From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-1.mimecast.com ([205.139.110.61]:59776 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728033AbgE0Jmu (ORCPT ); Wed, 27 May 2020 05:42:50 -0400 Date: Wed, 27 May 2020 11:42:39 +0200 From: Cornelia Huck Subject: Re: [kvm-unit-tests PATCH v7 09/12] s390x: css: msch, enable test Message-ID: <20200527114239.65fa9473.cohuck@redhat.com> In-Reply-To: <1589818051-20549-10-git-send-email-pmorel@linux.ibm.com> References: <1589818051-20549-1-git-send-email-pmorel@linux.ibm.com> <1589818051-20549-10-git-send-email-pmorel@linux.ibm.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, 18 May 2020 18:07:28 +0200 Pierre Morel wrote: > A second step when testing the channel subsystem is to prepare a channel > for use. > This includes: > - Get the current subchannel Information Block (SCHIB) using STSCH > - Update it in memory to set the ENABLE bit > - Tell the CSS that the SCHIB has been modified using MSCH > - Get the SCHIB from the CSS again to verify that the subchannel is > enabled. > - If the subchannel is not enabled retry a predefined retries count. > > This tests the MSCH instruction to enable a channel succesfuly. > This is NOT a routine to really enable the channel, no retry is done, > in case of error, a report is made. Hm... so you retry if the subchannel is not enabled after cc 0, but you don't retry if the cc indicates busy/status pending? Makes sense, as we don't expect the subchannel to be busy, but a more precise note in the patch description would be good :) > > Signed-off-by: Pierre Morel > --- > s390x/css.c | 67 +++++++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 67 insertions(+) > > diff --git a/s390x/css.c b/s390x/css.c > index d7989d8..1b60a47 100644 > --- a/s390x/css.c > +++ b/s390x/css.c > @@ -16,6 +16,7 @@ > #include > #include > #include > +#include > > #include > > @@ -65,11 +66,77 @@ out: > scn, scn_found, dev_found); > } > > +#define MAX_ENABLE_RETRIES 5 > +static void test_enable(void) > +{ > + struct pmcw *pmcw = &schib.pmcw; > + int retry_count = 0; > + int cc; > + > + if (!test_device_sid) { > + report_skip("No device"); > + return; > + } > + > + /* Read the SCHIB for this subchannel */ > + cc = stsch(test_device_sid, &schib); > + if (cc) { > + report(0, "stsch cc=%d", cc); > + return; > + } > + > + if (pmcw->flags & PMCW_ENABLE) { > + report(1, "stsch: sch %08x already enabled", test_device_sid); > + return; > + } > + > +retry: > + /* Update the SCHIB to enable the channel */ > + pmcw->flags |= PMCW_ENABLE; > + > + /* Tell the CSS we want to modify the subchannel */ > + cc = msch(test_device_sid, &schib); > + if (cc) { > + /* > + * If the subchannel is status pending or > + * if a function is in progress, > + * we consider both cases as errors. Could also be cc 3, but that would be even more weird. Just logging the cc seems fine, though. > + */ > + report(0, "msch cc=%d", cc); > + return; > + } > + > + /* > + * Read the SCHIB again to verify the enablement > + */ > + cc = stsch(test_device_sid, &schib); > + if (cc) { > + report(0, "stsch cc=%d", cc); > + return; > + } > + > + if (pmcw->flags & PMCW_ENABLE) { > + report(1, "msch: sch %08x enabled after %d retries", > + test_device_sid, retry_count); > + return; > + } > + > + if (retry_count++ < MAX_ENABLE_RETRIES) { > + mdelay(10); /* the hardware was not ready, let it some time */ s/let/give/ > + goto retry; > + } > + > + report(0, > + "msch: enabling sch %08x failed after %d retries. pmcw: %x", > + test_device_sid, retry_count, pmcw->flags); > +} > + > static struct { > const char *name; > void (*func)(void); > } tests[] = { > { "enumerate (stsch)", test_enumerate }, > + { "enable (msch)", test_enable }, > { NULL, NULL } > }; > Otherwise, Reviewed-by: Cornelia Huck