From: Viresh Kumar <viresh.kumar@linaro.org>

VIRTIO_I2C_F_ZERO_LENGTH_REQUEST is a mandatory feature, that must be
implemented by everyone. Add its support.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Message-Id: <fc47ab63b1cd414319c9201e8d6c7705b5ec3bd9.1644490993.git.viresh.kumar@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 include/hw/virtio/vhost-user-i2c.h |  3 +++
 hw/virtio/vhost-user-i2c.c         | 11 +++++++++--
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/include/hw/virtio/vhost-user-i2c.h b/include/hw/virtio/vhost-user-i2c.h
index deae47a76d..d8372f3b43 100644
--- a/include/hw/virtio/vhost-user-i2c.h
+++ b/include/hw/virtio/vhost-user-i2c.h
@@ -25,4 +25,7 @@ struct VHostUserI2C {
     bool connected;
 };
 
+/* Virtio Feature bits */
+#define VIRTIO_I2C_F_ZERO_LENGTH_REQUEST		0
+
 #endif /* _QEMU_VHOST_USER_I2C_H */
diff --git a/hw/virtio/vhost-user-i2c.c b/hw/virtio/vhost-user-i2c.c
index d172632bb0..42c7f6d9e5 100644
--- a/hw/virtio/vhost-user-i2c.c
+++ b/hw/virtio/vhost-user-i2c.c
@@ -19,6 +19,11 @@
 #define VIRTIO_ID_I2C_ADAPTER                34
 #endif
 
+static const int feature_bits[] = {
+    VIRTIO_I2C_F_ZERO_LENGTH_REQUEST,
+    VHOST_INVALID_FEATURE_BIT
+};
+
 static void vu_i2c_start(VirtIODevice *vdev)
 {
     BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
@@ -113,8 +118,10 @@ static void vu_i2c_set_status(VirtIODevice *vdev, uint8_t status)
 static uint64_t vu_i2c_get_features(VirtIODevice *vdev,
                                     uint64_t requested_features, Error **errp)
 {
-    /* No feature bits used yet */
-    return requested_features;
+    VHostUserI2C *i2c = VHOST_USER_I2C(vdev);
+
+    virtio_add_feature(&requested_features, VIRTIO_I2C_F_ZERO_LENGTH_REQUEST);
+    return vhost_get_features(&i2c->vhost_dev, feature_bits, requested_features);
 }
 
 static void vu_i2c_handle_output(VirtIODevice *vdev, VirtQueue *vq)
-- 
MST