From 88378d17a24c1a49d5f5bfa7534e99a24d93ae6c Mon Sep 17 00:00:00 2001
From: Rob Bradford <robert.bradford@intel.com>
Date: Mon, 11 Oct 2021 16:51:15 +0100
Subject: [PATCH] vmm: Take PCI segment ID into BAR size allocation

Move the decision on whether to use a 64-bit bar up to the DeviceManager
so that it can use both the device type (e.g. block) and the PCI segment
ID to decide what size bar should be used.

Signed-off-by: Rob Bradford <robert.bradford@intel.com>
---
 virtio-devices/src/transport/pci_device.rs | 16 +++++-----------
 vmm/src/device_manager.rs                  |  6 ++++++
 2 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/virtio-devices/src/transport/pci_device.rs b/virtio-devices/src/transport/pci_device.rs
index ed6d6a6fc..7da606ba7 100644
--- a/virtio-devices/src/transport/pci_device.rs
+++ b/virtio-devices/src/transport/pci_device.rs
@@ -350,6 +350,7 @@ impl VirtioPciDevice {
         interrupt_manager: &Arc<dyn InterruptManager<GroupConfig = MsiIrqGroupConfig>>,
         pci_device_bdf: u32,
         activate_evt: EventFd,
+        use_64bit_bar: bool,
     ) -> Result<Self> {
         let device_clone = device.clone();
         let locked_device = device_clone.lock().unwrap();
@@ -389,22 +390,15 @@ impl VirtioPciDevice {
             (None, None)
         };
 
-        // All device types *except* virtio block devices should be allocated a 64-bit bar
-        // The block devices should be given a 32-bit BAR so that they are easily accessible
-        // to firmware without requiring excessive identity mapping.
-        let mut use_64bit_bar = true;
         let (class, subclass) = match VirtioDeviceType::from(locked_device.device_type()) {
             VirtioDeviceType::Net => (
                 PciClassCode::NetworkController,
                 &PciNetworkControllerSubclass::EthernetController as &dyn PciSubclass,
             ),
-            VirtioDeviceType::Block => {
-                use_64bit_bar = false;
-                (
-                    PciClassCode::MassStorage,
-                    &PciMassStorageSubclass::MassStorage as &dyn PciSubclass,
-                )
-            }
+            VirtioDeviceType::Block => (
+                PciClassCode::MassStorage,
+                &PciMassStorageSubclass::MassStorage as &dyn PciSubclass,
+            ),
             _ => (
                 PciClassCode::Other,
                 &PciVirtioSubclass::NonTransitionalBase as &dyn PciSubclass,
diff --git a/vmm/src/device_manager.rs b/vmm/src/device_manager.rs
index 4fdcb7ff3..0d053dad6 100644
--- a/vmm/src/device_manager.rs
+++ b/vmm/src/device_manager.rs
@@ -3236,6 +3236,7 @@ impl DeviceManager {
         };
 
         let memory = self.memory_manager.lock().unwrap().guest_memory();
+        let device_type = virtio_device.lock().unwrap().device_type();
         let mut virtio_pci_device = VirtioPciDevice::new(
             id.clone(),
             memory,
@@ -3247,6 +3248,11 @@ impl DeviceManager {
             self.activate_evt
                 .try_clone()
                 .map_err(DeviceManagerError::EventFd)?,
+            // All device types *except* virtio block devices should be allocated a 64-bit bar
+            // The block devices should be given a 32-bit BAR so that they are easily accessible
+            // to firmware without requiring excessive identity mapping.
+            // The exception being if not on the default PCI segment.
+            pci_segment_id > 0 || device_type != VirtioDeviceType::Block as u32,
         )
         .map_err(DeviceManagerError::VirtioDevice)?;