From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55857) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1drOZM-0003Ui-Mt for qemu-devel@nongnu.org; Mon, 11 Sep 2017 09:16:09 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1drOZH-0007en-9P for qemu-devel@nongnu.org; Mon, 11 Sep 2017 09:16:08 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:33627) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1drOZH-0007eB-0W for qemu-devel@nongnu.org; Mon, 11 Sep 2017 09:16:03 -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 v8BDEPZx010793 for ; Mon, 11 Sep 2017 09:16:01 -0400 Received: from e06smtp15.uk.ibm.com (e06smtp15.uk.ibm.com [195.75.94.111]) by mx0a-001b2d01.pphosted.com with ESMTP id 2cwssdf0ut-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Mon, 11 Sep 2017 09:16:01 -0400 Received: from localhost by e06smtp15.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 11 Sep 2017 14:15:58 +0100 References: <20170908152446.14606-1-pasic@linux.vnet.ibm.com> <20170908152446.14606-2-pasic@linux.vnet.ibm.com> <20170911113314.45ef089e.cohuck@redhat.com> From: Halil Pasic Date: Mon, 11 Sep 2017 15:15:54 +0200 MIME-Version: 1.0 In-Reply-To: <20170911113314.45ef089e.cohuck@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Message-Id: Subject: Re: [Qemu-devel] [PATCH 1/4] s390x/css: drop data-check in interpretation List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Cornelia Huck Cc: Dong Jia Shi , Pierre Morel , qemu-devel@nongnu.org On 09/11/2017 11:33 AM, Cornelia Huck wrote: > On Fri, 8 Sep 2017 17:24:43 +0200 > Halil Pasic wrote: > >> The architecture says that channel-data check is indicating that >> an uncorrected storage (memory) error has been detected in regard >> to the data residing in main storage (memory) that is currently >> used for an I/O operation. The described detection is done using >> the CBC technology. >> >> The ccw interpretation code is however generating a channel-data check >> effectively when the (device specific) ccw_cb returns -EFAULT. In case >> of virtio-ccw devices this happens when mapping memory fails, or when a >> NULL pointer is encountered. So this behavior is not architecture >> conform. >> >> Furthermore the best fit for these situations (null pointer, mapping a >> piece of guest memory fails) from architectural perspective the condition >> described as the channel subsystem refers to a location that is not >> available, which when encountered shall result in a channel-program >> check. >> >> To fix this, all we have to do is to get rid of the switch case matching >> -EFAULT: the default is generating a channel-program check. >> >> --- >> >> Was posted as stand alone patch. See: >> http://patchwork.ozlabs.org/patch/810995/ >> >> If you are going to, *please review there*. > > Countered. *Please review here* > > (It makes it easier for me.) > >> >> Signed-off-by: Halil Pasic > > Your s-o-b should go before the triple-dash delimiter. I can fix that > up. Thanks! Btw. the original (there) was correct in this respect. > >> --- >> hw/s390x/css.c | 9 --------- >> 1 file changed, 9 deletions(-) >> >> diff --git a/hw/s390x/css.c b/hw/s390x/css.c >> index 901dc6a0f3..09f6ba0310 100644 >> --- a/hw/s390x/css.c >> +++ b/hw/s390x/css.c >> @@ -980,15 +980,6 @@ static void sch_handle_start_func_virtual(SubchDev *sch) >> SCSW_STCTL_ALERT | SCSW_STCTL_STATUS_PEND; >> s->cpa = sch->channel_prog + 8; >> break; >> - case -EFAULT: >> - /* memory problem, generate channel data check */ >> - s->ctrl &= ~SCSW_ACTL_START_PEND; >> - s->cstat = SCSW_CSTAT_DATA_CHECK; >> - s->ctrl &= ~SCSW_CTRL_MASK_STCTL; >> - s->ctrl |= SCSW_STCTL_PRIMARY | SCSW_STCTL_SECONDARY | >> - SCSW_STCTL_ALERT | SCSW_STCTL_STATUS_PEND; >> - s->cpa = sch->channel_prog + 8; >> - break; >> case -EBUSY: >> /* subchannel busy, generate deferred cc 1 */ >> s->flags &= ~SCSW_FLAGS_MASK_CC; > > Looks reasonable. Queued. > Thanks! Halil