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Re: [Qemu-devel] [PATCH 1/3] virtio: let devices be permissive on enable
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] [PATCH 1/3] virtio: let devices be permissive on enabled features |
Date: |
Tue, 6 Mar 2012 15:33:32 +0200 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Tue, Mar 06, 2012 at 01:22:05PM +0100, Paolo Bonzini wrote:
> virtio_load checks features that are enabled by the guest and
> blocks migration if they are not available in the destination
> host. However, in some cases we can let features through because
> we know that guests will be able to proceed even without it.
>
> Signed-off-by: Paolo Bonzini <address@hidden>
So why do we need these hacks? You are saying things
work fine without this information. Then,
why not just have the bit set in supported features always?
> ---
> hw/virtio-balloon.c | 2 +-
> hw/virtio-blk.c | 2 +-
> hw/virtio-net.c | 2 +-
> hw/virtio-scsi.c | 2 +-
> hw/virtio-serial-bus.c | 2 +-
> hw/virtio.c | 8 +++++---
> hw/virtio.h | 2 +-
> 7 files changed, 11 insertions(+), 9 deletions(-)
>
> diff --git a/hw/virtio-balloon.c b/hw/virtio-balloon.c
> index 075ed87..0ade8b0 100644
> --- a/hw/virtio-balloon.c
> +++ b/hw/virtio-balloon.c
> @@ -216,7 +216,7 @@ static int virtio_balloon_load(QEMUFile *f, void *opaque,
> int version_id)
> if (version_id != 1)
> return -EINVAL;
>
> - ret = virtio_load(&s->vdev, f);
> + ret = virtio_load(&s->vdev, f, 0);
> if (ret) {
> return ret;
> }
> diff --git a/hw/virtio-blk.c b/hw/virtio-blk.c
> index d4bb400..c95f8fc 100644
> --- a/hw/virtio-blk.c
> +++ b/hw/virtio-blk.c
> @@ -542,7 +542,7 @@ static int virtio_blk_load(QEMUFile *f, void *opaque, int
> version_id)
> if (version_id != 2)
> return -EINVAL;
>
> - ret = virtio_load(&s->vdev, f);
> + ret = virtio_load(&s->vdev, f, 0);
> if (ret) {
> return ret;
> }
> diff --git a/hw/virtio-net.c b/hw/virtio-net.c
> index 3f190d4..719ba96 100644
> --- a/hw/virtio-net.c
> +++ b/hw/virtio-net.c
> @@ -896,7 +896,7 @@ static int virtio_net_load(QEMUFile *f, void *opaque, int
> version_id)
> if (version_id < 2 || version_id > VIRTIO_NET_VM_VERSION)
> return -EINVAL;
>
> - ret = virtio_load(&n->vdev, f);
> + ret = virtio_load(&n->vdev, f, 0);
> if (ret) {
> return ret;
> }
> diff --git a/hw/virtio-scsi.c b/hw/virtio-scsi.c
> index 9797847..da281e2 100644
> --- a/hw/virtio-scsi.c
> +++ b/hw/virtio-scsi.c
> @@ -560,7 +560,7 @@ static int virtio_scsi_load(QEMUFile *f, void *opaque,
> int version_id)
> VirtIOSCSI *s = opaque;
> int ret;
>
> - ret = virtio_load(&s->vdev, f);
> + ret = virtio_load(&s->vdev, f, 0);
> if (ret) {
> return ret;
> }
> diff --git a/hw/virtio-serial-bus.c b/hw/virtio-serial-bus.c
> index 4a33872..5ef7d30 100644
> --- a/hw/virtio-serial-bus.c
> +++ b/hw/virtio-serial-bus.c
> @@ -597,7 +597,7 @@ static int virtio_serial_load(QEMUFile *f, void *opaque,
> int version_id)
> }
>
> /* The virtio device */
> - ret = virtio_load(&s->vdev, f);
> + ret = virtio_load(&s->vdev, f, 0);
> if (ret) {
> return ret;
> }
> diff --git a/hw/virtio.c b/hw/virtio.c
> index 064aecf..fdbb286 100644
> --- a/hw/virtio.c
> +++ b/hw/virtio.c
> @@ -777,11 +777,12 @@ int virtio_set_features(VirtIODevice *vdev, uint32_t
> val)
> return bad ? -1 : 0;
> }
>
> -int virtio_load(VirtIODevice *vdev, QEMUFile *f)
> +int virtio_load(VirtIODevice *vdev, QEMUFile *f, int additional_features)
int? Should be uint32_t?
> {
> int num, i, ret;
> uint32_t features;
> uint32_t supported_features;
> + uint32_t disabled_features;
>
> if (vdev->binding->load_config) {
> ret = vdev->binding->load_config(vdev->binding_opaque, f);
> @@ -794,8 +795,9 @@ int virtio_load(VirtIODevice *vdev, QEMUFile *f)
> qemu_get_be16s(f, &vdev->queue_sel);
> qemu_get_be32s(f, &features);
>
> - if (virtio_set_features(vdev, features) < 0) {
> - supported_features =
> vdev->binding->get_features(vdev->binding_opaque);
> + supported_features = vdev->binding->get_features(vdev->binding_opaque);
> + disabled_features = additional_features & ~supported_features;
> + if (virtio_set_features(vdev, features & ~disabled_features) < 0) {
> error_report("Features 0x%x unsupported. Allowed features: 0x%x",
> features, supported_features);
> return -1;
> diff --git a/hw/virtio.h b/hw/virtio.h
> index 400c092..2e8dd20 100644
> --- a/hw/virtio.h
> +++ b/hw/virtio.h
> @@ -154,7 +154,7 @@ void virtio_notify(VirtIODevice *vdev, VirtQueue *vq);
>
> void virtio_save(VirtIODevice *vdev, QEMUFile *f);
>
> -int virtio_load(VirtIODevice *vdev, QEMUFile *f);
> +int virtio_load(VirtIODevice *vdev, QEMUFile *f, int additional_features);
>
> void virtio_cleanup(VirtIODevice *vdev);
>
> --
> 1.7.7.6
>
- Re: [Qemu-devel] [PATCH 3/3] virtio-blk: note optional features, (continued)
[Qemu-devel] [PATCH 2/3] virtio-balloon: note optional features, Paolo Bonzini, 2012/03/06
[Qemu-devel] [PATCH 1/3] virtio: let devices be permissive on enabled features, Paolo Bonzini, 2012/03/06
- Re: [Qemu-devel] [PATCH 1/3] virtio: let devices be permissive on enabled features,
Michael S. Tsirkin <=