Re: [Xen-devel] [PATCH 1/7] xen/arm: SMMU: Implement the add_device callback in SMMU

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Fri, 30 Jun 2017, Wei Chen wrote:
> This add_device callback function is taking care of adding a device
> to SMMU and make sure it is fully prepare to be used by the SMMU
> afterwards.
> 
> In previous code, we don't implement the add_device callback in
> iommu_ops for ARM SMMU. We placed the work of add_device to
> assign_device callback. The function assign_device should not care
> about adding the device to an iommu_group. It might not even be
> able to decide how to do that. In this patch, we move this work
> back to add_device callback.
> 
> This add_device callback is only called while we are handling all
> devices for constructing the Domain0.
> 
> Signed-off-by: Wei Chen <Wei.Chen@xxxxxxx>
> ---
>  xen/drivers/passthrough/arm/smmu.c | 34 +++++++++++++++++++++++-----------
>  1 file changed, 23 insertions(+), 11 deletions(-)
> 
> diff --git a/xen/drivers/passthrough/arm/smmu.c 
> b/xen/drivers/passthrough/arm/smmu.c
> index 74c09b0..2efa52d 100644
> --- a/xen/drivers/passthrough/arm/smmu.c
> +++ b/xen/drivers/passthrough/arm/smmu.c
> @@ -2591,6 +2591,26 @@ static void arm_smmu_destroy_iommu_domain(struct 
> iommu_domain *domain)
>       xfree(domain);
>  }
>  
> +static int arm_smmu_xen_add_device(u8 devfn, struct device*dev)
> +{
> +     if (dt_device_is_protected(dev->of_node)) {
> +             if (!dev->archdata.iommu) {
> +                     dev->archdata.iommu = xzalloc(struct 
> arm_smmu_xen_device);
> +                     if (!dev->archdata.iommu)
> +                             return -ENOMEM;
> +             }
> +
> +             if (!dev_iommu_group(dev))
> +                     return arm_smmu_add_device(dev);
> +     }
> +
> +     /*
> +      * Return 0 if the device is not protected to follow the behavior
> +      * of PCI add device.

What does this comment mean?


> +      */
> +     return 0;
> +}
> +
>  static int arm_smmu_assign_dev(struct domain *d, u8 devfn,
>                              struct device *dev, u32 flag)
>  {
> @@ -2600,17 +2620,8 @@ static int arm_smmu_assign_dev(struct domain *d, u8 
> devfn,
>  
>       xen_domain = dom_iommu(d)->arch.priv;
>  
> -     if (!dev->archdata.iommu) {
> -             dev->archdata.iommu = xzalloc(struct arm_smmu_xen_device);
> -             if (!dev->archdata.iommu)
> -                     return -ENOMEM;
> -     }
> -
> -     if (!dev_iommu_group(dev)) {
> -             ret = arm_smmu_add_device(dev);
> -             if (ret)
> -                     return ret;
> -     }
> +     if (!dev_iommu_group(dev))
> +         return -ENODEV;
>  
>       spin_lock(&xen_domain->lock);
>  
> @@ -2784,6 +2795,7 @@ static const struct iommu_ops arm_smmu_iommu_ops = {
>      .teardown = arm_smmu_iommu_domain_teardown,
>      .iotlb_flush = arm_smmu_iotlb_flush,
>      .iotlb_flush_all = arm_smmu_iotlb_flush_all,
> +    .add_device = arm_smmu_xen_add_device,
>      .assign_device = arm_smmu_assign_dev,
>      .reassign_device = arm_smmu_reassign_dev,
>      .map_page = arm_smmu_map_page,
> -- 
> 2.7.4
> 
> 
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> https://lists.xen.org/xen-devel
> 

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