Re: [PATCH v6 4/5] iommu/vt-d: Add iommu_ops support for subdevice bus

[Alex Williamson]

On Fri, 30 Oct 2020 12:58:08 +0800
Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx> wrote:

> +static const struct iommu_ops siov_iommu_ops = {
> +	.capable		= intel_iommu_capable,
> +	.domain_alloc		= siov_iommu_domain_alloc,
> +	.domain_free		= intel_iommu_domain_free,
> +	.attach_dev		= siov_iommu_attach_device,
> +	.detach_dev		= siov_iommu_detach_device,
> +	.map			= intel_iommu_map,
> +	.unmap			= intel_iommu_unmap,
> +	.iova_to_phys		= intel_iommu_iova_to_phys,
> +	.probe_device		= siov_iommu_probe_device,
> +	.release_device		= siov_iommu_release_device,
> +	.get_resv_regions	= siov_iommu_get_resv_regions,
> +	.put_resv_regions	= generic_iommu_put_resv_regions,
> +	.device_group		= generic_device_group,
> +	.pgsize_bitmap		= (~0xFFFUL),
> +};
> +
> +void intel_siov_init(void)
> +{
> +	if (!scalable_mode_support() || !iommu_pasid_support())
> +		return;
> +
> +	bus_set_iommu(&mdev_bus_type, &siov_iommu_ops);
> +	pr_info("Intel(R) Scalable I/O Virtualization supported\n");
> +}

How can you presume to take over iommu_ops for an entire virtual bus?
This also forces mdev and all the dependencies of mdev to be built into
the kernel.  I don't find that acceptable.  Thanks,

Alex