From aace90f270503a6429254751c41a6287d0f88d80 Mon Sep 17 00:00:00 2001
From: Pascal Scholz <pascal.scholz@cyberus-technology.de>
Date: Fri, 13 Mar 2026 09:00:41 +0100
Subject: [PATCH] vmm: Propagate PCI device ID from the config

We pass the device ID from the config to the allocation routine, where
it is then used as the preferred device ID alongside the existing PCI
segment ID.

Signed-off-by: Pascal Scholz <pascal.scholz@cyberus-technology.de>
On-behalf-of: SAP pascal.scholz@sap.com
Signed-off-by: Rob Bradford <rbradford@meta.com>
---
 vmm/src/device_manager.rs | 31 +++++++++++++++++++++----------
 1 file changed, 21 insertions(+), 10 deletions(-)

diff --git a/vmm/src/device_manager.rs b/vmm/src/device_manager.rs
index cb88fb8cc..1f1dd2f05 100644
--- a/vmm/src/device_manager.rs
+++ b/vmm/src/device_manager.rs
@@ -1711,6 +1711,7 @@ impl DeviceManager {
                     &id,
                     handle.pci_common.pci_segment,
                     handle.dma_handler,
+                    handle.pci_common.pci_device_id,
                 )?;
 
                 // Track device BDF for Generic Initiator support
@@ -1742,7 +1743,8 @@ impl DeviceManager {
             }
 
             if let Some(iommu_device) = iommu_device {
-                let dev_id = self.add_virtio_pci_device(iommu_device, &None, &iommu_id, 0, None)?;
+                let dev_id =
+                    self.add_virtio_pci_device(iommu_device, &None, &iommu_id, 0, None, None)?;
                 self.iommu_attached_devices = Some((dev_id, iommu_attached_devices));
             }
         }
@@ -3656,7 +3658,7 @@ impl DeviceManager {
         let pci_segment_id = 0x0_u16;
 
         let (pci_segment_id, pci_device_bdf, resources) =
-            self.pci_resources(&id, pci_segment_id)?;
+            self.pci_resources(&id, pci_segment_id, None)?;
 
         info!("Creating pvmemcontrol device: id = {id}");
         let (pvmemcontrol_pci_device, pvmemcontrol_bus_device) =
@@ -3922,8 +3924,11 @@ impl DeviceManager {
             id
         };
 
-        let (pci_segment_id, pci_device_bdf, resources) =
-            self.pci_resources(&vfio_name, device_cfg.pci_common.pci_segment)?;
+        let (pci_segment_id, pci_device_bdf, resources) = self.pci_resources(
+            &vfio_name,
+            device_cfg.pci_common.pci_segment,
+            device_cfg.pci_common.pci_device_id,
+        )?;
 
         let mut needs_dma_mapping = false;
 
@@ -4184,8 +4189,11 @@ impl DeviceManager {
             id
         };
 
-        let (pci_segment_id, pci_device_bdf, resources) =
-            self.pci_resources(&vfio_user_name, device_cfg.pci_common.pci_segment)?;
+        let (pci_segment_id, pci_device_bdf, resources) = self.pci_resources(
+            &vfio_user_name,
+            device_cfg.pci_common.pci_segment,
+            device_cfg.pci_common.pci_device_id,
+        )?;
 
         let legacy_interrupt_group =
             if let Some(legacy_interrupt_manager) = &self.legacy_interrupt_manager {
@@ -4301,6 +4309,7 @@ impl DeviceManager {
         virtio_device_id: &str,
         pci_segment_id: u16,
         dma_handler: Option<Arc<dyn ExternalDmaMapping>>,
+        pci_device_id: Option<u8>,
     ) -> DeviceManagerResult<PciBdf> {
         let id = format!("{VIRTIO_PCI_DEVICE_NAME_PREFIX}-{virtio_device_id}");
 
@@ -4309,7 +4318,7 @@ impl DeviceManager {
         node.children = vec![virtio_device_id.to_string()];
 
         let (pci_segment_id, pci_device_bdf, resources) =
-            self.pci_resources(&id, pci_segment_id)?;
+            self.pci_resources(&id, pci_segment_id, pci_device_id)?;
 
         // Update the existing virtio node by setting the parent.
         if let Some(node) = self.device_tree.lock().unwrap().get_mut(virtio_device_id) {
@@ -4446,7 +4455,7 @@ impl DeviceManager {
         info!("Creating pvpanic device {id}");
 
         let (pci_segment_id, pci_device_bdf, resources) =
-            self.pci_resources(&id, pci_segment_id)?;
+            self.pci_resources(&id, pci_segment_id, None)?;
 
         let snapshot = snapshot_from_id(self.snapshot.as_ref(), id.as_str());
 
@@ -4484,7 +4493,7 @@ impl DeviceManager {
         info!("Creating ivshmem device {id}");
 
         let (pci_segment_id, pci_device_bdf, resources) =
-            self.pci_resources(&id, pci_segment_id)?;
+            self.pci_resources(&id, pci_segment_id, None)?;
         let snapshot = snapshot_from_id(self.snapshot.as_ref(), id.as_str());
 
         let ivshmem_ops = Arc::new(Mutex::new(IvshmemHandler {
@@ -4529,6 +4538,7 @@ impl DeviceManager {
         &self,
         id: &str,
         pci_segment_id: u16,
+        pci_device_id: Option<u8>,
     ) -> DeviceManagerResult<(u16, PciBdf, Option<Vec<Resource>>)> {
         // Look for the id in the device tree. If it can be found, that means
         // the device is being restored, otherwise it's created from scratch.
@@ -4556,7 +4566,7 @@ impl DeviceManager {
             (pci_segment_id, pci_device_bdf, resources)
         } else {
             let pci_device_bdf =
-                self.pci_segments[pci_segment_id as usize].allocate_device_id(None)?;
+                self.pci_segments[pci_segment_id as usize].allocate_device_id(pci_device_id)?;
 
             (pci_segment_id, pci_device_bdf, None)
         })
@@ -5075,6 +5085,7 @@ impl DeviceManager {
             &id,
             handle.pci_common.pci_segment,
             handle.dma_handler,
+            handle.pci_common.pci_device_id,
         )?;
 
         // Update the PCIU bitmap