Re: [PATCH v4 6/6] iommu/virtio: Enable x86 support

[Eric Auger <eric.auger@redhat.com>]

Hi jean,

On 6/10/21 9:51 AM, Jean-Philippe Brucker wrote:
> With the VIOT support in place, x86 platforms can now use the
> virtio-iommu.
>
> Because the other x86 IOMMU drivers aren't yet ready to use the
> acpi_dma_setup() path, x86 doesn't implement arch_setup_dma_ops() at the
> moment. Similarly to Vt-d and AMD IOMMU, call iommu_setup_dma_ops() from
> probe_finalize().
>
> Acked-by: Joerg Roedel <jroedel@suse.de>
> Acked-by: Michael S. Tsirkin <mst@redhat.com>
> Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Reviewed-by: Eric Auger <eric.auger@redhat.com>

Eric
> ---
>  drivers/iommu/Kconfig        | 3 ++-
>  drivers/iommu/dma-iommu.c    | 1 +
>  drivers/iommu/virtio-iommu.c | 8 ++++++++
>  3 files changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
> index aff8a4830dd1..07b7c25cbed8 100644
> --- a/drivers/iommu/Kconfig
> +++ b/drivers/iommu/Kconfig
> @@ -400,8 +400,9 @@ config HYPERV_IOMMU
>  config VIRTIO_IOMMU
>  	tristate "Virtio IOMMU driver"
>  	depends on VIRTIO
> -	depends on ARM64
> +	depends on (ARM64 || X86)
>  	select IOMMU_API
> +	select IOMMU_DMA
>  	select INTERVAL_TREE
>  	select ACPI_VIOT if ACPI
>  	help
> diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
> index 175f8eaeb5b3..46ed43c400cf 100644
> --- a/drivers/iommu/dma-iommu.c
> +++ b/drivers/iommu/dma-iommu.c
> @@ -1332,6 +1332,7 @@ void iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 dma_limit)
>  	 pr_warn("Failed to set up IOMMU for device %s; retaining platform DMA ops\n",
>  		 dev_name(dev));
>  }
> +EXPORT_SYMBOL_GPL(iommu_setup_dma_ops);
>  
>  static struct iommu_dma_msi_page *iommu_dma_get_msi_page(struct device *dev,
>  		phys_addr_t msi_addr, struct iommu_domain *domain)
> diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c
> index 218fe8560e8d..77aee1207ced 100644
> --- a/drivers/iommu/virtio-iommu.c
> +++ b/drivers/iommu/virtio-iommu.c
> @@ -1026,6 +1026,13 @@ static struct iommu_device *viommu_probe_device(struct device *dev)
>  	return ERR_PTR(ret);
>  }
>  
> +static void viommu_probe_finalize(struct device *dev)
> +{
> +#ifndef CONFIG_ARCH_HAS_SETUP_DMA_OPS
> +	iommu_setup_dma_ops(dev, 0, U64_MAX);
> +#endif
> +}
> +
>  static void viommu_release_device(struct device *dev)
>  {
>  	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
> @@ -1062,6 +1069,7 @@ static struct iommu_ops viommu_ops = {
>  	.iova_to_phys		= viommu_iova_to_phys,
>  	.iotlb_sync		= viommu_iotlb_sync,
>  	.probe_device		= viommu_probe_device,
> +	.probe_finalize		= viommu_probe_finalize,
>  	.release_device		= viommu_release_device,
>  	.device_group		= viommu_device_group,
>  	.get_resv_regions	= viommu_get_resv_regions,