Linux kernel framework for PCIe device emulation, in userspace

Summary

A Linux kernel framework for synthetic PCIe device emulation entirely in userspace. What is PCIem? PCIem is a framework that creates virtual PCIe devices in the Linux kernel by leveraging a few novel techniques to populate synthetic cards as legitimate PCI devices to the host OS. To brief what PCIem is: a framework for developing and testing PCIe device drivers without requiring actual hardware. Architecture ┌──────────────────────────────────────────┐ ┌──────────────────────────────────────────────────┐ │ │ │ │ │ ┌─────────►Host Linux Kernel │ │ Linux Userspace │ │ │ │ │ │ │ │ │ │ │ │ │ ┌────────────────────────────┐ │ │ ┌────────────────────────────────────────┐ │ │ │ │ PCIem Framework ◄──────┼────────────►/dev/pciem◄───────────┼────► Userspace PCI shim │ │ │ │ │ │ │ │ │ │ │ │ │ │ - PCI Config Space │ │ │ │ - Emulates PCIe device logic │ │ │ │ │ │ │ │ │ │ │ │ │ │ - BAR Mappings │ │ │ └────────────────────────────────────────┘ │ │ │ │ │ │ │ │ │ │◄───┤ - INT/MSI/MSI-X Interrupts │ │ │ │ │ │ │ │ │ └──────────────────────────────────────────────────┘ │ │ │ - DMA (With/without IOMMU) │ │ Userspace │ │ │ │ │ │ │ │ - P2P DMA │ │ │ │ │ │ │ │ │ └────────────────────────────┘ │ │ │ │ │ │ │ │ │ PCIe driver is unaware of PCIem │ │ │ │ │ │ │ │ │ ┌──────────────────────────────────┐ │ │ │ │ Real PCIe Driver │ │ │ │ │ │ │ │ └─┤ - Untouched logic from production│ │ │ │ │ │ │ └──────────────────────────────────┘ │ │ │ └──────────────────────────────────────────┘ Kernel Space Current Features BAR Support : Register and manage BARs programmatically : Register and manage BARs programmatically Watchpoints : Event-driven architecture using CPU watchpoints for access detection : Event-driven architecture using CPU watchpoints for access detection Legacy IRQ/MSI/MSI-X Support : Full interrupt support with dynamic triggering : Full interrupt support with dynamic triggering PCI Capability Framework : Modular PCI capabilities system (Linked-list underneath) : Modular PCI capabilities system...