From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1NFfpS-0005nc-6p for qemu-devel@nongnu.org; Tue, 01 Dec 2009 22:24:34 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1NFfpM-0005kw-Ad for qemu-devel@nongnu.org; Tue, 01 Dec 2009 22:24:32 -0500 Received: from [199.232.76.173] (port=44455 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1NFfpM-0005kk-5W for qemu-devel@nongnu.org; Tue, 01 Dec 2009 22:24:28 -0500 Received: from e38.co.us.ibm.com ([32.97.110.159]:56216) by monty-python.gnu.org with esmtps (TLS-1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1NFfpL-0000TE-N9 for qemu-devel@nongnu.org; Tue, 01 Dec 2009 22:24:27 -0500 Received: from d03relay01.boulder.ibm.com (d03relay01.boulder.ibm.com [9.17.195.226]) by e38.co.us.ibm.com (8.14.3/8.13.1) with ESMTP id nB23JStb012466 for ; Tue, 1 Dec 2009 20:19:28 -0700 Received: from d03av03.boulder.ibm.com (d03av03.boulder.ibm.com [9.17.195.169]) by d03relay01.boulder.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id nB23O9NC175182 for ; Tue, 1 Dec 2009 20:24:10 -0700 Received: from d03av03.boulder.ibm.com (loopback [127.0.0.1]) by d03av03.boulder.ibm.com (8.14.3/8.13.1/NCO v10.0 AVout) with ESMTP id nB23O8xr007224 for ; Tue, 1 Dec 2009 20:24:09 -0700 Date: Tue, 1 Dec 2009 21:24:04 -0600 From: Ryan Harper Subject: Re: [Qemu-devel] [PATCH] vmstate: Avoid seeking Message-ID: <20091202032404.GV32229@us.ibm.com> References: <4B15A8FA.5080804@web.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4B15A8FA.5080804@web.de> List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jan Kiszka Cc: Anthony Liguori , Juan Quintela , qemu-devel , Liran Schour , Pierre Riteau * Jan Kiszka [2009-12-01 17:44]: > Seeking on vmstate save/load does not work if the underlying file is a > stream. We could try to make all QEMUFile* forward-seek-aware, but first > attempts in this direction indicated that it's saner to convert the few > qemu_fseek-on-vmstates users to plain reads/writes. > > This fixes various subtle vmstate corruptions where unused fields were > involved. > > Signed-off-by: Jan Kiszka With this patch and the VMSTATE_MACADDR patch, localhost migration with e1000 is working again. Acked-by: Ryan Harper > --- > > hw/virtio-net.c | 7 ++----- > savevm.c | 18 ++++++++++++++++-- > 2 files changed, 18 insertions(+), 7 deletions(-) > > diff --git a/hw/virtio-net.c b/hw/virtio-net.c > index 2f147e5..9ccd4c8 100644 > --- a/hw/virtio-net.c > +++ b/hw/virtio-net.c > @@ -745,12 +745,9 @@ static int virtio_net_load(QEMUFile *f, void *opaque, int version_id) > > if (version_id >= 5) { > n->mac_table.in_use = qemu_get_be32(f); > + qemu_get_buffer(f, n->mac_table.macs, n->mac_table.in_use * ETH_ALEN); > /* MAC_TABLE_ENTRIES may be different from the saved image */ > - if (n->mac_table.in_use <= MAC_TABLE_ENTRIES) { > - qemu_get_buffer(f, n->mac_table.macs, > - n->mac_table.in_use * ETH_ALEN); > - } else if (n->mac_table.in_use) { > - qemu_fseek(f, n->mac_table.in_use * ETH_ALEN, SEEK_CUR); > + if (n->mac_table.in_use > MAC_TABLE_ENTRIES) { > n->mac_table.multi_overflow = n->mac_table.uni_overflow = 1; > n->mac_table.in_use = 0; > } > diff --git a/savevm.c b/savevm.c > index 8fe9349..1e54a42 100644 > --- a/savevm.c > +++ b/savevm.c > @@ -959,13 +959,27 @@ const VMStateInfo vmstate_info_buffer = { > > static int get_unused_buffer(QEMUFile *f, void *pv, size_t size) > { > - qemu_fseek(f, size, SEEK_CUR); > + uint8_t buf[1024]; > + int block_len; > + > + while (size > 0) { > + block_len = MIN(sizeof(buf), size); > + size -= block_len; > + qemu_get_buffer(f, buf, block_len); > + } > return 0; > } > > static void put_unused_buffer(QEMUFile *f, void *pv, size_t size) > { > - qemu_fseek(f, size, SEEK_CUR); > + static const uint8_t buf[1024]; > + int block_len; > + > + while (size > 0) { > + block_len = MIN(sizeof(buf), size); > + size -= block_len; > + qemu_put_buffer(f, buf, block_len); > + } > } > > const VMStateInfo vmstate_info_unused_buffer = { > -- Ryan Harper Software Engineer; Linux Technology Center IBM Corp., Austin, Tx ryanh@us.ibm.com