3 files changed, 23 insertions, 6 deletions

diff --git a/hw/virtio/virtio-bus.c b/hw/virtio/virtio-bus.c
index 11adfbf3ab..cef944e015 100644
--- a/hw/virtio/virtio-bus.c
+++ b/hw/virtio/virtio-bus.c
@@ -62,9 +62,14 @@ void virtio_bus_device_plugged(VirtIODevice *vdev, Error **errp)
     }
 
     /* Get the features of the plugged device. */
-    assert(vdc->get_features != NULL);
-    vdev->host_features = vdc->get_features(vdev, vdev->host_features,
-                                            &local_err);
+    if (vdc->get_features_ex) {
+        vdc->get_features_ex(vdev, vdev->host_features_ex, &local_err);
+    } else {
+        assert(vdc->get_features != NULL);
+        virtio_features_from_u64(vdev->host_features_ex,
+                                 vdc->get_features(vdev, vdev->host_features,
+                                                   &local_err));
+    }
     if (local_err) {
         error_propagate(errp, local_err);
         return;
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index bf53c211e5..34f977a3c9 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -3103,7 +3103,9 @@ static int virtio_set_features_nocheck(VirtIODevice *vdev, const uint64_t *val)
     bad = virtio_features_andnot(tmp, val, vdev->host_features_ex);
     virtio_features_and(tmp, val, vdev->host_features_ex);
 
-    if (k->set_features) {
+    if (k->set_features_ex) {
+        k->set_features_ex(vdev, val);
+    } else if (k->set_features) {
         bad = bad || virtio_features_use_ex(tmp);
         k->set_features(vdev, tmp[0]);
     }
@@ -3149,6 +3151,13 @@ virtio_set_features_nocheck_maybe_co(VirtIODevice *vdev,
 int virtio_set_features(VirtIODevice *vdev, uint64_t val)
 {
     uint64_t features[VIRTIO_FEATURES_NU64S];
+
+    virtio_features_from_u64(features, val);
+    return virtio_set_features_ex(vdev, features);
+}
+
+int virtio_set_features_ex(VirtIODevice *vdev, const uint64_t *features)
+{
     int ret;
     /*
      * The driver must not attempt to set features after feature negotiation
@@ -3158,13 +3167,12 @@ int virtio_set_features(VirtIODevice *vdev, uint64_t val)
         return -EINVAL;
     }
 
-    if (val & (1ull << VIRTIO_F_BAD_FEATURE)) {
+    if (features[0] & (1ull << VIRTIO_F_BAD_FEATURE)) {
         qemu_log_mask(LOG_GUEST_ERROR,
                       "%s: guest driver for %s has enabled UNUSED(30) feature bit!\n",
                       __func__, vdev->name);
     }
 
-    virtio_features_from_u64(features, val);
     ret = virtio_set_features_nocheck(vdev, features);
     if (virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) {
         /* VIRTIO_RING_F_EVENT_IDX changes the size of the caches.  */
diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
index 39e4059a66..2aeb021fb3 100644
--- a/include/hw/virtio/virtio.h
+++ b/include/hw/virtio/virtio.h
@@ -178,6 +178,9 @@ struct VirtioDeviceClass {
     /* This is what a VirtioDevice must implement */
     DeviceRealize realize;
     DeviceUnrealize unrealize;
+    void (*get_features_ex)(VirtIODevice *vdev, uint64_t *requested_features,
+                            Error **errp);
+    void (*set_features_ex)(VirtIODevice *vdev, const uint64_t *val);
     uint64_t (*get_features)(VirtIODevice *vdev,
                              uint64_t requested_features,
                              Error **errp);
@@ -373,6 +376,7 @@ void virtio_queue_reset(VirtIODevice *vdev, uint32_t queue_index);
 void virtio_queue_enable(VirtIODevice *vdev, uint32_t queue_index);
 void virtio_update_irq(VirtIODevice *vdev);
 int virtio_set_features(VirtIODevice *vdev, uint64_t val);
+int virtio_set_features_ex(VirtIODevice *vdev, const uint64_t *val);
 
 /* Base devices.  */
 typedef struct VirtIOBlkConf VirtIOBlkConf;