From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-2.mimecast.com ([207.211.31.81]:37593 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726617AbgGIOW1 (ORCPT ); Thu, 9 Jul 2020 10:22:27 -0400 Date: Thu, 9 Jul 2020 16:22:10 +0200 From: Cornelia Huck Subject: Re: [kvm-unit-tests PATCH v11 8/9] s390x: css: msch, enable test Message-ID: <20200709162210.7fe6f9cb.cohuck@redhat.com> In-Reply-To: References: <1594282068-11054-1-git-send-email-pmorel@linux.ibm.com> <1594282068-11054-9-git-send-email-pmorel@linux.ibm.com> <20200709134056.0d267b6c.cohuck@redhat.com> <20200709153055.6f2b5e59.cohuck@redhat.com> <4f861a9c-179b-5376-5f0f-dce30f31da71@linux.ibm.com> <20200709155241.3014e3d6.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, drjones@redhat.com On Thu, 9 Jul 2020 15:58:07 +0200 Pierre Morel wrote: > On 2020-07-09 15:52, Cornelia Huck wrote: > > On Thu, 9 Jul 2020 15:41:56 +0200 > > Pierre Morel wrote: > > > >> On 2020-07-09 15:30, Cornelia Huck wrote: > >>> On Thu, 9 Jul 2020 15:12:05 +0200 > >>> Pierre Morel wrote: > >>> > >>>> On 2020-07-09 13:40, Cornelia Huck wrote: > >>>>> On Thu, 9 Jul 2020 10:07:47 +0200 > >>>>> Pierre Morel wrote: > >>>>> (...) > >>>>> > >>>>>> +/* > >>>>>> + * css_msch: enable subchannel and set with specified ISC > >>>>> > >>>>> "css_enable: enable the subchannel with the specified ISC" > >>>>> > >>>>> ? > >>>>> > >>>>>> + * @schid: Subchannel Identifier > >>>>>> + * @isc : number of the interruption subclass to use > >>>>>> + * Return value: > >>>>>> + * On success: 0 > >>>>>> + * On error the CC of the faulty instruction > >>>>>> + * or -1 if the retry count is exceeded. > >>>>>> + */ > >>>>>> +int css_enable(int schid, int isc) > >>>>>> +{ > >>>>>> + struct pmcw *pmcw = &schib.pmcw; > >>>>>> + int retry_count = 0; > >>>>>> + uint16_t flags; > >>>>>> + int cc; > >>>>>> + > >>>>>> + /* Read the SCHIB for this subchannel */ > >>>>>> + cc = stsch(schid, &schib); > >>>>>> + if (cc) { > >>>>>> + report_info("stsch: sch %08x failed with cc=%d", schid, cc); > >>>>>> + return cc; > >>>>>> + } > >>>>>> + > >>>>>> + flags = PMCW_ENABLE | (isc << PMCW_ISC_SHIFT); > >>>>>> + if ((pmcw->flags & flags) == flags) { > >>>>> > >>>>> I think you want (pmcw->flags & PMCW_ENABLE) == PMCW_ENABLE -- this > >>>>> catches the case of "subchannel has been enabled before, but with a > >>>>> different isc". > >>>> > >>>> If with a different ISC, we need to modify the ISC. > >>>> Don't we ? > >>> > >>> I think that's a policy decision (I would probably fail and require a > >>> disable before setting another isc, but that's a matter of taste). > >>> > >>> Regardless, I think the current check doesn't even catch the 'different > >>> isc' case? > >> > >> hum, right. > >> If it is OK I remove this one. > >> And I must rework the same test I do later > >> in this patch. > > > > So, you mean checking for PMCW_ENABLE? Or not at all? > > > > (I'd check for PMCW_ENABLE.) > > > > - if ((pmcw->flags & flags) == flags) { > + if ((pmcw->flags & (PMCW_ISC_MASK | PMCW_ENABLE)) == flags) { > report_info("stsch: sch %08x already enabled", schid); > return 0; > } > > I keep both, otherwise I return 0 without setting the ISC. Ah, I missed the 'return 0'. > then I have another error: > > retry: > /* Update the SCHIB to enable the channel and set the ISC */ > + pmcw->flags &= ~(PMCW_ISC_MASK | PMCW_ENABLE); Maybe ~PMCW_ISC_MASK is enough? > pmcw->flags |= flags; > > and finaly the same as the first later... > > - if ((pmcw->flags & flags) == flags) { > + if ((pmcw->flags & (PMCW_ISC_MASK | PMCW_ENABLE)) == flags) { I think you can keep that as-is. > report_info("stsch: sch %08x successfully modified > after %d retries", > schid, retry_count); > > > is better I think. > What do you think? It's probably the right direction.