vmm: Add iommu=on|off option for --pmem

Having the virtual IOMMU created with --iommu is one thing, but we also
need a way to decide if a virtio-pmem device should be attached to this
virtual IOMMU or not. That's why we introduce an extra option "iommu"
with the value "on" or "off". By default, the device is not attached,
which means "iommu=off".

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

src/main.rs

@@ -171,7 +171,7 @@ fn main() {
                 .long("pmem")
                 .help(
                     "Persistent memory parameters \"file=<backing_file_path>,\
-                     size=<persistent_memory_size>\"",
+                     size=<persistent_memory_size>,iommu=on|off\"",
                 )
                 .takes_value(true)
                 .min_values(1)

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

@@ -289,6 +289,9 @@ components:
           type: string
         size:
           type: integer
+        iommu:
+          type: boolean
+          default: false
 
     ConsoleConfig:
       required:

vmm/src/config.rs

@@ -448,6 +448,8 @@ impl FsConfig {
 pub struct PmemConfig {
     pub file: PathBuf,
     pub size: u64,
+    #[serde(default)]
+    pub iommu: bool,
 }
 
 impl PmemConfig {
@@ -457,12 +459,15 @@ impl PmemConfig {
 
         let mut file_str: &str = "";
         let mut size_str: &str = "";
+        let mut iommu_str: &str = "";
 
         for param in params_list.iter() {
             if param.starts_with("file=") {
                 file_str = &param[5..];
             } else if param.starts_with("size=") {
                 size_str = &param[5..];
+            } else if param.starts_with("iommu=") {
+                iommu_str = &param[6..];
             }
         }
 
@@ -473,6 +478,7 @@ impl PmemConfig {
         Ok(PmemConfig {
             file: PathBuf::from(file_str),
             size: parse_size(size_str)?,
+            iommu: parse_iommu(iommu_str)?,
         })
     }
 }
@@ -788,7 +794,11 @@ impl VmConfig {
         if let Some(pmem_list) = &vm_params.pmem {
             let mut pmem_config_list = Vec::new();
             for item in pmem_list.iter() {
-                pmem_config_list.push(PmemConfig::parse(item)?);
+                let pmem_config = PmemConfig::parse(item)?;
+                if pmem_config.iommu {
+                    iommu = true;
+                }
+                pmem_config_list.push(pmem_config);
             }
             pmem = Some(pmem_config_list);
         }