QEMU Meson tests, optional HMP, and PostgreSQL replication fixes

QEMU developers advanced several large patch series on test infrastructure, monitor optionality, and migration performance. PostgreSQL hackers examined a logical replication bug and a control-file API dispute.

QEMU TCG tests migrate to Meson

A 104-patch series proposes moving all TCG tests from Makefiles to Meson. The work adds proper dependencies and configure-time checks. Maintainers gain more reliable test builds under the modern build system.

HMP becomes compile-time optional

The third revision of a 49-patch series makes the Human Monitor Protocol optional via a --disable-hmp configure flag. The change aims to shrink attack surface in minimal builds. Operators who ship hardened or reduced QEMU configurations have a clearer path to drop the monitor.

Fast snapshot load via postcopy

Version 5 of an 11-patch series introduces fast snapshot load that combines postcopy with userfaultfd for lazy RAM restore. The series targets quicker VM state restoration. Virtualization operators who rely on frequent snapshots benefit from the reduced load latency.

IOThread holder tracking and query support

The twelfth version of a 15-patch series adds tracking of IOThread holders and exposes them through query-iothreads. Device and export observability improves as a result. Developers diagnosing I/O threading interactions obtain clearer runtime visibility.

TCG dispatch overhead reductions

An eight-patch RFC proposes cuts to per-block dispatch overhead through changes to dispatch, cache, and can_do_io paths. Reported gains land in the 4-9 percent range on large user-mode workloads. Users of QEMU user-mode emulation see direct performance relevance.

Logical replication loses unchanged toasted columns

PostgreSQL hackers discussed a bug in which row filters on logical replication turn unchanged toasted columns into NULL on the subscriber. Fix approaches are under review. Replication deployments that combine row filters with TOASTed data are directly affected.

vhost-user optional memory isolation

An RFC second version containing 13 patches adds an optional memory-isolation mode for vhost-user based on bounce buffers and shadow virtqueues. The series strengthens isolation between frontend and backend. Secure device-backend deployments gain a new hardening option.

pg_control data_checksum_version debate

After a push, developers disputed whether to retain data_checksum_version_init on pg_control for pg_control_init accuracy or revert it for PostgreSQL 19 release timing. The exchange centers on control-file consistency versus schedule pressure. Contributors tracking catalog and init changes for the next major release need to follow the outcome.