From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:43160) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gU9y5-0008Pe-Dk for qemu-devel@nongnu.org; Tue, 04 Dec 2018 07:38:27 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gU9y0-0005sS-F3 for qemu-devel@nongnu.org; Tue, 04 Dec 2018 07:38:25 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:55712 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 1gU9y0-0005r5-8d for qemu-devel@nongnu.org; Tue, 04 Dec 2018 07:38:20 -0500 Received: from pps.filterd (m0098421.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id wB4CZGPA051548 for ; Tue, 4 Dec 2018 07:38:18 -0500 Received: from e06smtp01.uk.ibm.com (e06smtp01.uk.ibm.com [195.75.94.97]) by mx0a-001b2d01.pphosted.com with ESMTP id 2p5runtsn5-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Tue, 04 Dec 2018 07:38:18 -0500 Received: from localhost by e06smtp01.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 4 Dec 2018 12:38:16 -0000 Date: Tue, 4 Dec 2018 13:38:10 +0100 From: Halil Pasic In-Reply-To: <20181122165432.4437-1-cohuck@redhat.com> References: <20181122165432.4437-1-cohuck@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Message-Id: <20181204133810.66e8cfe5@oc2783563651> Subject: Re: [Qemu-devel] [PATCH 0/3] vfio-ccw: support hsch/csch (kernel part) List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Cornelia Huck Cc: Eric Farman , Farhan Ali , Pierre Morel , linux-s390@vger.kernel.org, kvm@vger.kernel.org, qemu-s390x@nongnu.org, qemu-devel@nongnu.org, Alex Williamson On Thu, 22 Nov 2018 17:54:29 +0100 Cornelia Huck wrote: > [This is the Linux kernel part, git tree is available at > https://git.kernel.org/pub/scm/linux/kernel/git/kvms390/vfio-ccw.git vfio-ccw-caps > > The companion QEMU patches are available at > https://github.com/cohuck/qemu vfio-ccw-caps] > > Currently, vfio-ccw only relays START SUBCHANNEL requests to the real > device. This tends to work well for the most common 'good path' scenarios; > however, as we emulate {HALT,CLEAR} SUBCHANNEL in QEMU, things like > clearing pending requests at the device is currently not supported. > This may be a problem for e.g. error recovery. I'm wondering: what about MODIFY SUBCHANNEL? Do we plan to add MSCH as well or is it supposed to remain 'userspace emulated'? AFAIR MSCH may have an effect on error recovery as well. BTW I would like to have the concurrency discussion sorted out before I proceed with my review, because reviewing the stuff without a fair idea of what exactly are we trying to achieve would yield poor results. Regards, Halil