From c8c3cad8cb790d253f6d9f2fb53bb16f8155e081 Mon Sep 17 00:00:00 2001
From: Sebastien Boeuf <sebastien.boeuf@intel.com>
Date: Wed, 17 Mar 2021 18:45:57 +0100
Subject: [PATCH] vmm: device_manager: Update structure holding PCI IRQs

Make the code a bit clearer by changing the naming of the structure
holding the list of IRQs reserved for PCI devices. It is also modified
into an array of 32 entries since we know this is the amount of PCI
slots that is supported.

Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
---
 vmm/src/device_manager.rs | 27 +++++++++++++--------------
 1 file changed, 13 insertions(+), 14 deletions(-)

diff --git a/vmm/src/device_manager.rs b/vmm/src/device_manager.rs
index eace4798e..628f9edcd 100644
--- a/vmm/src/device_manager.rs
+++ b/vmm/src/device_manager.rs
@@ -903,8 +903,8 @@ pub struct DeviceManager {
     // BTreeMap of PCI b/d/f to their corresponding MetaPciDevice.
     pci_devices: BTreeMap<u32, (String, PciDeviceHandle)>,
 
-    // BTreeMap of PCI b/d/f to their allocated IRQ.
-    pci_device_irqs: BTreeMap<u32, u32>,
+    // List of allocated IRQs for each PCI slot.
+    pci_irq_slots: [u8; 32],
 
     // Tree of devices, representing the dependencies between devices.
     // Useful for introspection, snapshot and restore.
@@ -1008,7 +1008,7 @@ impl DeviceManager {
             pci_devices_up: 0,
             pci_devices_down: 0,
             pci_devices: BTreeMap::new(),
-            pci_device_irqs: BTreeMap::new(),
+            pci_irq_slots: [0; 32],
             device_tree,
             #[cfg(feature = "acpi")]
             exit_evt: _exit_evt.try_clone().map_err(DeviceManagerError::EventFd)?,
@@ -1135,7 +1135,7 @@ impl DeviceManager {
     fn reserve_legacy_interrupts_for_pci_devices(&mut self) -> DeviceManagerResult<()> {
         // Reserve 8 IRQs which will be shared across all PCI devices.
         let num_irqs = 8;
-        let mut irqs: Vec<u32> = Vec::new();
+        let mut irqs: Vec<u8> = Vec::new();
         for _ in 0..num_irqs {
             irqs.push(
                 self.address_manager
@@ -1143,14 +1143,13 @@ impl DeviceManager {
                     .lock()
                     .unwrap()
                     .allocate_irq()
-                    .ok_or(DeviceManagerError::AllocateIrq)?,
+                    .ok_or(DeviceManagerError::AllocateIrq)? as u8,
             );
         }
 
         // There are 32 devices on the PCI bus, let's assign them an IRQ.
         for i in 0..32 {
-            self.pci_device_irqs
-                .insert(i << 3, irqs[(i % num_irqs) as usize]);
+            self.pci_irq_slots[i] = irqs[(i % num_irqs) as usize];
         }
 
         Ok(())
@@ -2840,14 +2839,13 @@ impl DeviceManager {
             }
         }
 
-        let legacy_interrupt_group = if let (Some(irq), Some(legacy_interrupt_manager)) = (
-            self.pci_device_irqs.get(&pci_device_bdf),
-            &self.legacy_interrupt_manager,
-        ) {
+        let legacy_interrupt_group = if let Some(legacy_interrupt_manager) =
+            &self.legacy_interrupt_manager
+        {
             Some(
                 legacy_interrupt_manager
                     .create_group(LegacyIrqGroupConfig {
-                        irq: *irq as InterruptIndex,
+                        irq: self.pci_irq_slots[(pci_device_bdf >> 3) as usize] as InterruptIndex,
                     })
                     .map_err(DeviceManagerError::CreateInterruptGroup)?,
             )
@@ -3758,9 +3756,10 @@ impl Aml for DeviceManager {
 
         // Build PCI routing table, listing IRQs assigned to PCI devices.
         let prt_package_list: Vec<(u32, u32)> = self
-            .pci_device_irqs
+            .pci_irq_slots
             .iter()
-            .map(|(bdf, irq)| (((((*bdf >> 3) & 0x1fu32) << 16) | 0xffffu32), *irq))
+            .enumerate()
+            .map(|(i, irq)| (((((i as u32) & 0x1fu32) << 16) | 0xffffu32), *irq as u32))
             .collect();
         let prt_package_list: Vec<aml::Package> = prt_package_list
             .iter()