kerf: preserve PCI host bridge metadata - #11
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The topology models, allocation policies and validators already existed but were dead code in practice: the baseline DTB generator never emitted the topology section, so every create/update reading state back from the kernel saw no topology, and nothing ever discovered it from the host. Make the support real: - Emit the topology section (NUMA nodes, per-node memory range, CPUs as 64-bit physical ID cells, distance matrix as <target distance> pairs, memory type) and device numa-node into the baseline DTB, and parse them back, so topology survives the kernel round trip. - Add kerf/topology.py to discover the host topology at kerf init time: NUMA nodes and distances from /sys/devices/system/node, per-node memory ranges from /proc/zoneinfo, and PCI device locality from sysfs. Sysfs is keyed by logical CPU while kerf speaks physical APIC IDs, so discovery translates through the processor/apicid pairs in /proc/cpuinfo. - Fix DTS parsing bugs that broke hand-written topology sections: the topology/numa-nodes/cores regexes could not handle nested braces (only the first node parsed), comments inside multi-line property values broke value parsing, and the pool memory-base regex could match a NUMA node's memory-base instead. - Keep manual allocation authoritative: explicit --cpus no longer gets a compact affinity policy attached implicitly, so deliberate topology-crossing layouts do not accumulate spurious warnings. Auto-allocation (--cpu-count) still defaults to compact. Topology violations remain warnings; only impossible requests are errors. - Fold the topology documentation into README.md, replacing the stale docs/CPU_NUMA_TOPOLOGY.md, and update the NUMA examples to the supported format. Instance memory is still allocated first-fit from a single pool; NUMA-aware per-node pools via /dev/lazy_cma's node parameter are the next step.
Kerf rebuilds an instance device tree from the parsed baseline. Dropping pci-host-bridges during that round trip leaves the spawned kernel without the immutable ECAM descriptors required to construct its synthetic PCI roots. Add a PCI host-bridge model, parse it from binary and source device trees, validate segment and bus ranges, ECAM alignment, and overlap, and emit the metadata into generated instance trees. Cover valid round trips and malformed descriptors in the baseline tests. Signed-off-by: Nikolay Nikolaev <nicknickolaev@gmail.com>
The device-tree compiler can render CPU lists with an explicit /bits/ width and hexadecimal cells. Treating that syntax as plain decimal values makes Kerf reject valid extracted instance trees.\n\nAccept the 32-bit and 64-bit forms, parse each cell with base detection, and limit the lookup to direct /resources properties so nested NUMA CPU lists cannot shadow the global inventory. Cover the legacy and explicit-width forms in the parser tests.\n\nSigned-off-by: Nikolay Nikolaev <nicknickolaev@gmail.com>
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Kerf must preserve PCI host-bridge information when parsing and generating Multikernel device trees. A spawned kernel
needs the PCI segment, bus range, and ECAM base to discover and access its assigned SR-IOV VF.
This change:
This complements the Linux SR-IOV assignment work in multikernel/linux#4.