From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A10E8C7618B for ; Thu, 25 Jul 2019 12:37:09 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 7429822C7B for ; Thu, 25 Jul 2019 12:37:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7429822C7B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:59674 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hqczc-0005CV-MU for qemu-devel@archiver.kernel.org; Thu, 25 Jul 2019 08:37:08 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:36143) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hqczT-0004o5-7I for qemu-devel@nongnu.org; Thu, 25 Jul 2019 08:37:00 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hqczS-0005Oo-7q for qemu-devel@nongnu.org; Thu, 25 Jul 2019 08:36:59 -0400 Received: from mx1.redhat.com ([209.132.183.28]:43360) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hqczS-0005OH-2B; Thu, 25 Jul 2019 08:36:58 -0400 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id A193D308427C; Thu, 25 Jul 2019 12:36:55 +0000 (UTC) Received: from colo-mx.corp.redhat.com (colo-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.20]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 9506160148; Thu, 25 Jul 2019 12:36:55 +0000 (UTC) Received: from zmail21.collab.prod.int.phx2.redhat.com (zmail21.collab.prod.int.phx2.redhat.com [10.5.83.24]) by colo-mx.corp.redhat.com (Postfix) with ESMTP id 00EAA1800205; Thu, 25 Jul 2019 12:36:54 +0000 (UTC) Date: Thu, 25 Jul 2019 08:36:54 -0400 (EDT) From: Pankaj Gupta To: David Hildenbrand Message-ID: <748941041.4528533.1564058214607.JavaMail.zimbra@redhat.com> In-Reply-To: <20190725113638.4702-2-david@redhat.com> References: <20190725113638.4702-1-david@redhat.com> <20190725113638.4702-2-david@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Originating-IP: [10.67.116.53, 10.4.195.23] Thread-Topic: virtio-balloon: Fix wrong sign extension of PFNs Thread-Index: jz5vhQP+4366z+KjHUdULHkZ4ANVgA== X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.40]); Thu, 25 Jul 2019 12:36:56 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [PATCH-for-4.1 v4 1/7] virtio-balloon: Fix wrong sign extension of PFNs X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "Michael S . Tsirkin" , qemu-stable@nongnu.org, qemu-devel@nongnu.org, Stefan Hajnoczi , Igor Mammedov , David Gibson Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" > > If we directly cast from int to uint64_t, we will first sign-extend to > an int64_t, which is wrong. We actually want to treat the PFNs like > unsigned values. > > As far as I can see, this dates back to the initial virtio-balloon > commit, but wasn't triggered as fairly big guests would be required. > > Cc: qemu-stable@nongnu.org > Reported-by: Michael S. Tsirkin > Reviewed-by: David Gibson > Signed-off-by: David Hildenbrand > --- > hw/virtio/virtio-balloon.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c > index e85d1c0d5c..515abf6553 100644 > --- a/hw/virtio/virtio-balloon.c > +++ b/hw/virtio/virtio-balloon.c > @@ -343,8 +343,8 @@ static void virtio_balloon_handle_output(VirtIODevice > *vdev, VirtQueue *vq) > } > > while (iov_to_buf(elem->out_sg, elem->out_num, offset, &pfn, 4) == > 4) { > + unsigned int p = virtio_ldl_p(vdev, &pfn); > hwaddr pa; > - int p = virtio_ldl_p(vdev, &pfn); > > pa = (hwaddr) p << VIRTIO_BALLOON_PFN_SHIFT; > offset += 4; > -- > 2.21.0 Reviewed-by: Pankaj Gupta > > >