When CoW can be used, the VM restoration time is reduced, but the pages
are not populated. This can lead to some slowness from the guest when
accessing these pages.
Depending on the use case, we might prefer a slower boot time for better
performances from guest runtime. The way to achieve this is to prefault
the pages in this case, using the MAP_POPULATE flag along with CoW.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
This patch extends the previous behavior on the restore codepath.
Instead of copying the memory regions content from the snapshot files
into the new memory regions, the VMM will use the snapshot region files
as the backing files behind each mapped region. This is done in order to
reduce the time for the VM to be restored.
When the source VM has been initially started with a backing file, this
means it has been mapped with the MAP_SHARED flag. For this case, we
cannot use the CoW trick to speed up the VM restore path and we simply
fallback onto the copy of the memory regions content.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
Whenever a MemoryManager is restored from a snapshot, the memory regions
associated with it might need to directly back the mapped memory for
increased performances. If that's the case, a list of external regions
is provided and the MemoryManager should simply ignore what's coming
from the MemoryConfig.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
Now that we can choose specific mmap flags for the guest RAM, we create
a new parameter "copy_on_write" meaning that the memory mappings backed
by a file should be performed with MAP_PRIVATE instead of MAP_SHARED.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
In order to anticipate the need for special mmap flags when memory
mapping the guest RAM, we need to switch from from_file() wrapper to
build() wrapper.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
A few KVM ioctls were missing in order to perform both snapshot and
restore while keeping seccomp enabled.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
This connects the dots together, making the request from the user reach
the actual implementation for restoring the VM.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
This connects the dots together, making the request from the user reach
the actual implementation for snapshotting the VM.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
The MemoryManager is somehow a special case, as its restore() function
was not implemented as part of the Snapshottable trait. Instead, and
because restoring memory regions rely both on vm.json and every memory
region snapshot file, the memory manager is restored at creation time.
This makes the restore path slightly different from CpuManager, Vcpu,
DeviceManager and Vm, but achieve the correct restoration of the
MemoryManager along with its memory regions filled with the correct
content.
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
This is only implementing the send() function in order to store all Vm
states into a file.
This needs to be extended for live migration, by adding more transport
methods, and also the recv() function must be implemented.
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
By aggregating snapshots from the CpuManager, the MemoryManager and the
DeviceManager, Vm implements the snapshot() function from the
Snapshottable trait.
And by restoring snapshots from the CpuManager, the MemoryManager and
the DeviceManager, Vm implements the restore() function from the
Snapshottable trait.
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Yi Sun <yi.y.sun@linux.intel.com>
This implements the send() function of the Transportable trait, so that
the guest memory regions can be saved into one file per region.
This will need to be extended for live migration, as it will require
other transport methods and the recv() function will need to be
implemented too.
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
In order to snapshot the content of the guest RAM, the MemoryManager
must implement the Snapshottable trait.
Signed-off-by: Yi Sun <yi.y.sun@linux.intel.com>
Implement the Snapshottable trait for Vcpu, and then implements it for
CpuManager. Note that CpuManager goes through the Snapshottable
implementation of Vcpu for every vCPU in order to implement the
Snapshottable trait for itself.
Signed-off-by: Yi Sun <yi.y.sun@linux.intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Anticipating the need for a slightly different function for restoring
vCPUs, this patch factorizes most of the vCPU creation, so that it can
be reused for migration purposes.
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
These two new helpers will be useful to capture a vCPU state and being
able to restore it at a later time.
Signed-off-by: Cathy Zhang <cathy.zhang@intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
In anticipation for the CpuManager to aggregate all Vcpu snapshots
together, this change makes sure the CpuManager has a handle onto
every vCPU.
Signed-off-by: Cathy Zhang <cathy.zhang@intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Based on the list of Migratable devices stored by the DeviceManager, the
DeviceManager can implement the Snapshottable trait by aggregating all
devices snapshots together.
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Serial and Ioapic both implement the Migratable trait, hence the
DeviceManager can store them in the list of Migratable devices.
Signed-off-by: Yi Sun <yi.y.sun@linux.intel.com>
We need the project to rely on kvm-bindings and kvm-ioctls branches
which include the serde derive to be able to serialize and deserialize
some KVM structures.
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
The parse_size helper function can now be consolidated into the
ByteSized FromStr implementation.
Signed-off-by: Rob Bradford <robert.bradford@intel.com>
Now all parsing code makes use of the Toggle and it's FromStr support
move the helper function into the from_str() implementation.
Signed-off-by: Rob Bradford <robert.bradford@intel.com>
The integration tests and documentation make use of empty value strings
like "--net tap=" accept them but return None so that the default value
will be used as expected.
Signed-off-by: Rob Bradford <robert.bradford@intel.com>
This simplifies the parsing of the option by using OptionParser along
with its automatic conversion behaviour.
Signed-off-by: Rob Bradford <robert.bradford@intel.com>
Byte sizes are quantities ending in "K", "M", "G" and by implementing
this type with a FromStr implementation the values can be converted
using .parse().
Signed-off-by: Rob Bradford <robert.bradford@intel.com>
