From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56471) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Ykqn2-0005tv-2z for qemu-devel@nongnu.org; Wed, 22 Apr 2015 05:17:53 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Ykqmz-0004fv-4b for qemu-devel@nongnu.org; Wed, 22 Apr 2015 05:17:52 -0400 Received: from cantor2.suse.de ([195.135.220.15]:38679 helo=mx2.suse.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Ykqmy-0004fk-U1 for qemu-devel@nongnu.org; Wed, 22 Apr 2015 05:17:49 -0400 Message-ID: <553766D0.8090709@suse.de> Date: Wed, 22 Apr 2015 11:16:00 +0200 From: Alexander Graf MIME-Version: 1.0 References: <1429257161-29597-1-git-send-email-cornelia.huck@de.ibm.com> <1429257161-29597-4-git-send-email-cornelia.huck@de.ibm.com> <5536A051.9000901@suse.de> <20150422103212.403e6050.cornelia.huck@de.ibm.com> In-Reply-To: <20150422103212.403e6050.cornelia.huck@de.ibm.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 3/6] s390/kvm: diag288 instruction interception and handling List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Cornelia Huck Cc: armbru@redhat.com, mdroth@linux.vnet.ibm.com, qemu-devel@nongnu.org, borntraeger@de.ibm.com, jfrei@linux.vnet.ibm.com, Xu Wang , lcapitulino@redhat.com On 04/22/2015 10:32 AM, Cornelia Huck wrote: > On Tue, 21 Apr 2015 21:09:05 +0200 > Alexander Graf wrote: > >> On 04/17/2015 09:52 AM, Cornelia Huck wrote: >>> From: Xu Wang >>> >>> Intercept the diag288 requests from kvm guests, and hand the >>> requested command to the diag288 watchdog device for further >>> handling. >>> >>> Signed-off-by: Xu Wang >>> Reviewed-by: David Hildenbrand >>> Signed-off-by: Cornelia Huck >> We're getting a lot of random devices allocating diag intercepts. Can't >> we make this an actual interface, similar to the hypercall registration >> on sPAPR? > I've looked at the sPAPR hcall code, and it seems to basically provide > a table with a nice registration interface (we already use something > similar for the diagnose 500 virtio subcodes, btw.) > > While we could move our basic diagnose handling over to a table-like > approach and registering new diagnoses, I think this is orthogonal to > introducing a diag288 watchdog device: It just makes sense to model the > watchdog as a device that just happens to be poked via a diagnose. If > we introduce any further diagnoses to manipulate timing etc., I agree > we don't want to add a device for each of these. My thinking was in the opposite level. I really like the idea of having separate devices for each function. But I think that they should be completely self-contained with well defined interfaces. Alex