vrunner: use QMP quit before SIGTERM in daemon_stop escalation

When the SHUTDOWN-via-virtio-serial poll window expires and the QEMU
process is still alive, send a QMP quit before SIGTERMing. Functionally
near-equivalent to SIGTERM at the process level (both converge on
qemu_system_killed() and a block-layer flush) but goes through QEMU's
monitor interface, which is the same mechanism hv_idle_shutdown() already
uses for idle-timeout shutdowns. Unifying the two escalation paths
makes the code easier to reason about — one channel for "ask QEMU to
exit cleanly," one fallback for "the monitor isn't responding."

QMP quit is NOT a replacement for the virtio-serial ===SHUTDOWN===
command: it stops QEMU without giving the guest a chance to run its
own graceful_shutdown() (which is what cleanly unmounts the state
disk). It's only an improvement over SIGTERM as the *fallback* when
the guest hasn't responded to the SHUTDOWN command within the poll
window. The full architectural fix — QMP system_powerdown driving an
ACPI handler in the guest that calls graceful_shutdown() — needs
guest-side acpid wiring and is tracked separately.

SIGTERM and SIGKILL remain as further fallbacks for cases where QMP
itself is unresponsive (e.g. older configs without a QMP socket, or
QEMU hung in a state where the monitor stops servicing commands).

Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>

0 files changed, 0 insertions, 0 deletions