[tanabarr]

bdev_busid_range assumed PCI domain 0x0000 and only encoded an 8-bit
bus-ID range. On multi-PCI-segment platforms with non-zero domains,
this silently filtered the wrong bus-IDs (DAOS-19772: a hot-plugged
drive was claimed by the wrong engine).

Add bdev_hotplug_range, a config array of PCI domain + bus-ID-range
entries (one domain per entry; plain hex, no "0x" prefix, matching
ordinary PCI address formatting), replacing the legacy domain-0x00-
only bdev_busid_range (kept for backward compatibility). When unset,
ranges are now auto-derived directly from bdev_list's actual PCI
addresses instead of NUMA-node topology, collapsing only truly-
contiguous bus-IDs so the filter never admits an address absent from
bdev_list; VMD still allows all. Thread the resulting ranges through
to the SPDK JSON config and bio_config.c's hotplug_filter_fn, which
now matches domain+bus-ID per entry instead of a single bus-ID range.

Update daos_server.yml/admin guide to describe only the automatic
behavior; manual syntax is retained only in the design doc and
src/control/server/storage/README.md as an undocumented, experimental
escape hatch. Decimal notation is no longer accepted, hex only.

Add design/control/hotplug-pci-domain-design.md.

Features: control

Steps for the author:

• Commit message follows the guidelines.
• Appropriate Features or Test-tag pragmas were used.
• Appropriate Functional Test Stages were run.
• At least two positive code reviews including at least one code owner from each category referenced in the PR.
• Testing is complete. If necessary, forced-landing label added and a reason added in a comment.

After all prior steps are complete:

• Gatekeeper requested (daos-gatekeeper added as a reviewer).

[github-actions]

Ticket title is 'Hot-plugged drive claimed by the wrong engine'
Status is 'In Review'
Labels: 'request_for_2.8.2'
https://daosio.atlassian.net/browse/DAOS-19772