System requirements

Validated hardware (MX1P)

Validated host platforms

Vendor Part Name CPU
Supermicro SYS-221H-TNR Intel Xeon6
Supermicro SYS-222HA-TN Intel Xeon6
Gigabyte G494-ZB0-AAP2 AMD EPYC 9005
Gigabyte G494-SB0-AAP2 Intel Xeon6
Dell R770 Intel Xeon6

Validated DDR5 RDIMM modules

Vendor Part Number Density Speed (MT/s)
Samsung M321R8GA0EB2-CCP 64GB 6400
Samsung M321R8GA0EB2-CCPKC 64GB 6400
Samsung M321RAJA0MB2-CCPWF 128GB 6400
SK hynix HMCG94AHBRA481N 64GB 6400
SK hynix HMCG94AGBRA181N-AA 64GB 5600
Micron MTC40F2046S1RC64BD2 64GB 6400
Micron MTC40F2047S1RC64BB1 128GB 6400

BIOS configuration

AMD platforms

  • SPM(Special Purpose Memory) configuration

    AMD CBS → CXL Common Options → CXL Memory Attribute : Enabled
    Warning
    If disabled, the CXL memory lacks EFI_MEMORY_SP attribute, causing the OS to boot it as standard system-ram(CPU-less NUMA node via SRAT).
    Once it is integrated into system memory, it cannot be reconfigured to DAX.

  • Use CPU address space

    AMD CBS → CXL Common Options → CXL Physical Addressing : System address
    Warning
    If not set to System address, a mismatch between SPA(System Physical Address) and HPA(Host Physical Address) occurs.
    It prevents the HDM(Host-managed Device Memory) Decoder from validating the memory range, making it impossible to create CXL Region.
    Without a valid region, the memory cannot be assigned to DAX.

  • Enable MSI multi vector

    AMD CBS → NBIO Common Options → IOMMU/Security → IOMMU : Enabled
    Warning
    If disabled, Interrupt Remapping is unavailable, limiting the CXL device to a single MSI vector.
    But our device is using multi vector MSI, so it should be enabled.

OS

OS Release status SDK tarball
Ubuntu 24.04 LTS Stable — officially supported xcena_sdk_<ver>_ubuntu_24.04.tar.xz
openSUSE Leap 16.0 Experimental xcena_sdk_<ver>_opensuse-leap_16.0.tar.xz
RHEL 9.6+ / Rocky Linux 9.6+ / AlmaLinux 9.6+ Experimental xcena_sdk_<ver>_el9.tar.xz

Experimental targets

openSUSE Leap and RHEL 9 support is preview-quality. The install and host-setup flow is verified on validated hardware — openSUSE Leap 16.0 and Rocky Linux 9.6 — but these targets are less battle-tested than Ubuntu; please report any issues you hit.

On Red Hat Enterprise Linux itself, enable CodeReady Builder and EPEL before installing; the SDK’s build dependencies (dkms, fmt-devel, gtest) live there, and unlike Rocky/AlmaLinux they are not reachable from the stock repositories:

sudo subscription-manager repos --enable codeready-builder-for-rhel-9-$(arch)-rpms
sudo dnf install -y https://dl.fedoraproject.org/pub/epel/epel-release-latest-9.noarch.rpm

CXL devdax host setup

For the CXL memory to be usable as devdax (required for computing), the host needs three things: memhp_default_state=offline on the kernel cmdline, the distro’s memory auto-online udev rule neutralized, and a boot-time service that re-applies the devdax conversion (the kernel re-binds the memory to system-ram on every boot).

scripts/setup_host.sh (shipped with the SDK) does all three per-distro — the kernel cmdline (grubby on RHEL 9’s BLS, GRUB regeneration elsewhere), the udev override (Ubuntu 90-daxctl-device.rules, openSUSE 80-hotplug-cpu-mem.rules, RHEL 9 40-redhat.rules), and the boot-time xcena-devdax.service. Run it once and reboot:

sudo ./scripts/setup_host.sh
sudo reboot

install.sh does not run this by default because it rewrites boot and memory policy and needs a reboot; run the installer with ./install.sh --with-host-setup to include it.

Why it’s needed

When CXL memory is onlined as system-ram, the kernel manages it as regular RAM and it can no longer be offlined or converted to devdax (daxctl reconfigure-device then fails with Device or resource busy). memhp_default_state=offline stops the kernel auto-onlining it, the udev override stops the distro force-onlining it anyway, and xcena-devdax.service performs the devdax conversion on each boot.

Note

xcena-devdax.service converts only dax devices under an XCENA CXL region (PCI vendor 0x20a6). If the XCENA memory instead surfaces as a soft-reserved hmem dax — a dax device not under /sys/bus/cxl/devices/region*, usually with the CXL region left disabled — the CXL region failed to form. Recheck the BIOS CXL Physical Addressing = System address / HDM decoder settings above.

Manual equivalent — what setup_host.sh does, for reference or advanced setups

1. Kernel cmdline — add memhp_default_state=offline (append to GRUB_CMDLINE_LINUX in /etc/default/grub, keeping existing parameters), then apply per bootloader and reboot:

sudo update-grub                                                     # Ubuntu
sudo grub2-mkconfig -o /boot/grub2/grub.cfg                          # openSUSE
sudo grubby --update-kernel=ALL --args=memhp_default_state=offline   # RHEL 9 (BLS)
sudo reboot

Verify after reboot: cat /proc/cmdline | grep memhp_default_state.

2. udev override — the distro rule that force-onlines hot-plugged memory (90-daxctl-device.rules / 80-hotplug-cpu-mem.rules / 40-redhat.rules) is shadowed under /etc/udev/rules.d/ with its online action disabled, so memhp_default_state=offline is not undone at boot.

3. boot-time conversion — xcena-devdax.service runs daxctl reconfigure-device --mode=devdax on the XCENA dax devices at each boot (the kernel re-binds them to system-ram otherwise).

Required system packages

Ubuntu (apt):

build-essential cmake ninja-build wget
python3-dev python3-pip python3-venv libncurses6
libglib2.0-0 libslirp0 liburing2 libcurl3-gnutls

openSUSE Leap 16 (zypper — daxctl is provided by the ndctl package):

gcc gcc-c++ make cmake ninja wget
python313-devel python313-pip libncurses6
libglib-2_0-0 libslirp0 liburing2 libcurl4
ndctl dkms kernel-default-devel

The full per-distro lists live in deps/*.list and are installed by install_dependencies.sh.

Kernel headers
The mx_dma DKMS build needs headers for the booted kernel (linux-headers-$(uname -r) / kernel-default-devel / kernel-devel-$(uname -r)). install_dependencies.sh installs them best-effort — they cannot be pinned in deps/*.list, which has no way to name the running kernel. When they are unavailable the install warns and skips the driver step instead of failing: see Install skips the driver. —

Required Python packages 

numpy tomli capstone cxxfilt pyelftools

Docker

  • Optional, recommended for consistent build environments Note
    For non-Ubuntu systems, it is recommended to use the official Docker image to ensure full compatibility.