From: Nicolin Chen <nicol...@nvidia.com>

The iopt_table_enforce_dev_resv_regions() and iopt_remove_reserved_iova()
require callers to pass in an ioas->iopt pointer. It simply works with a
kernel-managed hw_pagetable by passing in its hwpt->ioas->iopt pointer.
However, now there could be a user-managed hw_pagetable that doesn't have
an ioas pointer. And typically most of device reserved regions should be
enforced to a kernel-managed domain only, although the IOMMU_RESV_SW_MSI
used by SMMU will introduce some complication.

Add a pair of iommufd_device_enforce_rr/iommufd_device_remove_rr helpers
that calls iopt_table_enforce_dev_resv_regions/iopt_remove_reserved_iova
functions after some additional checks. This would also ease any further
extension to support the IOMMU_RESV_SW_MSI complication mentioned above.

For the replace() routine, add another helper to compare ioas pointers,
with the support of user-managed hw_pagetables.

Signed-off-by: Nicolin Chen <nicol...@nvidia.com>
Signed-off-by: Yi Liu <yi.l....@intel.com>
---
 drivers/iommu/iommufd/device.c          | 42 ++++++++++++++++++-------
 drivers/iommu/iommufd/iommufd_private.h | 18 +++++++++++
 2 files changed, 48 insertions(+), 12 deletions(-)

diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
index 104dd061a2a3..10e6ec590ede 100644
--- a/drivers/iommu/iommufd/device.c
+++ b/drivers/iommu/iommufd/device.c
@@ -329,6 +329,28 @@ static int iommufd_group_setup_msi(struct iommufd_group 
*igroup,
        return 0;
 }
 
+static void iommufd_device_remove_rr(struct iommufd_device *idev,
+                                    struct iommufd_hw_pagetable *hwpt)
+{
+       if (WARN_ON(!hwpt))
+               return;
+       if (hwpt->user_managed)
+               return;
+       iopt_remove_reserved_iova(&hwpt->ioas->iopt, idev->dev);
+}
+
+static int iommufd_device_enforce_rr(struct iommufd_device *idev,
+                                    struct iommufd_hw_pagetable *hwpt,
+                                    phys_addr_t *sw_msi_start)
+{
+       if (WARN_ON(!hwpt))
+               return -EINVAL;
+       if (hwpt->user_managed)
+               return 0;
+       return iopt_table_enforce_dev_resv_regions(&hwpt->ioas->iopt, idev->dev,
+                                                  sw_msi_start);
+}
+
 int iommufd_hw_pagetable_attach(struct iommufd_hw_pagetable *hwpt,
                                struct iommufd_device *idev)
 {
@@ -348,8 +370,7 @@ int iommufd_hw_pagetable_attach(struct iommufd_hw_pagetable 
*hwpt,
                        goto err_unlock;
        }
 
-       rc = iopt_table_enforce_dev_resv_regions(&hwpt->ioas->iopt, idev->dev,
-                                                &idev->igroup->sw_msi_start);
+       rc = iommufd_device_enforce_rr(idev, hwpt, &idev->igroup->sw_msi_start);
        if (rc)
                goto err_unlock;
 
@@ -375,7 +396,7 @@ int iommufd_hw_pagetable_attach(struct iommufd_hw_pagetable 
*hwpt,
        mutex_unlock(&idev->igroup->lock);
        return 0;
 err_unresv:
-       iopt_remove_reserved_iova(&hwpt->ioas->iopt, idev->dev);
+       iommufd_device_remove_rr(idev, hwpt);
 err_unlock:
        mutex_unlock(&idev->igroup->lock);
        return rc;
@@ -392,7 +413,7 @@ iommufd_hw_pagetable_detach(struct iommufd_device *idev)
                iommu_detach_group(hwpt->domain, idev->igroup->group);
                idev->igroup->hwpt = NULL;
        }
-       iopt_remove_reserved_iova(&hwpt->ioas->iopt, idev->dev);
+       iommufd_device_remove_rr(idev, hwpt);
        mutex_unlock(&idev->igroup->lock);
 
        /* Caller must destroy hwpt */
@@ -444,10 +465,9 @@ iommufd_device_do_replace(struct iommufd_device *idev,
        }
 
        old_hwpt = igroup->hwpt;
-       if (hwpt->ioas != old_hwpt->ioas) {
+       if (iommufd_hw_pagetable_compare_ioas(old_hwpt, hwpt)) {
                list_for_each_entry(cur, &igroup->device_list, group_item) {
-                       rc = iopt_table_enforce_dev_resv_regions(
-                               &hwpt->ioas->iopt, cur->dev, NULL);
+                       rc = iommufd_device_enforce_rr(cur, hwpt, NULL);
                        if (rc)
                                goto err_unresv;
                }
@@ -461,12 +481,10 @@ iommufd_device_do_replace(struct iommufd_device *idev,
        if (rc)
                goto err_unresv;
 
-       if (hwpt->ioas != old_hwpt->ioas) {
+       if (iommufd_hw_pagetable_compare_ioas(old_hwpt, hwpt)) {
                list_for_each_entry(cur, &igroup->device_list, group_item)
-                       iopt_remove_reserved_iova(&old_hwpt->ioas->iopt,
-                                                 cur->dev);
+                       iommufd_device_remove_rr(cur, hwpt);
        }
-
        igroup->hwpt = hwpt;
 
        /*
@@ -483,7 +501,7 @@ iommufd_device_do_replace(struct iommufd_device *idev,
        return old_hwpt;
 err_unresv:
        list_for_each_entry(cur, &igroup->device_list, group_item)
-               iopt_remove_reserved_iova(&hwpt->ioas->iopt, cur->dev);
+               iommufd_device_remove_rr(cur, hwpt);
 err_unlock:
        mutex_unlock(&idev->igroup->lock);
        return ERR_PTR(rc);
diff --git a/drivers/iommu/iommufd/iommufd_private.h 
b/drivers/iommu/iommufd/iommufd_private.h
index 34940596c2c2..b14f23d3f42e 100644
--- a/drivers/iommu/iommufd/iommufd_private.h
+++ b/drivers/iommu/iommufd/iommufd_private.h
@@ -281,6 +281,24 @@ static inline void iommufd_hw_pagetable_put(struct 
iommufd_ctx *ictx,
                refcount_dec(&hwpt->obj.users);
 }
 
+static inline bool
+iommufd_hw_pagetable_compare_ioas(struct iommufd_hw_pagetable *old_hwpt,
+                                 struct iommufd_hw_pagetable *new_hwpt)
+{
+       struct iommufd_ioas *old_ioas, *new_ioas;
+
+       WARN_ON(!old_hwpt || !new_hwpt);
+       if (old_hwpt->user_managed)
+               old_ioas = old_hwpt->parent->ioas;
+       else
+               old_ioas = old_hwpt->ioas;
+       if (new_hwpt->user_managed)
+               new_ioas = new_hwpt->parent->ioas;
+       else
+               new_ioas = new_hwpt->ioas;
+       return old_ioas != new_ioas;
+}
+
 struct iommufd_group {
        struct kref ref;
        struct mutex lock;
-- 
2.34.1

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