From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCH 05/21] virtio: modify save/load handler to handle inuse varialble. Date: Sun, 28 Nov 2010 13:46:28 +0200 Message-ID: <20101128114627.GC4499@redhat.com> References: <1290665220-26478-1-git-send-email-tamura.yoshiaki@lab.ntt.co.jp> <1290665220-26478-6-git-send-email-tamura.yoshiaki@lab.ntt.co.jp> <20101128092857.GA3342@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: kvm@vger.kernel.org, qemu-devel@nongnu.org, avi@redhat.com, anthony@codemonkey.ws, aliguori@us.ibm.com, mtosatti@redhat.com, dlaor@redhat.com, ananth@in.ibm.com, psuriset@linux.vnet.ibm.com, vatsa@linux.vnet.ibm.com, stefanha@linux.vnet.ibm.com, ohmura.kei@lab.ntt.co.jp To: Yoshiaki Tamura Return-path: Received: from mx1.redhat.com ([209.132.183.28]:12402 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752436Ab0K1LrO (ORCPT ); Sun, 28 Nov 2010 06:47:14 -0500 Content-Disposition: inline In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: On Sun, Nov 28, 2010 at 08:27:58PM +0900, Yoshiaki Tamura wrote: > 2010/11/28 Michael S. Tsirkin : > > On Thu, Nov 25, 2010 at 03:06:44PM +0900, Yoshiaki Tamura wrote: > >> Modify inuse type to uint16_t, let save/load to handle, and revert > >> last_avail_idx with inuse if there are outstanding emulation. > >> > >> Signed-off-by: Yoshiaki Tamura > > > > This changes migration format, so it will break compatibility with > > existing drivers. More generally, I think migrating internal > > state that is not guest visible is always a mistake > > as it ties migration format to an internal implementation > > (yes, I know we do this sometimes, but we should at least > > try not to add such cases). =A0I think the right thing to do in thi= s case > > is to flush outstanding > > work when vm is stopped. =A0Then, we are guaranteed that inuse is 0= =2E > > I sent patches that do this for virtio net and block. >=20 > Could you give me the link of your patches? I'd like to test > whether they work with Kemari upon failover. If they do, I'm > happy to drop this patch. >=20 > Yoshi Look for this: stable migration image on a stopped vm sent on: Wed, 24 Nov 2010 17:52:49 +0200 > > > >> --- > >> =A0hw/virtio.c | =A0 =A08 +++++++- > >> =A01 files changed, 7 insertions(+), 1 deletions(-) > >> > >> diff --git a/hw/virtio.c b/hw/virtio.c > >> index 849a60f..5509644 100644 > >> --- a/hw/virtio.c > >> +++ b/hw/virtio.c > >> @@ -72,7 +72,7 @@ struct VirtQueue > >> =A0 =A0 =A0VRing vring; > >> =A0 =A0 =A0target_phys_addr_t pa; > >> =A0 =A0 =A0uint16_t last_avail_idx; > >> - =A0 =A0int inuse; > >> + =A0 =A0uint16_t inuse; > >> =A0 =A0 =A0uint16_t vector; > >> =A0 =A0 =A0void (*handle_output)(VirtIODevice *vdev, VirtQueue *vq= ); > >> =A0 =A0 =A0VirtIODevice *vdev; > >> @@ -671,6 +671,7 @@ void virtio_save(VirtIODevice *vdev, QEMUFile = *f) > >> =A0 =A0 =A0 =A0 =A0qemu_put_be32(f, vdev->vq[i].vring.num); > >> =A0 =A0 =A0 =A0 =A0qemu_put_be64(f, vdev->vq[i].pa); > >> =A0 =A0 =A0 =A0 =A0qemu_put_be16s(f, &vdev->vq[i].last_avail_idx); > >> + =A0 =A0 =A0 =A0qemu_put_be16s(f, &vdev->vq[i].inuse); > >> =A0 =A0 =A0 =A0 =A0if (vdev->binding->save_queue) > >> =A0 =A0 =A0 =A0 =A0 =A0 =A0vdev->binding->save_queue(vdev->binding= _opaque, i, f); > >> =A0 =A0 =A0} > >> @@ -711,6 +712,11 @@ int virtio_load(VirtIODevice *vdev, QEMUFile = *f) > >> =A0 =A0 =A0 =A0 =A0vdev->vq[i].vring.num =3D qemu_get_be32(f); > >> =A0 =A0 =A0 =A0 =A0vdev->vq[i].pa =3D qemu_get_be64(f); > >> =A0 =A0 =A0 =A0 =A0qemu_get_be16s(f, &vdev->vq[i].last_avail_idx); > >> + =A0 =A0 =A0 =A0qemu_get_be16s(f, &vdev->vq[i].inuse); > >> + > >> + =A0 =A0 =A0 =A0/* revert last_avail_idx if there are outstanding= emulation. */ > >> + =A0 =A0 =A0 =A0vdev->vq[i].last_avail_idx -=3D vdev->vq[i].inuse= ; > >> + =A0 =A0 =A0 =A0vdev->vq[i].inuse =3D 0; > >> > >> =A0 =A0 =A0 =A0 =A0if (vdev->vq[i].pa) { > >> =A0 =A0 =A0 =A0 =A0 =A0 =A0virtqueue_init(&vdev->vq[i]); > >> -- > >> 1.7.1.2 > >> > >> -- > >> To unsubscribe from this list: send the line "unsubscribe kvm" in > >> the body of a message to majordomo@vger.kernel.org > >> More majordomo info at =A0http://vger.kernel.org/majordomo-info.ht= ml > > -- > > To unsubscribe from this list: send the line "unsubscribe kvm" in > > the body of a message to majordomo@vger.kernel.org > > More majordomo info at =A0http://vger.kernel.org/majordomo-info.htm= l > >