[PATCH 00/11] rust: migration: add high-level migration wrappers

[Paolo Bonzini <pbonzini@redhat.com>]

This series adds high-level wrappers to handle migration state; they consist
of a Migratable<> type that implements the snapshotting technique mentioned
in Zhao and my KVM Forum presentation.

The wrappers (should) make it possible to easily implement migration of
thread-safe devices.  I say "should" because, even though there are tests
included in the series, they are anything but "battle tested"; for this
reason they are marked as "proof of concept" in docs/devel/rust.rst.
The first device to use this will be HPET.

This is an interesting step in enabling usage of Rust in QEMU; instead of
just wrapping existing C APIs, it provides a new interface that deals
better with unique features of the Rust language.  In other words,
something like Migratable<> and ToMigrationState might hypothetically
exist even if QEMU was written in Rust from scratch.

Paolo


RFC->v1:

new patches
- rust: migration: do not pass raw pointer to VMStateDescription::fields
- rust: migration: do not store raw pointers into VMStateSubsectionsWrapper
- rust: migration: validate termination of subsection arrays
- timer: constify some functions

changes
- use UnsafeCell::get_mut()
- add and use Timer::expire_time_ns()
- small reordering of the implementations of ToMigrationState/ToMigrationStateShared
- list migration::migratable in docs/devel/rust.rst


Paolo Bonzini (11):
  rust: bql: add BqlRefCell::get_mut()
  rust: migration: do not pass raw pointer to VMStateDescription::fields
  rust: migration: do not store raw pointers into
    VMStateSubsectionsWrapper
  rust: migration: validate termination of subsection arrays
  rust: migration: extract vmstate_fields_ref
  rust: move VMState from bql to migration
  rust: migration: add high-level migration wrappers
  rust: qemu-macros: add ToMigrationState derive macro
  timer: constify some functions
  rust: migration: implement ToMigrationState for Timer
  rust: migration: implement ToMigrationState as part of
    impl_vmstate_bitsized

 docs/devel/rust.rst                     |   1 +
 include/qemu/timer.h                    |   6 +-
 util/qemu-timer.c                       |   8 +-
 rust/Cargo.lock                         |   5 +-
 rust/bql/Cargo.toml                     |   3 -
 rust/bql/meson.build                    |   1 -
 rust/bql/src/cell.rs                    |  23 +-
 rust/meson.build                        |   2 +-
 rust/migration/Cargo.toml               |   2 +
 rust/migration/meson.build              |   7 +-
 rust/migration/src/lib.rs               |   5 +
 rust/migration/src/migratable.rs        | 473 ++++++++++++++++++++++++
 rust/migration/src/vmstate.rs           |  85 +++--
 rust/qemu-macros/src/lib.rs             |  88 +++++
 rust/qemu-macros/src/migration_state.rs | 296 +++++++++++++++
 rust/qemu-macros/src/tests.rs           | 112 +++++-
 rust/util/src/timer.rs                  |  10 +-
 17 files changed, 1071 insertions(+), 56 deletions(-)
 create mode 100644 rust/migration/src/migratable.rs
 create mode 100644 rust/qemu-macros/src/migration_state.rs

-- 
2.51.0