Re: [PATCH i-g-t 09/10] tools/vmtb: Support max VFs configuration

["Bernatowicz, Marcin" <marcin.bernatowicz@linux.intel.com>]

On 2/24/2026 8:50 AM, Adam Miszczak wrote:
> Enable maximum VFs test configuration variant, for both:
> auto-provisioning and vGPU profiles.
> Max VFs is device-specific value read via sysfs.
> For auto-provisioning, max VFs always equals sysfs/sriov_totalvfs,
> but the highest supported number of VFs defined by vGPU profiles
> may differ from the hardware max value.
>
> Max VFs test config variant can be requested by passing MAX_VFS label
> to VmmTestingConfig structure (num_vfs) or convenience tuple, for example:
> test_variants = [(MAX_VFS, VfProvisioningMode.AUTO, VfSchedulingMode.INFINITE),
>                   (MAX_VFS, VfProvisioningMode.VGPU_PROFILE, VfSchedulingMode.DEFAULT_PROFILE)]
>
> Signed-off-by: Adam Miszczak <adam.miszczak@linux.intel.com>
> ---
>   tools/vmtb/vmm_flows/conftest.py | 29 ++++++++++++++++++++++++++---
>   1 file changed, 26 insertions(+), 3 deletions(-)
>
> diff --git a/tools/vmtb/vmm_flows/conftest.py b/tools/vmtb/vmm_flows/conftest.py
> index ae149d652..02c297f93 100644
> --- a/tools/vmtb/vmm_flows/conftest.py
> +++ b/tools/vmtb/vmm_flows/conftest.py
> @@ -32,6 +32,10 @@ def pytest_addoption(parser):
>                        help='Device card index for test execution')
>   
>   
> +# Label indicating Max VFs configurarion variant, intended for pass to VmmTestingConfig.
> +MAX_VFS = "Max"
> +
> +
>   @dataclass
>   class VmmTestingConfig:
>       """Structure represents test configuration used by a setup fixture.
> @@ -54,16 +58,23 @@ class VmmTestingConfig:
>       auto_poweron_vm: bool = True
>       auto_probe_vm_driver: bool = True
>       unload_host_drivers_on_teardown: bool = False
> +    enable_max_vfs: bool = False
>       # Temporary W/A: reduce size of LMEM assigned to VFs to speed up a VF state save-restore process
>       wa_reduce_vf_lmem: bool = False
>   
> +    def __post_init__(self):
> +        if self.num_vfs is MAX_VFS:
> +            self.enable_max_vfs = True
> +            self.num_vfs = 0 # Actual value set in VmmTestingSetup
> +
>       def __str__(self) -> str:
> -        test_config_id = f'{self.num_vfs}VF-(P:{self.provisioning_mode.name} S:{self.scheduling_mode.name})'
> +        test_config_id = (f'{self.num_vfs if not self.enable_max_vfs else "Max"}VF'
> +                          + f'-(P:{self.provisioning_mode.name} S:{self.scheduling_mode.name})')
>           return test_config_id
>   
>       def __repr__(self) -> str:
>           return (f'\nVmmTestingConfig:'
> -                f'\nNum VFs = {self.num_vfs} / max num VMs = {self.max_num_vms}'
> +                f'\nNum VFs = {self.num_vfs if not self.enable_max_vfs else "Max"} / max num VMs = {self.max_num_vms}'
>                   f'\nVF provisioning mode = {self.provisioning_mode.name}'
>                   f'\nVF scheduling mode = {self.scheduling_mode.name}'
>                   f'\nSetup flags:'
> @@ -89,6 +100,7 @@ class VmmTestingSetup:
>           self.host.load_drivers()
>           self.host.discover_devices()
>           self.dut: Device = self.host.get_device(self.dut_index)
> +        self.total_vfs: int = self.get_dut().driver.get_totalvfs()
>   
>           # 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')
> @@ -98,11 +110,13 @@ class VmmTestingSetup:
>                       "\n\tPCI BDF: %s "
>                       "\n\tDevice ID: %s (%s)"
>                       "\n\tHost DRM driver: %s"
> -                    "\n\tVF migration support: %s",
> +                    "\n\tMax VFs supported: %s"
> +                    "\n\tVF migration supported: %s",
>                       self.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.total_vfs,
>                       vf_migration_support)
>   
>           vmtb_root_path = vmtb_config.vmtb_config_file.parent
> @@ -115,6 +129,9 @@ class VmmTestingSetup:
>               or self.testing_config.scheduling_mode is not VfSchedulingMode.INFINITE):
>               self.vgpu_profile: VgpuProfile = self.get_vgpu_profile()
>   
> +        if self.testing_config.provisioning_mode is VfProvisioningMode.AUTO and self.testing_config.enable_max_vfs:
> +            self.testing_config.num_vfs = self.total_vfs
> +
>           # Start maximum requested number of VMs, but not more than VFs supported by the given vGPU profile
>           self.vms: typing.List[VirtualMachine] = [
>               VirtualMachine(vm_idx, self.guest_os_image,
> @@ -125,6 +142,12 @@ class VmmTestingSetup:
>   
>       def get_vgpu_profile(self) -> VgpuProfile:
>           configurator = VgpuProfileConfigurator(self.vgpu_profiles_dir, self.get_dut().gpu_model)
> +        if self.testing_config.enable_max_vfs:
> +            # Get a vGPU profile with the most VFs (not necessarily equal to sysfs/sriov_totalvfs)
> +            self.testing_config.num_vfs = max(configurator.supported_vgpu_profiles.vf_resources,
> +                                              key=lambda profile: profile.vf_count).vf_count
> +            logger.debug("Max VFs supported by vGPU profiles: %s", self.testing_config.num_vfs)
> +
LGTM,
Reviewed-by: Marcin Bernatowicz <marcin.bernatowicz@linux.intel.com>
>           try:
>               vgpu_profile = configurator.get_vgpu_profile(self.testing_config.num_vfs,
>                                                            self.testing_config.scheduling_mode)