vmm: Add the 'shared' and 'hugepages' controls to MemoryConfig

The new 'shared' and 'hugepages' controls aim to replace the 'file'
option in MemoryConfig. This patch also updated all related integration
tests to use the new controls (instead of providing explicit paths to
"/dev/shm" or "/dev/hugepages").

Fixes: #1011

Signed-off-by: Rob Bradford <robert.bradford@intel.com>
Signed-off-by: Bo Chen <chen.bo@intel.com>

vmm/src/config.rs

@@ -438,6 +438,10 @@ pub struct MemoryConfig {
     pub hotplug_method: HotplugMethod,
     #[serde(default)]
     pub hotplug_size: Option<u64>,
+    #[serde(default)]
+    pub shared: bool,
+    #[serde(default)]
+    pub hugepages: bool,
 }
 
 impl MemoryConfig {
@@ -448,7 +452,9 @@ impl MemoryConfig {
             .add("file")
             .add("mergeable")
             .add("hotplug_method")
-            .add("hotplug_size");
+            .add("hotplug_size")
+            .add("shared")
+            .add("hugepages");
         parser.parse(memory).map_err(Error::ParseMemory)?;
 
         let size = parser
@@ -470,6 +476,16 @@ impl MemoryConfig {
             .convert::<ByteSized>("hotplug_size")
             .map_err(Error::ParseMemory)?
             .map(|v| v.0);
+        let shared = parser
+            .convert::<Toggle>("shared")
+            .map_err(Error::ParseMemory)?
+            .unwrap_or(Toggle(false))
+            .0;
+        let hugepages = parser
+            .convert::<Toggle>("hugepages")
+            .map_err(Error::ParseMemory)?
+            .unwrap_or(Toggle(false))
+            .0;
 
         Ok(MemoryConfig {
             size,
@@ -477,6 +493,8 @@ impl MemoryConfig {
             mergeable,
             hotplug_method,
             hotplug_size,
+            shared,
+            hugepages,
         })
     }
 }
@@ -489,6 +507,8 @@ impl Default for MemoryConfig {
             mergeable: false,
             hotplug_method: HotplugMethod::Acpi,
             hotplug_size: None,
+            shared: false,
+            hugepages: false,
         }
     }
 }
@@ -1223,6 +1243,10 @@ impl VmConfig {
             return Err(ValidationError::CpusMaxLowerThanBoot);
         }
 
+        if self.memory.file.is_some() {
+            error!("Use of backing file ('--memory file=') is deprecated. Use the 'shared' and 'hugepages' controls.");
+        }
+
         if let Some(disks) = &self.disks {
             for disk in disks {
                 if disk.vhost_socket.as_ref().and(disk.path.as_ref()).is_some() {
@@ -1869,6 +1893,8 @@ mod tests {
                 mergeable: false,
                 hotplug_method: HotplugMethod::Acpi,
                 hotplug_size: None,
+                shared: false,
+                hugepages: false,
             },
             kernel: Some(KernelConfig {
                 path: PathBuf::from("/path/to/kernel"),