PCIe Subsystem Internals

Describe the PCIe layered architecture, including root complex, switches, and endpoints.

Explain PCIe enumeration and how the kernel discovers and configures devices during boot.

Write a PCIe driver skeleton that registers with the PCI subsystem and reads device configuration space.

Extend a PCIe driver to request, map, and access a device's Base Address Registers (BARs) for MMIO.

Explain MSI and MSI-X interrupt mechanisms and configure them in a PCIe driver.

Explain how the IOMMU enables secure DMA and device isolation for security and virtualization.

Configure and observe PCIe device power management (ASPM) state transitions.

Debug a PCIe device initialization failure using lspci, setpci, and kernel log analysis.