Validate that all files that are necessary for TLS encryption are in the
given folder. The knowledge which files are necessary is part of the TLS
module.
On-behalf-of: SAP sebastian.eydam@sap.com
Signed-off-by: Sebastian Eydam <sebastian.eydam@cyberus-technology.de>
Extend ReceiveListener with a TLS-backed listener variant for migration
receivers.
Store the TCP listener together with the server TLS configuration, wrap
accepted sockets in TlsStream::new_server(), and preserver the existing
listener cloning and fd polling behavior so receive-side migration code
can treat TLS listeners like the existing TCP and UNIX cases.
On-behalf-of: SAP sebastian.eydam@sap.com
Signed-off-by: Sebastian Eydam <sebastian.eydam@cyberus-technology.de>
Teach the migration transport to handle TLS-backed streams alongside
plain TCP and UNIX sockets.
Introduce a Tls variant in SocketStream and implement the necessary
traits.
Also updates the local-migration error path to reject any non-UNIX
transport, which now includes TLS-wrapped TCP connections.
On-behalf-of: SAP sebastian.eydam@sap.com
Signed-off-by: Sebastian Eydam <sebastian.eydam@cyberus-technology.de>
TLS connections have a TLS server (listens for incoming connections) and
a TLS client (initiates the connection). This commit adds the code for
the client side, which is the sender of a migration
On-behalf-of: SAP sebastian.eydam@sap.com
Signed-off-by: Sebastian Eydam <sebastian.eydam@cyberus-technology.de>
Validate the sender's migration protocol version when
handling the initial Start request.
Read the version from the Start command header, accept only
the supported version window n-1..=n, and reject unsupported
versions with Error. A rejected Start moves the receiver to
the aborted state.
This keeps compatibility one-way, from older protocol
versions to newer ones, and leaves later version-based
branching on the receiver side.
Log the protocol version on both sender and receiver to make
the active migration path visible.
On-behalf-of: SAP leander.kohler@sap.com
Signed-off-by: Leander Kohler <leander.kohler@cyberus-technology.de>
Add protocol-side support for migration protocol versioning.
Use the existing 6-byte Start command header, which was
previously zero padding, to carry the sender's migration
protocol version without changing the wire layout.
Store the version as a little-endian u16 in the first two
bytes and ignore the remaining four bytes. A zeroed command
header continues to mean a legacy v0 sender.
This keeps the message flow unchanged for rollout:
Start is still followed by plain OK or Error (Aborted), and no new
command is needed.
On-behalf-of: SAP leander.kohler@sap.com
Signed-off-by: Leander Kohler <leander.kohler@cyberus-technology.de>
Import the std modules used in the crate instead of spelling the full
paths at every use site.
Signed-off-by: Henry Hrvoje Tonkovac <htonkovac@gmail.com>
Assisted-by: Claude:Opus-4.8
Reordering commands or adding commands in-between is breaking the
migration protocol. By using explicit numbers, we can increase the
attention required when touching this code.
On-behalf-of: SAP philipp.schuster@sap.com
Signed-off-by: Philipp Schuster <philipp.schuster@cyberus-technology.de>
Add two explicit disconnected-backend error paths before wiring them
into the call sites.
MigratableError::DeviceDisconnected is the lifecycle sentinel for
operations that were skipped because a component is already known to be
disconnected. It lets the caller log and continue without treating it as
a VMM-fatal condition.
Error::BackendDisconnected is the vhost-user-local error used when
VhostUserCommon refuses to call a backend after its disconnected flag is
set. The transport classifier treats socket close/reset/EOF and
vhost-user partial-message/disconnected cases as transport loss, while
backend NACKs, invalid protocol state, and retry-able socket errors
remain ordinary operation failures.
Signed-off-by: Dylan Reid <dgreid@fb.com>
This extends migration to also support paused VMs, preserving the
paused state on the destination.
Changes:
- Add CompletePaused protocol command that finalizes migration without
resuming the VM on the destination
- Skip the pause step during migration if the VM is already paused
- On migration failure, only restore the running state if
the VM was originally running (not paused)
Signed-off-by: Nguyen Dinh Phi <phind.uet@gmail.com>
Add migration-level context types that extend the existing memory-only
metrics with overall migration duration and downtime breakdown.
OngoingMigrationContext models the sender-side migration progress until
all inputs needed for final downtime accounting are available.
CompletedMigrationContext then stores the finalized migration metrics,
including the final memory iteration, snapshotting, snapshot transfer,
and completion phase.
This provides the data needed to log effective downtime in the VMM and
lays the groundwork for future migration statistics reporting.
# Terminology
At first glance, the use of "state" and "[VM] snapshot" may seem
confusing. As discussed in [0], we use "state" consistently in the
migration code. On the VM side, "snapshotting" is merely the mechanism
used to obtain the VM state.
[0] https://github.com/cloud-hypervisor/cloud-hypervisor/pull/7979#discussion_r3061359899
On-behalf-of: SAP philipp.schuster@sap.com
Signed-off-by: Philipp Schuster <philipp.schuster@cyberus-technology.de>
Expose the finalized per-iteration timing fields needed by higher-level
migration metrics and factor the iteration-overhead calculation into a
small helper.
This keeps the existing MemoryMigrationContext behavior intact while
making the timing data easier to consume from migration-level context
in the following commits.
On-behalf-of: SAP philipp.schuster@sap.com
Signed-off-by: Philipp Schuster <philipp.schuster@cyberus-technology.de>
For sending memory over multiple connections, we need a way to split up
the work. With these changes, we can chop a memory table into same-sized
chunks for transmit
On-behalf-of: SAP sebastian.eydam@sap.com
Signed-off-by: Sebastian Eydam <sebastian.eydam@cyberus-technology.de>
Wire the new `downtime_ms`, `timeout_s`, and `timeout_strategy` fields
from `VmSendMigrationData` into the precopy loop, replacing the previous
hard-coded 5-iteration cap.
Each iteration now evaluates three convergence criteria in order:
- no dirty pages remain;
- the estimated final-iteration downtime is within the configured budget
- or the overall migration timeout has elapsed.
On timeout, `TimeoutStrategy::Cancel` aborts and keeps the VM live on
the source, while `TimeoutStrategy::Force` proceeds regardless of the
downtime target. The convergence callback is updated to return a Result
to propagate the cancel error cleanly up the call stack.
With the recent changes [0], it is fairly easy to implement the new
checks and operate on actual metrics.
These changes are inspired by [1] but differ significantly in details.
[0] https://github.com/cloud-hypervisor/cloud-hypervisor/pull/7799
[1] https://github.com/cloud-hypervisor/cloud-hypervisor/pull/7033
Signed-off-by: Philipp Schuster <philipp.schuster@cyberus-technology.de>
On-behalf-of: SAP philipp.schuster@sap.com
When memory_restore_mode=ondemand is specified on the restore command,
the memory manager creates a userfaultfd descriptor, registers each
guest RAM range for missing-page fault interception, and spawns a
handler thread that serves page faults from the snapshot file using
UFFDIO_COPY. This avoids reading the entire memory-ranges file into
guest RAM before restore completes.
The handler uses epoll to multiplex the userfaultfd and a stop eventfd
for clean shutdown. Concurrent faults from multiple vCPUs are handled
by treating EEXIST as a benign race and waking blocked threads with
UFFDIO_WAKE. Once all pages have been served the handler exits
automatically. If the handler thread panics the VMM is signalled to
exit since the VM cannot continue without page fault service.
MemoryZone gains a backing_page_size field so the handler resolves
fault granularity from the zone rather than the top-level config.
Errors from the UFFD setup path use a structured UffdError enum
and a new MigratableError::OnDemandRestore variant, with a From
impl to keep call sites concise.
The seccomp filter is updated to allow the userfaultfd syscall and
the four uffd ioctls (UFFDIO_API, UFFDIO_COPY, UFFDIO_REGISTER,
UFFDIO_WAKE) under the VMM thread profile.
Signed-off-by: Shayon Mukherjee <shayonj@gmail.com>
Introduce MemoryMigrationContext to track internal metrics of an ongoing
precopy memory migration.
The context aggregates information such as iteration count, transferred
bytes, durations, bandwidth, and estimated downtime. This enables
migration logic to make decisions based on runtime characteristics,
such as terminating iterations once the expected downtime is below a
target threshold.
The type is used in the next commit to implement iteration-based
migration metrics.
Signed-off-by: Philipp Schuster <philipp.schuster@cyberus-technology.de>
On-behalf-of: SAP philipp.schuster@sap.com
Moves the MSRV requirement to the workspace and expands it to all
cloud-hypervisor dependencies and dev-dependencies.
This improves discoverability for new contributors working on crates
other than the cloud-hypervisor itself and creates consistency regarding
the MSRV of cloud-hypervisor dependencies.
Functionally, this doesn't change anything for dependencies of the
cloud-hypervisor crate as the MSRV requirement is already enforced by CI
when building the cloud-hypervisor with the MSRV versioned compiler.
On-behalf-of: SAP julian.schindel@sap.com
Signed-off-by: Julian Schindel <julian.schindel@cyberus-technology.de>
The pointer created by `Vec::as_ptr` may not be used for mutation of the
underlying data [0].
This PR switches to `Vec::as_mut_ptr` and uses `cast` to avoid
mutability changes when casting.
Also improves safety reasoning, separates the unsafe call from the
call to `read_exact` to improve clarity and simplifies the vector
creation.
[0]: https://doc.rust-lang.org/alloc/vec/struct.Vec.html#method.as_ptr
On-behalf-of: SAP julian.schindel@sap.com
Signed-off-by: Julian Schindel <julian.schindel@cyberus-technology.de>
This helps to uncover expensive and needless clones in the code base.
For example, I prevented extensive clones in the snapshot path where
(nested) BTreeMap's have been cloned over and over again. Further,
the lint helps devs to much better reason about the ownership of
parameters.
All of these changes have been done manually with the necessary
caution. A few structs that are cheap to clone are now `copy` so that
this lint won't trigger for them.
I didn't enable the lint so far as it is a massive rabbit hole and
needs much more fixes. Nevertheless, it is very useful.
Signed-off-by: Philipp Schuster <philipp.schuster@cyberus-technology.de>
On-behalf-of: SAP philipp.schuster@sap.com
This better aligns with the rest of the code and makes it clearer
that these tests can run "as is" in a normal hosted environments
without the special test environment.
Signed-off-by: Philipp Schuster <philipp.schuster@cyberus-technology.de>
On-behalf-of: SAP philipp.schuster@sap.com
A major improvement to the developer experience of clippy in
Cloud Hypervisor.
1. Make `cargo clippy` just work with the same lints we use in CI
2. Simplify adding new lints
Signed-off-by: Philipp Schuster <philipp.schuster@cyberus-technology.de>
On-behalf-of: SAP philipp.schuster@sap.com
Adding itertools as dependency improves the iteration code in the
following significantly.
With this change, we don't need a copy of the vector. Just something
that can be coerced into an iterator. We also use the bit position
iterator to make the code somewhat clearer. The new code is much
faster, because it will not iterate over every bit, just each 1 bit in
the input.
The next commit will complete this optimization and have some concrete
numbers.
On-behalf-of: SAP julian.stecklina@sap.com
Signed-off-by: Julian Stecklina <julian.stecklina@cyberus-technology.de>
Fix clippy warning `uninlined_format_args` reported by rustc rustc
1.89.0 (29483883e 2025-08-04).
```console
warning: variables can be used directly in the `format!` string
--> block/src/lib.rs:649:17
|
649 | info!("{} failed to create io_uring instance: {}", error_msg, e);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#uninlined_format_args
= note: `#[warn(clippy::uninlined_format_args)]` on by default
help: change this to
|
649 - info!("{} failed to create io_uring instance: {}", error_msg, e);
649 + info!("{error_msg} failed to create io_uring instance: {e}");
|
```
Signed-off-by: Ruoqing He <heruoqing@iscas.ac.cn>
Many of the workspace members in the Cloud-hypervisor workspace share
common dependencies. Making these workspace dependencies reduces
duplication and improves maintainability.
Signed-off-by: Oliver Anderson <oliver.anderson@cyberus-technology.de>
On-behalf-of: SAP oliver.anderson@sap.com
# What
This commit introduces file-based advisory locking for the files backing
up the block devices by using the fcntl() syscall with OFD locks. The
per-open-file-descriptor (OFD) locks are more robust than traditional
POSIX locks (F_SETLK) as they are not tied to process IDs and avoid
common issues in multithreaded or multi-fd scenarios [1]. Therefore,
we don't use `std::fs::File::try_lock()`, which is backed by F_SETLKW.
The locking mechanism is aware of the `readonly` property and allows
`n` readers or `1` writer (exclusive mode).
As the locks are advisory, multiple cloud-hypervisor processes can
prevent themselves from writing to the same file. However, this is not
a system-wide file-system level locking mechanism preventing to open()
a file.
The introduced new locking mechanism does not cover vhost-user devices.
# Why
To prevent misconfiguration and improve safety, it is good practice to
protect disk image files with a locking mechanism. Experience and common
best practices suggest that advisory locks are preferable over mandatory
locks due to better compatibility and fewer pitfalls (in fs space).
The introduced functionality is aligned with the approach taken by
QEMU [0], and is also recommended in [1].
# Implementation Details
We need to ensure that not only normal operation keeps working but also
state save/resume and live-migration. Especially for live migration,
it is crucial that the sender VMM releases the locks when the VM stops
so the receiver VMM can acquire them right after that.
Therefore, the locking and releasing happen directly on the block
device struct. The device manager knows all block devices and can
forward requests to these types.
Last but not least, this commit uses on explicit lock acquiring
but implicit lock releasing (FD close). It only explicitly releases
the locks where this integrates more smoothly into the existing
code.
# Testing
I tested
- normal operation
- state save/resume,
- device hot plugging,
- and live-migration
with read/shared and write/exclusive locks.
One can use the `fcntl-tool` to test if locks are actually acquired
or released [2].
# Links
[0] 825b96dbce/util/osdep.c (L266)
[1] https://apenwarr.ca/log/20101213
[2] https://crates.io/crates/fcntl-tool
Signed-off-by: Philipp Schuster <philipp.schuster@cyberus-technology.de>
On-behalf-of: SAP philipp.schuster@sap.com
`serde_json` crate is referenced by multiple components, centralize it
to workspace to better manage this crate.
Signed-off-by: Jinank Jain <jinankjain@microsoft.com>
Historically the Cloud Hypervisor coding style has been to ensure that
all imports are ordered and placed in a single group. Unfortunately
cargo fmt has no support for ensuring that all imports are in a single
group so if whitespace lines were added as part of the import statements
then they would only be odered correctly in the group.
By adopting "group_imports="StdExternalCrate" we can enforce a style
where imports are placed in at most three groups for std, external
crates and the crate itself. Choosing a style enforceable by the tooling
reduces the reviewer burden.
Signed-off-by: Rob Bradford <rbradford@rivosinc.com>
Modify `Cargo.toml` in each member crate to follow the dependencies
specified in root `Cargo.toml` file.
Signed-off-by: Ruoqing He <heruoqing@iscas.ac.cn>
