From mboxrd@z Thu Jan 1 00:00:00 1970 From: Cornelia Huck Subject: Re: [PATCH v2 1/1] vfio: ccw: fix bad ptr math for TIC cda translation Date: Mon, 24 Jul 2017 10:01:31 +0200 Message-ID: <20170724100131.702103ff@gondolin> References: <20170721011436.76112-1-bjsdjshi@linux.vnet.ibm.com> <20170724071053.GA7483@bjsdjshi@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: pasic@linux.vnet.ibm.com, linux-s390@vger.kernel.org, kvm@vger.kernel.org, borntraeger@de.ibm.com, "Jason J. Herne" To: Dong Jia Shi Return-path: Received: from mx1.redhat.com ([209.132.183.28]:52316 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750998AbdGXIBf (ORCPT ); Mon, 24 Jul 2017 04:01:35 -0400 In-Reply-To: <20170724071053.GA7483@bjsdjshi@linux.vnet.ibm.com> Sender: kvm-owner@vger.kernel.org List-ID: On Mon, 24 Jul 2017 15:10:53 +0800 Dong Jia Shi wrote: > * Dong Jia Shi [2017-07-21 03:14:36 +0200]: > > As Halil requested, add him into the loop. > > > 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; > > } Thanks, applied.