Re: [PATCH v1 2/8] iommu: Introduce a new iommu_group_replace_domain() API

On 2023/2/2 15:05, Nicolin Chen wrote:

+/**

• • iommu_group_replace_domain - replace the domain that a group is attached to
• • @new_domain: new IOMMU domain to replace with
• • @group: IOMMU group that will be attached to the new domain
• • This API allows the group to switch domains without being forced to go to
• • the blocking domain in-between.
• • If the attached domain is a core domain (e.g. a default_domain), it will act
• • just like the iommu_attach_group().

I am not following above two lines. Why and how could iommufd set a core domain to an iommu_group?

• */

+int iommu_group_replace_domain(struct iommu_group *group,

• 	       struct iommu_domain *new_domain)
  

+{

• int ret;
• if (!new_domain)

• return -EINVAL;
  

• mutex_lock(&group->mutex);
• ret = __iommu_group_set_domain(group, new_domain);
• if (ret) {

• if (__iommu_group_set_domain(group, group->domain))
  

• 	__iommu_group_set_core_domain(group);
  

• }
• mutex_unlock(&group->mutex);
• return ret;

+} +EXPORT_SYMBOL_NS_GPL(iommu_group_replace_domain, IOMMUFD_INTERNAL);

Best regards, baolu