First enforcement step of the IOVA track. A vendor-neutral IOMMU core
(iommu.zig) drives an Intel VT-d backend (iommu-intel.zig) to give DMA a
real translation layer instead of the fail-open free-for-all M16 left.
- Boot posture is now stated explicitly: "iommu online (Intel VT-d)"
with version/agaw/rmrr, or "none present - DMA fail-open (unisolated)".
- DMAR parsing extended to select the INCLUDE_PCI_ALL unit (real Intel
PCs put an iGPU-scoped unit first) and record single-path-endpoint
RMRRs; multi-hop scopes and extra DRHDs are counted and warned, never
silently dropped.
- Translation is enabled at boot into a blanket identity domain (all RAM
+ RMRRs, 2 MiB leaves). PCI functions are enumerated post-boot by the
ring-3 pci-bus driver, so a device is attached to the domain when its
driver claims it (confineDevice, with claim rollback if confinement
fails) and detached on driver death, before broker release and DMA
frame teardown. Unclaimed devices are non-present: their DMA faults.
- Interrupt remapping stays off, so MSI writes to 0xFEE00000 bypass
translation and the interrupt-driven xHC keeps working.
- devices-broker gains pciAddressOf (derives BDF from the config-space
ECAM offset), unclaim, and forEachPciFunction.
Faults are drained and logged rate-limited as DANOS-IOMMU-FAULT.
Cases: iommu extended (translation on, scratch-domain map/resolve/unmap,
zero idle faults); new iommu-usb-storage and iommu-usb-hid run the full
storage + input stacks through translated DMA with MSI intact. 103/103.
Follow-up cleanup of the just-moved kernel device code:
- power.zig -> acpi.zig. Its reboot() is built entirely on the FADT reset
register (acpi.power_information) plus the legacy 0xCF9/8042 fallbacks — it is
ACPI reboot, so it becomes acpi.reboot (the "P" in ACPI). platform.reboot
still delegates; soft-off/S5 stays the ring-3 acpi service's job as before.
- device-tree.zig -> fdt.zig. It is a discovery *backend* (the ARM/FDT parser,
a sibling of acpi.zig), not part of the model — renaming it to its actual
subject kills the confusing device-tree / device-model DeviceTree name clash
and makes acpi.zig + fdt.zig read as the two parallel backends.
- Flatten: device-model.zig, acpi.zig, fdt.zig, platform.zig move out of the
system/kernel/devices/ subdir up into system/kernel/, joining devices-broker.zig
(already flat). The kernel dir is a flat pile by convention (only architecture/
is a subdir), so the subdir — and its poor "devices" name — is gone.
Pure restructure; "platform" module name unchanged, all cross-file deps are
relative siblings that moved together. zig build + test green; smoke, discovery,
acpi-parse, acpi-ps2, acpi-report, power-button, orderly-shutdown, reboot pass.
Daniel Samson