Hi,

On 23/05/18 10:38, Xu Zaibo wrote:

quoted

+static int vfio_iommu_bind_group(struct vfio_iommu *iommu,
+???????????????? struct vfio_group *group,
+???????????????? struct vfio_mm *vfio_mm)
+{
+??? int ret;
+??? bool enabled_sva = false;
+??? struct vfio_iommu_sva_bind_data data = {
+??????? .vfio_mm??? = vfio_mm,
+??????? .iommu??????? = iommu,
+??????? .count??????? = 0,
+??? };
+
+??? if (!group->sva_enabled) {
+??????? ret = iommu_group_for_each_dev(group->iommu_group, NULL,
+?????????????????????????? vfio_iommu_sva_init);

Do we need to do *sva_init here or do anything to avoid repeated
initiation?
while another process already did initiation at this device, I think
that current process will get an EEXIST.

Right, sva_init() must be called once for any device that intends to use
bind(). For the second process though, group->sva_enabled will be true
so we won't call sva_init() again, only bind().

Thanks,
Jean