vmm: Include device tree in vm.info API

The DeviceNode cannot be fully represented as it embeds a Rust style
enum (i.e. with data) which is instead represented by a simple
associative array.

Fixes: #1167

Signed-off-by: Rob Bradford <robert.bradford@intel.com>

vmm/src/api/mod.rs

@@ -39,6 +39,7 @@ pub mod http_endpoint;
 use crate::config::{
     DeviceConfig, DiskConfig, FsConfig, NetConfig, PmemConfig, RestoreConfig, VmConfig, VsockConfig,
 };
+use crate::device_tree::DeviceTree;
 use crate::vm::{Error as VmError, VmState};
 use micro_http::Body;
 use std::io;
@@ -153,6 +154,7 @@ pub struct VmInfo {
     pub config: Arc<Mutex<VmConfig>>,
     pub state: VmState,
     pub memory_actual_size: u64,
+    pub device_tree: Option<Arc<Mutex<DeviceTree>>>,
 }
 
 #[derive(Clone, Deserialize, Serialize)]

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

@@ -363,8 +363,30 @@ components:
         memory_actual_size:
           type: integer
           format: int64
+        device_tree:
+          type: object
+          additionalProperties:
+            $ref: '#/components/schemas/DeviceNode'
       description: Virtual Machine information
 
+    DeviceNode:
+      type: object
+      properties:
+        id:
+          type: string
+        resources:
+          type: array
+          items:
+            # Rust enum type (with data) which can't be better represented here
+            type: object
+        children:
+          type: array
+          items:
+            type: string
+        pci_bdf:
+          type: integer
+          format: int32
+        
     VmCounters:
       type: object
       additionalProperties:

vmm/src/device_manager.rs

@@ -3134,6 +3134,10 @@ impl DeviceManager {
 
         0
     }
+
+    pub fn device_tree(&self) -> Arc<Mutex<DeviceTree>> {
+        self.device_tree.clone()
+    }
 }
 
 #[cfg(feature = "acpi")]

vmm/src/lib.rs

@@ -484,10 +484,13 @@ impl Vmm {
                     memory_actual_size -= vm.balloon_size();
                 }
 
+                let device_tree = self.vm.as_ref().map(|vm| vm.device_tree());
+
                 Ok(VmInfo {
                     config,
                     state,
                     memory_actual_size,
+                    device_tree,
                 })
             }
             None => Err(VmError::VmNotCreated),

vmm/src/vm.rs

@@ -30,6 +30,7 @@ use crate::config::{
 };
 use crate::cpu;
 use crate::device_manager::{self, get_win_size, Console, DeviceManager, DeviceManagerError};
+use crate::device_tree::DeviceTree;
 use crate::memory_manager::{Error as MemoryManagerError, MemoryManager};
 use crate::migration::{get_vm_snapshot, url_to_path, VM_SNAPSHOT_FILE};
 use crate::seccomp_filters::{get_seccomp_filter, Thread};
@@ -1717,6 +1718,10 @@ impl Vm {
             .unwrap()
             .dirty_memory_range_table()
     }
+
+    pub fn device_tree(&self) -> Arc<Mutex<DeviceTree>> {
+        self.device_manager.lock().unwrap().device_tree()
+    }
 }
 
 impl Pausable for Vm {