We cannot reliably send Request::abandon() on every kind of failure on
the sender side, as we might be in the middle of a memory transmission.
The receiver would not reliably know what to do with that. So instead,
when the receiver cannot read from the socket, we log that the migration
sender failed, which is the only likely cause of that failure.
On-behalf-of: SAP philipp.schuster@sap.com
Signed-off-by: Philipp Schuster <philipp.schuster@cyberus-technology.de>
This improves the observability whether a migration failed because of
the sender or because of some error on the receiving side.
Using a simple log message is simpler than introducing a new error enum
to differentiate between SendError and RemoteError.
On-behalf-of: SAP philipp.schuster@sap.com
Signed-off-by: Philipp Schuster <philipp.schuster@cyberus-technology.de>
When the receiver of a live migration encounters an error, it sends an
error response. The sender of the migration would then send an abandon
request and wait for a response. This abandon request is not necessary,
because the receiver already abandoned the migration due to the error it
encountered.
From now on this function will not send an abandon request to the
receiver anymore, thus it was renamed to "ok_or_error".
Also, this case was always broken, because after sending the error
response, the receiver just exits without waiting for the additional
abandon request.
On-behalf-of: SAP sebastian.eydam@sap.com
Signed-off-by: Sebastian Eydam <sebastian.eydam@cyberus-technology.de>
Getting rid of the unsafe ByteValued implementation for MemoryRange,
Request and Response structures, by relying on zerocopy's safe
implementation instead.
Signed-off-by: Sebastien Boeuf <sboeuf@meta.com>
Assisted-by: Claude:claude-opus-4-8
size_of is part of std::prelude as of Rust 1.80 (with size_of_val,
align_of, align_of_val), and the workspace MSRV is 1.89, so qualifying
it (mem::size_of, std::mem::size_of, core::mem::size_of) is unnecessary.
Convert every qualified size_of call-site to the bare prelude form and
drop the now-redundant `use std::mem::size_of;` imports, keeping
`use std::mem;` where it still serves non-prelude items (transmute,
swap, replace, take, zeroed, MaybeUninit, offset_of). size_of is the
only one of the four currently used in the tree.
Pure refactor, no behavioural change. Follow-up to the
clippy::absolute_paths cleanup (#7670), as discussed in #8444.
Signed-off-by: Henry Hrvoje Tonkovac <htonkovac@gmail.com>
Assisted-by: Claude:Opus-4.8
Introducing PageFault as the new wire command needed by both postcopy
live migration and on demand restore from the offload daemon. This new
command describes the need from the destination to fault the page
content in. This request describes the page through a MemoryRange
structure, and the response can be either 0 or the actual page size.
In case it is 0, that means the source had access to the guest memory
and was able to copy the page content directly. In case the response is
the actual page size, there is a payload associated which contains the
page content.
We can expect local live migration and offload restore to run locally
and therefore have access to the guest memory. The remote live migration
over the network is the case where we would expect the page content to
be sent over the wire.
This command is served through an additional connection happening on the
UNIX or TCP socket. The goal is to keep the same codepath between local
and remote migrations. This additional channel allows PageFault commands
to be issued asynchronously so they can be served without blocking the
main connection.
A connection role is introduced in order to identify an additional
connection related to pre-copy memory versus the newly introduced
channel for serving post-copy requests.
Signed-off-by: Sebastien Boeuf <sboeuf@meta.com>
Assisted-by: Claude:claude-opus-4-7
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>
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>
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>
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
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 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
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>
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>
This method will return the existing Response if the status is
successful (Status::Ok) otherwise issue a command to abandon the
migration and return the desired error.
Signed-off-by: Rob Bradford <rbradford@rivosinc.com>
This fixes all typos found by the typos utility with respect to the config file.
Signed-off-by: Philipp Schuster <philipp.schuster@cyberus-technology.de>
warning: casting raw pointers to the same type and constness is unnecessary (`*const protocol::MemoryRange` -> `*const protocol::MemoryRange`)
--> vm-migration/src/protocol.rs:280:17
|
280 | self.data.as_ptr() as *const MemoryRange as *const u8,
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `self.data.as_ptr()`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_cast
= note: `#[warn(clippy::unnecessary_cast)]` on by default
Signed-off-by: Yu Li <liyu.yukiteru@bytedance.com>
There is no need to include serde_derive separately,
as it can be specified as serde feature instead.
Signed-off-by: Maksym Pavlenko <pavlenko.maksym@gmail.com>
Always properly initialize vectors so that we don't run in undefined
behaviors when the vector gets dropped.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
Instead of creating a MemoryManager from scratch, let's reuse the same
code path used by snapshot/restore, so that memory regions are created
identically to what they were on the source VM.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
During snapshot/restore we will need to store this structure, which is
why it must derive the Versionize trait.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
This will be helpful to support the creation of a MemoryRangeTable from
virtio-mem, as it uses 2M pages.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
In anticipation for supporting the merge of multiple dirty pages coming
from multiple devices, this patch factorizes the creation of a
MemoryRangeTable from a bitmap, as well as providing a simple method for
merging the dirty pages regions under a single MemoryRangeTable.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
This addresses a newly added clippy issue:
error: methods called `as_*` usually take self by reference or self by mutable reference; consider choosing a less ambiguous name
--> vm-migration/src/protocol.rs:57:34
|
57 | fn as_mut_bytes<T: Sized>(p: &mut T) -> &mut [u8] {
| ^^^^^^
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#wrong_self_convention
error: aborting due to 2 previous errors
error: could not compile `vm-migration`
Signed-off-by: Rob Bradford <robert.bradford@intel.com>
Prior to sending the memory the full state is not needed only the
configuration. This is sufficient to create the appropriate structures
in the guest and have the memory allocations ready for filling.
Update the protocol documentation to add a separate config step and move
the state to after the memory is transferred. As the VM is created in a
separate step to restoring it the requires a slightly different
constructor as well as saving the VM object for the subsequent commands.
Signed-off-by: Rob Bradford <robert.bradford@intel.com>
