From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:45264 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1730429AbfFRUYB (ORCPT ); Tue, 18 Jun 2019 16:24:01 -0400 Received: from pps.filterd (m0098416.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x5IKHAlF099966 for ; Tue, 18 Jun 2019 16:24:00 -0400 Received: from e06smtp02.uk.ibm.com (e06smtp02.uk.ibm.com [195.75.94.98]) by mx0b-001b2d01.pphosted.com with ESMTP id 2t758mvjdk-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Tue, 18 Jun 2019 16:24:00 -0400 Received: from localhost by e06smtp02.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 18 Jun 2019 21:23:59 +0100 From: Eric Farman Subject: [RFC PATCH v1 3/5] vfio-ccw: Copy CCW data outside length calculation Date: Tue, 18 Jun 2019 22:23:50 +0200 In-Reply-To: <20190618202352.39702-1-farman@linux.ibm.com> References: <20190618202352.39702-1-farman@linux.ibm.com> Message-Id: <20190618202352.39702-4-farman@linux.ibm.com> Sender: linux-s390-owner@vger.kernel.org List-ID: To: Cornelia Huck , Farhan Ali Cc: Halil Pasic , linux-s390@vger.kernel.org, kvm@vger.kernel.org, Eric Farman It doesn't make much sense to "hide" the copy to the channel_program struct inside a routine that calculates the length of the chain. Let's move it to the calling routine, which will later copy from channel_program to the memory it allocated itself. Signed-off-by: Eric Farman --- drivers/s390/cio/vfio_ccw_cp.c | 19 +++++++------------ 1 file changed, 7 insertions(+), 12 deletions(-) diff --git a/drivers/s390/cio/vfio_ccw_cp.c b/drivers/s390/cio/vfio_ccw_cp.c index 37d513e86530..a55f8d110920 100644 --- a/drivers/s390/cio/vfio_ccw_cp.c +++ b/drivers/s390/cio/vfio_ccw_cp.c @@ -381,18 +381,8 @@ static void ccwchain_cda_free(struct ccwchain *chain, int idx) static int ccwchain_calc_length(u64 iova, struct channel_program *cp) { struct ccw1 *ccw = cp->guest_cp; - int cnt; + int cnt = 0; - /* - * Copy current chain from guest to host kernel. - * Currently the chain length is limited to CCWCHAIN_LEN_MAX (256). - * So copying 2K is enough (safe). - */ - cnt = copy_ccw_from_iova(cp, ccw, iova, CCWCHAIN_LEN_MAX); - if (cnt) - return cnt; - - cnt = 0; do { cnt++; @@ -446,7 +436,12 @@ static int ccwchain_handle_ccw(u32 cda, struct channel_program *cp) struct ccwchain *chain; int len; - /* Copy the chain from cda to cp, and count the CCWs in it */ + /* Copy 2K (the most we support today) of possible CCWs */ + len = copy_ccw_from_iova(cp, cp->guest_cp, cda, CCWCHAIN_LEN_MAX); + if (len) + return len; + + /* Count the CCWs in the current chain */ len = ccwchain_calc_length(cda, cp); if (len < 0) return len; -- 2.17.1