When the compute is itself a Hyper-V guest without an invariant TSC (e.g.
the GNS3 VM on hosts whose CPU lacks TSC scaling), Linux falls back to the
hyperv_clocksource_tsc_page clocksource and the guest timekeeping KVM
derives from the TSC is broken with recent kernels:
- kvmclock runs thousands of times too fast: Linux guests (MikroTik
RouterOS, ...) panic with "watchdog: BUG: soft lockup - CPU#0 stuck for
29604s" and reboot in a loop right after boot;
- TSC deadline timers fire far too late: guests with -cpu host hang.
The only workaround so far was -machine accel=tcg, i.e. no KVM at all.
Add a kvmclock setting to the [Qemu] section (auto, enabled, disabled).
In auto mode, KVM guests started on a host whose clocksource is a Hyper-V
one get kvmclock and tsc-deadline turned off: on the -cpu given in the
additional options (unless it sets these features itself), otherwise on
QEMU's default CPU model.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Preserve image reconciliation, locking, and regression coverage while integrating upstream release, dependency, typing, and formatting updates. Align feature code with the new Ruff checks.
Document all 70 configuration fields with pydantic Field
descriptions, ported from the config sample comments and verified
against the actual consumers (allow_remote_console and local had
no documentation anywhere). The descriptions flow into the
OpenAPI schema of GET /v3/settings, giving the Web UI tooltips,
defaults and validation bounds from a single source. Response
models re-declare six path fields as plain strings, which drops
the inherited description — restore them explicitly.
Sync the config sample: document local and allow_remote_console,
drop hardware_virtualization_check which no longer exists in the
schema.
GET returns all settings sections except the deprecated
VirtualBox/VMware ones (Server.Audit privilege); secrets are
masked and Controller.jwt_secret_key is excluded entirely.
PUT applies a partial update (Server.Modify privilege): masked
or empty secrets mean unchanged, null removes the option, the
response carries the new values plus restart_required, and a
settings.updated notification is emitted. New
Server.Audit/Server.Modify privileges are seeded into the
Administrator role at table creation.
