Architecture
Drivers
Platform and device driver architecture
SlopOS targets QEMU q35 first and expects modern interrupt delivery.
Platform baseline
| Feature | Role |
|---|---|
| ACPI tables | Discover CPUs, interrupt controllers, HPET, and PCIe configuration |
| HPET | High-precision reference clock and time source |
| LAPIC | Per-CPU interrupt controller, timer, and IPIs |
| IOAPIC | Platform interrupt routing |
| MSI/MSI-X | Preferred PCI device interrupt delivery |
| PCIe ECAM | PCI configuration access |
Timer model
HPET plus LAPIC timer are the primary timing stack:
- HPET is used for high-precision time and timer calibration.
- LAPIC timer provides periodic scheduler ticks and one-shot wake deadlines.
- PIT is only a legacy polled fallback for calibration. It is not initialized as a periodic IRQ source and does not drive scheduling.
Device families
| Family | Status |
|---|---|
| VirtIO block | Root and test disk images |
| VirtIO net | Network device, RX/TX queues, interrupt handling, zero-copy hooks |
| PCI | Device discovery and capability parsing |
| PS/2 input | Keyboard and mouse input |
| Serial | Early and runtime logging |
| TTY/PTY | Terminal line discipline, sessions, job control |
Interrupt constraints
Legacy PIC code is not the supported interrupt path. VirtIO devices are attached with legacy mode disabled; device probe expects MSI-X or MSI. IOAPIC is required for platform interrupts that are not MSI/MSI-X.