vhost-vsock: handle common features in vhost-vsock-common

virtio-vsock features, like VIRTIO_VSOCK_F_SEQPACKET, can be handled
by vhost-vsock-common parent class. In this way, we can reuse the
same code for all virtio-vsock backends (i.e. vhost-vsock,
vhost-user-vsock).

Let's move `seqpacket` property to vhost-vsock-common class, add
vhost_vsock_common_get_features() used by children, and disable
`seqpacket` for vhost-user-vsock device for machine types < 6.2.

The behavior of vhost-vsock device doesn't change; vhost-user-vsock
device now supports `seqpacket` property.

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Message-Id: <20210921161642.206461-3-sgarzare@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 31 insertions, 0 deletions

diff --git a/hw/virtio/vhost-vsock-common.c b/hw/virtio/vhost-vsock-common.c
index 4ad6e234ad..3f3771274e 100644
--- a/hw/virtio/vhost-vsock-common.c
+++ b/hw/virtio/vhost-vsock-common.c
@@ -18,6 +18,30 @@
 #include "qemu/iov.h"
 #include "monitor/monitor.h"
 
+const int feature_bits[] = {
+    VIRTIO_VSOCK_F_SEQPACKET,
+    VHOST_INVALID_FEATURE_BIT
+};
+
+uint64_t vhost_vsock_common_get_features(VirtIODevice *vdev, uint64_t features,
+                                         Error **errp)
+{
+    VHostVSockCommon *vvc = VHOST_VSOCK_COMMON(vdev);
+
+    if (vvc->seqpacket != ON_OFF_AUTO_OFF) {
+        virtio_add_feature(&features, VIRTIO_VSOCK_F_SEQPACKET);
+    }
+
+    features = vhost_get_features(&vvc->vhost_dev, feature_bits, features);
+
+    if (vvc->seqpacket == ON_OFF_AUTO_ON &&
+        !virtio_has_feature(features, VIRTIO_VSOCK_F_SEQPACKET)) {
+        error_setg(errp, "vhost-vsock backend doesn't support seqpacket");
+    }
+
+    return features;
+}
+
 int vhost_vsock_common_start(VirtIODevice *vdev)
 {
     VHostVSockCommon *vvc = VHOST_VSOCK_COMMON(vdev);
@@ -231,11 +255,18 @@ void vhost_vsock_common_unrealize(VirtIODevice *vdev)
     virtio_cleanup(vdev);
 }
 
+static Property vhost_vsock_common_properties[] = {
+    DEFINE_PROP_ON_OFF_AUTO("seqpacket", VHostVSockCommon, seqpacket,
+                            ON_OFF_AUTO_AUTO),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
 static void vhost_vsock_common_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);
     VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
 
+    device_class_set_props(dc, vhost_vsock_common_properties);
     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
     vdc->guest_notifier_mask = vhost_vsock_common_guest_notifier_mask;
     vdc->guest_notifier_pending = vhost_vsock_common_guest_notifier_pending;