net/virtio-user: enable feature checking

virtio 1.0 introduced a mechanism for the driver to verify that the
feature bits it sets are accepted by the device. This mechanism consists
in setting the VIRTIO_STATUS_FEATURE_OK status bit and re-reading it,
which gives a chance for the device to clear it if the features
were not accepted.

This is currently being done only in modern virtio-pci devices but since
the appropriate vhost-user messages have been added, it can also be done
in virtio-user (vhost-user only).

This patch activates this mechanism on virtio-user.

Reviewed-by: Chenbo Xia <chenbo.xia@intel.com>
Signed-off-by: Adrian Moreno <amorenoz@redhat.com>

diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c
index dac0f23..013a290 100644 (file)
--- a/drivers/net/virtio/virtio_ethdev.c
+++ b/drivers/net/virtio/virtio_ethdev.c
@@ -1354,12 +1354,13 @@ virtio_negotiate_features(struct virtio_hw *hw, uint64_t req_features)
        PMD_INIT_LOG(DEBUG, "features after negotiate = %" PRIx64,
                hw->guest_features);
 
-       if (hw->modern) {
-               if (!vtpci_with_feature(hw, VIRTIO_F_VERSION_1)) {
-                       PMD_INIT_LOG(ERR,
-                               "VIRTIO_F_VERSION_1 features is not enabled.");
-                       return -1;
-               }
+       if (hw->modern && !vtpci_with_feature(hw, VIRTIO_F_VERSION_1)) {
+               PMD_INIT_LOG(ERR,
+                       "VIRTIO_F_VERSION_1 features is not enabled.");
+               return -1;
+       }
+
+       if (hw->modern || hw->virtio_user_dev) {
                vtpci_set_status(hw, VIRTIO_CONFIG_STATUS_FEATURES_OK);
                if (!(vtpci_get_status(hw) & VIRTIO_CONFIG_STATUS_FEATURES_OK)) {
                        PMD_INIT_LOG(ERR,