b50-sriov-alloc

Vulkan application for Intel Arc Pro B50/B70 (Battlemage) SR-IOV VF provisioning. By Default it allocates 2GB GPU memory before creating VFs to ensure host has usable VRAM.

Dependencies (Ubuntu)

sudo apt install libvulkan-dev vulkan-tools mesa-vulkan-drivers cmake g++ make

Build

mkdir build && cd build
cmake ..
make

Usage

Run as root (required for sysfs SR-IOV writes).

# Auto-detect Intel Arc Pro B50/B70 and create 3 VFs
sudo ./b50-sriov-alloc --sriov 3

# Specify PCI address manually (format: domain:bus:device, function=0 is forced)
sudo ./b50-sriov-alloc --pci 0000:0d:00 --sriov 3

Options

• --pci <domain:bus:device> — Target PCI device (default: auto-detect Arc Pro B50/B70)
• --sriov <num> — Create <num> SR-IOV VFs after allocating PF memory
• --memory <MB> — GPU memory (VRAM) to reserve for the PF before creating VFs (default: 2048)
• --reset-vfs — Disable all VFs (sriov_numvfs=0) without allocating any GPU memory. Use this before re-running with different --memory/--sriov values
• --persist — After performing the requested allocation/VF setup, install a systemd service that replays the same command on every boot (see Persistence across reboots)
• --undo-persist — Remove the boot-persistence service and exit
• --help — Show usage and exit

Examples

# Auto-detect, create 3 VFs, allocate 2GB
sudo ./b50-sriov-alloc --sriov 3

# Allocate 512 MB, create 3 VFs
sudo ./b50-sriov-alloc --memory 512 --sriov 3

# Allocate 4GB, create 6 VFs
sudo ./b50-sriov-alloc --memory 4096 --sriov 6

# Multi-GPU: specify device explicitly (domain:bus:device)
sudo ./b50-sriov-alloc --pci 0000:0d:00 --sriov 3

# Disable all existing VFs (e.g. before re-running with different --memory/--sriov)
sudo ./b50-sriov-alloc --reset-vfs

# Create 3 VFs now AND re-apply on every boot
sudo ./b50-sriov-alloc --sriov 3 --persist

# Stop re-applying on boot
sudo ./b50-sriov-alloc --undo-persist

# On systems where the system Mesa is too old for this GPU's PCI ID (e.g. Arc
# Pro B70 / 0xe223 on Proxmox VE 9.2's Mesa 25.0.7), use run.sh instead - it
# wraps the binary above and picks up a custom Mesa build at /opt/mesa-intel
# if present (see "Arc Pro B70 (0xe223) on older Mesa" below)
sudo ./run.sh --sriov 3

VRAM Status Script

vram-status.sh shows the current LMEM (VRAM) split between the PF and each SR-IOV VF, in GB. Requires VFs to already be created (see --sriov above) and debugfs to be mounted (default on most distros). Run as root:

sudo ./vram-status.sh

Example output:

VFs:
  vf1: 9.89 GB
  vf2: 9.89 GB
  vf3: 9.89 GB
PF:    2.20 GB
Spare: 0.12 GB
Total: 32.00 GB

Arc Pro B70 (0xe223) on older Mesa (e.g. Proxmox VE 9.2)

The B70 (0xe223) was added to Mesa's anv Vulkan driver in Mesa 25.1. Proxmox VE 9.2 (Debian 13 "trixie") ships Mesa 25.0.7, so the system Vulkan ICD prints MESA: warning: Driver does not support the 0xe223 PCI ID, falls back to llvmpipe, and device selection fails.

Solution: build Mesa 26.x from source into an isolated /opt/mesa-intel prefix (system Mesa is left untouched). ./run.sh automatically uses /opt/mesa-intel's ICD if present.

If the --persist flag is used to install the service on boot, the environment variable will be carried over to the persistence service (so ./run.sh is not required).

# Build dependencies
sudo apt install -y git build-essential meson ninja-build pkg-config python3-mako \
  libdrm-dev libexpat1-dev zlib1g-dev libelf-dev bison flex glslang-tools \
  libclc-19-dev llvm-19-dev clang-19 libclang-cpp19-dev libllvmspirvlib-19-dev

# Mesa's intel_clc needs Clang's full C++ headers (Driver/CodeGen/Frontend), which
# Debian's clang-19 packages don't ship - install from apt.llvm.org instead
wget https://apt.llvm.org/llvm.sh
chmod +x llvm.sh
sudo ./llvm.sh 19 all

# Build and install Mesa into an isolated prefix
git clone --depth 1 --branch mesa-26.0.8 https://gitlab.freedesktop.org/mesa/mesa.git
cd mesa
meson setup build --prefix=/opt/mesa-intel \
  -Dbuildtype=release -Dplatforms= -Dgallium-drivers= \
  -Dvulkan-drivers=intel -Dintel-rt=disabled -Dvideo-codecs= \
  -Dvalgrind=disabled -Dlibunwind=disabled
ninja -C build
sudo ninja -C build install

Persistence across reboots

The PF memory reservation is transient (held only while the process runs) and SR-IOV VFs are reset to 0 on every reboot, so the PF/VF configuration does not survive a restart on its own. --persist solves this by installing a systemd oneshot service (/etc/systemd/system/b50-sriov-alloc.service, WantedBy=multi-user.target) that replays the exact command you ran — minus --persist — on every boot.

# Apply now and on every boot
sudo ./b50-sriov-alloc --sriov 3 --persist

Because the service runs the binary on every boot, it should live in a stable location. If the binary is not already under /opt or /usr, --persist prompts to copy it to /opt/b50-sriov-alloc/b50-sriov-alloc and points the service at that copy. If you used run.sh for a custom Mesa build, the VK_ICD_FILENAMES value is captured into the service so the B70-on-older-Mesa case keeps working at boot (where run.sh's environment is not present).

Inspect or remove persistence:

systemctl status b50-sriov-alloc.service     # check it
journalctl -u b50-sriov-alloc.service        # see boot-time output
sudo ./b50-sriov-alloc --undo-persist        # disable + remove the service

--undo-persist disables and deletes the service unit; the installed binary under /opt/b50-sriov-alloc/ is left in place (remove it manually if desired).

Notes

• If multiple Intel Arc Pro B50/B70 devices found use --pci to specify
• To force Mesa Vulkan to report only one default GPU (typically VF 0), use:

export MESA_VK_DEVICE_SELECT_FORCE_DEFAULT_DEVICE=1