018 09:46, Dong Jia Shi wrote: > * Cornelia Huck [2018-04-30 17:33:05 +0200]: > >> On Thu, 26 Apr 2018 15:48:06 +0800 >> Dong Jia Shi wrote: >> >>> * Dong Jia Shi [2018-04-26 15:30:54 +0800]: >>> >>> [...] >>> >>>>> @@ -179,7 +160,7 @@ static int fsm_irq(struct vfio_ccw_private *private, >>>>> if (private->io_trigger) >>>>> eventfd_signal(private->io_trigger, 1); >>>>> >>>>> - return private->state; >>>>> + return VFIO_CCW_STATE_IDLE; >>>> This is not right. For example, if we are in STANDBY state (subch driver >>>> is probed, but mdev device is not created), we can not jump to IDLE >>>> state. >>>> >>> I see my problem, for STANDBY state, we should introduce another event >>> callback for VFIO_CCW_EVENT_INTERRUPT. It doesn't make sense to call >>> fsm_irq() which tries to signal userspace with interrupt notification >>> when mdev is not created yet... So we'd need a separated fix for this >>> issue too. >> But how do we even get into that situation when we don't have an mdev >> yet? >> > We cann't... So let's assign fsm_nop() as the interrupt callback for > STANDBY state? > :) Isn't it exactly what my patch series handle? -- Pierre Morel Linux/KVM/QEMU in Böblingen - Germany