[dpdk-dev] [RFC] vhost: support raising device error

[Xueming Li <xuemingl@nvidia.com>]

According to virtio spec, The device SHOULD set DEVICE_NEEDS_RESET when
it enters an error state that a reset is needed. If DRIVER_OK is set,
after it sets DEVICE_NEEDS_RESET, the device MUST send a device
configuration change notification to the driver.

This patch introduces new api to raise vDPA hardware error and escalates
configuration change to vhost via client message
VHOST_USER_SLAVE_CONFIG_CHANGE_MSG.

The vhost should check DRIVER_OK and decide whether to notify driver.

Signed-off-by: Xueming Li <xuemingl@nvidia.com>
---
 lib/librte_vhost/rte_vdpa_dev.h | 12 ++++++++++++
 lib/librte_vhost/version.map    |  1 +
 lib/librte_vhost/vhost_user.c   | 14 ++++++++++++++
 3 files changed, 27 insertions(+)

diff --git a/lib/librte_vhost/rte_vdpa_dev.h b/lib/librte_vhost/rte_vdpa_dev.h
index a60183f780..87b7397c6f 100644
--- a/lib/librte_vhost/rte_vdpa_dev.h
+++ b/lib/librte_vhost/rte_vdpa_dev.h
@@ -117,6 +117,18 @@ rte_vdpa_unregister_device(struct rte_vdpa_device *dev);
 int
 rte_vhost_host_notifier_ctrl(int vid, uint16_t qid, bool enable);
 
+/**
+ * Set device hardware error and notify host.
+ *
+ * @param vid
+ *  vhost device id
+ * @return
+ *  0 on success, -1 on failure
+ */
+__rte_experimental
+int
+rte_vhost_host_raise_error(int vid);
+
 /**
  * Synchronize the used ring from mediated ring to guest, log dirty
  * page for each writeable buffer, caller should handle the used
diff --git a/lib/librte_vhost/version.map b/lib/librte_vhost/version.map
index 9183d6f2fc..5a4c5dc818 100644
--- a/lib/librte_vhost/version.map
+++ b/lib/librte_vhost/version.map
@@ -76,4 +76,5 @@ EXPERIMENTAL {
 	rte_vhost_async_channel_unregister;
 	rte_vhost_submit_enqueue_burst;
 	rte_vhost_poll_enqueue_completed;
+	rte_vhost_host_raise_error;
 };
diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
index d20c8c57ad..d8353176f2 100644
--- a/lib/librte_vhost/vhost_user.c
+++ b/lib/librte_vhost/vhost_user.c
@@ -2992,6 +2992,20 @@ rte_vhost_slave_config_change(int vid, bool need_reply)
 	return vhost_user_slave_config_change(dev, need_reply);
 }
 
+int
+rte_vhost_host_raise_error(int vid)
+{
+	struct virtio_net *dev;
+
+	dev = get_device(vid);
+	if (!dev)
+		return -ENODEV;
+
+	dev->status |= VIRTIO_DEVICE_STATUS_DEV_NEED_RESET;
+
+	return vhost_user_slave_config_change(dev, 0);
+}
+
 static int vhost_user_slave_set_vring_host_notifier(struct virtio_net *dev,
 						    int index, int fd,
 						    uint64_t offset,
-- 
2.25.1