RE: [RFC PATCH 03/10] iommu/vt-d: Allocate groups for mediated devices

[Liu, Yi L]

> From: Lu Baolu [mailto:baolu.lu@xxxxxxxxxxxxxxx]
> Sent: Sunday, July 22, 2018 2:09 PM
> 
> With the Intel IOMMU supporting PASID granularity isolation and protection, a
> mediated device could be isolated and protected by an IOMMU unit. We need to
> allocate a new group instead of a PCI group.

Existing vfio mdev framework also allocates an iommu group for mediate device.

mdev_probe()
  |_ mdev_attach_iommu()
       |_ iommu_group_alloc()

IMHO, this patch actually do a wrapper to the group allocation API. The reason is: it
is not necessary to apply the group allocation rules when the allocation is for mediated
device. Instead, just allocate a new one for it. :)

Thanks,
Yi Liu
> 
> Cc: Ashok Raj <ashok.raj@xxxxxxxxx>
> Cc: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
> Cc: Kevin Tian <kevin.tian@xxxxxxxxx>
> Cc: Liu Yi L <yi.l.liu@xxxxxxxxx>
> Signed-off-by: Sanjay Kumar <sanjay.k.kumar@xxxxxxxxx>
> Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> ---
>  drivers/iommu/intel-iommu.c | 13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index
> 3ede34a..57ccfc4 100644
> --- a/drivers/iommu/intel-iommu.c
> +++ b/drivers/iommu/intel-iommu.c
> @@ -5276,6 +5276,17 @@ static void intel_iommu_put_resv_regions(struct device
> *dev,
>  	}
>  }
> 
> +static struct iommu_group *intel_iommu_device_group(struct device *dev)
> +{
> +	if (dev_is_pci(dev))
> +		return pci_device_group(dev);
> +
> +	if (dev_is_mdev(dev))
> +		return iommu_group_alloc();
> +
> +	return ERR_PTR(-EINVAL);
> +}
> +
>  #ifdef CONFIG_INTEL_IOMMU_SVM
>  int intel_iommu_enable_pasid(struct intel_iommu *iommu, struct intel_svm_dev
> *sdev)  { @@ -5370,7 +5381,7 @@ const struct iommu_ops intel_iommu_ops = {
>  	.remove_device		= intel_iommu_remove_device,
>  	.get_resv_regions	= intel_iommu_get_resv_regions,
>  	.put_resv_regions	= intel_iommu_put_resv_regions,
> -	.device_group		= pci_device_group,
> +	.device_group		= intel_iommu_device_group,
>  	.pgsize_bitmap		= INTEL_IOMMU_PGSIZES,
>  };
> 
> --
> 2.7.4