User-space PCIe libraries

uPCIe is a set of header-only C libraries for user-space PCIe device interaction on Linux. It provides hugepage-backed DMA, MMIO accessors, PCI discovery and BAR mapping, VFIO wrappers, dma-buf helpers, and a minimalist NVMe driver, with no dependencies beyond the Linux UAPI headers.

It started as a way to explore the boundary between safe and unsafe user-space PCIe practices. It targets both the IOMMU-protected path (vfio-pci) and the raw-physical path (uio_pci_generic with hugepages). The companion tooling lives in its own repositories: devbind, hugepages, and iommu.

Design goals

• Header-only

• Idiomatic, with a consistent error and ownership model

• Zero-dependency, beyond the Linux UAPI headers

• Minimalistic

• Low-coupling

• C11

Topics of interest

• Mapping PCIe BAR spaces via vfio-pci and uio_pci_generic

• IOMMU-protected memory for safe DMA

• Hugepages for raw-physical DMA with uio_pci_generic

• PCIe driver binding and unbinding

• Interrupts and how to handle them

Get started

• Overview
  • Layers
  • Errors and ownership
  • Companion tools
• Quickstart
• Building and testing
  • Guest-based testing
  • Retargeting

Reference

• Libraries
  • Primitives
  • PCI and VFIO
  • Host memory
  • dma-buf
  • DMA memory
  • Experimental
  • Umbrella
  • NVMe driver components
• API reference
  • Primitives
  • PCI and VFIO
  • Host memory
  • dma-buf
  • NVMe