From patchwork Tue Jun 18 20:23:48 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Farman X-Patchwork-Id: 11002669 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id D7C536C5 for ; Tue, 18 Jun 2019 20:24:07 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C971228A53 for ; Tue, 18 Jun 2019 20:24:07 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id BD7E228ABB; Tue, 18 Jun 2019 20:24:07 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id CD04528A53 for ; Tue, 18 Jun 2019 20:24:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730633AbfFRUYE (ORCPT ); Tue, 18 Jun 2019 16:24:04 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:51576 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1730577AbfFRUYD (ORCPT ); Tue, 18 Jun 2019 16:24:03 -0400 Received: from pps.filterd (m0098417.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x5IKI89F007405 for ; Tue, 18 Jun 2019 16:24:01 -0400 Received: from e06smtp04.uk.ibm.com (e06smtp04.uk.ibm.com [195.75.94.100]) by mx0a-001b2d01.pphosted.com with ESMTP id 2t75ky3vtt-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Tue, 18 Jun 2019 16:24:01 -0400 Received: from localhost by e06smtp04.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Tue, 18 Jun 2019 21:23:56 +0100 Received: from d06av26.portsmouth.uk.ibm.com (d06av26.portsmouth.uk.ibm.com [9.149.105.62]) by b06avi18626390.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x5IKNkpX36241814 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 18 Jun 2019 20:23:46 GMT Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 56E1CAE059; Tue, 18 Jun 2019 20:23:54 +0000 (GMT) Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 3C520AE051; Tue, 18 Jun 2019 20:23:54 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.152.85.9]) by d06av26.portsmouth.uk.ibm.com (Postfix) with ESMTPS; Tue, 18 Jun 2019 20:23:54 +0000 (GMT) Received: by tuxmaker.boeblingen.de.ibm.com (Postfix, from userid 4958) id C957BE0215; Tue, 18 Jun 2019 22:23:53 +0200 (CEST) From: Eric Farman To: Cornelia Huck , Farhan Ali Cc: Halil Pasic , linux-s390@vger.kernel.org, kvm@vger.kernel.org, Eric Farman Subject: [RFC PATCH v1 1/5] vfio-ccw: Move guest_cp storage into common struct Date: Tue, 18 Jun 2019 22:23:48 +0200 X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190618202352.39702-1-farman@linux.ibm.com> References: <20190618202352.39702-1-farman@linux.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 19061820-0016-0000-0000-0000028A3755 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19061820-0017-0000-0000-000032E78A61 Message-Id: <20190618202352.39702-2-farman@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-06-18_09:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1906180161 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Rather than allocating/freeing a piece of memory every time we try to figure out how long a CCW chain is, let's use a piece of memory allocated for each device. The io_mutex added with commit 4f76617378ee9 ("vfio-ccw: protect the I/O region") is held for the duration of the VFIO_CCW_EVENT_IO_REQ event that accesses/uses this space, so there should be no race concerns with another CPU attempting an (unexpected) SSCH for the same device. Suggested-by: Cornelia Huck Signed-off-by: Eric Farman Reviewed-by: Cornelia Huck --- Conny, your suggestion [1] did not go unnoticed. :) [1] https://patchwork.kernel.org/comment/22312659/ --- drivers/s390/cio/vfio_ccw_cp.c | 23 ++++------------------- drivers/s390/cio/vfio_ccw_cp.h | 7 +++++++ drivers/s390/cio/vfio_ccw_drv.c | 7 +++++++ 3 files changed, 18 insertions(+), 19 deletions(-) diff --git a/drivers/s390/cio/vfio_ccw_cp.c b/drivers/s390/cio/vfio_ccw_cp.c index 90d86e1354c1..f358502376be 100644 --- a/drivers/s390/cio/vfio_ccw_cp.c +++ b/drivers/s390/cio/vfio_ccw_cp.c @@ -16,12 +16,6 @@ #include "vfio_ccw_cp.h" -/* - * Max length for ccw chain. - * XXX: Limit to 256, need to check more? - */ -#define CCWCHAIN_LEN_MAX 256 - struct pfn_array { /* Starting guest physical I/O address. */ unsigned long pa_iova; @@ -386,7 +380,7 @@ static void ccwchain_cda_free(struct ccwchain *chain, int idx) */ static int ccwchain_calc_length(u64 iova, struct channel_program *cp) { - struct ccw1 *ccw, *p; + struct ccw1 *ccw = cp->guest_cp; int cnt; /* @@ -394,15 +388,9 @@ static int ccwchain_calc_length(u64 iova, struct channel_program *cp) * Currently the chain length is limited to CCWCHAIN_LEN_MAX (256). * So copying 2K is enough (safe). */ - p = ccw = kcalloc(CCWCHAIN_LEN_MAX, sizeof(*ccw), GFP_KERNEL); - if (!ccw) - return -ENOMEM; - cnt = copy_ccw_from_iova(cp, ccw, iova, CCWCHAIN_LEN_MAX); - if (cnt) { - kfree(ccw); + if (cnt) return cnt; - } cnt = 0; do { @@ -413,10 +401,8 @@ static int ccwchain_calc_length(u64 iova, struct channel_program *cp) * orb specified one of the unsupported formats, we defer * checking for IDAWs in unsupported formats to here. */ - if ((!cp->orb.cmd.c64 || cp->orb.cmd.i2k) && ccw_is_idal(ccw)) { - kfree(p); + if ((!cp->orb.cmd.c64 || cp->orb.cmd.i2k) && ccw_is_idal(ccw)) return -EOPNOTSUPP; - } /* * We want to keep counting if the current CCW has the @@ -435,7 +421,6 @@ static int ccwchain_calc_length(u64 iova, struct channel_program *cp) if (cnt == CCWCHAIN_LEN_MAX + 1) cnt = -EINVAL; - kfree(p); return cnt; } @@ -461,7 +446,7 @@ static int ccwchain_handle_ccw(u32 cda, struct channel_program *cp) struct ccwchain *chain; int len, ret; - /* Get chain length. */ + /* Copy the chain from cda to cp, and count the CCWs in it */ len = ccwchain_calc_length(cda, cp); if (len < 0) return len; diff --git a/drivers/s390/cio/vfio_ccw_cp.h b/drivers/s390/cio/vfio_ccw_cp.h index 3c20cd208da5..7cdc38049033 100644 --- a/drivers/s390/cio/vfio_ccw_cp.h +++ b/drivers/s390/cio/vfio_ccw_cp.h @@ -16,6 +16,12 @@ #include "orb.h" +/* + * Max length for ccw chain. + * XXX: Limit to 256, need to check more? + */ +#define CCWCHAIN_LEN_MAX 256 + /** * struct channel_program - manage information for channel program * @ccwchain_list: list head of ccwchains @@ -32,6 +38,7 @@ struct channel_program { union orb orb; struct device *mdev; bool initialized; + struct ccw1 *guest_cp; }; extern int cp_init(struct channel_program *cp, struct device *mdev, diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c index 66a66ac1f3d1..34a9a5e3fd36 100644 --- a/drivers/s390/cio/vfio_ccw_drv.c +++ b/drivers/s390/cio/vfio_ccw_drv.c @@ -129,6 +129,11 @@ static int vfio_ccw_sch_probe(struct subchannel *sch) if (!private) return -ENOMEM; + private->cp.guest_cp = kcalloc(CCWCHAIN_LEN_MAX, sizeof(struct ccw1), + GFP_KERNEL); + if (!private->cp.guest_cp) + goto out_free; + private->io_region = kmem_cache_zalloc(vfio_ccw_io_region, GFP_KERNEL | GFP_DMA); if (!private->io_region) @@ -169,6 +174,7 @@ static int vfio_ccw_sch_probe(struct subchannel *sch) kmem_cache_free(vfio_ccw_cmd_region, private->cmd_region); if (private->io_region) kmem_cache_free(vfio_ccw_io_region, private->io_region); + kfree(private->cp.guest_cp); kfree(private); return ret; } @@ -185,6 +191,7 @@ static int vfio_ccw_sch_remove(struct subchannel *sch) kmem_cache_free(vfio_ccw_cmd_region, private->cmd_region); kmem_cache_free(vfio_ccw_io_region, private->io_region); + kfree(private->cp.guest_cp); kfree(private); return 0;