[dpdk-dev] [PATCH v3 4/4] net/virtio: enable feature checking on virtio-user

[Adrian Moreno <amorenoz@redhat.com>]

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 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>
---
 drivers/net/virtio/virtio_ethdev.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c
index dc0093bdf..9063bfeb2 100644
--- a/drivers/net/virtio/virtio_ethdev.c
+++ b/drivers/net/virtio/virtio_ethdev.c
@@ -1355,12 +1355,13 @@ 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,
-- 
2.26.2