L4Re same-page merging

spmm is the same-page merging monitor for the L4Re operating system. It provides an interface to supply memory to other L4Re components. The memory that it administers is periodically scanned and memory pages with matching contents are merged together.

Structure

.
├── conf    # module configurations and ned launcher scripts for same-page merging examples.
├── l4re    # location of the replacable L4Re-snapshot.
├── patch   # collection of patches for the L4Re-snapshot.
└── spmm    # L4Re-package that contains the same-page merging monitor.

Installation/Update

1. Obtain the latest L4Re-snapshot, unpack it and place it into l4re/.

2. Apply the following patches:

   Mandatory: These patches are required for same-page merging (increase kernel memory, tweak uvmm, etc.).

   git apply patch/req.patch

   Optional: These patches tweak the snapshot for usage under NixOS:

   git apply patch/nixos.patch

3. Follow the build instructions from the official L4Re-website.

   Hint: On NixOS, the prefix of the cross compilation toolchain is: aarch64-unknown-linux-gnu-. This is different from the one assumed in the snapshot. The flake provided in this repository automatically sets the CROSS_COMPILE environment variable correctly. In addition to that, be sure to configure the correct prefix when asked during make setup.

   Important: Don't forget to build the external packages for same-page merging as well.

4. Create a Makeconf.boot for your local system by following the instructions in l4re/src/l4/conf/Makeconf.boot.example.

   Important: In order for L4Re to find the same-page merging examples provided in this repository, append the following configuration to the end of your Makeconf.boot:

   # SPM configuration
   SPM_CONFIG_DIR = <absolute/path/to/your/l4re-spm/repo>/conf
   MODULE_SEARCH_PATH += $(SPM_CONFIG_DIR) 
   MODULES_LIST += $(SPM_CONFIG_DIR)/spm_modules.list

License

Detailed licensing information can be found in the LICENSE file.