From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dong Jia Shi Subject: [PATCH v2 1/1] vfio: ccw: fix bad ptr math for TIC cda translation Date: Fri, 21 Jul 2017 03:14:36 +0200 Message-ID: <20170721011436.76112-1-bjsdjshi@linux.vnet.ibm.com> Cc: cohuck@redhat.com, borntraeger@de.ibm.com, bjsdjshi@linux.vnet.ibm.com, "Jason J. Herne" To: linux-s390@vger.kernel.org, kvm@vger.kernel.org Return-path: Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:44588 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S965597AbdGUBOn (ORCPT ); Thu, 20 Jul 2017 21:14:43 -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 v6L1EXnb133996 for ; Thu, 20 Jul 2017 21:14:43 -0400 Received: from e34.co.us.ibm.com (e34.co.us.ibm.com [32.97.110.152]) by mx0a-001b2d01.pphosted.com with ESMTP id 2bu29hurqd-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Thu, 20 Jul 2017 21:14:42 -0400 Received: from localhost by e34.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 20 Jul 2017 19:14:42 -0600 Sender: kvm-owner@vger.kernel.org List-ID: From: "Jason J. Herne" When we are translating channel data addresses from guest to host address space for TIC instructions we are getting incorrect addresses because of a pointer arithmetic error. We currently calculate the offset of the TIC's cda from the start of the channel program chain (ccw->cda - ccw_head). We then add that to the address of the ccw chain in host memory (iter->ch_ccw). The problem is that iter->ch_ccw is a pointer to struct ccw1 so when we increment it we are actually incrementing by the size of struct ccw1 which is 8 bytes. The intent was to increment by n-bytes, not n*8. The fix: cast iter->ch_ccw to char* so it will be incremented by n*1. Reviewed-by: Dong Jia Shi Signed-off-by: Jason J. Herne Signed-off-by: Dong Jia Shi --- drivers/s390/cio/vfio_ccw_cp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/s390/cio/vfio_ccw_cp.c b/drivers/s390/cio/vfio_ccw_cp.c index ba6ac83a6c25..5ccfdc80d0ec 100644 --- a/drivers/s390/cio/vfio_ccw_cp.c +++ b/drivers/s390/cio/vfio_ccw_cp.c @@ -481,7 +481,7 @@ static int ccwchain_fetch_tic(struct ccwchain *chain, ccw_tail = ccw_head + (iter->ch_len - 1) * sizeof(struct ccw1); if ((ccw_head <= ccw->cda) && (ccw->cda <= ccw_tail)) { - ccw->cda = (__u32) (addr_t) (iter->ch_ccw + + ccw->cda = (__u32) (addr_t) (((char *)iter->ch_ccw) + (ccw->cda - ccw_head)); return 0; } -- 2.11.2