[PATCH i-g-t 01/10] tools/vmtb: Update QEMU parameters

Adam Miszczak
2026-02-24T08:23:09Z

1. Enable SSH access to VM/Guest OS

Add QEMU options to open guest SSH connection:
- enable default emulated NIC
- redirect host's TCP port 10000+N connections to
guest's SSH server on port 22
(where N is booted VM number, starting from 0)

For example, login to VM0 (from host) as:
$ ssh -p 10000 gta@localhost

2. Enable migration based on VFIO driver

Set 'enable-migration' option introducing QEMU VF migration support.

VF migration is supported by a vendor specific VFIO driver (xe-vfio-pci).
In case of regular 'vfio-pci', QEMU command option 'enable-migration'
should not be explicitly enabled to prevent VM start failure:
'vfio 0000:00:02.1: VFIO migration is not supported in kernel'

3. Disable QEMU emulated VGA card

Disable standard emulated VGA on QEMU VMs to avoid issues
emerging from a bochs DRM driver.
Standard VGA is enumerated as PCI device BDF 00:02.0
on minor 0 (drm/card0) - this causes troubles with VirtualMachine class
reserving card0 for passed VF.
Also, bochs driver obscures guest dmesg with verbose debug logs.

Signed-off-by: Adam Miszczak <adam.miszczak@linux.intel.com>
---
tools/vmtb/bench/machines/virtual/vm.py | 14 ++++++++++----
tools/vmtb/vmm_flows/conftest.py | 25 +++++++++++++++----------
2 files changed, 25 insertions(+), 14 deletions(-)

diff --git a/tools/vmtb/bench/machines/virtual/vm.py b/tools/vmtb/bench/machines/virtual/vm.py
index e75de590d..9f4ca1de7 100644
--- a/tools/vmtb/bench/machines/virtual/vm.py
+++ b/tools/vmtb/bench/machines/virtual/vm.py
@@ -1,5 +1,5 @@
# SPDX-License-Identifier: MIT
-# Copyright © 2024 Intel Corporation
+# Copyright © 2024-2026 Intel Corporation

import base64
import json
@@ -58,7 +58,8 @@ class VirtualMachine(MachineInterface):

return timeout_wrapper

- def __init__(self, vm_number: int, backing_image: str, driver: str, igt_config: VmtbIgtConfig) -> None:
+ def __init__(self, vm_number: int, backing_image: str, driver: str,
+ igt_config: VmtbIgtConfig, vf_migration_support: bool) -> None:
self.vf_bdf: typing.Optional[str] = None
self.process: typing.Optional[subprocess.Popen] = None
self.vmnum: int = vm_number
@@ -68,6 +69,7 @@ class VirtualMachine(MachineInterface):
self.qmp_sockpath = posixpath.join('/tmp', f'mon{self.vmnum}.sock')
self.drm_driver_name: str = driver
self.igt_config: VmtbIgtConfig = igt_config
+ self.vf_migration: bool = vf_migration_support

if not posixpath.exists(backing_image):
logger.error('No image for VM%s', self.vmnum)
@@ -153,6 +155,9 @@ class VirtualMachine(MachineInterface):
'-vnc', f':{self.vmnum}',
'-serial', 'stdio',
'-m', '4096',
+ '-vga', 'none',
+ '-net', 'nic',
+ '-net', f'user,hostfwd=tcp::{10000 + self.vmnum}-:22',
'-drive', f'file={self.image if not self.migrate_destination_vm else self.migrate_source_image}',
'-chardev', f'socket,path={self.questagent_sockpath},server=on,wait=off,id=qga{self.vmnum}',
'-device', 'virtio-serial',
@@ -161,8 +166,9 @@ class VirtualMachine(MachineInterface):
'-mon', f'chardev=mon{self.vmnum},mode=control']

if self.vf_bdf:
- command.extend(['-enable-kvm', '-cpu', 'host'])
- command.extend(['-device', f'vfio-pci,host={self.vf_bdf},enable-migration=on'])
+ command.extend(['-enable-kvm', '-cpu', 'host', '-device', f'vfio-pci,host={self.vf_bdf}'])
+ if self.vf_migration:
+ command[-1] += ',enable-migration=on'

if self.migrate_destination_vm:
# If VM is migration destination - run in stopped/prelaunch state (explicit resume required)
diff --git a/tools/vmtb/vmm_flows/conftest.py b/tools/vmtb/vmm_flows/conftest.py
index 7b6eacd51..675312253 100644
--- a/tools/vmtb/vmm_flows/conftest.py
+++ b/tools/vmtb/vmm_flows/conftest.py
@@ -1,26 +1,25 @@
# SPDX-License-Identifier: MIT
-# Copyright © 2024 Intel Corporation
+# Copyright © 2024-2026 Intel Corporation

import json
import logging
import re
import typing
-
from dataclasses import dataclass
from pathlib import Path

import pytest

from bench import exceptions
-from bench.helpers.helpers import (modprobe_driver, modprobe_driver_check)
-from bench.helpers.log import HOST_DMESG_FILE
-from bench.configurators.vgpu_profile_config import VgpuProfileConfigurator, VfSchedulingMode
from bench.configurators.vgpu_profile import VgpuProfile
+from bench.configurators.vgpu_profile_config import (VfSchedulingMode,
+ VgpuProfileConfigurator)
from bench.configurators.vmtb_config import VmtbConfigurator
-from bench.machines.host import Host, Device
+from bench.helpers.helpers import modprobe_driver, modprobe_driver_check
+from bench.helpers.log import HOST_DMESG_FILE
+from bench.machines.host import Device, Host
from bench.machines.virtual.vm import VirtualMachine

-
logger = logging.getLogger('Conftest')

@@ -89,15 +88,20 @@ class VmmTestingSetup:
self.host.load_drivers()
self.host.discover_devices()

+ # VF migration requires vendor specific VFIO driver (e.g. xe-vfio-pci)
+ vf_migration_support: bool = self.host.is_driver_loaded(f'{self.host.drm_driver_name}-vfio-pci')
+
logger.info("\nDUT info:"
"\n\tCard index: %s"
"\n\tPCI BDF: %s "
"\n\tDevice ID: %s (%s)"
- "\n\tHost DRM driver: %s",
+ "\n\tHost DRM driver: %s"
+ "\n\tVF migration support: %s",
self.host.dut_index,
self.get_dut().pci_info.bdf,
self.get_dut().pci_info.devid, self.get_dut().gpu_model,
- self.get_dut().driver.get_name())
+ self.get_dut().driver.get_name(),
+ vf_migration_support)

self.vgpu_profile: VgpuProfile = self.get_vgpu_profile()

@@ -105,7 +109,8 @@ class VmmTestingSetup:
self.vms: typing.List[VirtualMachine] = [
VirtualMachine(vm_idx, self.guest_os_image,
vmtb_config.get_guest_config().driver,
- vmtb_config.get_guest_config().igt_config)
+ vmtb_config.get_guest_config().igt_config,
+ vf_migration_support)
for vm_idx in range(min(self.vgpu_profile.num_vfs, self.testing_config.max_num_vms))]

def get_vgpu_profile(self) -> VgpuProfile:
--
2.39.1