VirtIO capability structures can start at non-page-aligned offsets within\nBARs. The kernel physmap requires page-aligned addresses. Align the physical\naddress down, adjust the size, and apply the page offset to the returned\npointer. Track the original map pointer/size separately for correct unmapping.
Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)
Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>
The previous BAR size calculation used !(inverted & mask) & mask which\nproduces incorrect results when the BAR has a non-zero base address.\nUse lowest-set-bit extraction (masked & (!masked + 1)) to correctly\ncompute the BAR size from the writable bit pattern read back from hardware.
Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)
Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>
Add missing alloc_cpu_id() function (atomic round-robin CPU selection).
Fix type chain: MsiAllocation.irq u8→u32 to match allocate_irq_vector
return type. irq_set_affinity accepts u32 irq for consistency.
Verified: driver-sys compiles on Linux (x86_64-unknown-linux-gnu).
Full redbear-mini image builds and boots in QEMU.
dma.rs: IommuDmaAllocator (145 lines)
- New struct wires existing IOMMU daemon (1003 lines) to existing DmaBuffer (261)
- allocate(): phys-contiguous alloc via scheme:memory, then MAP through IOMMU domain
- unmap(): sends UNMAP to IOMMU domain, releases IOVA
- Inlined IOMMU protocol constants — no new crate dependency
- encode_iommu_request/decode_iommu_response for scheme write/read cycle
Documentation updates:
- IMPLEMENTATION-MASTER-PLAN.md: K2 DMA/IOMMU section expanded from 3-line gap
list to full audit with component inventory, gap analysis, implementation plan
(D2.1-D2.5), Linux reference table. Added K2b thread/fork audit.
- CPU-DMA-IRQ-MSI-SCHEDULER-FIX-PLAN.md: Phase 1 (MSI) marked complete with
per-task status. Phase 2 (DMA) re-scoped from 'create' to 'wire' based on
audit. Phase 3 (scheduler) marked mostly done.
- IRQ-AND-LOWLEVEL-CONTROLLERS-ENHANCEMENT-PLAN.md: kernel MSI support noted
as materially strong with P8-msi.patch reference.
Audit findings:
- IOMMU daemon is solid: 1003-line lib.rs with full scheme protocol,
427-line amd_vi.rs, host-runnable tests. Needs wiring, not rewriting.
- DmaBuffer exists but is IOMMU-unaware — IommuDmaAllocator bridges this.
- relibc rlct_clone is correct for threads (shares addr space implicitly).
'3 IPC hops' claim is microkernel-architectural, not a real perf issue.
- No stale docs to archive at this time.
Consolidate the active desktop path around redbear-full while landing the greeter/session stack and the runtime fixes needed to keep Wayland and KWin bring-up moving forward.
Derivative of Redox OS (https://www.redox-os.org) adding:
- AMD GPU driver (amdgpu) via LinuxKPI compat layer
- ext4 filesystem support (ext4d scheme daemon)
- ACPI fixes for AMD bare metal (x2APIC, DMAR, IVRS, MCFG)
- Custom branding (hostname, os-release, boot identity)
Build system is full upstream Redox with RBOS overlay in local/.
Patches for kernel, base, and relibc are symlinked from local/patches/
and protected from make clean/distclean. Custom recipes live in
local/recipes/ with symlinks into the recipes/ search path.
Build: make all CONFIG_NAME=redbear-full
Sync: ./local/scripts/sync-upstream.sh
vasilito