Add generic ISA DMA support to chipset resources

[moor-coding]

This PR:

• Adds a generic ISA DMA resource handle and resolver registration.
• Adds ISA DMA controller capability plumbing in the chipset device abstraction layer.
• Updates base chipset wiring to resolve DMA before floppy wiring, preventing runtime NoDmaForFloppy failures.
• Normalizes DMA module layout with a dedicated resolver module.

[Copilot]

Pull request overview

Adds resource-level support for ISA DMA (and normalizes PIT/UHCI stub to resources) so the base chipset can resolve DMA early enough for floppy wiring, while also carrying optional static PCI placement metadata in chipset device handles.

Changes:

• Introduces GenericIsaDmaDeviceHandle (+ resolver) and exposes ISA DMA controller access via ChipsetDevice::supports_isa_dma_controller.
• Reworks base chipset wiring to resolve ISA DMA handles before floppy setup; shifts PIT and PIIX4 UHCI stub instantiation to resource resolvers and manifest handles (with optional fixed PCI placement).
• Plumbs a new with_pit boolean through config/worker paths for ACPI table generation and adds manifest-builder tests around PIT attachment.

Reviewed changes

Copilot reviewed 25 out of 26 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
vmm_core/vmotherboard/src/lib.rs	Adds ChipsetDevicePciPlacement and extends ChipsetDeviceHandle with optional PCI placement metadata.
vmm_core/vmotherboard/src/base_chipset.rs	Resolves ISA DMA device handle early (before floppy wiring), applies optional PCI placement when resolving handles, and adapts DMA channel wiring to erased devices.
vmm_core/vm_manifest_builder/src/lib.rs	Adds DMA/PIT/UHCI stub handles to manifests, provides with_pit() helper, and adds unit tests for PIT attachment matrix/idempotency.
vm/devices/chipset_resources/src/lib.rs	Adds resource IDs for PIT, generic ISA DMA, and PIIX4 UHCI stub.
vm/devices/chipset_legacy/src/piix4_uhci/resolver.rs	New async resolver for the PIIX4 UHCI stub device.
vm/devices/chipset_legacy/src/piix4_uhci.rs	Exposes the new UHCI resolver module.
vm/devices/chipset_legacy/Cargo.toml	Adds dependencies needed for chipset-device resource resolving (and async resolver).
vm/devices/chipset/src/pit/resolver.rs	New PIT resolver that wires IRQ2 and vmtime access.
vm/devices/chipset/src/pit/mod.rs	Exposes PIT resolver module.
vm/devices/chipset/src/dma/resolver.rs	New resolver for the generic ISA DMA controller.
vm/devices/chipset/src/dma/mod.rs	Adds ISA DMA controller capability plumbing to the DMA device.
vm/chipset_device_resources/src/lib.rs	Extends erased chipset device wrapper to forward ISA DMA controller capability.
vm/chipset_device/src/lib.rs	Adds supports_isa_dma_controller() capability hook and exports new isa_dma module.
vm/chipset_device/src/isa_dma.rs	Introduces the ISA DMA controller capability trait and transfer types.
petri/src/vm/openvmm/modify.rs	Updates chipset device handle construction for the new pci_placement field.
petri/src/vm/openvmm/construct.rs	Captures manifest with_pit() and propagates it into OpenVMM config; updates handle construction.
openvmm/openvmm_resources/src/lib.rs	Registers new chipset resolvers (DMA, PIT, UHCI stub) for OpenVMM.
openvmm/openvmm_resources/Cargo.toml	Adds chipset_legacy dependency to support UHCI stub resolver registration.
openvmm/openvmm_entry/src/ttrpc/mod.rs	Propagates with_pit from manifest into worker config.
openvmm/openvmm_entry/src/lib.rs	Propagates with_pit from manifest into worker config; updates handle construction.
openvmm/openvmm_defs/src/config.rs	Adds with_pit: bool to worker Config.
openvmm/openvmm_core/src/worker/dispatch.rs	Uses with_pit (plus manifest flags) for ACPI table generation and carries capabilities through VM lifecycle.
openhcl/underhill_core/src/worker.rs	Removes PIT/UHCI deps plumbing and updates handle construction for pci_placement.
openhcl/openvmm_hcl_resources/src/lib.rs	Registers PIT and UHCI stub resolvers for OpenVMM-HCL (but currently missing DMA resolver).
openhcl/openvmm_hcl_resources/Cargo.toml	Adds chipset_legacy dependency for UHCI stub resolver registration.
Cargo.lock	Lockfile updates for new/changed dependencies.

Comments suppressed due to low confidence (1)

vm/devices/chipset/src/dma/mod.rs:225

• impl IsaDmaController for DmaController currently calls self.check_transfer_size(...) inside check_transfer_size, which resolves back to the same trait method and will recurse until stack overflow. Disambiguate the call to the inherent method (or rename one of the methods) so the trait implementation delegates to the existing controller logic instead of recursing.

[Copilot]

Pull request overview

Copilot reviewed 29 out of 30 changed files in this pull request and generated 3 comments.

[Copilot]

PciPlacementHint::bus_name is typed as &'static str, which forces callers without truly-static bus names (e.g. remote device proxies) to leak memory or otherwise manufacture a 'static reference. Since BusId::new only needs &str (it clones into Arc<str>), consider making bus_name owned (e.g. Arc<str>/Box<str>/String) or lifetime-parameterized so implementations can return borrowed data without leaks.

[Copilot]

Using Box::leak here permanently leaks the bus name string for every proxied device instance, which can accumulate across VM create/destroy cycles. If the goal is only to pass a placement hint through, consider adjusting the PciPlacementHint API to avoid requiring a 'static bus name (or store the owned string in the proxy and return a borrowed reference tied to self).

Suggested change

	// The transport payload is owned String; leak once to satisfy the
	// static lifetime required by PciPlacementHint.
	bus_name: Box::leak(placement.bus_name.into_boxed_str()),
	// The transport payload is an owned String; store it directly to avoid leaks.
	bus_name: placement.bus_name,

[Copilot]

attach_piix4_pci_usb_uhci_stub is not idempotent (unlike attach_generic_isa_dma/attach_pit), so callers that already provided a Piix4PciUsbUhciStubDeviceHandle can end up with duplicate UHCI stub devices in chipset_devices. Consider checking for an existing handle (by resource.id()) and returning early if present.