monitor: only run coroutine commands in qemu_aio_context

monitor_qmp_dispatcher_co() runs in the iohandler AioContext that is not
polled during nested event loops. The coroutine currently reschedule

monitor: only run coroutine commands in qemu_aio_context

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: 7bed89958bfbf40df9ca681cefbdca63abdde39d ("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 commit effd60c878176bcaf97fa7ce2b12d04bb8ead6f7)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

show more ...

Merge tag 'for-upstream' of https://repo.or.cz/qemu/kevin into staging

Block layer patches

- virtio-blk: Multiqueue fixes and cleanups
- blklogwrites: Fixes for write_zeroes and superblock update r

Merge tag 'for-upstream' of https://repo.or.cz/qemu/kevin into staging

Block layer patches

- virtio-blk: Multiqueue fixes and cleanups
- blklogwrites: Fixes for write_zeroes and superblock update races
- commit/stream: Allow users to request only format driver names in
backing file format
- monitor: only run coroutine commands in qemu_aio_context
- Some iotest fixes

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# uv8oE813E30=
# =KQJl
# -----END PGP SIGNATURE-----
# gpg: Signature made Fri 26 Jan 2024 12:26:20 GMT
# gpg: using RSA key DC3DEB159A9AF95D3D7456FE7F09B272C88F2FD6
# gpg: issuer "kwolf@redhat.com"
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>" [full]
# Primary key fingerprint: DC3D EB15 9A9A F95D 3D74 56FE 7F09 B272 C88F 2FD6

* tag 'for-upstream' of https://repo.or.cz/qemu/kevin:
iotests/277: Use iotests.sock_dir for socket creation
iotests/iothreads-stream: Use the right TimeoutError
tests/unit: Bump test-replication timeout to 60 seconds
iotests/264: Use iotests.sock_dir for socket creation
block/blklogwrites: Protect mutable driver state with a mutex.
virtio-blk: always set ioeventfd during startup
virtio-blk: tolerate failure to set BlockBackend AioContext
virtio-blk: restart s->rq reqs in vq AioContexts
virtio-blk: rename dataplane to ioeventfd
virtio-blk: rename dataplane create/destroy functions
virtio-blk: move dataplane code into virtio-blk.c
monitor: only run coroutine commands in qemu_aio_context
iotests: port 141 to Python for reliable QMP testing
iotests: add filter_qmp_generated_node_ids()
stream: Allow users to request only format driver names in backing file format
commit: Allow users to request only format driver names in backing file format
string-output-visitor: Fix (pseudo) struct handling
block/blklogwrites: Fix a bug when logging "write zeroes" operations.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

show more ...

monitor: only run coroutine commands in qemu_aio_context

monitor_qmp_dispatcher_co() runs in the iohandler AioContext that is not
polled during nested event loops. The coroutine currently reschedule

monitor: only run coroutine commands in qemu_aio_context

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: 7bed89958bfbf40df9ca681cefbdca63abdde39d ("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>

show more ...

Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into staging

Block layer patches:

- file-posix: Mitigate file fragmentation with extent size hints
- Tighten qemu-img rules on missing

Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into staging

Block layer patches:

- file-posix: Mitigate file fragmentation with extent size hints
- Tighten qemu-img rules on missing backing format
- qemu-img map: Don't limit block status request size
- Fix crash with virtio-scsi and iothreads

# gpg: Signature made Tue 14 Jul 2020 14:24:19 BST
# gpg: using RSA key DC3DEB159A9AF95D3D7456FE7F09B272C88F2FD6
# gpg: issuer "kwolf@redhat.com"
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>" [full]
# Primary key fingerprint: DC3D EB15 9A9A F95D 3D74 56FE 7F09 B272 C88F 2FD6

* remotes/kevin/tags/for-upstream:
block: Avoid stale pointer dereference in blk_get_aio_context()
qemu-img: Deprecate use of -b without -F
block: Add support to warn on backing file change without format
iotests: Specify explicit backing format where sensible
qcow2: Deprecate use of qemu-img amend to change backing file
block: Error if backing file fails during creation without -u
qcow: Tolerate backing_fmt=
vmdk: Add trivial backing_fmt support
sheepdog: Add trivial backing_fmt support
block: Finish deprecation of 'qemu-img convert -n -o'
qemu-img: Flush stdout before before potential stderr messages
file-posix: Mitigate file fragmentation with extent size hints
iotests/059: Filter out disk size with more standard filter
qemu-img map: Don't limit block status request size
iotests: Simplify _filter_img_create() a bit

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

show more ...

iotests: Specify explicit backing format where sensible

There are many existing qcow2 images that specify a backing file but
no format. This has been the source of CVEs in the past, but has
become

iotests: Specify explicit backing format where sensible

There are many existing qcow2 images that specify a backing file but
no format. This has been the source of CVEs in the past, but has
become more prominent of a problem now that libvirt has switched to
-blockdev. With older -drive, at least the probing was always done by
qemu (so the only risk of a changed format between successive boots of
a guest was if qemu was upgraded and probed differently). But with
newer -blockdev, libvirt must specify a format; if libvirt guesses raw
where the image was formatted, this results in data corruption visible
to the guest; conversely, if libvirt guesses qcow2 where qemu was
using raw, this can result in potential security holes, so modern
libvirt instead refuses to use images without explicit backing format.

The change in libvirt to reject images without explicit backing format
has pointed out that a number of tools have been far too reliant on
probing in the past. It's time to set a better example in our own
iotests of properly setting this parameter.

iotest calls to create, rebase, and convert are all impacted to some
degree. It's a bit annoying that we are inconsistent on command line
- while all of those accept -o backing_file=...,backing_fmt=..., the
shortcuts are different: create and rebase have -b and -F, while
convert has -B but no -F. (amend has no shortcuts, but the previous
patch just deprecated the use of amend to change backing chains).

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <20200706203954.341758-9-eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

show more ...

Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into staging

Block layer patches:

- iotests: Fix output of qemu-io related tests
- Don't ignore bdrv_set_aio_context() for nodes with

Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into staging

Block layer patches:

- iotests: Fix output of qemu-io related tests
- Don't ignore bdrv_set_aio_context() for nodes with bs->drv = NUL
- vmdk: Set vmdk parent backing_format to vmdk
- qcow2: Preallocation fixes (especially for external data files)
- Add linear-buffer-based APIs (as wrappers around qiov-based ones)
- Various code cleanups and small corner case fixes

# gpg: Signature made Tue 30 Apr 2019 16:35:09 BST
# gpg: using RSA key 7F09B272C88F2FD6
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>" [full]
# Primary key fingerprint: DC3D EB15 9A9A F95D 3D74 56FE 7F09 B272 C88F 2FD6

* remotes/kevin/tags/for-upstream: (27 commits)
block/qed: add missed coroutine_fn markers
iotests: Check that images are in read-only mode after block-commit
commit: Make base read-only if there is an early failure
qemu-img: use buffer-based io
block/stream: use buffer-based io
block/commit: use buffer-based io
block/backup: use buffer-based io
block/parallels: use buffer-based io
block/qed: use buffer-based io
block/qcow: use buffer-based io
block/qcow2: use buffer-based io
block: introduce byte-based io helpers
qcow2: Fix error handling in the compression code
qcow2: Fix qcow2_make_empty() with external data file
qemu-img: Make create hint at protocol options
iotests: Perform the correct test in 082
qcow2: Fix full preallocation with external data file
qcow2: Add errp to preallocate_co()
qcow2: Avoid COW during metadata preallocation
qemu-img: Saner printing of large file sizes
...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

show more ...

qemu-img: Saner printing of large file sizes

Disk sizes close to INT64_MAX cause overflow, for some pretty
ridiculous output:

$ ./nbdkit -U - memory size=$((2**63 - 512)) --run 'qemu-img info $nb

qemu-img: Saner printing of large file sizes

Disk sizes close to INT64_MAX cause overflow, for some pretty
ridiculous output:

$ ./nbdkit -U - memory size=$((2**63 - 512)) --run 'qemu-img info $nbd'
image: nbd+unix://?socket=/tmp/nbdkitHSAzNz/socket
file format: raw
virtual size: -8388607T (9223372036854775296 bytes)
disk size: unavailable

But there's no reason to have two separate implementations of integer
to human-readable abbreviation, where one has overflow and stops at
'T', while the other avoids overflow and goes all the way to 'E'. With
this patch, the output now claims 8EiB instead of -8388607T, which
really is the correct rounding of largest file size supported by qemu
(we could go 511 bytes larger if we used byte-accurate sizing instead
of rounding up to the next sector boundary, but that wouldn't change
the human-readable result).

Quite a few iotests need updates to expected output to match.

Reported-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
Tested-by: Richard W.M. Jones <rjones@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Tested-by: Max Reitz <mreitz@redhat.com>

show more ...

Merge remote-tracking branch 'remotes/armbru/tags/pull-qapi-2018-12-18' into staging

QAPI patches for 2018-12-18

# gpg: Signature made Tue 18 Dec 2018 07:20:11 GMT
# gpg: using RSA k

Merge remote-tracking branch 'remotes/armbru/tags/pull-qapi-2018-12-18' into staging

QAPI patches for 2018-12-18

# gpg: Signature made Tue 18 Dec 2018 07:20:11 GMT
# gpg: using RSA key 3870B400EB918653
# gpg: Good signature from "Markus Armbruster <armbru@redhat.com>"
# gpg: aka "Markus Armbruster <armbru@pond.sub.org>"
# Primary key fingerprint: 354B C8B3 D7EB 2A6B 6867 4E5F 3870 B400 EB91 8653

* remotes/armbru/tags/pull-qapi-2018-12-18:
qapi: fix flat union on uncovered branches conditionals
qmp hmp: Make system_wakeup check wake-up support and run state
qga: update guest-suspend-ram and guest-suspend-hybrid descriptions
qmp: query-current-machine with wakeup-suspend-support
qmp: Split ShutdownCause host-qmp into quit and system-reset
qmp: Add reason to SHUTDOWN and RESET events
qapi: Turn ShutdownCause into QAPI enum

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

show more ...

qmp: Split ShutdownCause host-qmp into quit and system-reset

It is interesting to know whether the shutdown cause was 'quit' or
'reset', especially when using "--no-reboot". In that case, a manageme

qmp: Split ShutdownCause host-qmp into quit and system-reset

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>

show more ...

qmp: Add reason to SHUTDOWN and RESET events

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 event

qmp: Add reason to SHUTDOWN and RESET events

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>

show more ...

Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into staging

Block layer patches

# gpg: Signature made Tue 26 Sep 2017 14:52:32 BST
# gpg: using RSA key 0x7F09B272C88F

Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into staging

Block layer patches

# gpg: Signature made Tue 26 Sep 2017 14:52:32 BST
# gpg: using RSA key 0x7F09B272C88F2FD6
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>"
# Primary key fingerprint: DC3D EB15 9A9A F95D 3D74 56FE 7F09 B272 C88F 2FD6

* remotes/kevin/tags/for-upstream: (24 commits)
block/qcow2-bitmap: fix use of uninitialized pointer
qemu-iotests: add shrinking image test
qcow2: add shrink image support
qcow2: add qcow2_cache_discard
qemu-img: add --shrink flag for resize
iotests: fix 181: enable postcopy-ram capability on target
qemu-iotests: Test change-backing-file command
block: Fix permissions after bdrv_reopen()
block: reopen: Queue children after their parents
block: Base permissions on rw state after reopen
block: Add reopen queue to bdrv_check_perm()
block: Add reopen_queue to bdrv_child_perm()
qemu-io: Drop write permissions before read-only reopen
block: Clean up some bad code in the vvfat driver
block/throttle-groups.c: allocate RestartData on the heap
throttle: Assert that bkt->max is valid in throttle_compute_wait()
iotests: Print full path of bad output if mismatch
iotests: use virtio aliases for 067
iotests: use -ccw on s390x for 051
iotests: use -ccw on s390x for 040, 139, and 182
...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

show more ...

qemu-iotests: Test change-backing-file command

This involves a temporary read-write reopen if the backing file link in
the middle of a backing file chain should be changed and is therefore a
good te

qemu-iotests: Test change-backing-file command

This involves a temporary read-write reopen if the backing file link in
the middle of a backing file chain should be changed and is therefore a
good test for the latest bdrv_reopen() vs. op blockers fixes.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>

show more ...