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

Block layer patches

- virtio-blk: Multiqueue support (configurable iothread per queue)
- Made NBD export and hw/scsi thread-sa

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

Block layer patches

- virtio-blk: Multiqueue support (configurable iothread per queue)
- Made NBD export and hw/scsi thread-safe without AioContext lock
- Fix crash when loading snapshot on inactive node

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# gpg: Signature made Thu 21 Dec 2023 18:02:23 EST
# 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: (33 commits)
virtio-blk: add iothread-vq-mapping parameter
qdev: add IOThreadVirtQueueMappingList property type
qdev-properties: alias all object class properties
string-output-visitor: show structs as "<omitted>"
block-coroutine-wrapper: use qemu_get_current_aio_context()
block: remove outdated AioContext locking comments
job: remove outdated AioContext locking comments
scsi: remove outdated AioContext lock comment
docs: remove AioContext lock from IOThread docs
aio: remove aio_context_acquire()/aio_context_release() API
aio-wait: draw equivalence between AIO_WAIT_WHILE() and AIO_WAIT_WHILE_UNLOCKED()
scsi: remove AioContext locking
block: remove bdrv_co_lock()
block: remove AioContext locking
graph-lock: remove AioContext locking
aio: make aio_context_acquire()/aio_context_release() a no-op
tests: remove aio_context_acquire() tests
scsi: assert that callbacks run in the correct AioContext
virtio-scsi: replace AioContext lock with tmf_bh_lock
dma-helpers: don't lock AioContext in dma_blk_cb()
...

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

show more ...

graph-lock: remove AioContext locking

Stop acquiring/releasing the AioContext lock in
bdrv_graph_wrlock()/bdrv_graph_unlock() since the lock no longer has any
effect.

The distinction between bdrv_g

graph-lock: remove AioContext locking

Stop acquiring/releasing the AioContext lock in
bdrv_graph_wrlock()/bdrv_graph_unlock() since the lock no longer has any
effect.

The distinction between bdrv_graph_wrunlock() and
bdrv_graph_wrunlock_ctx() becomes meaningless and they can be collapsed
into one function.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20231205182011.1976568-6-stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

show more ...

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

Block layer patches

- Fix graph lock related deadlocks with the stream job
- ahci: Fix legacy software reset
- ide/via: Fix sw

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

Block layer patches

- Fix graph lock related deadlocks with the stream job
- ahci: Fix legacy software reset
- ide/via: Fix switch between compatibility and native mode

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# 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:
hw/ide/via: implement legacy/native mode switching
ide/via: don't attempt to set default BAR addresses
ide/pci: introduce pci_ide_update_mode() function
ide/ioport: move ide_portio_list[] and ide_portio_list2[] definitions to IDE core
iotests: Test two stream jobs in a single iothread
stream: Fix AioContext locking during bdrv_graph_wrlock()
block: Fix deadlocks in bdrv_graph_wrunlock()
block: Fix bdrv_graph_wrlock() call in blk_remove_bs()
hw/ide/ahci: fix legacy software reset

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

show more ...

block: Fix deadlocks in bdrv_graph_wrunlock()

bdrv_graph_wrunlock() calls aio_poll(), which may run callbacks that
have a nested event loop. Nested event loops can depend on other
iothreads making p

block: Fix deadlocks in bdrv_graph_wrunlock()

bdrv_graph_wrunlock() calls aio_poll(), which may run callbacks that
have a nested event loop. Nested event loops can depend on other
iothreads making progress, so in order to allow them to make progress it
must not hold the AioContext lock of another thread while calling
aio_poll().

This introduces a @bs parameter to bdrv_graph_wrunlock() whose
AioContext is temporarily dropped (which matches bdrv_graph_wrlock()),
and a bdrv_graph_wrunlock_ctx() that can be used if the BlockDriverState
doesn't necessarily exist any more when unlocking.

This also requires a change to bdrv_schedule_unref(), which was relying
on the incorrectly taken lock. It needs to take the lock itself now.
While this is a separate bug, it can't be fixed a separate patch because
otherwise the intermediate state would either deadlock or try to release
a lock that we don't even hold.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20231115172012.112727-3-kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
[kwolf: Fixed up bdrv_schedule_unref()]
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

show more ...

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

Block layer patches

- Clean up coroutine versions of bdrv_{is_allocated,block_status}*
- Graph locking part 5 (protect childre

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

Block layer patches

- Clean up coroutine versions of bdrv_{is_allocated,block_status}*
- Graph locking part 5 (protect children/parent links)

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# gpg: Signature made Thu 12 Oct 2023 12:20:15 EDT
# 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: (26 commits)
block: Add assertion for bdrv_graph_wrlock()
block: Protect bs->children with graph_lock
block: Protect bs->parents with graph_lock
block: Mark bdrv_get_specific_info() and callers GRAPH_RDLOCK
block: Mark bdrv_apply_auto_read_only() and callers GRAPH_RDLOCK
block: Mark bdrv_op_is_blocked() and callers GRAPH_RDLOCK
qcow2: Mark check_constraints_on_bitmap() GRAPH_RDLOCK
qcow2: Mark qcow2_inactivate() and callers GRAPH_RDLOCK
qcow2: Mark qcow2_signal_corruption() and callers GRAPH_RDLOCK
block: Mark bdrv_amend_options() and callers GRAPH_RDLOCK
block: Mark bdrv_get_parent_name() and callers GRAPH_RDLOCK
block: Mark bdrv_primary_child() and callers GRAPH_RDLOCK
block: Mark bdrv_refresh_filename() and callers GRAPH_RDLOCK
block: Mark bdrv_get_xdbg_block_graph() and callers GRAPH_RDLOCK
block: Take graph rdlock in parts of reopen
block: Mark bdrv_snapshot_fallback() and callers GRAPH_RDLOCK
block: Mark bdrv_parent_cb_resize() and callers GRAPH_RDLOCK
block: Mark drain related functions GRAPH_RDLOCK
block: Mark bdrv_first_blk() and bdrv_is_root_node() GRAPH_RDLOCK
block: Take graph rdlock in bdrv_inactivate_all()
...

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

show more ...

block: Add assertion for bdrv_graph_wrlock()

bdrv_graph_wrlock() can't run in a coroutine (because it polls) and
requires holding the BQL. We already have GLOBAL_STATE_CODE() to assert
the latter. A

block: Add assertion for bdrv_graph_wrlock()

bdrv_graph_wrlock() can't run in a coroutine (because it polls) and
requires holding the BQL. We already have GLOBAL_STATE_CODE() to assert
the latter. Assert the former as well and add a no_coroutine_fn marker.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20230929145157.45443-23-kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

show more ...

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

Block layer patches

- Graph locking part 4 (node management)
- qemu-img map: report compressed data blocks
- block-backend: pr

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

Block layer patches

- Graph locking part 4 (node management)
- qemu-img map: report compressed data blocks
- block-backend: process I/O in the current AioContext

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# gpg: Signature made Wed 20 Sep 2023 12:31:49 EDT
# 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: (28 commits)
block: mark aio_poll as non-coroutine
block-backend: process zoned requests in the current AioContext
block-backend: process I/O in the current AioContext
test-bdrv-drain: avoid race with BH in IOThread drain test
block: remove AIOCBInfo->get_aio_context()
qemu-img: map: report compressed data blocks
block: add BDRV_BLOCK_COMPRESSED flag for bdrv_block_status()
block: Mark bdrv_add/del_child() and caller GRAPH_WRLOCK
block: Mark bdrv_unref_child() GRAPH_WRLOCK
block: Mark bdrv_root_unref_child() GRAPH_WRLOCK
block: Take graph rdlock in bdrv_change_aio_context()
block: Take graph rdlock in bdrv_drop_intermediate()
block: Mark bdrv_parent_cb_change_media() GRAPH_RDLOCK
block: Mark bdrv_child_perm() GRAPH_RDLOCK
block: Mark bdrv_get_cumulative_perm() and callers GRAPH_RDLOCK
block: Mark bdrv_parent_perms_conflict() and callers GRAPH_RDLOCK
block: Mark bdrv_attach_child() GRAPH_WRLOCK
block: Call transaction callbacks with lock held
block: Mark bdrv_attach_child_common() GRAPH_WRLOCK
block: Mark bdrv_replace_child_tran() GRAPH_WRLOCK
...

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

show more ...

block: Introduce bdrv_schedule_unref()

bdrv_unref() is called by a lot of places that need to hold the graph
lock (it naturally happens in the context of operations that change the
graph). However,

block: Introduce bdrv_schedule_unref()

bdrv_unref() is called by a lot of places that need to hold the graph
lock (it naturally happens in the context of operations that change the
graph). However, bdrv_unref() takes the graph writer lock internally, so
it can't actually be called while already holding a graph lock without
causing a deadlock.

bdrv_unref() also can't just become GRAPH_WRLOCK because it drains the
node before closing it, and draining requires that the graph is
unlocked.

The solution is to defer deleting the node until we don't hold the lock
any more and draining is possible again.

Note that keeping images open for longer than necessary can create
problems, too: You can't open an image again before it is really closed
(if image locking didn't prevent it, it would cause corruption).
Reopening an image immediately happens at least during bdrv_open() and
bdrv_co_create().

In order to solve this problem, make sure to run the deferred unref in
bdrv_graph_wrunlock(), i.e. the first possible place where we can drain
again. This is also why bdrv_schedule_unref() is marked GRAPH_WRLOCK.

The output of iotest 051 is updated because the additional polling
changes the order of HMP output, resulting in a new "(qemu)" prompt in
the test output that was previously on a separate line and filtered out.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20230911094620.45040-6-kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

show more ...

Merge tag 'pull-trivial-patches' of https://gitlab.com/mjt0k/qemu into staging

trivial patches for 2023-09-08

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Merge tag 'pull-trivial-patches' of https://gitlab.com/mjt0k/qemu into staging

trivial patches for 2023-09-08

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# gpg: using RSA key 7B73BAD68BE7A2C289314B22701B4F6B1A693E59
# gpg: issuer "mjt@tls.msk.ru"
# gpg: Good signature from "Michael Tokarev <mjt@tls.msk.ru>" [full]
# gpg: aka "Michael Tokarev <mjt@corpit.ru>" [full]
# gpg: aka "Michael Tokarev <mjt@debian.org>" [full]
# Primary key fingerprint: 6EE1 95D1 886E 8FFB 810D 4324 457C E0A0 8044 65C5
# Subkey fingerprint: 7B73 BAD6 8BE7 A2C2 8931 4B22 701B 4F6B 1A69 3E59

* tag 'pull-trivial-patches' of https://gitlab.com/mjt0k/qemu: (22 commits)
qxl: don't assert() if device isn't yet initialized
hw/net/vmxnet3: Fix guest-triggerable assert()
tests/qtest/usb-hcd: Remove the empty "init" tests
target/ppc: use g_free() in test_opcode_table()
hw/ppc: use g_free() in spapr_tce_table_post_load()
trivial: Simplify the spots that use TARGET_BIG_ENDIAN as a numeric value
accel/tcg: Fix typo in translator_io_start() description
tests/qtest/test-hmp: Fix migrate_set_parameter xbzrle-cache-size test
docs tests: Fix use of migrate_set_parameter
qemu-options.hx: Rephrase the descriptions of the -hd* and -cdrom options
hw/display/xlnx_dp: update comments
block: spelling fixes
misc/other: spelling fixes
qga/: spelling fixes
tests/: spelling fixes
scripts/: spelling fixes
include/: spelling fixes
audio: spelling fixes
xen: spelling fix
riscv: spelling fixes
...

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

show more ...

block: spelling fixes

Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Reviewed-by: Eric Blake <eblake@redhat.com>

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

Block layer patches

- Re-enable the graph lock
- More fixes to coroutine_fn marking

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

Block layer patches

- Re-enable the graph lock
- More fixes to coroutine_fn marking

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# -----END PGP SIGNATURE-----
# gpg: Signature made Wed 28 Jun 2023 04:13:56 PM CEST
# gpg: using RSA key DC3DEB159A9AF95D3D7456FE7F09B272C88F2FD6
# gpg: issuer "kwolf@redhat.com"
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>" [full]

* tag 'for-upstream' of https://repo.or.cz/qemu/kevin: (23 commits)
block: use bdrv_co_debug_event in coroutine context
block: use bdrv_co_getlength in coroutine context
qcow2: mark more functions as coroutine_fns and GRAPH_RDLOCK
vhdx: mark more functions as coroutine_fns and GRAPH_RDLOCK
vmdk: mark more functions as coroutine_fns and GRAPH_RDLOCK
dmg: mark more functions as coroutine_fns and GRAPH_RDLOCK
cloop: mark more functions as coroutine_fns and GRAPH_RDLOCK
block: mark another function as coroutine_fns and GRAPH_UNLOCKED
bochs: mark more functions as coroutine_fns and GRAPH_RDLOCK
vpc: mark more functions as coroutine_fns and GRAPH_RDLOCK
qed: mark more functions as coroutine_fns and GRAPH_RDLOCK
file-posix: remove incorrect coroutine_fn calls
Revert "graph-lock: Disable locking for now"
graph-lock: Unlock the AioContext while polling
blockjob: Fix AioContext locking in block_job_add_bdrv()
block: Fix AioContext locking in bdrv_open_backing_file()
block: Fix AioContext locking in bdrv_open_inherit()
block: Fix AioContext locking in bdrv_reopen_parse_file_or_backing()
block: Fix AioContext locking in bdrv_attach_child_common()
block: Fix AioContext locking in bdrv_open_child()
...

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

show more ...

Revert "graph-lock: Disable locking for now"

Now that bdrv_graph_wrlock() temporarily drops the AioContext lock that
its caller holds, it can poll without causing deadlocks. We can now
re-enable gra

Revert "graph-lock: Disable locking for now"

Now that bdrv_graph_wrlock() temporarily drops the AioContext lock that
its caller holds, it can poll without causing deadlocks. We can now
re-enable graph locking.

This reverts commit ad128dff0bf4b6f971d05eb4335a627883a19c1d.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20230605085711.21261-12-kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

show more ...

graph-lock: Unlock the AioContext while polling

If the caller keeps the AioContext lock for a block node in an iothread,
polling in bdrv_graph_wrlock() deadlocks if the condition isn't
fulfilled imm

graph-lock: Unlock the AioContext while polling

If the caller keeps the AioContext lock for a block node in an iothread,
polling in bdrv_graph_wrlock() deadlocks if the condition isn't
fulfilled immediately.

Now that all callers make sure to actually have the AioContext locked
when they call bdrv_replace_child_noperm() like they should, we can
change bdrv_graph_wrlock() to take a BlockDriverState whose AioContext
lock the caller holds (NULL if it doesn't) and unlock it temporarily
while polling.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20230605085711.21261-11-kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

show more ...

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

Block layer patches

- qcow2 spec: Rename "zlib" compression to "deflate"
- Honour graph read lock even in the main thread + pr

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

Block layer patches

- qcow2 spec: Rename "zlib" compression to "deflate"
- Honour graph read lock even in the main thread + prerequisite fixes
- aio-posix: do not nest poll handlers (fixes infinite recursion)
- Refactor QMP blockdev transactions
- graph-lock: Disable locking for now
- iotests/245: Check if 'compress' driver is available

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# gpg: Signature made Fri 19 May 2023 10:17:09 AM PDT
# gpg: using RSA key DC3DEB159A9AF95D3D7456FE7F09B272C88F2FD6
# gpg: issuer "kwolf@redhat.com"
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>" [full]

* tag 'for-upstream' of https://repo.or.cz/qemu/kevin: (21 commits)
iotests: Test commit with iothreads and ongoing I/O
nbd/server: Fix drained_poll to wake coroutine in right AioContext
graph-lock: Disable locking for now
tested: add test for nested aio_poll() in poll handlers
aio-posix: do not nest poll handlers
iotests/245: Check if 'compress' driver is available
graph-lock: Honour read locks even in the main thread
blockjob: Adhere to rate limit even when reentered early
test-bdrv-drain: Call bdrv_co_unref() in coroutine context
test-bdrv-drain: Take graph lock more selectively
qemu-img: Take graph lock more selectively
qcow2: Unlock the graph in qcow2_do_open() where necessary
block/export: Fix null pointer dereference in error path
block: Call .bdrv_co_create(_opts) unlocked
docs/interop/qcow2.txt: fix description about "zlib" clusters
blockdev: qmp_transaction: drop extra generic layer
blockdev: use state.bitmap in block-dirty-bitmap-add action
blockdev: transaction: refactor handling transaction properties
blockdev: qmp_transaction: refactor loop to classic for
blockdev: transactions: rename some things
...

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

show more ...

graph-lock: Disable locking for now

In QEMU 8.0, we've been seeing deadlocks in bdrv_graph_wrlock(). They
come from callers that hold an AioContext lock, which is not allowed
during polling. In theo

graph-lock: Disable locking for now

In QEMU 8.0, we've been seeing deadlocks in bdrv_graph_wrlock(). They
come from callers that hold an AioContext lock, which is not allowed
during polling. In theory, we could temporarily release the lock, but
callers are inconsistent about whether they hold a lock, and if they do,
some are also confused about which one they hold. While all of this is
fixable, it's not trivial, and the best course of action for 8.0.1 is
probably just disabling the graph locking code temporarily.

We don't currently rely on graph locking yet. It is supposed to replace
the AioContext lock eventually to enable multiqueue support, but as long
as we still have the AioContext lock, it is sufficient without the graph
lock. Once the AioContext lock goes away, the deadlock doesn't exist any
more either and this commit can be reverted. (Of course, it can also be
reverted while the AioContext lock still exists if the callers have been
fixed.)

Cc: qemu-stable@nongnu.org
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20230517152834.277483-2-kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

show more ...

graph-lock: Honour read locks even in the main thread

There are some conditions under which we don't actually need to do
anything for taking a reader lock: Writing the graph is only possible
from th

graph-lock: Honour read locks even in the main thread

There are some conditions under which we don't actually need to do
anything for taking a reader lock: Writing the graph is only possible
from the main context while holding the BQL. So if a reader is running
in the main context under the BQL and knows that it won't be interrupted
until the next writer runs, we don't actually need to do anything.

This is the case if the reader code neither has a nested event loop
(this is forbidden anyway while you hold the lock) nor is a coroutine
(because a writer could run when the coroutine has yielded).

These conditions are exactly what bdrv_graph_rdlock_main_loop() asserts.
They are not fulfilled in bdrv_graph_co_rdlock(), which always runs in a
coroutine.

This deletes the shortcuts in bdrv_graph_co_rdlock() that skip taking
the reader lock in the main thread.

Reported-by: Fiona Ebner <f.ebner@proxmox.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20230510203601.418015-9-kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

show more ...

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

Block layer patches

- Graph locking, part 3 (more block drivers)
- Compile out assert_bdrv_graph_readable() by default
- Add c

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

Block layer patches

- Graph locking, part 3 (more block drivers)
- Compile out assert_bdrv_graph_readable() by default
- Add configure options for vmdk, vhdx and vpc
- Fix use after free in blockdev_mark_auto_del()
- migration: Attempt disk reactivation in more failure scenarios
- Coroutine correctness fixes

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# gpg: Signature made Wed 10 May 2023 01:18:41 PM BST
# gpg: using RSA key DC3DEB159A9AF95D3D7456FE7F09B272C88F2FD6
# gpg: issuer "kwolf@redhat.com"
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>" [full]

* tag 'for-upstream' of https://repo.or.cz/qemu/kevin: (28 commits)
block: compile out assert_bdrv_graph_readable() by default
block: Mark bdrv_refresh_limits() and callers GRAPH_RDLOCK
block: Mark bdrv_recurse_can_replace() and callers GRAPH_RDLOCK
block: Mark bdrv_query_block_graph_info() and callers GRAPH_RDLOCK
block: Mark bdrv_query_bds_stats() and callers GRAPH_RDLOCK
block: Mark BlockDriver callbacks for amend job GRAPH_RDLOCK
block: Mark bdrv_co_debug_event() GRAPH_RDLOCK
block: Mark bdrv_co_get_info() and callers GRAPH_RDLOCK
block: Mark bdrv_co_get_allocated_file_size() and callers GRAPH_RDLOCK
mirror: Require GRAPH_RDLOCK for accessing a node's parent list
vhdx: Require GRAPH_RDLOCK for accessing a node's parent list
nbd: Mark nbd_co_do_establish_connection() and callers GRAPH_RDLOCK
nbd: Remove nbd_co_flush() wrapper function
block: .bdrv_open is non-coroutine and unlocked
graph-lock: Fix GRAPH_RDLOCK_GUARD*() to be reader lock
graph-lock: Add GRAPH_UNLOCKED(_PTR)
test-bdrv-drain: Don't modify the graph in coroutines
iotests: Test resizing image attached to an iothread
block: Don't call no_coroutine_fns in qmp_block_resize()
block: bdrv/blk_co_unref() for calls in coroutine context
...

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

show more ...

block: compile out assert_bdrv_graph_readable() by default

reader_count() is a performance bottleneck because the global
aio_context_list_lock mutex causes thread contention. Put this debugging
asse

block: compile out assert_bdrv_graph_readable() by default

reader_count() is a performance bottleneck because the global
aio_context_list_lock mutex causes thread contention. Put this debugging
assertion behind a new ./configure --enable-debug-graph-lock option and
disable it by default.

The --enable-debug-graph-lock option is also enabled by the more general
--enable-debug option.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20230501173443.153062-1-stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

show more ...

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

Block layer patches

- Protect BlockBackend.queued_requests with its own lock
- Switch to AIO_WAIT_WHILE_UNLOCKED() where possi

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

Block layer patches

- Protect BlockBackend.queued_requests with its own lock
- Switch to AIO_WAIT_WHILE_UNLOCKED() where possible
- AioContext removal: LinuxAioState/LuringState/ThreadPool
- Add more coroutine_fn annotations, use bdrv/blk_co_*
- Fix crash when execute hmp_commit

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# gpg: Signature made Tue 25 Apr 2023 02:12:29 PM BST
# gpg: using RSA key DC3DEB159A9AF95D3D7456FE7F09B272C88F2FD6
# gpg: issuer "kwolf@redhat.com"
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>" [full]

* tag 'for-upstream' of https://repo.or.cz/qemu/kevin: (25 commits)
block/monitor: Fix crash when executing HMP commit
vmdk: make vmdk_is_cid_valid a coroutine_fn
qcow2: mark various functions as coroutine_fn and GRAPH_RDLOCK
tests: mark more coroutine_fns
qemu-pr-helper: mark more coroutine_fns
9pfs: mark more coroutine_fns
nbd: mark more coroutine_fns, do not use co_wrappers
mirror: make mirror_flush a coroutine_fn, do not use co_wrappers
blkdebug: add missing coroutine_fn annotation
vvfat: mark various functions as coroutine_fn
thread-pool: avoid passing the pool parameter every time
thread-pool: use ThreadPool from the running thread
io_uring: use LuringState from the running thread
linux-aio: use LinuxAioState from the running thread
block: add missing coroutine_fn to bdrv_sum_allocated_file_size()
include/block: fixup typos
monitor: convert monitor_cleanup() to AIO_WAIT_WHILE_UNLOCKED()
hmp: convert handle_hmp_command() to AIO_WAIT_WHILE_UNLOCKED()
block: convert bdrv_drain_all_begin() to AIO_WAIT_WHILE_UNLOCKED()
block: convert bdrv_graph_wrlock() to AIO_WAIT_WHILE_UNLOCKED()
...

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

show more ...

block: convert bdrv_graph_wrlock() to AIO_WAIT_WHILE_UNLOCKED()

The following conversion is safe and does not change behavior:

GLOBAL_STATE_CODE();
...
- AIO_WAIT_WHILE(qemu_get_aio_co

block: convert bdrv_graph_wrlock() to AIO_WAIT_WHILE_UNLOCKED()

The following conversion is safe and does not change behavior:

GLOBAL_STATE_CODE();
...
- AIO_WAIT_WHILE(qemu_get_aio_context(), ...);
+ AIO_WAIT_WHILE_UNLOCKED(NULL, ...);

Since we're in GLOBAL_STATE_CODE(), qemu_get_aio_context() is our home
thread's AioContext. Thus AIO_WAIT_WHILE() does not unlock the
AioContext:

if (ctx_ && in_aio_context_home_thread(ctx_)) { \
while ((cond)) { \
aio_poll(ctx_, true); \
waited_ = true; \
} \

And that means AIO_WAIT_WHILE_UNLOCKED(NULL, ...) can be substituted.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Tested-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20230309190855.414275-4-stefanha@redhat.com>
Reviewed-by: Wilfred Mallawa <wilfred.mallawa@wdc.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

show more ...

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

Block layer patches

- Code cleanups around block graph modification
- Simplify drain
- coroutine_fn correctness fixes, includi

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

Block layer patches

- Code cleanups around block graph modification
- Simplify drain
- coroutine_fn correctness fixes, including splitting generated
coroutine wrappers into co_wrapper (to be called only from
non-coroutine context) and co_wrapper_mixed (both coroutine and
non-coroutine context)
- Introduce a block graph rwlock

# gpg: Signature made Thu 15 Dec 2022 15:08:34 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: (50 commits)
block: GRAPH_RDLOCK for functions only called by co_wrappers
block: use co_wrapper_mixed_bdrv_rdlock in functions taking the rdlock
block-coroutine-wrapper.py: introduce annotations that take the graph rdlock
Mark assert_bdrv_graph_readable/writable() GRAPH_RD/WRLOCK
graph-lock: TSA annotations for lock/unlock functions
block: assert that graph read and writes are performed correctly
block: remove unnecessary assert_bdrv_graph_writable()
block: wrlock in bdrv_replace_child_noperm
block: Fix locking in external_snapshot_prepare()
test-bdrv-drain: Fix incorrrect drain assumptions
clang-tsa: Add macros for shared locks
clang-tsa: Add TSA_ASSERT() macro
Import clang-tsa.h
async: Register/unregister aiocontext in graph lock list
graph-lock: Implement guard macros
graph-lock: Introduce a lock to protect block graph operations
block: Factor out bdrv_drain_all_begin_nopoll()
block/dirty-bitmap: convert coroutine-only functions to co_wrapper
block: convert bdrv_create to co_wrapper
block-coroutine-wrapper.py: support also basic return types
...

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

show more ...

graph-lock: TSA annotations for lock/unlock functions

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20221207131838.239125-15-kwolf@redhat.com>
Reviewed-by: Emanuele Giuseppe Esposito <ee

graph-lock: TSA annotations for lock/unlock functions

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20221207131838.239125-15-kwolf@redhat.com>
Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

show more ...

block: assert that graph read and writes are performed correctly

Remove the old assert_bdrv_graph_writable, and replace it with
the new version using graph-lock API.

See the function documentation

block: assert that graph read and writes are performed correctly

Remove the old assert_bdrv_graph_writable, and replace it with
the new version using graph-lock API.

See the function documentation for more information.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20221207131838.239125-14-kwolf@redhat.com>
Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

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graph-lock: Introduce a lock to protect block graph operations

Block layer graph operations are always run under BQL in the main loop.
This is proved by the assertion qemu_in_main_thread() and its w

graph-lock: Introduce a lock to protect block graph operations

Block layer graph operations are always run under BQL in the main loop.
This is proved by the assertion qemu_in_main_thread() and its wrapper
macro GLOBAL_STATE_CODE.

However, there are also concurrent coroutines running in other iothreads
that always try to traverse the graph. Currently this is protected
(among various other things) by the AioContext lock, but once this is
removed, we need to make sure that reads do not happen while modifying
the graph.

We distinguish between writer (main loop, under BQL) that modifies the
graph, and readers (all other coroutines running in various AioContext),
that go through the graph edges, reading ->parents and->children.

The writer (main loop) has "exclusive" access, so it first waits for any
current read to finish, and then prevents incoming ones from entering
while it has the exclusive access.

The readers (coroutines in multiple AioContext) are free to access the
graph as long the writer is not modifying the graph. In case it is, they
go in a CoQueue and sleep until the writer is done.

If a coroutine changes AioContext, the counter in the original and new
AioContext are left intact, since the writer does not care where the
reader is, but only if there is one.

As a result, some AioContexts might have a negative reader count, to
balance the positive count of the AioContext that took the lock. This
also means that when an AioContext is deleted it may have a nonzero
reader count. In that case we transfer the count to a global shared
counter so that the writer is always aware of all readers.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20221207131838.239125-3-kwolf@redhat.com>
Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

show more ...