From nobody Tue Nov 4 22:05:02 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (208.118.235.17 [208.118.235.17]) by mx.zohomail.com with SMTPS id 1530760814320588.280119560629; Wed, 4 Jul 2018 20:20:14 -0700 (PDT) Received: from localhost ([::1]:50074 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fauoX-0005Lk-Gq for importer@patchew.org; Wed, 04 Jul 2018 23:20:13 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49814) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1faumX-00044b-31 for qemu-devel@nongnu.org; Wed, 04 Jul 2018 23:18:12 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1faumV-0001l8-To for qemu-devel@nongnu.org; Wed, 04 Jul 2018 23:18:09 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:47296 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1faumV-0001jk-Oz for qemu-devel@nongnu.org; Wed, 04 Jul 2018 23:18:07 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 4EE0781A4EAD for ; Thu, 5 Jul 2018 03:18:07 +0000 (UTC) Received: from xz-mi.nay.redhat.com (dhcp-14-142.nay.redhat.com [10.66.14.142]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5E7852166BA9; Thu, 5 Jul 2018 03:18:05 +0000 (UTC) From: Peter Xu To: qemu-devel@nongnu.org Date: Thu, 5 Jul 2018 11:17:49 +0800 Message-Id: <20180705031755.3254-4-peterx@redhat.com> In-Reply-To: <20180705031755.3254-1-peterx@redhat.com> References: <20180705031755.3254-1-peterx@redhat.com> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.6 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Thu, 05 Jul 2018 03:18:07 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Thu, 05 Jul 2018 03:18:07 +0000 (UTC) for IP:'10.11.54.6' DOMAIN:'int-mx06.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'peterx@redhat.com' RCPT:'' X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 66.187.233.73 Subject: [Qemu-devel] [PATCH for-3.0 3/9] migration: fix incorrect bitmap size calculation X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "Dr . David Alan Gilbert" , peterx@redhat.com, Juan Quintela Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" The calculation on size of received bitmap is incorrect for postcopy recovery. Here we wanted to let the size to cover all the valid bits in the bitmap, we should use DIV_ROUND_UP() instead of a division. For example, a RAMBlock with size=3D4K (which contains only one single 4K page) will have nbits=3D1, then nbits/8=3D0, then the real bitmap won't be sent to source at all. Signed-off-by: Peter Xu Reviewed-by: Dr. David Alan Gilbert Reviewed-by: Juan Quintela --- migration/ram.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/migration/ram.c b/migration/ram.c index fbeb23f750..203c691ded 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -235,7 +235,7 @@ int64_t ramblock_recv_bitmap_send(QEMUFile *file, bitmap_to_le(le_bitmap, block->receivedmap, nbits); =20 /* Size of the bitmap, in bytes */ - size =3D nbits / 8; + size =3D DIV_ROUND_UP(nbits, 8); =20 /* * size is always aligned to 8 bytes for 64bit machines, but it @@ -3944,7 +3944,7 @@ int ram_dirty_bitmap_reload(MigrationState *s, RAMBlo= ck *block) int ret =3D -EINVAL; QEMUFile *file =3D s->rp_state.from_dst_file; unsigned long *le_bitmap, nbits =3D block->used_length >> TARGET_PAGE_= BITS; - uint64_t local_size =3D nbits / 8; + uint64_t local_size =3D DIV_ROUND_UP(nbits, 8); uint64_t size, end_mark; =20 trace_ram_dirty_bitmap_reload_begin(block->idstr); --=20 2.17.1