From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51003) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dpVpm-0002fB-BW for qemu-devel@nongnu.org; Wed, 06 Sep 2017 04:37:19 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dpVpj-0007M7-3g for qemu-devel@nongnu.org; Wed, 06 Sep 2017 04:37:18 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:53166 helo=mx0a-001b2d01.pphosted.com) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dpVpi-0007Ly-UC for qemu-devel@nongnu.org; Wed, 06 Sep 2017 04:37:15 -0400 Received: from pps.filterd (m0098421.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id v868Tl38119836 for ; Wed, 6 Sep 2017 04:37:14 -0400 Received: from e18.ny.us.ibm.com (e18.ny.us.ibm.com [129.33.205.208]) by mx0a-001b2d01.pphosted.com with ESMTP id 2ctd7ch95k-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Wed, 06 Sep 2017 04:37:14 -0400 Received: from localhost by e18.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 6 Sep 2017 04:37:13 -0400 Date: Wed, 6 Sep 2017 16:37:08 +0800 From: Dong Jia Shi References: <20170830163609.50260-1-pasic@linux.vnet.ibm.com> <20170830163609.50260-3-pasic@linux.vnet.ibm.com> <20170831111953.242ddc28.cohuck@redhat.com> <20170905100234.7a92128e.cohuck@redhat.com> <20170905174606.1e0c6404.cohuck@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170905174606.1e0c6404.cohuck@redhat.com> Message-Id: <20170906083708.GA31680@bjsdjshi@linux.vnet.ibm.com> Subject: Re: [Qemu-devel] [PATCH 2/9] s390x: fix invalid use of cc 1 for SSCH List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Cornelia Huck Cc: Halil Pasic , Dong Jia Shi , Pierre Morel , qemu-devel@nongnu.org * Cornelia Huck [2017-09-05 17:46:06 +0200]: > On Tue, 5 Sep 2017 17:24:19 +0200 > Halil Pasic wrote: > > > My problem with a program check (indicated by SCSW word 2 bit 10) is > > that, in my reading of the architecture, the semantic behind it is: The > > channel subsystem (not the cu or device) has detected, that the > > the channel program (previously submitted as an ORB) is erroneous. Which > > programs are erroneous is specified by the architecture. What we have > > here does not qualify. > > > > My idea was to rather blame the virtual hardware (device) and put no blame > > on the program nor he channel subsystem. This could be done using device > > status (unit check with command reject, maybe unit exception) or interface > > check. My train of thought was, the problem is not consistent across a > > device type, so it has to be device specific. > > Unit exception might be a better way to express what is happening here. > At least, it moves us away from cc 1 and not towards cc 3 :) > > > > > Of course blaming the device could mislead the person encountering the > > problem, and make him believe it's an non-virtual hardware problem. > > > > About the misleading, I think the best we can do is log out a message > > indicating what really happened. > > Just document it in the code? If it doesn't happen with Linux as a > guest, it is highly unlikely to be seen in the wild. > > > > > In the end I don't care that deeply about vfio-ccw, and this problem > > already took me more time than I intended to spend on this. We have > > people driving this whole vfio-ccw stuff and I'm not one of them (I'm > > rather in the supporting role). > > > > I'm also fine with me being credited with a reported-by once the > > more involved people figure out what to do, and keeping the vfio-ccw > > stuff as is. Should we go with that option? > > If converting the reporting to a device status is straightforward > enough, let's do that. I'm fine with postponing this and waiting for a > real fix as well (I don't really have spare cycles to actually write > vfio-ccw code currently...) > I can do this after this series. [...] -- Dong Jia Shi