From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35330) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dcS3L-00085a-F8 for qemu-devel@nongnu.org; Tue, 01 Aug 2017 03:57:20 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dcS3I-0005dT-C9 for qemu-devel@nongnu.org; Tue, 01 Aug 2017 03:57:19 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:33669) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dcS3I-0005c8-2m for qemu-devel@nongnu.org; Tue, 01 Aug 2017 03:57:16 -0400 Received: from pps.filterd (m0098396.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id v717rxew006979 for ; Tue, 1 Aug 2017 03:57:14 -0400 Received: from e19.ny.us.ibm.com (e19.ny.us.ibm.com [129.33.205.209]) by mx0a-001b2d01.pphosted.com with ESMTP id 2c2nd1gsey-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Tue, 01 Aug 2017 03:57:13 -0400 Received: from localhost by e19.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 1 Aug 2017 03:57:12 -0400 Date: Tue, 1 Aug 2017 15:57:06 +0800 From: Dong Jia Shi References: <20170727015418.85407-1-bjsdjshi@linux.vnet.ibm.com> <20170727015418.85407-4-bjsdjshi@linux.vnet.ibm.com> <20170727135910.27d9e42e@gondolin> <20170731035137.GB21572@bjsdjshi@linux.vnet.ibm.com> <20170731131302.5bb2198c@gondolin> <20170801022910.GF12259@bjsdjshi@linux.vnet.ibm.com> <20170801092420.5217bd85@gondolin> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170801092420.5217bd85@gondolin> Message-Id: <20170801075706.GA9357@bjsdjshi@linux.vnet.ibm.com> Subject: Re: [Qemu-devel] [PATCH 3/3] s390x/css: generate channel path initialized CRW for channel path hotplug List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Cornelia Huck Cc: Dong Jia Shi , pasic@linux.vnet.ibm.com, pmorel@linux.vnet.ibm.com, qemu-devel@nongnu.org, agraf@suse.de, borntraeger@de.ibm.com, rth@twiddle.net * Cornelia Huck [2017-08-01 09:24:20 +0200]: > On Tue, 1 Aug 2017 10:29:10 +0800 > Dong Jia Shi wrote: > > > * Cornelia Huck [2017-07-31 13:13:02 +0200]: > > > > > On Mon, 31 Jul 2017 11:51:37 +0800 > > > Dong Jia Shi wrote: > > > > > When defining a vfio-ccw device, since the real subchannel implicitly > > > > indicates the chps it bound to, we grasp the CHPIDs from sysfs (or, with > > > > my current work, we could even retrieve these information from a new > > > > added MMIO region). In this case, defining some channel path devices > > > > separately does not make sense to me. > > > > > > We might want to pass only a subset of the channel paths to guest. This > > > can only work if we can define individual chp objects. > > Why would we want this? > > For example, if you know that a reconfiguration is coming on soon, you > can just exclude the paths that will go away anyway and the guest will > never know about them. Or for preferred pathing, although that one > fortunately seems to have died out. > > Not very strong reasons to spend time on this, though. Got it. > > > > > We can add, for example, a "chpids" parameter for the "vfio-ccw" device > > to limit its chpids to a subset that we want it to have? E.g.: > > > > For this mdev: > > MDEV Subchan. PIM PAM POM CHPIDs > > ------------------------------------------------------------------------------ > > 6dfd3ec5-e8b3-4e18-a6fe-57bc9eceb920 0.0.013f f0 f0 ff 42434445 00000000 > > > > We could use this command line: > > -device vfio-ccw,sysfsdev=$MDEV_CCW013f,devno=0.0.1234,chpids=4245000000000000 > > ^^^^ > > Yes, that would work, should we want that. We can probably do without for now. > Let's deffer this too! -- Dong Jia Shi