Re: [PATCH v4 4/7] iommu: Pass in old domain to attach_dev callback functions

Nicolin Chen
2025-09-19T22:57:17Z

On Sun, Aug 31, 2025 at 04:31:56PM -0700, Nicolin Chen wrote:
> @@ -2347,7 +2352,8 @@ static int __iommu_group_set_domain_internal(struct iommu_group *group,
> */
> result = 0;
> for_each_group_device(group, gdev) {
> - ret = __iommu_device_set_domain(group, gdev, new_domain, flags);
> + ret = __iommu_device_set_domain(group, gdev, new_domain,
> + group->domain, flags);
> if (ret) {
> result = ret;
> /*
> @@ -2379,7 +2385,7 @@ static int __iommu_group_set_domain_internal(struct iommu_group *group,
> */
> if (group->domain)
> WARN_ON(__iommu_device_set_domain(
> - group, gdev, group->domain,
> + group, gdev, group->domain, new_domain,
> IOMMU_SET_DOMAIN_MUST_SUCCEED));
> if (gdev == last_gdev)
> break;

This last_gdev is the device failing __iommu_device_set_domain()
previously, so it should not be reverted from the new_domain to
the group->domain, as it has never left the group->domain.

This isn't a problem without this patch, because the revert will
be simply a re-attach (from group->domain to group->domain).

I'm adding a new patch to the top of the series in v5, though it
doesn't worth being a bug fix IMHO.

Thanks
Nicolin