RE: [PATCH v2 3/7] iommu: Add iommu_report_device_broken() to quarantine a broken device

Tian, Kevin
2026-03-18T07:31:26Z

> From: Nicolin Chen <nicolinc@nvidia.com>
> Sent: Wednesday, March 18, 2026 3:16 AM
>
> +static void iommu_group_broken_worker(struct work_struct *work)
> +{
> + struct iommu_group *group =
> + container_of(work, struct iommu_group, broken_work);
> + struct pci_dev *pdev = NULL;
> + struct device *dev;
> +
> + scoped_guard(mutex, &group->mutex) {
> + /* Do not block the device again if it has been recovered */
> + if (!READ_ONCE(group->requires_reset))
> + goto out_put;
> + if (list_is_singular(&group->devices)) {
> + /* Note: only support group with a single device */

this series is about fixing a vulnerability. Then it sounds incomplete to
leave certain configuration still under risk. Probably we should first
ensure ATS can be enabled only in singleton group, just like how we
did for pci_enable_pasid()?

> + dev = iommu_group_first_dev(group);
> + if (dev_is_pci(dev)) {
> + pdev = to_pci_dev(dev);
> + pci_dev_get(pdev);
> + }
> + }
> + }
> +
> + if (pdev) {
> + /*
> + * Quarantine the device completely. This will be cleared
> upon
> + * a pci_dev_reset_iommu_done() call indicating the recovery.
> + */
> + pci_dev_lock(pdev);
> + pci_dev_reset_iommu_prepare(pdev);

let's rename it to iommu_quarantine_device() to be called here. then
have another wrapper pci_dev_reset_iommu_prepare() to call it too.

this path has nothing to do with reset.

> + pci_dev_unlock(pdev);
> + pci_dev_put(pdev);
> + }
> +out_put:
> + iommu_group_put(group);
> +}
> +