f389309d29
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> (cherry picked from commiteffd60c878) Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
81 lines
1.5 KiB
Plaintext
81 lines
1.5 KiB
Plaintext
QA output created by 195
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Formatting 'TEST_DIR/t.IMGFMT.base', fmt=IMGFMT size=67108864
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Formatting 'TEST_DIR/t.IMGFMT.mid', fmt=IMGFMT size=67108864 backing_file=TEST_DIR/t.IMGFMT.base backing_fmt=IMGFMT
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Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 backing_file=TEST_DIR/t.IMGFMT.mid backing_fmt=IMGFMT
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Change backing file of mid (opened read-only)
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Testing: -drive if=none,file=TEST_DIR/t.IMGFMT,backing.node-name=mid
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{
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QMP_VERSION
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}
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{
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"return": {
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}
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}
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{
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"return": {
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}
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}
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{
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"timestamp": {
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"seconds": TIMESTAMP,
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"microseconds": TIMESTAMP
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},
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"event": "SHUTDOWN",
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"data": {
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"guest": false,
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"reason": "host-qmp-quit"
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}
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}
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{
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"return": {
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}
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}
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image: TEST_DIR/t.IMGFMT.mid
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file format: IMGFMT
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virtual size: 64 MiB (67108864 bytes)
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cluster_size: 65536
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backing file: /dev/null
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backing file format: IMGFMT
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Change backing file of top (opened writable)
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Formatting 'TEST_DIR/t.IMGFMT.mid', fmt=IMGFMT size=67108864 backing_file=TEST_DIR/t.IMGFMT.base backing_fmt=IMGFMT
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Testing: -drive if=none,file=TEST_DIR/t.IMGFMT,node-name=top
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{
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QMP_VERSION
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}
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{
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"return": {
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}
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}
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{
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"return": {
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}
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}
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{
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"timestamp": {
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"seconds": TIMESTAMP,
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"microseconds": TIMESTAMP
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},
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"event": "SHUTDOWN",
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"data": {
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"guest": false,
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"reason": "host-qmp-quit"
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}
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}
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{
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"return": {
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}
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}
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image: TEST_DIR/t.IMGFMT
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file format: IMGFMT
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virtual size: 64 MiB (67108864 bytes)
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cluster_size: 65536
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backing file: /dev/null
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backing file format: IMGFMT
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*** done
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