From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60537) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZXAz0-0003VL-5F for qemu-devel@nongnu.org; Wed, 02 Sep 2015 12:33:59 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZXAyv-0000Gl-1U for qemu-devel@nongnu.org; Wed, 02 Sep 2015 12:33:58 -0400 Received: from e06smtp10.uk.ibm.com ([195.75.94.106]:56857) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZXAyu-0000Do-Kt for qemu-devel@nongnu.org; Wed, 02 Sep 2015 12:33:52 -0400 Received: from /spool/local by e06smtp10.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 2 Sep 2015 17:33:39 +0100 Received: from d06av02.portsmouth.uk.ibm.com (d06av02.portsmouth.uk.ibm.com [9.149.37.228]) by b06cxnps4076.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t82FxUiH17498246 for ; Wed, 2 Sep 2015 15:59:31 GMT Received: from d06av02.portsmouth.uk.ibm.com (localhost [127.0.0.1]) by d06av02.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t82FxUrg016168 for ; Wed, 2 Sep 2015 09:59:30 -0600 Date: Wed, 2 Sep 2015 17:59:27 +0200 From: Greg Kurz Message-ID: <20150902175927.56c24055@bahia.local> In-Reply-To: <1441164325-14417-6-git-send-email-jasowang@redhat.com> References: <1441164325-14417-1-git-send-email-jasowang@redhat.com> <1441164325-14417-6-git-send-email-jasowang@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH V2 5/8] memory: don't try to adjust endianness for zero length eventfd List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jason Wang Cc: cornelia.huck@de.ibm.com, Peter Maydell , Paolo Bonzini , qemu-devel@nongnu.org, mst@redhat.com On Wed, 2 Sep 2015 11:25:22 +0800 Jason Wang wrote: > There's no need to adjust endianness for zero length eventfd since the > data wrote was actually ignored by kernel. So skip the adjust in this > case to fix a possible crash when trying to use wildcard mmio eventfd > in ppc. > > Cc: Greg Kurz > Cc: Peter Maydell > Cc: Paolo Bonzini > Signed-off-by: Jason Wang > --- Indeed, this patch prevents the crash to occur on ppc64. Acked-by: Greg Kurz > memory.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/memory.c b/memory.c > index 0d8b2d9..de2d999 100644 > --- a/memory.c > +++ b/memory.c > @@ -1653,7 +1653,9 @@ void memory_region_add_eventfd(MemoryRegion *mr, > }; > unsigned i; > > - adjust_endianness(mr, &mrfd.data, size); > + if (size) { > + adjust_endianness(mr, &mrfd.data, size); > + } > memory_region_transaction_begin(); > for (i = 0; i < mr->ioeventfd_nb; ++i) { > if (memory_region_ioeventfd_before(mrfd, mr->ioeventfds[i])) { > @@ -1686,7 +1688,9 @@ void memory_region_del_eventfd(MemoryRegion *mr, > }; > unsigned i; > > - adjust_endianness(mr, &mrfd.data, size); > + if (size) { > + adjust_endianness(mr, &mrfd.data, size); > + } > memory_region_transaction_begin(); > for (i = 0; i < mr->ioeventfd_nb; ++i) { > if (memory_region_ioeventfd_equal(mrfd, mr->ioeventfds[i])) {