vhost-vsock: fix migration issue when seqpacket is supported

Commit 1e08fd0a46 ("vhost-vsock: SOCK_SEQPACKET feature bit support")
enabled the SEQPACKET feature bit.
This commit is released with QEMU 6.1, so if we try to migrate a VM where
the host kernel supports SEQPACKET but machine type version is less than
6.1, we get the following errors:

    Features 0x130000002 unsupported. Allowed features: 0x179000000
    Failed to load virtio-vhost_vsock:virtio
    error while loading state for instance 0x0 of device '0000:00:05.0/virtio-vhost_vsock'
    load of migration failed: Operation not permitted

Let's disable the feature bit for machine types < 6.1.
We add a new OnOffAuto property for this, called `seqpacket`.
When it is `auto` (default), QEMU behaves as before, trying to enable the
feature, when it is `on` QEMU will fail if the backend (vhost-vsock
kernel module) doesn't support it.

Fixes: 1e08fd0a46 ("vhost-vsock: SOCK_SEQPACKET feature bit support")
Cc: qemu-stable@nongnu.org
Reported-by: Jiang Wang <jiang.wang@bytedance.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Message-Id: <20210921161642.206461-2-sgarzare@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
staging
Stefano Garzarella 2021-09-21 18:16:41 +02:00 committed by Michael S. Tsirkin
parent d6ed27bae7
commit d6a9378f47
3 changed files with 20 additions and 3 deletions

View File

@ -46,6 +46,7 @@ GlobalProperty hw_compat_6_0[] = {
{ "nvme-ns", "eui64-default", "off"},
{ "e1000", "init-vet", "off" },
{ "e1000e", "init-vet", "off" },
{ "vhost-vsock-device", "seqpacket", "off" },
};
const size_t hw_compat_6_0_len = G_N_ELEMENTS(hw_compat_6_0);

View File

@ -114,10 +114,21 @@ static uint64_t vhost_vsock_get_features(VirtIODevice *vdev,
Error **errp)
{
VHostVSockCommon *vvc = VHOST_VSOCK_COMMON(vdev);
VHostVSock *vsock = VHOST_VSOCK(vdev);
virtio_add_feature(&requested_features, VIRTIO_VSOCK_F_SEQPACKET);
return vhost_get_features(&vvc->vhost_dev, feature_bits,
requested_features);
if (vsock->seqpacket != ON_OFF_AUTO_OFF) {
virtio_add_feature(&requested_features, VIRTIO_VSOCK_F_SEQPACKET);
}
requested_features = vhost_get_features(&vvc->vhost_dev, feature_bits,
requested_features);
if (vsock->seqpacket == ON_OFF_AUTO_ON &&
!virtio_has_feature(requested_features, VIRTIO_VSOCK_F_SEQPACKET)) {
error_setg(errp, "vhost-vsock backend doesn't support seqpacket");
}
return requested_features;
}
static const VMStateDescription vmstate_virtio_vhost_vsock = {
@ -218,6 +229,8 @@ static void vhost_vsock_device_unrealize(DeviceState *dev)
static Property vhost_vsock_properties[] = {
DEFINE_PROP_UINT64("guest-cid", VHostVSock, conf.guest_cid, 0),
DEFINE_PROP_STRING("vhostfd", VHostVSock, conf.vhostfd),
DEFINE_PROP_ON_OFF_AUTO("seqpacket", VHostVSock, seqpacket,
ON_OFF_AUTO_AUTO),
DEFINE_PROP_END_OF_LIST(),
};

View File

@ -30,6 +30,9 @@ struct VHostVSock {
VHostVSockCommon parent;
VHostVSockConf conf;
/* features */
OnOffAuto seqpacket;
/*< public >*/
};