Re: [Qemu-devel] [RFC PATCH 6/8] VFIO: do pasid table binding

[Alex Williamson]

On Wed, 26 Apr 2017 18:12:03 +0800
"Liu, Yi L" <address@hidden> wrote:

> From: "Liu, Yi L" <address@hidden>
> 
> This patch adds IOCTL processing in vfio_iommu_type1 for
> VFIO_IOMMU_SVM_BIND_TASK. Binds the PASID table bind by
> calling iommu_ops->bind_pasid_table to link the whole
> PASID table to pIOMMU.
> 
> For VT-d, it is linking the guest PASID table to host pIOMMU.
> This is key point to support SVM virtualization on VT-d.
> 
> Signed-off-by: Liu, Yi L <address@hidden>
> ---
>  drivers/vfio/vfio_iommu_type1.c | 72 
> +++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 72 insertions(+)
> 
> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> index b3cc33f..30b6d48 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
> @@ -1512,6 +1512,50 @@ static int vfio_domains_have_iommu_cache(struct 
> vfio_iommu *iommu)
>       return ret;
>  }
>  
> +struct vfio_svm_task {
> +     struct iommu_domain *domain;
> +     void *payload;
> +};
> +
> +static int bind_pasid_tbl_fn(struct device *dev, void *data)
> +{
> +     int ret = 0;
> +     struct vfio_svm_task *task = data;

Maybe avoid "task" or use svm_task to differentiate from task_struct
task used elsewhere in this file.

> +     struct pasid_table_info *pasidt_binfo;
> +
> +     pasidt_binfo = task->payload;
> +     ret = iommu_bind_pasid_table(task->domain, dev, pasidt_binfo);
> +     return ret;
> +}
> +
> +static int vfio_do_svm_task(struct vfio_iommu *iommu, void *data,
> +                             int (*fn)(struct device *, void *))
> +{
> +     int ret = 0;
> +     struct vfio_domain *d;
> +     struct vfio_group *g;
> +     struct vfio_svm_task task;
> +
> +     task.payload = data;
> +
> +     mutex_lock(&iommu->lock);
> +
> +     list_for_each_entry(d, &iommu->domain_list, next) {
> +             list_for_each_entry(g, &d->group_list, next) {
> +                     if (g->iommu_group != NULL) {

Can it ever be NULL?

> +                             task.domain = d->domain;
> +                             ret = iommu_group_for_each_dev(
> +                                     g->iommu_group, &task, fn);
> +                             if (ret != 0)
> +                                     break;
> +                     }
> +             }
> +     }
> +
> +     mutex_unlock(&iommu->lock);
> +     return ret;
> +}
> +
>  static long vfio_iommu_type1_ioctl(void *iommu_data,
>                                  unsigned int cmd, unsigned long arg)
>  {
> @@ -1582,6 +1626,34 @@ static long vfio_iommu_type1_ioctl(void *iommu_data,
>  
>               return copy_to_user((void __user *)arg, &unmap, minsz) ?
>                       -EFAULT : 0;
> +     } else if (cmd == VFIO_IOMMU_SVM_BIND_TASK) {
> +             struct vfio_device_svm hdr;
> +             u8 *data = NULL;

But it really should be a struct pasid_table_info.

> +             int ret = 0;
> +
> +             minsz = offsetofend(struct vfio_device_svm, length);
> +             if (copy_from_user(&hdr, (void __user *)arg, minsz))
> +                     return -EFAULT;
> +
> +             if (hdr.length == 0)
> +                     return -EINVAL;
> +
> +             data = memdup_user((void __user *)(arg + minsz),
> +                                     hdr.length);
> +             if (IS_ERR(data))
> +                     return PTR_ERR(data);
> +
> +             switch (hdr.flags & VFIO_SVM_TYPE_MASK) {
> +             case VFIO_SVM_BIND_PASIDTBL:
> +                     ret = vfio_do_svm_task(iommu, data,
> +                                             bind_pasid_tbl_fn);
> +                     break;
> +             default:
> +                     ret = -EINVAL;
> +                     break;
> +             }
> +             kfree(data);
> +             return ret;
>       }
>  
>       return -ENOTTY;