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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 67A30C76195 for ; Fri, 19 Jul 2019 17:54:20 +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 4150121872 for ; Fri, 19 Jul 2019 17:54:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4150121872 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]:47360 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hoX5H-0008TZ-6L for qemu-devel@archiver.kernel.org; Fri, 19 Jul 2019 13:54:19 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:59149) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hoX57-00082d-9R for qemu-devel@nongnu.org; Fri, 19 Jul 2019 13:54:10 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hoX56-0003VR-18 for qemu-devel@nongnu.org; Fri, 19 Jul 2019 13:54:09 -0400 Received: from mx1.redhat.com ([209.132.183.28]:18977) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hoX54-0003RI-7n for qemu-devel@nongnu.org; Fri, 19 Jul 2019 13:54:07 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 2CCDDC06511C; Fri, 19 Jul 2019 17:54:04 +0000 (UTC) Received: from work-vm (ovpn-117-245.ams2.redhat.com [10.36.117.245]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 013F0608D0; Fri, 19 Jul 2019 17:54:02 +0000 (UTC) Date: Fri, 19 Jul 2019 18:54:00 +0100 From: "Dr. David Alan Gilbert" To: Wei Yang , rth@twiddle.net Message-ID: <20190719175400.GJ3000@work-vm> References: <20190712032704.7826-1-richardw.yang@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190712032704.7826-1-richardw.yang@linux.intel.com> User-Agent: Mutt/1.12.0 (2019-05-25) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Fri, 19 Jul 2019 17:54:04 +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] migration: check length directly to make sure the range is aligned 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: pbonzini@redhat.com, qemu-devel@nongnu.org, quintela@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Wei Yang (richardw.yang@linux.intel.com) wrote: > Since the start addr is already checked, to make sure the range is > aligned, checking the length is enough. > > Signed-off-by: Wei Yang > --- > exec.c | 7 +++---- > 1 file changed, 3 insertions(+), 4 deletions(-) > > diff --git a/exec.c b/exec.c > index 50ea9c5aaa..8fa980baae 100644 > --- a/exec.c > +++ b/exec.c > @@ -4067,10 +4067,9 @@ int ram_block_discard_range(RAMBlock *rb, uint64_t start, size_t length) > > if ((start + length) <= rb->used_length) { > bool need_madvise, need_fallocate; > - uint8_t *host_endaddr = host_startaddr + length; > - if ((uintptr_t)host_endaddr & (rb->page_size - 1)) { > - error_report("ram_block_discard_range: Unaligned end address: %p", > - host_endaddr); > + if (length & (rb->page_size - 1)) { > + error_report("ram_block_discard_range: Unaligned length: %lx", > + length); Yes, I *think* this is safe, we'll need to watch out for any warnings; David Gibson's balloon fix from February means that the balloon code should now warn in it's case. rth: Want to pick this up? Reviewed-by: Dr. David Alan Gilbert > goto err; > } > > -- > 2.17.1 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK