vmm: Add iommu parameter to VdpaConfig

Add a new iommu parameter to VdpaConfig in order to place the vDPA
device behind a virtual IOMMU.

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

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

@@ -965,6 +965,9 @@ components:
         num_queues:
           type: integer
           default: 1
+        iommu:
+          type: boolean
+          default: false
         pci_segment:
           type: integer
           format: int16

vmm/src/config.rs

@@ -1964,6 +1964,8 @@ pub struct VdpaConfig {
     #[serde(default = "default_vdpaconfig_num_queues")]
     pub num_queues: usize,
     #[serde(default)]
+    pub iommu: bool,
+    #[serde(default)]
     pub id: Option<String>,
     #[serde(default)]
     pub pci_segment: u16,
@@ -1982,6 +1984,7 @@ impl VdpaConfig {
         parser
             .add("path")
             .add("num_queues")
+            .add("iommu")
             .add("id")
             .add("pci_segment");
         parser.parse(vdpa).map_err(Error::ParseVdpa)?;
@@ -1994,6 +1997,11 @@ impl VdpaConfig {
             .convert("num_queues")
             .map_err(Error::ParseVdpa)?
             .unwrap_or_else(default_vdpaconfig_num_queues);
+        let iommu = parser
+            .convert::<Toggle>("iommu")
+            .map_err(Error::ParseVdpa)?
+            .unwrap_or(Toggle(false))
+            .0;
         let id = parser.get("id");
         let pci_segment = parser
             .convert("pci_segment")
@@ -2003,6 +2011,7 @@ impl VdpaConfig {
         Ok(VdpaConfig {
             path,
             num_queues,
+            iommu,
             id,
             pci_segment,
         })
@@ -2015,8 +2024,8 @@ impl VdpaConfig {
             }
 
             if let Some(iommu_segments) = platform_config.iommu_segments.as_ref() {
-                if iommu_segments.contains(&self.pci_segment) {
-                    return Err(ValidationError::IommuNotSupported(self.pci_segment));
+                if iommu_segments.contains(&self.pci_segment) && !self.iommu {
+                    return Err(ValidationError::OnIommuSegment(self.pci_segment));
                 }
             }
         }
@@ -2566,6 +2575,9 @@ impl VmConfig {
             let mut vdpa_config_list = Vec::new();
             for item in vdpa_list.iter() {
                 let vdpa_config = VdpaConfig::parse(item)?;
+                if vdpa_config.iommu {
+                    iommu = true;
+                }
                 vdpa_config_list.push(vdpa_config);
             }
             vdpa = Some(vdpa_config_list);
@@ -3656,7 +3668,7 @@ mod tests {
         }]);
         assert_eq!(
             invalid_config.validate(),
-            Err(ValidationError::IommuNotSupported(1))
+            Err(ValidationError::OnIommuSegment(1))
         );
 
         let mut invalid_config = valid_config;

vmm/src/device_manager.rs

@@ -2947,7 +2947,7 @@ impl DeviceManager {
 
         Ok(MetaVirtioDevice {
             virtio_device: vdpa_device as Arc<Mutex<dyn virtio_devices::VirtioDevice>>,
-            iommu: false,
+            iommu: vdpa_cfg.iommu,
             id,
             pci_segment: vdpa_cfg.pci_segment,
             dma_handler: Some(vdpa_mapping),
@@ -4010,6 +4010,10 @@ impl DeviceManager {
     }
 
     pub fn add_vdpa(&mut self, vdpa_cfg: &mut VdpaConfig) -> DeviceManagerResult<PciDeviceInfo> {
+        if vdpa_cfg.iommu && !self.is_iommu_segment(vdpa_cfg.pci_segment) {
+            return Err(DeviceManagerError::InvalidIommuHotplug);
+        }
+
         let device = self.make_vdpa_device(vdpa_cfg)?;
         self.hotplug_virtio_pci_device(device)
     }