Messages in this thread | | | Date | Tue, 10 May 2022 12:23:30 -0300 | From | Jason Gunthorpe <> | Subject | Re: [PATCH v6 08/12] iommu/sva: Use attach/detach_pasid_dev in SVA interfaces |
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On Tue, May 10, 2022 at 02:17:34PM +0800, Lu Baolu wrote:
> +/** > + * iommu_sva_bind_device() - Bind a process address space to a device > + * @dev: the device > + * @mm: the mm to bind, caller must hold a reference to mm_users > + * @drvdata: opaque data pointer to pass to bind callback > + * > + * Create a bond between device and address space, allowing the device to access > + * the mm using the returned PASID. If a bond already exists between @device and > + * @mm, it is returned and an additional reference is taken. Caller must call > + * iommu_sva_unbind_device() to release each reference. > + * > + * iommu_dev_enable_feature(dev, IOMMU_DEV_FEAT_SVA) must be called first, to > + * initialize the required SVA features. > + * > + * On error, returns an ERR_PTR value. > + */ > +struct iommu_sva * > +iommu_sva_bind_device(struct device *dev, struct mm_struct *mm, void *drvdata) > +{ > + int ret = -EINVAL; > + struct iommu_sva *handle; > + struct iommu_domain *domain; > + > + /* > + * TODO: Remove the drvdata parameter after kernel PASID support is > + * enabled for the idxd driver. > + */ > + if (drvdata) > + return ERR_PTR(-EOPNOTSUPP);
Why is this being left behind? Clean up the callers too please.
> + /* Allocate mm->pasid if necessary. */ > + ret = iommu_sva_alloc_pasid(mm, 1, (1U << dev->iommu->pasid_bits) - 1); > + if (ret) > + return ERR_PTR(ret); > + > + mutex_lock(&iommu_sva_lock); > + /* Search for an existing bond. */ > + handle = xa_load(&dev->iommu->sva_bonds, mm->pasid); > + if (handle) { > + refcount_inc(&handle->users); > + goto out_success; > + }
How can there be an existing bond?
dev->iommu is per-device
The device_group_immutable_singleton() insists on a single device group
Basically 'sva_bonds' is the same thing as the group->pasid_array.
Assuming we leave room for multi-device groups this logic should just be
group = iommu_group_get(dev); if (!group) return -ENODEV;
mutex_lock(&group->mutex); domain = xa_load(&group->pasid_array, mm->pasid); if (!domain || domain->type != IOMMU_DOMAIN_SVA || domain->mm != mm) domain = iommu_sva_alloc_domain(dev, mm);
?
And stick the refcount in the sva_domain
Also, given the current arrangement it might make sense to have a struct iommu_domain_sva given that no driver is wrappering this in something else.
Jason
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