chore(pci): gracefully handle errors in the PCI restore code

All errors were previously unwrapped, differently from MMIO where they
were handled. Refactor the code to handle the errors in the same way as
MMIO.

Signed-off-by: Riccardo Mancini <mancio@amazon.com>

Author: Manciukic

src/vmm/src/builder.rs

@@ -26,7 +26,7 @@ use crate::cpu_config::templates::{GetCpuTemplate, GetCpuTemplateError, GuestCon
 use crate::device_manager;
 use crate::device_manager::pci_mngr::PciManagerError;
 use crate::device_manager::{
-    AttachDeviceError, DeviceManager, DeviceManagerCreateError, DevicePersistError,
+    AttachDeviceError, DeviceManager, DeviceManagerCreateError, DeviceManagerPersistError,
     DeviceRestoreArgs,
 };
 use crate::devices::virtio::balloon::Balloon;
@@ -424,7 +424,7 @@ pub enum BuildMicrovmFromSnapshotError {
     /// Failed to apply VMM secccomp filter: {0}
     SeccompFiltersInternal(#[from] crate::seccomp::InstallationError),
     /// Failed to restore devices: {0}
-    RestoreDevices(#[from] DevicePersistError),
+    RestoreDevices(#[from] DeviceManagerPersistError),
 }
 
 /// Builds and starts a microVM based on the provided MicrovmState.

src/vmm/src/device_manager/mod.rs

@@ -31,11 +31,20 @@ use crate::devices::legacy::RTCDevice;
 use crate::devices::legacy::serial::SerialOut;
 use crate::devices::legacy::{IER_RDA_BIT, IER_RDA_OFFSET, SerialDevice};
 use crate::devices::pseudo::BootTimer;
+use crate::devices::virtio::ActivateError;
+use crate::devices::virtio::balloon::BalloonError;
+use crate::devices::virtio::block::BlockError;
 use crate::devices::virtio::device::{VirtioDevice, VirtioDeviceType};
+use crate::devices::virtio::mem::persist::VirtioMemPersistError;
+use crate::devices::virtio::net::persist::NetPersistError;
+use crate::devices::virtio::pmem::persist::PmemPersistError;
+use crate::devices::virtio::rng::persist::EntropyPersistError;
 use crate::devices::virtio::transport::mmio::{IrqTrigger, MmioTransport};
+use crate::devices::virtio::vsock::{VsockError, VsockUnixBackendError};
 use crate::resources::VmResources;
 use crate::snapshot::Persist;
 use crate::utils::open_file_nonblock;
+use crate::vmm_config::mmds::MmdsConfigError;
 use crate::vstate::bus::BusError;
 use crate::vstate::memory::GuestMemoryMmap;
 use crate::{EmulateSerialInitError, EventManager, Vm};
@@ -406,14 +415,51 @@ pub struct DevicesState {
     pub pci_state: pci_mngr::PciDevicesState,
 }
 
+/// Errors for (de)serialization of the devices.
 #[derive(Debug, thiserror::Error, displaydoc::Display)]
 pub enum DevicePersistError {
+    /// Balloon: {0}
+    Balloon(#[from] BalloonError),
+    /// Block: {0}
+    Block(#[from] BlockError),
+    /// MMIO Device manager: {0}
+    MmioDeviceManager(#[from] mmio::MmioError),
+    /// Mmio transport
+    MmioTransport,
+    /// PCI Device manager: {0}
+    PciDeviceManager(#[from] PciManagerError),
+    /// Bus error: {0}
+    Bus(#[from] BusError),
+    #[cfg(target_arch = "aarch64")]
+    /// Legacy: {0}
+    Legacy(#[from] std::io::Error),
+    /// Net: {0}
+    Net(#[from] NetPersistError),
+    /// Vsock: {0}
+    Vsock(#[from] VsockError),
+    /// VsockUnixBackend: {0}
+    VsockUnixBackend(#[from] VsockUnixBackendError),
+    /// MmdsConfig: {0}
+    MmdsConfig(#[from] MmdsConfigError),
+    /// Entropy: {0}
+    Entropy(#[from] EntropyPersistError),
+    /// Pmem: {0}
+    Pmem(#[from] PmemPersistError),
+    /// virtio-mem: {0}
+    VirtioMem(#[from] VirtioMemPersistError),
+    /// Could not activate device: {0}
+    DeviceActivation(#[from] ActivateError),
+}
+
+/// Errors for (de)serialization of the device manager.
+#[derive(Debug, thiserror::Error, displaydoc::Display)]
+pub enum DeviceManagerPersistError {
     /// Error restoring MMIO devices: {0}
-    MmioRestore(#[from] persist::DevicePersistError),
+    MmioRestore(DevicePersistError),
     /// Error restoring ACPI devices: {0}
     AcpiRestore(#[from] ACPIDeviceError),
     /// Error restoring PCI devices: {0}
-    PciRestore(#[from] PciManagerError),
+    PciRestore(DevicePersistError),
     /// Error resetting serial console: {0}
     SerialRestore(#[from] EmulateSerialInitError),
     /// Error inserting device in bus: {0}
@@ -445,7 +491,7 @@ impl std::fmt::Debug for DeviceRestoreArgs<'_> {
 impl<'a> Persist<'a> for DeviceManager {
     type State = DevicesState;
     type ConstructorArgs = DeviceRestoreArgs<'a>;
-    type Error = DevicePersistError;
+    type Error = DeviceManagerPersistError;
 
     fn save(&self) -> Self::State {
         DevicesState {
@@ -476,7 +522,8 @@ impl<'a> Persist<'a> for DeviceManager {
             vm_resources: constructor_args.vm_resources,
             instance_id: constructor_args.instance_id,
         };
-        let mmio_devices = MMIODeviceManager::restore(mmio_ctor_args, &state.mmio_state)?;
+        let mmio_devices = MMIODeviceManager::restore(mmio_ctor_args, &state.mmio_state)
+            .map_err(DeviceManagerPersistError::MmioRestore)?;
 
         // Restore ACPI devices
         let acpi_devices = ACPIDeviceManager::restore(constructor_args.vm, &state.acpi_state)?;
@@ -489,7 +536,8 @@ impl<'a> Persist<'a> for DeviceManager {
             instance_id: constructor_args.instance_id,
             event_manager: constructor_args.event_manager,
         };
-        let pci_devices = PciDevices::restore(pci_ctor_args, &state.pci_state)?;
+        let pci_devices = PciDevices::restore(pci_ctor_args, &state.pci_state)
+            .map_err(DeviceManagerPersistError::PciRestore)?;
 
         let device_manager = DeviceManager {
             mmio_devices,