From 08604ac6a8b92643a77bc33abfd88dbb60d42cd8 Mon Sep 17 00:00:00 2001
From: Sebastien Boeuf <sebastien.boeuf@intel.com>
Date: Fri, 6 Mar 2020 14:18:07 +0100
Subject: [PATCH] vmm: Store PCI devices as Any devices from DeviceManager

As we try to keep track of every PCI device related to the VM, we don't
want to have separate lists depending on the concrete type associated
with the PciDevice trait. Also, we want to be able to cast the actual
type into any trait or concrete type.

The most efficient way to solve all these issues is to store every
device as an Arc<dyn Any + Send + Sync>. This gives the ability to
downcast into the appropriate concrete type, and then to cast back into
any trait that we might need.

Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
---
 vmm/src/device_manager.rs | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/vmm/src/device_manager.rs b/vmm/src/device_manager.rs
index f7e330fe3..e8bb07a6b 100644
--- a/vmm/src/device_manager.rs
+++ b/vmm/src/device_manager.rs
@@ -33,6 +33,8 @@ use pci::{
     DeviceRelocation, PciBarRegionType, PciBus, PciConfigIo, PciConfigMmio, PciDevice, PciRoot,
 };
 use qcow::{self, ImageType, QcowFile};
+#[cfg(feature = "pci_support")]
+use std::any::Any;
 use std::collections::HashMap;
 use std::fs::{File, OpenOptions};
 use std::io::{self, sink, stdout};
@@ -479,6 +481,10 @@ pub struct DeviceManager {
     // Counter to keep track of the consumed device IDs.
     #[cfg(feature = "pci_support")]
     device_id_cnt: Wrapping<usize>,
+
+    // Hashmap of PCI b/d/f to their corresponding Arc<Mutex<dyn PciDevice>>.
+    #[cfg(feature = "pci_support")]
+    pci_devices: HashMap<u32, Arc<dyn Any + Send + Sync>>,
 }
 
 impl DeviceManager {
@@ -582,6 +588,8 @@ impl DeviceManager {
             pci_id_list: HashMap::new(),
             #[cfg(feature = "pci_support")]
             device_id_cnt: Wrapping(0),
+            #[cfg(feature = "pci_support")]
+            pci_devices: HashMap::new(),
         };
 
         device_manager
@@ -1494,6 +1502,10 @@ impl DeviceManager {
         pci.add_device(vfio_pci_device.clone())
             .map_err(DeviceManagerError::AddPciDevice)?;
 
+        self.pci_devices.insert(
+            pci_device_bdf,
+            Arc::clone(&vfio_pci_device) as Arc<dyn Any + Send + Sync>,
+        );
         self.bus_devices
             .push(Arc::clone(&vfio_pci_device) as Arc<Mutex<dyn BusDevice>>);