From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:10103 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726670AbfGCJHH (ORCPT ); Wed, 3 Jul 2019 05:07:07 -0400 Date: Wed, 3 Jul 2019 11:07:04 +0200 From: Cornelia Huck Subject: Re: [PATCH] vfio-ccw: Fix the conversion of Format-0 CCWs to Format-1 Message-ID: <20190703110704.21509e60.cohuck@redhat.com> In-Reply-To: <20190702180928.18113-1-farman@linux.ibm.com> References: <20190702180928.18113-1-farman@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-s390-owner@vger.kernel.org List-ID: To: Eric Farman Cc: Farhan Ali , Halil Pasic , linux-s390@vger.kernel.org, kvm@vger.kernel.org On Tue, 2 Jul 2019 20:09:28 +0200 Eric Farman wrote: > When processing Format-0 CCWs, we use the "len" variable as the > number of CCWs to convert to Format-1. But that variable > contains zero here, and is not a meaningful CCW count until > ccwchain_calc_length() returns. Since that routine requires and > expects Format-1 CCWs to identify the chaining behavior, the > format conversion must be done first. The usage of the 'len' variable in the function is a bit confusing anyway. > > Convert the 2KB we copied even if it's more than we need. > > Fixes: 7f8e89a8f2fd ("vfio-ccw: Factor out the ccw0-to-ccw1 transition") > Reported-by: Farhan Ali > Signed-off-by: Eric Farman > --- > 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 9cddc1288059..a870bde10445 100644 > --- a/drivers/s390/cio/vfio_ccw_cp.c > +++ b/drivers/s390/cio/vfio_ccw_cp.c > @@ -431,7 +431,7 @@ static int ccwchain_handle_ccw(u32 cda, struct channel_program *cp) > > /* Convert any Format-0 CCWs to Format-1 */ > if (!cp->orb.cmd.fmt) > - convert_ccw0_to_ccw1(cp->guest_cp, len); > + convert_ccw0_to_ccw1(cp->guest_cp, CCWCHAIN_LEN_MAX); > > /* Count the CCWs in the current chain */ > len = ccwchain_calc_length(cda, cp); Reviewed-by: Cornelia Huck