On 24/04/18 02:32, Sinan Kaya wrote:
> On 2/12/2018 1:33 PM, Jean-Philippe Brucker wrote:
>> /**
>> * iommu_sva_device_init() - Initialize Shared Virtual Addressing for a device
>> * @dev: the device
>> @@ -129,7 +439,10 @@ EXPORT_SYMBOL_GPL(iommu_sva_device_shutdown);
>> int iommu_sva_bind_device(struct device *dev, struct mm_struct *mm, int *pasid,
>> unsigned long flags, void *drvdata)
>> {
>> + int i, ret;
>> + struct io_mm *io_mm = NULL;
>> struct iommu_domain *domain;
>> + struct iommu_bond *bond = NULL, *tmp;
>> struct iommu_param *dev_param = dev->iommu_param;
>>
>> domain = iommu_get_domain_for_dev(dev);
>> @@ -145,7 +458,42 @@ int iommu_sva_bind_device(struct device *dev, struct mm_struct *mm, int *pasid,
>> if (flags != (IOMMU_SVA_FEAT_PASID | IOMMU_SVA_FEAT_IOPF))
>> return -EINVAL;
>>
>> - return -ENOSYS; /* TODO */
>> + /* If an io_mm already exists, use it */
>> + spin_lock(&iommu_sva_lock);
>> + idr_for_each_entry(&iommu_pasid_idr, io_mm, i) {
>> + if (io_mm->mm != mm || !io_mm_get_locked(io_mm))
>> + continue;
>> +
>> + /* Is it already bound to this device? */
>> + list_for_each_entry(tmp, &io_mm->devices, mm_head) {
>> + if (tmp->dev != dev)
>> + continue;
>> +
>> + bond = tmp;
>> + refcount_inc(&bond->refs);
>> + io_mm_put_locked(io_mm);
>> + break;
>> + }
>> + break;
>> + }
>> + spin_unlock(&iommu_sva_lock);
>> +
>> + if (bond)
>
> Please return pasid when you find an io_mm that is already bound. Something like
> *pasid = io_mm->pasid should do the work here when bond is true.
Right. I think we should also keep returning 0, not switch to -EEXIST or
similar. So in next version a driver can call bind(devX, mmY) multiple
times, but the first unbind() removes the bond.
Thanks,
Jean
