Re: [PATCH v6 06/10] vfio: selftests: Allow drivers to specify required region size

[Jason Gunthorpe <jgg@nvidia.com>]

On Thu, Sep 17, 2026 at 11:52:45PM +0000, sashiko-bot@kernel.org wrote:
> Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
> - [Medium] selftests: kvm/irq_test overwrites dynamic driver region size
> --
> 
> commit 97ad8ed7fec97be65848236fd1c8afab2ff66a54
> Author: Jason Gunthorpe <jgg@ziepe.ca>
> 
> vfio: selftests: Allow drivers to specify required region size
> 
> This commit adds a region_size field to struct vfio_pci_driver_ops to let
> drivers declare their required DMA-mapped region size. It updates the core
> driver probe and the vfio_pci_driver_test to use this dynamically probed
> size instead of hardcoding 2MB.
> 
> > diff --git a/tools/testing/selftests/vfio/vfio_pci_driver_test.c b/tools/testing/selftests/vfio/vfio_pci_driver_test.c
> > index 761bf117d624f..2bd949aafd731 100644
> > --- a/tools/testing/selftests/vfio/vfio_pci_driver_test.c
> > +++ b/tools/testing/selftests/vfio/vfio_pci_driver_test.c
> > @@ -87,7 +87,8 @@ FIXTURE_SETUP(vfio_pci_driver_test)
> >  	driver = &self->device->driver;
> >  
> >  	region_setup(self->iommu, self->iova_allocator, &self->memcpy_region, SZ_1G);
> > -	region_setup(self->iommu, self->iova_allocator, &driver->region, SZ_2M);
> > +	region_setup(self->iommu, self->iova_allocator, &driver->region,
> > +		     driver->region.size);
> 
> [Severity: Medium]
> Since this changes the vfio test to use the dynamic driver->region.size
> instead of SZ_2M, should tools/testing/selftests/kvm/irq_test.c be updated
> as well?
> 
> It looks like vfio_setup_msi() in kvm/irq_test.c still forcefully overwrites
> the dynamically probed size back to 2MB:
> 
> tools/testing/selftests/kvm/irq_test.c:vfio_setup_msi() {
> 	...
> 	region = &device->driver.region;
> 	region->size = SZ_2M;
> 	region->iova = iova_allocator_alloc(allocator, region->size);
> 	...
> }
> 
> Will this cause the KVM irq_test to fail with a VFIO_ASSERT_GE during driver
> initialization via vfio_pci_driver_init() when tested with a driver that
> requires a larger region, such as the mlx5 driver mentioned in the commit
> message?

I have no idea, Dave? Did kvm start using this stuff?

Jason