vmm: api: Match VhostUserNetConfig defaults between CLI and HTTP API

In order to let the CLI and the HTTP API behave the same regarding the
VhostUserNetConfig structure, this patch defines some default values
for num_queues, queue_size and mac.

num_queues is 2 since that's a pair of TX/RX queues, queue_size is 256
and mac is a randomly generated value.

Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>

vmm/src/api/openapi/cloud-hypervisor.yaml

@@ -375,17 +375,16 @@ components:
     VhostUserNetConfig:
       required:
       - sock
-      - num_queues
-      - queue_size
-      - mac
       type: object
       properties:
         sock:
           type: string
         num_queues:
           type: integer
+          default: 2
         queue_size:
           type: integer
+          default: 256
         mac:
           type: string
 

vmm/src/config.rs

@@ -15,6 +15,8 @@ use std::result;
 pub const DEFAULT_VCPUS: u8 = 1;
 pub const DEFAULT_MEMORY_MB: u64 = 512;
 pub const DEFAULT_RNG_SOURCE: &str = "/dev/urandom";
+pub const DEFAULT_NUM_QUEUES_VUNET: usize = 2;
+pub const DEFAULT_QUEUE_SIZE_VUNET: u16 = 256;
 
 /// Errors associated with VM configuration parameters.
 #[derive(Debug)]
@@ -696,11 +698,26 @@ impl DeviceConfig {
 #[derive(Clone, Debug, Deserialize, Serialize)]
 pub struct VhostUserNetConfig {
     pub sock: String,
+    #[serde(default = "default_vunetconfig_num_queues")]
     pub num_queues: usize,
+    #[serde(default = "default_vunetconfig_queue_size")]
     pub queue_size: u16,
+    #[serde(default = "default_vunetconfig_mac")]
     pub mac: MacAddr,
 }
 
+fn default_vunetconfig_num_queues() -> usize {
+    DEFAULT_NUM_QUEUES_VUNET
+}
+
+fn default_vunetconfig_queue_size() -> u16 {
+    DEFAULT_QUEUE_SIZE_VUNET
+}
+
+fn default_vunetconfig_mac() -> MacAddr {
+    MacAddr::local_random()
+}
+
 impl VhostUserNetConfig {
     pub fn parse(vhost_user_net: &str) -> Result<Self> {
         // Split the parameters based on the comma delimiter
@@ -723,9 +740,9 @@ impl VhostUserNetConfig {
             }
         }
 
-        let mut mac: MacAddr = MacAddr::local_random();
-        let mut num_queues: usize = 2;
-        let mut queue_size: u16 = 256;
+        let mut mac: MacAddr = default_vunetconfig_mac();
+        let mut num_queues: usize = default_vunetconfig_num_queues();
+        let mut queue_size: u16 = default_vunetconfig_queue_size();
 
         if !mac_str.is_empty() {
             mac = MacAddr::parse_str(mac_str).map_err(Error::ParseVuNetMacParam)?;