From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44057) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dqL9T-0000bA-Ek for qemu-devel@nongnu.org; Fri, 08 Sep 2017 11:25:04 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dqL9O-0004of-Ez for qemu-devel@nongnu.org; Fri, 08 Sep 2017 11:25:03 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:45748 helo=mx0a-001b2d01.pphosted.com) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dqL9O-0004nj-8q for qemu-devel@nongnu.org; Fri, 08 Sep 2017 11:24:58 -0400 Received: from pps.filterd (m0098421.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id v88FO09h032292 for ; Fri, 8 Sep 2017 11:24:55 -0400 Received: from e06smtp10.uk.ibm.com (e06smtp10.uk.ibm.com [195.75.94.106]) by mx0a-001b2d01.pphosted.com with ESMTP id 2cuvvtb7gr-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Fri, 08 Sep 2017 11:24:54 -0400 Received: from localhost by e06smtp10.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 8 Sep 2017 16:24:53 +0100 From: Halil Pasic Date: Fri, 8 Sep 2017 17:24:43 +0200 In-Reply-To: <20170908152446.14606-1-pasic@linux.vnet.ibm.com> References: <20170908152446.14606-1-pasic@linux.vnet.ibm.com> Message-Id: <20170908152446.14606-2-pasic@linux.vnet.ibm.com> Subject: [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, Halil Pasic 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*. Signed-off-by: Halil Pasic --- 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; -- 2.13.5