Commit graph

120873 commits

Author SHA1 Message Date
Paolo Bonzini
0b9d05e3c9 rust: cell: add wrapper for FFI types
Inspired by the same-named type in Linux.  This type provides the compiler
with a correct view of what goes on with FFI types.  In addition, it
separates the glue code from the bindgen-generated code, allowing
traits such as Send, Sync or Zeroable to be specified independently
for C and Rust structs.

Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2025-03-06 12:44:46 +01:00
Nabih Estefan
cff666a3ae scripts: dump stdin on meson-buildoptions error
Dump sys.stdin when it errors on meson-buildoptions.py, letting us debug
the build errors instead of just saying "Couldn't parse"

Signed-off-by: Nabih Estefan <nabihestefan@google.com>
Signed-off-by: Patrick Venture <venture@google.com>
Link: https://lore.kernel.org/r/20250227180454.2006757-1-venture@google.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2025-03-06 12:44:46 +01:00
Paolo Bonzini
41494da7df chardev: express dependency on io/
chardev is using qio functions, so express that in the Meson internal
dependency.  (I found this when adding character devices bindings for
Rust; they initially needed the io dependency added by hand).

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2025-03-06 12:44:46 +01:00
Markus Armbruster
71ba2613ad docs/devel/qapi-code-gen: Discourage use of 'prefix'
QAPI's 'prefix' feature can make the connection between enumeration
type and its constants less than obvious.  It's best used with
restraint.  Commit 7bbadc60b5..64f5e9db77 eliminated most uses.
Discourage new ones.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20250228134335.132278-1-armbru@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2025-03-06 10:33:05 +01:00
Markus Armbruster
45e5b49360 qdev: Improve a few more PropertyInfo @description members
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20250227085601.4140852-7-armbru@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2025-03-06 10:33:05 +01:00
Markus Armbruster
0b9d12b03c qdev: Improve PropertyInfo member @description for enum properties
Consistently use format "DESCRIPTION (VALUE/VALUE...)".

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20250227085601.4140852-6-armbru@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2025-03-06 10:33:05 +01:00
Markus Armbruster
ff30d3b1ac qdev: Change values of PropertyInfo member @type to be QAPI types
PropertyInfo member @type is externally visible via QMP
device-list-properties and qom-list-properies.

Its meaning is not documented at its definition.

It gets passed as @type argument to object_property_add() and
object_class_property_add().  This argument's documentation isn't of
much help, either:

 * @type: the type name of the property.  This namespace is pretty loosely
 *   defined.  Sub namespaces are constructed by using a prefix and then
 *   to angle brackets.  For instance, the type 'virtio-net-pci' in the
 *   'link' namespace would be 'link<virtio-net-pci>'.

The two QMP commands document it as

 # @type: the type of the property.  This will typically come in one of
 #     four forms:
 #
 #     1) A primitive type such as 'u8', 'u16', 'bool', 'str', or
 #        'double'.  These types are mapped to the appropriate JSON
 #        type.
 #
 #     2) A child type in the form 'child<subtype>' where subtype is a
 #        qdev device type name.  Child properties create the
 #        composition tree.
 #
 #     3) A link type in the form 'link<subtype>' where subtype is a
 #        qdev device type name.  Link properties form the device model
 #        graph.

"Typically come in one of four forms" followed by three items inspires
the level of trust that is appropriate here.

Clean up a bunch of funnies:

* qdev_prop_fdc_drive_type.type is "FdcDriveType".  Its .enum_table
  refers to QAPI type "FloppyDriveType".  So use that.

* qdev_prop_reserved_region is "reserved_region".  Its only user is an
  array property called "reserved-regions".  Its .set() visits str.
  So change @type to "str".

* trng_prop_fault_event_set.type is "uint32:bits".  Its .set() visits
  uint32, so change @type to "uint32".  If we believe mentioning it's
  actually bits is useful, the proper place would be .description.

* ccw_loadparm.type is "ccw_loadparm".  It's users are properties
  called "loadparm".  Its .set() visits str.  So change @type to
  "str".

* qdev_prop_nv_gpudirect_clique.type is "uint4".  Its set() visits
  uint8, so change @type to "uint8".  If we believe mentioning the
  range is useful, the proper place would be .description.

* s390_pci_fid_propinfo.type is "zpci_fid".  Its .set() visits uint32.
  So change type to that, and move the "zpci_fid" to .description.
  This is admittedly a lousy description, but it's still an
  improvement; for instance, output of -device zpci,help changes from

      fid=<zpci_fid>

  to

      fid=<uint32>           - zpci_fid

* Similarly for a raft of PropertyInfo in target/riscv/cpu.c.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20250227085601.4140852-5-armbru@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
[Commit message typo fixed]
2025-03-06 10:33:05 +01:00
Markus Armbruster
c98dac169e qdev: Rename PropertyInfo member @name to @type
PropertyInfo member @name becomes ObjectProperty member @type, while
Property member @name becomes ObjectProperty member @name.  Rename the
former.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20250227085601.4140852-4-armbru@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
[One missed instance of @type fixed]
2025-03-06 10:30:58 +01:00
Markus Armbruster
e09daf1dff qdev: Change qdev_prop_pci_devfn member @name from "int32" to "str"
Properties using qdev_prop_pci_devfn initially accepted a string of
the form "DEV.FN" or "DEV" where DEV and FN are in hexadecimal.
Member @name was "pci-devfn" initially.

Commit b403298adb (qdev: make the non-legacy pci address property
accept an integer) changed them to additionally accept integers: bits
3..7 are DEV, and bits 0..2 are FN.  This is inaccessible externally
in device_add so far.

The commit also changed @name to "int32", and set member @legacy-name
to "pci-devfn".  Together, this kept QMP command
device-list-properties unaffected: it used @name only when
@legacy_name was null.

Commit 07d09c58db (qmp: Print descriptions of object properties)
quietly dumbed that down to use @name always, and the next commit
18b91a3e082q (qdev: Drop legacy_name from qdev properties) dropped
member @legacy_name.  This changed the value of @type reported by QMP
command device-list-properties from "pci-devfn" to "int32".

But "int32" is misleading: device_add actually wants QAPI type "str".
So change @name to that.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20250227085601.4140852-3-armbru@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2025-03-06 10:09:27 +01:00
Markus Armbruster
744bce1bf7 qdev: Delete unused qdev_prop_enum
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20250227085601.4140852-2-armbru@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2025-03-06 10:09:27 +01:00
Markus Armbruster
e6985cc440 qapi/introspect: Use @dataclass to simplify
A TODO comment in class Annotated reminds us to simplify it once we
can use @dataclass, new in Python 3.7.  We have that now, so do it.

There's a similar comment in scripts/qapi/source.py, but I can't
figure out how to use @dataclass there.  Left for another day.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20250227080757.3978333-4-armbru@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2025-03-06 10:09:25 +01:00
Markus Armbruster
5fbc8126ac qapi: Eliminate OrderedDict
We use OrderedDict to ensure dictionary order is insertion order.
Plain dict does that since Python 3.6, but it wasn't guaranteed until
3.7.  Since we have 3.7 now, replace OrderedDict by dict.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20250227080757.3978333-3-armbru@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2025-03-06 10:09:22 +01:00
Markus Armbruster
87c8b4fc3c docs/about/build-platforms: Correct minimum supported Python version
Fixes: ca056f4499 (Python: Drop support for Python 3.7)
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20250227080757.3978333-2-armbru@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
2025-03-06 10:09:10 +01:00
Daniel P. Berrangé
188f719295 tests/functional: reduce tuxrun maxmem to work on 32-bit hosts
maxmem=4G is too large to address on 32-bit hosts, so reduce it
to 2G since the tuxrun tests don't actually need such an elevated
memory limit.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-ID: <20250228102738.3064045-5-berrange@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
2025-03-06 08:10:04 +01:00
Daniel P. Berrangé
8188356a26 tests/functional: set 'qemu_bin' as an object level field
The 'qemu_bin' field is currently set on the class, despite being
accessed as if it were an object instance field with 'self.qemu_bin'.

This is no obvious need to have it as a class field, so move it into
the object instance.

Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-ID: <20250228102738.3064045-3-berrange@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
2025-03-06 08:10:04 +01:00
Daniel P. Berrangé
6c5a1467f8 tests/functional: remove unused 'bin_prefix' variable
This was copied over from avocado but has not been used in the new
functional tests.

Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-ID: <20250228102738.3064045-2-berrange@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
2025-03-06 08:10:04 +01:00
Maciej S. Szmigiero
59a67e7095 hw/core/machine: Add compat for x-migration-multifd-transfer VFIO property
Add a hw_compat entry for recently added x-migration-multifd-transfer VFIO
property.

Reviewed-by: Cédric Le Goater <clg@redhat.com>
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Link: https://lore.kernel.org/qemu-devel/92c354f0457c152d1f267cc258c6967fff551cb1.1741124640.git.maciej.szmigiero@oracle.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2025-03-06 06:47:34 +01:00
Maciej S. Szmigiero
4c765ceaac vfio/migration: Make x-migration-multifd-transfer VFIO property mutable
DEFINE_PROP_ON_OFF_AUTO() property isn't runtime-mutable so using it
would mean that the source VM would need to decide upfront at startup
time whether it wants to do a multifd device state transfer at some
point.

Source VM can run for a long time before being migrated so it is
desirable to have a fallback mechanism to the old way of transferring
VFIO device state if it turns to be necessary.

This brings this property to the same mutability level as ordinary
migration parameters, which too can be adjusted at the run time.

Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Link: https://lore.kernel.org/qemu-devel/f2f2d66bda477da3e6cb8c0311006cff36e8651d.1741124640.git.maciej.szmigiero@oracle.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2025-03-06 06:47:34 +01:00
Maciej S. Szmigiero
623af41dd3 vfio/migration: Add x-migration-multifd-transfer VFIO property
This property allows configuring whether to transfer the particular device
state via multifd channels when live migrating that device.

It defaults to AUTO, which means that VFIO device state transfer via
multifd channels is attempted in configurations that otherwise support it.

Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Link: https://lore.kernel.org/qemu-devel/d6dbb326e3d53c7104d62c96c9e3dd64e1c7b940.1741124640.git.maciej.szmigiero@oracle.com
[ clg: Added documentation ]
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2025-03-06 06:47:34 +01:00
Maciej S. Szmigiero
6d644baef2 vfio/migration: Multifd device state transfer support - send side
Implement the multifd device state transfer via additional per-device
thread inside save_live_complete_precopy_thread handler.

Switch between doing the data transfer in the new handler and doing it
in the old save_state handler depending if VFIO multifd transfer is enabled
or not.

Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Link: https://lore.kernel.org/qemu-devel/4d727e2e0435e0022d50004e474077632830e08d.1741124640.git.maciej.szmigiero@oracle.com
[ clg: - Reordered savevm_vfio_handlers
       - Updated save_live_complete_precopy* documentation ]
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2025-03-06 06:47:34 +01:00
Maciej S. Szmigiero
b659c07c53 vfio/migration: Multifd device state transfer support - config loading support
Load device config received via multifd using the existing machinery
behind vfio_load_device_config_state().

Also, make sure to process the relevant main migration channel flags.

Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Link: https://lore.kernel.org/qemu-devel/5dbd3f3703ec1097da2cf82a7262233452146fee.1741124640.git.maciej.szmigiero@oracle.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2025-03-06 06:47:34 +01:00
Maciej S. Szmigiero
fda70ed83d migration/qemu-file: Define g_autoptr() cleanup function for QEMUFile
Automatic memory management helps avoid memory safety issues.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Link: https://lore.kernel.org/qemu-devel/2fd01d773a783d572dcf538a064a98cc09e75c12.1741124640.git.maciej.szmigiero@oracle.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2025-03-06 06:47:34 +01:00
Maciej S. Szmigiero
c59748c1ff vfio/migration: Multifd device state transfer support - load thread
Add a thread which loads the VFIO device state buffers that were received
via multifd.

Each VFIO device that has multifd device state transfer enabled has one
such thread, which is created using migration core API
qemu_loadvm_start_load_thread().

Since it's important to finish loading device state transferred via the
main migration channel (via save_live_iterate SaveVMHandler) before
starting loading the data asynchronously transferred via multifd the thread
doing the actual loading of the multifd transferred data is only started
from switchover_start SaveVMHandler.

switchover_start handler is called when MIG_CMD_SWITCHOVER_START
sub-command of QEMU_VM_COMMAND is received via the main migration channel.

This sub-command is only sent after all save_live_iterate data have already
been posted so it is safe to commence loading of the multifd-transferred
device state upon receiving it - loading of save_live_iterate data happens
synchronously in the main migration thread (much like the processing of
MIG_CMD_SWITCHOVER_START) so by the time MIG_CMD_SWITCHOVER_START is
processed all the proceeding data must have already been loaded.

Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Link: https://lore.kernel.org/qemu-devel/9abe612d775aaf42e31646796acd2363c723a57a.1741124640.git.maciej.szmigiero@oracle.com
[ clg: - Reordered savevm_vfio_handlers
       - Added switchover_start documentation ]
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2025-03-06 06:47:34 +01:00
Maciej S. Szmigiero
3228d311ab vfio/migration: Multifd device state transfer support - received buffers queuing
The multifd received data needs to be reassembled since device state
packets sent via different multifd channels can arrive out-of-order.

Therefore, each VFIO device state packet carries a header indicating its
position in the stream.
The raw device state data is saved into a VFIOStateBuffer for later
in-order loading into the device.

The last such VFIO device state packet should have
VFIO_DEVICE_STATE_CONFIG_STATE flag set and carry the device config state.

Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Link: https://lore.kernel.org/qemu-devel/e3bff515a8d61c582b94b409eb12a45b1a143a69.1741124640.git.maciej.szmigiero@oracle.com
[ clg: - Reordered savevm_vfio_handlers
       - Added load_state_buffer documentation ]
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2025-03-06 06:47:34 +01:00
Maciej S. Szmigiero
6bcffb1cad vfio/migration: Setup and cleanup multifd transfer in these general methods
Wire VFIO multifd transfer specific setup and cleanup functions into
general VFIO load/save setup and cleanup methods.

Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Link: https://lore.kernel.org/qemu-devel/b1f864a65fafd4fdab1f89230df52e46ae41f2ac.1741124640.git.maciej.szmigiero@oracle.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2025-03-06 06:47:34 +01:00
Maciej S. Szmigiero
ff2fd1f7e2 vfio/migration: Multifd setup/cleanup functions and associated VFIOMultifd
Add multifd setup/cleanup functions and an associated VFIOMultifd data
structure that will contain most of the receive-side data together
with its init/cleanup methods.

Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Link: https://lore.kernel.org/qemu-devel/c0520523053b1087787152ddf2163257d3030be0.1741124640.git.maciej.szmigiero@oracle.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2025-03-06 06:47:34 +01:00
Maciej S. Szmigiero
2efa35d34e vfio/migration: Multifd device state transfer - add support checking function
Add vfio_multifd_transfer_supported() function that tells whether the
multifd device state transfer is supported.

Reviewed-by: Cédric Le Goater <clg@redhat.com>
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Link: https://lore.kernel.org/qemu-devel/8ce50256f341b3d47342bb217cb5fbb2deb14639.1741124640.git.maciej.szmigiero@oracle.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2025-03-06 06:47:34 +01:00
Maciej S. Szmigiero
961165122b vfio/migration: Multifd device state transfer support - basic types
Add basic types and flags used by VFIO multifd device state transfer
support.

Since we'll be introducing a lot of multifd transfer specific code,
add a new file migration-multifd.c to home it, wired into main VFIO
migration code (migration.c) via migration-multifd.h header file.

Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Link: https://lore.kernel.org/qemu-devel/4eedd529e6617f80f3d6a66d7268a0db2bc173fa.1741124640.git.maciej.szmigiero@oracle.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2025-03-06 06:47:34 +01:00
Maciej S. Szmigiero
eb6608619a vfio/migration: Move migration channel flags to vfio-common.h header file
This way they can also be referenced in other translation
units than migration.c.

Reviewed-by: Cédric Le Goater <clg@redhat.com>
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Link: https://lore.kernel.org/qemu-devel/26a940f6b22c1b685818251b7a3ddbbca601b1d6.1741124640.git.maciej.szmigiero@oracle.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2025-03-06 06:47:33 +01:00
Maciej S. Szmigiero
47c7133629 vfio/migration: Add vfio_add_bytes_transferred()
This way bytes_transferred can also be incremented in other translation
units than migration.c.

Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Link: https://lore.kernel.org/qemu-devel/d1fbc27ac2417b49892f354ba20f6c6b3f7209f8.1741124640.git.maciej.szmigiero@oracle.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2025-03-06 06:47:33 +01:00
Maciej S. Szmigiero
bd846c5d58 vfio/migration: Convert bytes_transferred counter to atomic
So it can be safety accessed from multiple threads.

This variable type needs to be changed to unsigned long since
32-bit host platforms lack the necessary addition atomics on 64-bit
variables.

Using 32-bit counters on 32-bit host platforms should not be a problem
in practice since they can't realistically address more memory anyway.

Reviewed-by: Cédric Le Goater <clg@redhat.com>
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Link: https://lore.kernel.org/qemu-devel/dc391771d2d9ad0f311994f0cb9e666da564aeaf.1741124640.git.maciej.szmigiero@oracle.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2025-03-06 06:47:33 +01:00
Maciej S. Szmigiero
5963c219a0 vfio/migration: Add load_device_config_state_start trace event
And rename existing load_device_config_state trace event to
load_device_config_state_end for consistency since it is triggered at the
end of loading of the VFIO device config state.

This way both the start and end points of particular device config
loading operation (a long, BQL-serialized operation) are known.

Reviewed-by: Cédric Le Goater <clg@redhat.com>
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Link: https://lore.kernel.org/qemu-devel/1b6c5a2097e64c272eb7e53f9e4cca4b79581b38.1741124640.git.maciej.szmigiero@oracle.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2025-03-06 06:47:33 +01:00
Maciej S. Szmigiero
8305921a91 migration: Add save_live_complete_precopy_thread handler
This SaveVMHandler helps device provide its own asynchronous transmission
of the remaining data at the end of a precopy phase via multifd channels,
in parallel with the transfer done by save_live_complete_precopy handlers.

These threads are launched only when multifd device state transfer is
supported.

Management of these threads in done in the multifd migration code,
wrapping them in the generic thread pool.

Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Link: https://lore.kernel.org/qemu-devel/eac74a4ca7edd8968bbf72aa07b9041c76364a16.1741124640.git.maciej.szmigiero@oracle.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2025-03-06 06:47:33 +01:00
Maciej S. Szmigiero
a1131aa942 migration/multifd: Add multifd_device_state_supported()
Since device state transfer via multifd channels requires multifd
channels with packets and is currently not compatible with multifd
compression add an appropriate query function so device can learn
whether it can actually make use of it.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Link: https://lore.kernel.org/qemu-devel/1ff0d98b85f470e5a33687406e877583b8fab74e.1741124640.git.maciej.szmigiero@oracle.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2025-03-06 06:47:33 +01:00
Peter Xu
99fab22350 migration/multifd: Make MultiFDSendData a struct
The newly introduced device state buffer can be used for either storing
VFIO's read() raw data, but already also possible to store generic device
states.  After noticing that device states may not easily provide a max
buffer size (also the fact that RAM MultiFDPages_t after all also want to
have flexibility on managing offset[] array), it may not be a good idea to
stick with union on MultiFDSendData.. as it won't play well with such
flexibility.

Switch MultiFDSendData to a struct.

It won't consume a lot more space in reality, after all the real buffers
were already dynamically allocated, so it's so far only about the two
structs (pages, device_state) that will be duplicated, but they're small.

With this, we can remove the pretty hard to understand alloc size logic.
Because now we can allocate offset[] together with the SendData, and
properly free it when the SendData is freed.

[MSS: Make sure to clear possible device state payload before freeing
MultiFDSendData, remove placeholders for other patches not included]

Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Acked-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/qemu-devel/7b02baba8e6ddb23ef7c349d312b9b631db09d7e.1741124640.git.maciej.szmigiero@oracle.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2025-03-06 06:47:33 +01:00
Maciej S. Szmigiero
0525b91a0b migration/multifd: Device state transfer support - send side
A new function multifd_queue_device_state() is provided for device to queue
its state for transmission via a multifd channel.

Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Link: https://lore.kernel.org/qemu-devel/ebd55768d3e5fecb5eb3f197bad9c0c07e5bc084.1741124640.git.maciej.szmigiero@oracle.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2025-03-06 06:47:33 +01:00
Maciej S. Szmigiero
7ecfab1ddd migration/multifd: Add an explicit MultiFDSendData destructor
This way if there are fields there that needs explicit disposal (like, for
example, some attached buffers) they will be handled appropriately.

Add a related assert to multifd_set_payload_type() in order to make sure
that this function is only used to fill a previously empty MultiFDSendData
with some payload, not the other way around.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Link: https://lore.kernel.org/qemu-devel/6755205f2b95abbed251f87061feee1c0e410836.1741124640.git.maciej.szmigiero@oracle.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2025-03-06 06:47:33 +01:00
Maciej S. Szmigiero
d19cc4dca0 migration/multifd: Make multifd_send() thread safe
multifd_send() function is currently not thread safe, make it thread safe
by holding a lock during its execution.

This way it will be possible to safely call it concurrently from multiple
threads.

Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Link: https://lore.kernel.org/qemu-devel/dd0f3bcc02ca96a7d523ca58ea69e495a33b453b.1741124640.git.maciej.szmigiero@oracle.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2025-03-06 06:47:33 +01:00
Maciej S. Szmigiero
f588f3c46a migration/multifd: Device state transfer support - receive side
Add a basic support for receiving device state via multifd channels -
channels that are shared with RAM transfers.

Depending whether MULTIFD_FLAG_DEVICE_STATE flag is present or not in the
packet header either device state (MultiFDPacketDeviceState_t) or RAM
data (existing MultiFDPacket_t) is read.

The received device state data is provided to
qemu_loadvm_load_state_buffer() function for processing in the
device's load_state_buffer handler.

Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Link: https://lore.kernel.org/qemu-devel/9b86f806c134e7815ecce0eee84f0e0e34aa0146.1741124640.git.maciej.szmigiero@oracle.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2025-03-06 06:47:33 +01:00
Maciej S. Szmigiero
8050c435b7 migration/multifd: Split packet into header and RAM data
Read packet header first so in the future we will be able to
differentiate between a RAM multifd packet and a device state multifd
packet.

Since these two are of different size we can't read the packet body until
we know which packet type it is.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Link: https://lore.kernel.org/qemu-devel/832ad055fe447561ac1ad565d61658660cb3f63f.1741124640.git.maciej.szmigiero@oracle.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2025-03-06 06:47:33 +01:00
Maciej S. Szmigiero
b1937fd1eb migration: Add thread pool of optional load threads
Some drivers might want to make use of auxiliary helper threads during VM
state loading, for example to make sure that their blocking (sync) I/O
operations don't block the rest of the migration process.

Add a migration core managed thread pool to facilitate this use case.

The migration core will wait for these threads to finish before
(re)starting the VM at destination.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Link: https://lore.kernel.org/qemu-devel/b09fd70369b6159c75847e69f235cb908b02570c.1741124640.git.maciej.szmigiero@oracle.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2025-03-06 06:47:33 +01:00
Maciej S. Szmigiero
18eb55546a error: define g_autoptr() cleanup function for the Error type
Automatic memory management helps avoid memory safety issues.

Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Link: https://lore.kernel.org/qemu-devel/a5843c5fa64d7e5239a4316092ec0ef0d10c2320.1741124640.git.maciej.szmigiero@oracle.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2025-03-06 06:47:33 +01:00
Maciej S. Szmigiero
6a76eb4872 migration: Always take BQL for migration_incoming_state_destroy()
All callers to migration_incoming_state_destroy() other than
postcopy_ram_listen_thread() do this call with BQL held.

Since migration_incoming_state_destroy() ultimately calls "load_cleanup"
SaveVMHandlers and it will soon call BQL-sensitive code it makes sense
to always call that function under BQL rather than to have it deal with
both cases (with BQL and without BQL).
Add the necessary bql_lock() and bql_unlock() to
postcopy_ram_listen_thread().

qemu_loadvm_state_main() in postcopy_ram_listen_thread() could call
"load_state" SaveVMHandlers that are expecting BQL to be held.

In principle, the only devices that should be arriving on migration
channel serviced by postcopy_ram_listen_thread() are those that are
postcopiable and whose load handlers are safe to be called without BQL
being held.

But nothing currently prevents the source from sending data for "unsafe"
devices which would cause trouble there.
Add a TODO comment there so it's clear that it would be good to improve
handling of such (erroneous) case in the future.

Acked-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Link: https://lore.kernel.org/qemu-devel/21bb5ca337b1d5a802e697f553f37faf296b5ff4.1741193259.git.maciej.szmigiero@oracle.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2025-03-06 06:47:33 +01:00
Maciej S. Szmigiero
a30363db08 migration: Add qemu_loadvm_load_state_buffer() and its handler
qemu_loadvm_load_state_buffer() and its load_state_buffer
SaveVMHandler allow providing device state buffer to explicitly
specified device via its idstr and instance id.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Link: https://lore.kernel.org/qemu-devel/71ca753286b87831ced4afd422e2e2bed071af25.1741124640.git.maciej.szmigiero@oracle.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2025-03-06 06:47:33 +01:00
Maciej S. Szmigiero
4e55cb3cde migration: Add MIG_CMD_SWITCHOVER_START and its load handler
This QEMU_VM_COMMAND sub-command and its switchover_start SaveVMHandler is
used to mark the switchover point in main migration stream.

It can be used to inform the destination that all pre-switchover main
migration stream data has been sent/received so it can start to process
post-switchover data that it might have received via other migration
channels like the multifd ones.

Add also the relevant MigrationState bit stream compatibility property and
its hw_compat entry.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Zhang Chen <zhangckid@gmail.com> # for the COLO part
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Link: https://lore.kernel.org/qemu-devel/311be6da85fc7e49a7598684d80aa631778dcbce.1741124640.git.maciej.szmigiero@oracle.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2025-03-06 06:47:33 +01:00
Maciej S. Szmigiero
b5aa74968b thread-pool: Implement generic (non-AIO) pool support
Migration code wants to manage device data sending threads in one place.

QEMU has an existing thread pool implementation, however it is limited
to queuing AIO operations only and essentially has a 1:1 mapping between
the current AioContext and the AIO ThreadPool in use.

Implement generic (non-AIO) ThreadPool by essentially wrapping Glib's
GThreadPool.

This brings a few new operations on a pool:
* thread_pool_wait() operation waits until all the submitted work requests
have finished.

* thread_pool_set_max_threads() explicitly sets the maximum thread count
in the pool.

* thread_pool_adjust_max_threads_to_work() adjusts the maximum thread count
in the pool to equal the number of still waiting in queue or unfinished work.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Link: https://lore.kernel.org/qemu-devel/b1efaebdbea7cb7068b8fb74148777012383e12b.1741124640.git.maciej.szmigiero@oracle.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2025-03-06 06:47:33 +01:00
Maciej S. Szmigiero
dc67daeed5 thread-pool: Rename AIO pool functions to *_aio() and data types to *Aio
These names conflict with ones used by future generic thread pool
equivalents.
Generic names should belong to the generic pool type, not specific (AIO)
type.

Acked-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Link: https://lore.kernel.org/qemu-devel/70f9e0fb4b01042258a1a57996c64d19779dc7f0.1741124640.git.maciej.szmigiero@oracle.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2025-03-06 06:47:33 +01:00
Maciej S. Szmigiero
03c6468a13 thread-pool: Remove thread_pool_submit() function
This function name conflicts with one used by a future generic thread pool
function and it was only used by one test anyway.

Update the trace event name in thread_pool_submit_aio() accordingly.

Acked-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Link: https://lore.kernel.org/qemu-devel/6830f07777f939edaf0a2d301c39adcaaf3817f0.1741124640.git.maciej.szmigiero@oracle.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2025-03-06 06:47:33 +01:00
Maciej S. Szmigiero
d3237d0d85 migration: Clarify that {load, save}_cleanup handlers can run without setup
It's possible for {load,save}_cleanup SaveVMHandlers to get called without
the corresponding {load,save}_setup handler being called first.

One such example is if {load,save}_setup handler of a proceeding device
returns error.
In this case the migration core cleanup code will call all corresponding
cleanup handlers, even for these devices which haven't had its setup
handler called.

Since this behavior can generate some surprises let's clearly document it
in these SaveVMHandlers description.

Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Link: https://lore.kernel.org/qemu-devel/991636623fb780350f493b5f045cb17e13ce4c0f.1741124640.git.maciej.szmigiero@oracle.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2025-03-06 06:47:33 +01:00
Eric Auger
8d8a30d1ac vfio-platform: Deprecate all forms of vfio-platform devices
As an outcome of KVM forum 2024 "vfio-platform: live and let die?"
talk, let's deprecate vfio-platform devices.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Link: https://lore.kernel.org/qemu-devel/20250305124225.952791-1-eric.auger@redhat.com
[ clg: Fixed spelling in vfio-amd-xgbe section ]
Signed-off-by: Cédric Le Goater <clg@redhat.com>
2025-03-06 06:47:33 +01:00