monitor_qmp_dispatcher_co() runs in the iohandler AioContext that is not
polled during nested event loops. The coroutine currently reschedules
itself in the main loop's qemu_aio_context AioContext, which is polled
during nested event loops. One known problem is that QMP device-add
calls drain_call_rcu(), which temporarily drops the BQL, leading to all
sorts of havoc like other vCPU threads re-entering device emulation code
while another vCPU thread is waiting in device emulation code with
aio_poll().
Paolo Bonzini suggested running non-coroutine QMP handlers in the
iohandler AioContext. This avoids trouble with nested event loops. His
original idea was to move coroutine rescheduling to
monitor_qmp_dispatch(), but I resorted to moving it to qmp_dispatch()
because we don't know if the QMP handler needs to run in coroutine
context in monitor_qmp_dispatch(). monitor_qmp_dispatch() would have
been nicer since it's associated with the monitor implementation and not
as general as qmp_dispatch(), which is also used by qemu-ga.
A number of qemu-iotests need updated .out files because the order of
QMP events vs QMP responses has changed.
Solves Issue #1933.
Cc: qemu-stable@nongnu.org
Fixes: 7bed89958b ("device_core: use drain_call_rcu in in qmp_device_add")
Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=2215192
Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=2214985
Buglink: https://issues.redhat.com/browse/RHEL-17369
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20240118144823.1497953-4-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Tested-by: Fiona Ebner <f.ebner@proxmox.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
It is interesting to know whether the shutdown cause was 'quit' or
'reset', especially when using "--no-reboot". In that case, a management
layer can now determine if the guest wanted a reboot or shutdown, and
can act accordingly.
Changes the output of the reason in the iotests from 'host-qmp' to
'host-qmp-quit'. This does not break compatibility because
the field was introduced in the same version.
Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
Message-Id: <20181205110131.23049-4-d.csapak@proxmox.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[Commit message tweaked]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
This makes it possible to determine what the exact reason was for
a RESET or a SHUTDOWN. A management layer might need the specific reason
of those events to determine which cleanups or other actions it needs to do.
This patch also updates the iotests to the new expected output that includes
the reason.
Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
Message-Id: <20181205110131.23049-3-d.csapak@proxmox.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[Commit message tweaked]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Libvirt would like to be able to distinguish between a SHUTDOWN
event triggered solely by guest request and one triggered by a
SIGTERM or other action on the host. While qemu_kill_report() was
already able to give different output to stderr based on whether a
shutdown was triggered by a host signal (but NOT by a host UI event,
such as clicking the X on the window), that information was then
lost to management. The previous patches improved things to use an
enum throughout all callsites, so now we have something ready to
expose through QMP.
Note that for now, the decision was to expose ONLY a boolean,
rather than promoting ShutdownCause to a QAPI enum; this is because
libvirt has not expressed an interest in anything finer-grained.
We can still add additional details, in a backwards-compatible
manner, if a need later arises (if the addition happens before 2.10,
we can replace the bool with an enum; otherwise, the enum will have
to be in addition to the bool); this patch merely adds a helper
shutdown_caused_by_guest() to map the internal enum into the
external boolean.
Update expected iotest outputs to match the new data (complete
coverage of the affected tests is obtained by -raw, -qcow2, and -nbd).
Here is output from 'virsh qemu-monitor-event --loop' with the
patch installed:
event SHUTDOWN at 1492639680.731251 for domain fedora_13: {"guest":true}
event STOP at 1492639680.732116 for domain fedora_13: <null>
event SHUTDOWN at 1492639680.732830 for domain fedora_13: {"guest":false}
Note that libvirt runs qemu with -no-shutdown: the first SHUTDOWN event
was triggered by an action I took directly in the guest (shutdown -h),
at which point qemu stops the vcpus and waits for libvirt to do any
final cleanups; the second SHUTDOWN event is the result of libvirt
sending SIGTERM now that it has completed cleanup. Libvirt is already
smart enough to only feed the first qemu SHUTDOWN event to the end user
(remember, virsh qemu-monitor-event is a low-level debugging interface
that is explicitly unsupported by libvirt, so it sees things that normal
end users do not); changing qemu to emit SHUTDOWN only once is outside
the scope of this series.
See also https://bugzilla.redhat.com/1384007
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20170515214114.15442-6-eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
This adds tests for overriding the qemu-internal BDRV_O_PROTOCOL flag by
explicitly specifying a block driver. As one test must be run over the
NBD protocol while the other must not, this patch adds two separate
iotests.
Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Stefan Hajnoczi