Re: [PATCH v1 5/8] iommu/amd: Use iommu_attach/detach_device()

[Jason Gunthorpe]

On Thu, Jan 06, 2022 at 10:20:50AM +0800, Lu Baolu wrote:
> The individual device driver should use iommu_attach/detach_device()
> for domain attachment/detachment.
> 
> Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
>  drivers/iommu/amd/iommu_v2.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iommu/amd/iommu_v2.c b/drivers/iommu/amd/iommu_v2.c
> index 58da08cc3d01..7d9d0fe89064 100644
> +++ b/drivers/iommu/amd/iommu_v2.c
> @@ -133,7 +133,7 @@ static void free_device_state(struct device_state *dev_state)
>  	if (WARN_ON(!group))
>  		return;
>  
> -	iommu_detach_group(dev_state->domain, group);
> +	iommu_detach_device(dev_state->domain, &dev_state->pdev->dev);
>  
>  	iommu_group_put(group);

This is the only user of the group in the function all the
group_get/put should be deleted too.

Joerg said in commit 55c99a4dc50f ("iommu/amd: Use
iommu_attach_group()") that the device API doesn't work here because
there are multi-device groups?

But I'm not sure how this can work with multi-device groups - this
seems to assigns a domain setup for direct map, so perhaps this only
works if all devices are setup for direct map?

> @@ -791,7 +791,7 @@ int amd_iommu_init_device(struct pci_dev *pdev, int pasids)
>  		goto out_free_domain;
>  	}
>  
> -	ret = iommu_attach_group(dev_state->domain, group);
> +	ret = iommu_attach_device(dev_state->domain, &pdev->dev);
>  	if (ret != 0)
>  		goto out_drop_group;

Same comment here

Jason