feat: Assign pio/mmio resource for pci devices

[junyu0312]

Summary by CodeRabbit

• New Features

  • PCI-backed virtual devices now initialize with automatic BAR window allocation, improving device setup consistency.
  • Added clearer device transport handling for virtio and VFIO devices.

• Bug Fixes

  • Improved PCI BAR reporting and routing so devices are mapped to the correct I/O or memory regions.
  • Enhanced error messages for several PCI-related failures to make troubleshooting easier.

• Refactor

  • Streamlined PCI root complex and device construction to use shared allocation flows.

[coderabbitai]

Caution

Review failed

The pull request is closed.

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 51bf487d-4f77-474f-b605-bf2799753458

📥 Commits

Reviewing files that changed from the base of the PR and between fc1c2b0 and 997d6c1.

⛔ Files ignored due to path filters (1)

• Cargo.lock is excluded by !**/*.lock

📒 Files selected for processing (15)

• crates/vm-cli/src/cmd/device.rs
• crates/vm-device/src/device/mod.rs
• crates/vm-pci/src/device/function/type0.rs
• crates/vm-pci/src/error.rs
• crates/vm-pci/src/host_bridge.rs
• crates/vm-pci/src/root_complex/pci_root_complex.rs
• crates/vm-pci/src/root_complex_device.rs
• crates/vm-pci/src/types/bar.rs
• crates/vm-pci/src/types/function/type0.rs
• crates/vm-vfio/Cargo.toml
• crates/vm-vfio/src/vfio_pci/device.rs
• crates/vm-vfio/src/vfio_pci/function.rs
• crates/vm-virtio/src/transport/pci.rs
• crates/vm-vmm/src/vm/device_builder.rs
• crates/vm-vmm/src/vm/device_builder/vfio.rs

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📝 Walkthrough

Walkthrough

Virtio device conversion now uses VirtioTransport. The PCI stack adds PciBarInfo, allocator-backed BAR programming, and allocator plumbing through Type0 functions, root-complex setup, VFIO PCI handling, virtio PCI transport, and VM device construction.

Changes

Virtio transport rename

Layer / File(s)	Summary
Transport type rename crates/vm-device/src/device/mod.rs, crates/vm-cli/src/cmd/device.rs	VirtioBlk, VirtioBalloon, and VirtioEntropy now use VirtioTransport, and the CLI conversion maps virtio devices to the renamed transport enum.

PCI BAR allocator flow

Layer / File(s)	Summary
BAR contract crates/vm-pci/src/types/bar.rs, crates/vm-pci/src/error.rs	PciBarInfo and BAR construction helpers are added, and PCI error variants gain explicit thiserror messages.
Type0 BAR programming crates/vm-pci/src/device/function/type0.rs, crates/vm-pci/src/types/function/type0.rs, crates/vm-pci/src/host_bridge.rs	Type0 BAR reads and router updates use PciBarInfo, Type0Function programs BARs from allocator inputs, and HostBridgeFunction adopts bar_info() with allocator-aware construction.
Root complex allocators crates/vm-pci/src/root_complex/pci_root_complex.rs, crates/vm-pci/src/root_complex_device.rs	PciRootComplex::new replaces Default, and PciRootComplexDevice::new threads allocator inputs into root-complex construction.
VFIO BAR allocation crates/vm-vfio/Cargo.toml, crates/vm-vfio/src/vfio_pci/device.rs	VfioPciDevice::new allocates PCI BAR windows from passed allocators and stores PciBarInfo values.
VFIO BAR routing crates/vm-vfio/src/vfio_pci/function.rs	VfioPciFunction switches BAR sizing and router callbacks to PciBarInfo.
Virtio PCI transport crates/vm-virtio/src/transport/pci.rs	VirtioPciTransport reports PciBarInfo, builds Type0Function with allocators, and removes the TryFrom conversion path.
VM builder PCI wiring crates/vm-vmm/src/vm/device_builder.rs, crates/vm-vmm/src/vm/device_builder/vfio.rs	DeviceManagerBuilder stores PCI allocators, installs them during PCI root-complex setup, and passes them into virtio and VFIO PCI device construction.

Sequence Diagram(s)

sequenceDiagram
  participant DeviceManagerBuilder
  participant PciRootComplexDevice
  participant VirtioPciDevice
  participant VirtioPciTransport
  participant Type0Function

  DeviceManagerBuilder->>PciRootComplexDevice: new(..., pci_pio_allocator, pci_mmio_allocator)
  DeviceManagerBuilder->>VirtioPciDevice: into_pci_device(pci_io_window_allocator, pci_mmio_window_allocator)
  VirtioPciDevice->>VirtioPciTransport: into_pci_device(pci_io_window_allocator, pci_mmio_window_allocator)
  VirtioPciTransport->>Type0Function: new_with_configuration_space(..., configuration_space, function)
  Type0Function-->>VirtioPciTransport: BARs programmed from bar_info()

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Estimated code review effort

🎯 4 (Complex) | ⏱️ ~60 minutes

Possibly related PRs

• junyu0312/rust-vm#170: Introduces the virtio transport enum and the same virtio PCI wiring that this PR renames and updates.
• junyu0312/rust-vm#176: Touches the same PCI Type0 command-routing path that this PR refactors to use PciBarInfo.
• junyu0312/rust-vm#169: Modifies the VFIO PCI device/function code that this PR updates for allocator-backed BAR handling.

Poem

🐇 I hopped through windows, BARs aglow,
and named the virtio paths anew.
The allocators now help things flow,
while PCI lines stay neat and true.
Hoppity! ✨

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch dev

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