pci_core: introduce DmaTarget to bundle DMA memory and MSI identity

[jstarks]

PCI bus-mastered transactions—DMA reads/writes and MSI interrupts—are both identified by a device's Requester ID. Today those two concerns are plumbed through device construction separately, as a GuestMemory and an MsiTarget, which makes it easy to hand a device a DMA path and an MSI path that disagree on identity and leaves no single place to derive a per-function identity for SR-IOV virtual functions.

This introduces DmaTarget in pci_core, bundling a device's GuestMemory, its MsiTarget, and an optional IOMMU factory into one value. with_devfn and with_rid derive both the DMA and MSI identity for a given function or Requester ID together, so the two cannot drift apart. When an IOMMU is present the factory—implemented by iommu_common's TranslatingDmaTarget over the shared IommuTranslator—produces per-RID translating GuestMemory, and the SMMU and AMD IOMMU wiring both flow through it.

DmaTarget is threaded through the PCIe device wiring, the device resolvers, and device_builder, replacing the separate guest_memory and software_iommu plumbing. This is groundwork for NVMe SR-IOV, where each virtual function needs a distinct, consistent DMA and MSI identity.

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[Copilot]

Pull request overview

This PR introduces pci_core::dma::DmaTarget, a new plumbing type that bundles a PCI device’s DMA memory (GuestMemory), MSI identity/routing (MsiTarget), and optional IOMMU-backed per-RID translation factory to keep DMA and MSI requester identity consistent (notably for SR-IOV VFs).

Changes:

• Added pci_core::dma::DmaTarget (+ DmaTargetIommu) and threaded it through PCI device resolution/building to replace separate guest_memory / msi_target (and software_iommu) parameters.
• Extended MsiTarget with with_rid() and added range validation so out-of-range RID bus overrides drop/disable MSI delivery rather than using an invalid identity.
• Added generic IOMMU support for per-RID translating DMA memory via iommu_common::TranslatingDmaTarget and updated SMMU/AMD-IOMMU wiring to feed this into DmaTarget.

Reviewed changes

Copilot reviewed 18 out of 18 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
vmm_core/src/device_builder.rs	Switches PCI device resolution to pass DmaTarget instead of separate DMA/MSI inputs.
vm/devices/virtio/virtio/src/resolver.rs	Uses input.dma_target to obtain GuestMemory + MsiTarget for virtio PCI devices.
vm/devices/storage/nvme/src/tests/controller_tests.rs	Updates NVMe tests to construct/pass DmaTarget.
vm/devices/storage/nvme/src/resolver.rs	Updates NVMe resolver to pass DmaTarget into controller construction.
vm/devices/storage/nvme/src/pci.rs	Updates NvmeController::new to take &DmaTarget and derive DMA/MSI from it.
vm/devices/storage/nvme_test/src/resolver.rs	Updates NVMe fault controller resolver to derive DMA/MSI from DmaTarget.
vm/devices/pci/vfio_assigned_device/src/resolver.rs	Switches VFIO assignment checks/MSI wiring to use DmaTarget (software_iommu() + MSI target access).
vm/devices/pci/pci_resources/src/lib.rs	Updates resolve parameter struct to carry &DmaTarget instead of separate fields.
vm/devices/pci/pci_core/src/msi.rs	Adds with_rid() and validates override bus against assigned bus range; adds tests for new behavior.
vm/devices/pci/pci_core/src/lib.rs	Exposes the new dma module.
vm/devices/pci/pci_core/src/dma.rs	Adds DmaTarget and the IOMMU factory trait for per-function/RID DMA memory derivation.
vm/devices/net/gdma/src/resolver.rs	Updates GDMA resolver to use DmaTarget for DMA/MSI inputs.
vm/devices/iommu/smmu/src/shared.rs	Derives Clone for SmmuTranslator to support per-VF factory cloning.
vm/devices/iommu/iommu_common/src/lib.rs	Adds per-RID translating GuestMemory and TranslatingDmaTarget implementation of DmaTargetIommu.
vm/devices/iommu/amd_iommu/src/lib.rs	Derives Clone for AmdTranslator and adjusts tests/imports for bus range handling.
openvmm/openvmm_core/src/worker/dispatch/pcie_wiring.rs	Builds a per-device DmaTarget (optionally IOMMU-backed) as part of PCIe device wiring.
openvmm/openvmm_core/src/worker/dispatch.rs	Threads DmaTarget through PCIe device construction and updates VPCI resolve context creation.
openhcl/underhill_core/src/worker.rs	Updates Underhill VPCI device build path to create a DmaTarget-based resolve context.

[Copilot]

Pull request overview

Copilot reviewed 22 out of 23 changed files in this pull request and generated 3 comments.

[github-actions]

1 Petri tests failed (0 unstable)