RE: [PATCH rc v6] iommu: Fix nested pci_dev_reset_iommu_prepare/done()

[Tian, Kevin]

> From: Nicolin Chen <nicolinc@xxxxxxxxxx>
> Sent: Saturday, April 18, 2026 12:57 PM
> 
> On Fri, Apr 17, 2026 at 02:44:41PM -0700, Nicolin Chen wrote:
> > @@ -2469,9 +2469,2 @@ static int
> __iommu_group_set_domain_internal(struct iommu_group *group,
> >
> > -       /*
> > -        * This is a concurrent attach during device recovery. Reject it until
> > -        * pci_dev_reset_iommu_done() attaches the device to group->domain.
> > -        */
> > -       if (group->recovery_cnt)
> > -               return -EBUSY;
> > -
> 
> On a second thought, we may not simply drop this -- IIRC, we added
> it particularly to fence a case where gdevs share the same RID or
> some corner case like that?
> 

this is by design according to the original commit:

"
    Note that there are two corner cases:
     1. Devices in the same iommu_group
        Since an attachment is always per iommu_group, this means that any
        sibling devices in the iommu_group cannot change domain, to prevent
        race conditions.
    ...
"