PCI / PCI Express

The core

drivers/pci/driver_pci.c + driver_pcie.c: config-space access (type 0/1), BAR decoding, bridge handling, capabilities, MSI where devices use it.

Discovery from L1

driver_pci_find_class_exact / driver_pci_find_class_mask - the numbered surface every family init consumes (AHCI/NVMe/NIC/sound inits take the pci_dev).

Commands

oc> lspci           (device list)
oc> pcidump         (full config-space dump)
oc> pcibars         (BAR decode)
oc> pcie            (PCIe capabilities/links)
oc> msitest         (MSI paths)

Bring-up notes

• QEMU q35 exposes a richer PCIe topology than the default i440fx - both are supported; hotplug ports behave through the normal probe path.
• 64-bit BARs: high-word reads are validated (an xHCI probe refusal path exercises exactly this).