Merge tag 'pull-nbd-2023-09-07-v2' of https://repo.or.cz/qemu/ericb into staging

NBD patches for 2023-09-07

- Andrey Drobyshev - fix regression in iotest 197 under -nbd
- Stefan Hajnoczi - allow co

Merge tag 'pull-nbd-2023-09-07-v2' of https://repo.or.cz/qemu/ericb into staging

NBD patches for 2023-09-07

- Andrey Drobyshev - fix regression in iotest 197 under -nbd
- Stefan Hajnoczi - allow coroutine read and write context to split
across threads
- Philippe Mathieu-Daudé - remove a VLA allocation
- Denis V. Lunev - fix regression in iotest 233 with qemu-nbd -v --fork

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* tag 'pull-nbd-2023-09-07-v2' of https://repo.or.cz/qemu/ericb:
qemu-nbd: document -v behavior in respect to --fork in man
qemu-nbd: Restore "qemu-nbd -v --fork" output
qemu-nbd: invent nbd_client_release_pipe() helper
qemu-nbd: put saddr into into struct NbdClientOpts
qemu-nbd: move srcpath into struct NbdClientOpts
qemu-nbd: define struct NbdClientOpts when HAVE_NBD_DEVICE is not defined
qemu-nbd: improve error message for dup2 error
util/iov: Avoid dynamic stack allocation
io: follow coroutine AioContext in qio_channel_yield()
io: check there are no qio_channel_yield() coroutines during ->finalize()
nbd: drop unused nbd_start_negotiate() aio_context argument
nbd: drop unused nbd_receive_negotiate() aio_context argument
qemu-iotests/197: use more generic commands for formats other than qcow2

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

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io: follow coroutine AioContext in qio_channel_yield()

The ongoing QEMU multi-queue block layer effort makes it possible for multiple
threads to process I/O in parallel. The nbd block driver is not

io: follow coroutine AioContext in qio_channel_yield()

The ongoing QEMU multi-queue block layer effort makes it possible for multiple
threads to process I/O in parallel. The nbd block driver is not compatible with
the multi-queue block layer yet because QIOChannel cannot be used easily from
coroutines running in multiple threads. This series changes the QIOChannel API
to make that possible.

In the current API, calling qio_channel_attach_aio_context() sets the
AioContext where qio_channel_yield() installs an fd handler prior to yielding:

qio_channel_attach_aio_context(ioc, my_ctx);
...
qio_channel_yield(ioc); // my_ctx is used here
...
qio_channel_detach_aio_context(ioc);

This API design has limitations: reading and writing must be done in the same
AioContext and moving between AioContexts involves a cumbersome sequence of API
calls that is not suitable for doing on a per-request basis.

There is no fundamental reason why a QIOChannel needs to run within the
same AioContext every time qio_channel_yield() is called. QIOChannel
only uses the AioContext while inside qio_channel_yield(). The rest of
the time, QIOChannel is independent of any AioContext.

In the new API, qio_channel_yield() queries the AioContext from the current
coroutine using qemu_coroutine_get_aio_context(). There is no need to
explicitly attach/detach AioContexts anymore and
qio_channel_attach_aio_context() and qio_channel_detach_aio_context() are gone.
One coroutine can read from the QIOChannel while another coroutine writes from
a different AioContext.

This API change allows the nbd block driver to use QIOChannel from any thread.
It's important to keep in mind that the block driver already synchronizes
QIOChannel access and ensures that two coroutines never read simultaneously or
write simultaneously.

This patch updates all users of qio_channel_attach_aio_context() to the
new API. Most conversions are simple, but vhost-user-server requires a
new qemu_coroutine_yield() call to quiesce the vu_client_trip()
coroutine when not attached to any AioContext.

While the API is has become simpler, there is one wart: QIOChannel has a
special case for the iohandler AioContext (used for handlers that must not run
in nested event loops). I didn't find an elegant way preserve that behavior, so
I added a new API called qio_channel_set_follow_coroutine_ctx(ioc, true|false)
for opting in to the new AioContext model. By default QIOChannel uses the
iohandler AioHandler. Code that formerly called
qio_channel_attach_aio_context() now calls
qio_channel_set_follow_coroutine_ctx(ioc, true) once after the QIOChannel is
created.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Acked-by: Daniel P. Berrangé <berrange@redhat.com>
Message-ID: <20230830224802.493686-5-stefanha@redhat.com>
[eblake: also fix migration/rdma.c]
Signed-off-by: Eric Blake <eblake@redhat.com>

show more ...

Merge tag 'migration-20230206-pull-request' of https://gitlab.com/juan.quintela/qemu into staging

Migration Pull request

In this try
- rebase to latest upstream
- same than previous patch
- fix com

Merge tag 'migration-20230206-pull-request' of https://gitlab.com/juan.quintela/qemu into staging

Migration Pull request

In this try
- rebase to latest upstream
- same than previous patch
- fix compilation on non linux (userfaultfd.h) (me)
- query-migrationthreads (jiang)
- fix race on reading MultiFDPages_t.block (zhenzhong)
- fix flush of zero copy page send reuest (zhenzhong)

Please apply.

Previous try:
It includes:
- David Hildenbrand fixes for virtio-men
- David Gilbert canary to detect problems
- Fix for rdma return values (Fiona)
- Peter Xu uffd_open fixes
- Peter Xu show right downtime for postcopy
- manish.mishra msg fix fixes
- my vfio changes.

Please apply.

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# gpg: aka "Juan Quintela <quintela@trasno.org>" [full]
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* tag 'migration-20230206-pull-request' of https://gitlab.com/juan.quintela/qemu: (30 commits)
migration: save/delete migration thread info
migration: Introduce interface query-migrationthreads
multifd: Fix flush of zero copy page send request
multifd: Fix a race on reading MultiFDPages_t.block
migration: check magic value for deciding the mapping of channels
io: Add support for MSG_PEEK for socket channel
migration/dirtyrate: Show sample pages only in page-sampling mode
migration: Perform vmsd structure check during tests
migration: Add canary to VMSTATE_END_OF_LIST
migration/rdma: fix return value for qio_channel_rdma_{readv,writev}
migration: Show downtime during postcopy phase
virtio-mem: Proper support for preallocation with migration
virtio-mem: Migrate immutable properties early
virtio-mem: Fail if a memory backend with "prealloc=on" is specified
migration/ram: Factor out check for advised postcopy
migration/vmstate: Introduce VMSTATE_WITH_TMP_TEST() and VMSTATE_BITMAP_TEST()
migration/savevm: Allow immutable device state to be migrated early (i.e., before RAM)
migration/savevm: Prepare vmdesc json writer in qemu_savevm_state_setup()
migration/savevm: Move more savevm handling into vmstate_save()
migration/ram: Optimize ram_write_tracking_start() for RamDiscardManager
...

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

show more ...

io: Add support for MSG_PEEK for socket channel

MSG_PEEK peeks at the channel, The data is treated as unread and
the next read shall still return this data. This support is
currently added only for

io: Add support for MSG_PEEK for socket channel

MSG_PEEK peeks at the channel, The data is treated as unread and
the next read shall still return this data. This support is
currently added only for socket class. Extra parameter 'flags'
is added to io_readv calls to pass extra read flags like MSG_PEEK.

Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Suggested-by: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: manish.mishra <manish.mishra@nutanix.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

show more ...

Merge tag 'pull-migration-20220623b' of https://gitlab.com/dagrh/qemu into staging

[v3] Migration pull 2022-06-23

This replaces my and Juan's earlier pulls over the last 2 days;
4th time lucky?

Co

Merge tag 'pull-migration-20220623b' of https://gitlab.com/dagrh/qemu into staging

[v3] Migration pull 2022-06-23

This replaces my and Juan's earlier pulls over the last 2 days;
4th time lucky?

Compared to my pull earlier:
Removed Hyman's dirty ring set

In this migration PULL request:
- Dainiel Berrangé - qemufileops cleanup
- Leonardo Bras - cleanups for zero copy
- Juan Quintela - RDMA cleanups

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

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* tag 'pull-migration-20220623b' of https://gitlab.com/dagrh/qemu: (25 commits)
migration: remove the QEMUFileOps abstraction
migration: remove the QEMUFileOps 'get_return_path' callback
migration: remove the QEMUFileOps 'writev_buffer' callback
migration: remove the QEMUFileOps 'get_buffer' callback
migration: remove the QEMUFileOps 'close' callback
migration: remove the QEMUFileOps 'set_blocking' callback
migration: remove the QEMUFileOps 'shut_down' callback
migration: remove unused QEMUFileGetFD typedef / qemu_get_fd method
migration: introduce new constructors for QEMUFile
migration: hardcode assumption that QEMUFile is backed with QIOChannel
migration: stop passing 'opaque' parameter to QEMUFile hooks
migration: convert savevm to use QIOChannelBlock for VMState
migration: introduce a QIOChannel impl for BlockDriverState VMState
migration: rename qemu_file_update_transfer to qemu_file_acct_rate_limit
migration: rename qemu_update_position to qemu_file_credit_transfer
migration: rename qemu_ftell to qemu_file_total_transferred
migration: rename 'pos' field in QEMUFile to 'bytes_processed'
migration: rename rate limiting fields in QEMUFile
migration: remove unreachble RDMA code in save_hook impl
migration: switch to use QIOChannelNull for dummy channel
...

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

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io: add a QIOChannelNull equivalent to /dev/null

This is for code which needs a portable equivalent to a QIOChannelFile
connected to /dev/null.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.co

io: add a QIOChannelNull equivalent to /dev/null

This is for code which needs a portable equivalent to a QIOChannelFile
connected to /dev/null.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

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