pci: msi: Move MsiConfig to the new restore design

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

pci/src/msi.rs

@@ -39,13 +39,15 @@ pub fn msi_num_enabled_vectors(msg_ctl: u16) -> usize {
 }
 
 #[derive(Error, Debug)]
-enum Error {
+pub enum Error {
     #[error("Failed enabling the interrupt route: {0}")]
     EnableInterruptRoute(io::Error),
     #[error("Failed updating the interrupt route: {0}")]
     UpdateInterruptRoute(io::Error),
 }
 
+pub const MSI_CONFIG_ID: &str = "msi_config";
+
 #[derive(Clone, Copy, Default, Versionize)]
 pub struct MsiCap {
     // Message Control Register
@@ -172,7 +174,7 @@ impl MsiCap {
 }
 
 #[derive(Versionize)]
-struct MsiConfigState {
+pub struct MsiConfigState {
     cap: MsiCap,
 }
 
@@ -184,16 +186,47 @@ pub struct MsiConfig {
 }
 
 impl MsiConfig {
-    pub fn new(msg_ctl: u16, interrupt_source_group: Arc<dyn InterruptSourceGroup>) -> Self {
-        let cap = MsiCap {
-            msg_ctl,
-            ..Default::default()
+    pub fn new(
+        msg_ctl: u16,
+        interrupt_source_group: Arc<dyn InterruptSourceGroup>,
+        state: Option<MsiConfigState>,
+    ) -> Result<Self, Error> {
+        let cap = if let Some(state) = state {
+            if state.cap.enabled() {
+                for idx in 0..state.cap.num_enabled_vectors() {
+                    let config = MsiIrqSourceConfig {
+                        high_addr: state.cap.msg_addr_hi,
+                        low_addr: state.cap.msg_addr_lo,
+                        data: state.cap.msg_data as u32,
+                        devid: 0,
+                    };
+
+                    interrupt_source_group
+                        .update(
+                            idx as InterruptIndex,
+                            InterruptSourceConfig::MsiIrq(config),
+                            state.cap.vector_masked(idx),
+                        )
+                        .map_err(Error::UpdateInterruptRoute)?;
+                }
+
+                interrupt_source_group
+                    .enable()
+                    .map_err(Error::EnableInterruptRoute)?;
+            }
+
+            state.cap
+        } else {
+            MsiCap {
+                msg_ctl,
+                ..Default::default()
+            }
         };
 
-        MsiConfig {
+        Ok(MsiConfig {
             cap,
             interrupt_source_group,
-        }
+        })
     }
 
     fn state(&self) -> MsiConfigState {
@@ -281,7 +314,7 @@ impl Pausable for MsiConfig {}
 
 impl Snapshottable for MsiConfig {
     fn id(&self) -> String {
-        String::from("msi_config")
+        String::from(MSI_CONFIG_ID)
     }
 
     fn snapshot(&mut self) -> std::result::Result<Snapshot, MigratableError> {

pci/src/vfio.rs

@@ -735,7 +735,7 @@ impl VfioCommon {
             })
             .unwrap();
 
-        let msi_config = MsiConfig::new(msg_ctl, interrupt_source_group.clone());
+        let msi_config = MsiConfig::new(msg_ctl, interrupt_source_group.clone(), None).unwrap();
 
         self.interrupt.msi = Some(VfioMsi {
             cfg: msi_config,