From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-2.mimecast.com ([205.139.110.61]:60790 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727686AbfLBTtf (ORCPT ); Mon, 2 Dec 2019 14:49:35 -0500 Date: Mon, 2 Dec 2019 20:49:22 +0100 From: Cornelia Huck Subject: Re: [kvm-unit-tests PATCH v2 6/9] s390x: css: stsch, enumeration test Message-ID: <20191202204922.508d389f.cohuck@redhat.com> In-Reply-To: References: <1574945167-29677-1-git-send-email-pmorel@linux.ibm.com> <1574945167-29677-7-git-send-email-pmorel@linux.ibm.com> <20191202152246.4d627b0e.cohuck@redhat.com> <20191202191541.1ffd987e.cohuck@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-s390-owner@vger.kernel.org List-ID: To: Pierre Morel Cc: kvm@vger.kernel.org, linux-s390@vger.kernel.org, frankja@linux.ibm.com, david@redhat.com, thuth@redhat.com On Mon, 2 Dec 2019 19:33:59 +0100 Pierre Morel wrote: > On 2019-12-02 19:15, Cornelia Huck wrote: > > On Mon, 2 Dec 2019 18:53:16 +0100 > > Pierre Morel wrote: > > > >> On 2019-12-02 15:22, Cornelia Huck wrote: > >>> On Thu, 28 Nov 2019 13:46:04 +0100 > >>> Pierre Morel wrote: > > > >>>> +static int test_device_sid; > >>>> + > >>>> +static void test_enumerate(void) > >>>> +{ > >>>> + struct pmcw *pmcw = &schib.pmcw; > >>>> + int sid; > >>>> + int ret, i; > >>>> + int found = 0; > >>>> + > >>>> + for (sid = 0; sid < 0xffff; sid++) { > >>>> + ret = stsch(sid|SID_ONE, &schib); > >>> > >>> This seems a bit odd. You are basically putting the subchannel number > >>> into sid, OR in the one, and then use the resulting value as the sid > >>> (subchannel identifier). > >>> > >>>> + if (!ret && (pmcw->flags & PMCW_DNV)) { > >>>> + report_info("SID %04x Type %s PIM %x", sid, > >>> > >>> That's not a sid, but the subchannel number (see above). > >>> > >>>> + Channel_type[pmcw->st], pmcw->pim); > >>>> + for (i = 0; i < 8; i++) { > >>>> + if ((pmcw->pim << i) & 0x80) { > >>>> + report_info("CHPID[%d]: %02x", i, > >>>> + pmcw->chpid[i]); > >>>> + break; > >>>> + } > >>>> + } > >>>> + found++; > >>>> + > >>>> + } > >>> > >>> Here, you iterate over the 0-0xffff range, even if you got a condition > >>> code 3 (indicating no more subchannels in that set). Is that > >>> intentional? > >> > >> I thought there could be more subchannels. > >> I need then a break in the loop when this happens. > >> I will reread the PoP to see how to find that no more subchannel are in > >> that set. > > > > The fact that cc 3 for stsch == no more subchannels is unfortunately a > > bit scattered across the PoP :/ Dug it out some time ago, maybe it's > > still in the archives somewhere... > > So the the subchannel are always one after the other? While QEMU (and z/VM) usually do that, they can really be scattered around. For the in-between I/O subchannels that don't lead to a device, you'll still get cc 0, it's just the dnv bit that is 0. The cc 3 basically just tells you that you can stop looking.