[PATCH 10/17] iommufd/device: Move IOAS attaching and detaching operations into helpers

[Yi Liu <yi.l.liu@xxxxxxxxx>]

From: Nicolin Chen <nicolinc@xxxxxxxxxx>

When using a 2-stage nested hw_pagetable (hwpt) setup, the IOVA mappings
or SW MSI are at the stage-2 hwpt, while the device will be attached to
a stage-1 hwpt. And then the current do_attach() flow will fail to set up
MSI, since it always uses the attaching hwpt pointer (i.e. stage-1 in such
case).

As a preparatory change for the following nesting support patch, move all
related operations into a pair of separate functions, so we only need to
redirect the hwpt pointer to its stage-2 hwpt, when using a nested setup.

Signed-off-by: Nicolin Chen <nicolinc@xxxxxxxxxx>
Signed-off-by: Yi Liu <yi.l.liu@xxxxxxxxx>
---
 drivers/iommu/iommufd/device.c | 40 +++++++++++++++++++++++++++-------
 1 file changed, 32 insertions(+), 8 deletions(-)

diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
index dd7943ff02e4..cdc4ab36f52d 100644
--- a/drivers/iommu/iommufd/device.c
+++ b/drivers/iommu/iommufd/device.c
@@ -294,6 +294,36 @@ static bool iommufd_hw_pagetable_has_group(struct iommufd_hw_pagetable *hwpt,
 	return false;
 }
 
+static int iommufd_device_attach_ioas(struct iommufd_device *idev,
+				      struct iommufd_hw_pagetable *hwpt)
+{
+	phys_addr_t sw_msi_start = PHYS_ADDR_MAX;
+	struct io_pagetable *iopt;
+	int rc;
+
+	iopt = &hwpt->ioas->iopt;
+
+	rc = iopt_table_enforce_group_resv_regions(iopt, idev->dev,
+						   idev->group, &sw_msi_start);
+	if (rc)
+		return rc;
+
+	rc = iommufd_device_setup_msi(idev, hwpt, sw_msi_start);
+	if (rc)
+		goto out_iova;
+
+	return 0;
+out_iova:
+	iopt_remove_reserved_iova(iopt, idev->group);
+	return rc;
+}
+
+static void iommufd_device_detach_ioas(struct iommufd_device *idev,
+				       struct iommufd_hw_pagetable *hwpt)
+{
+	iopt_remove_reserved_iova(&hwpt->ioas->iopt, idev->dev);
+}
+
 /**
  * __iommmufd_device_detach - Detach a device from idev->hwpt to new_hwpt
  * @idev: device to detach
@@ -323,7 +353,7 @@ static void __iommmufd_device_detach(struct iommufd_device *idev,
 
 	if (hwpt->ioas != new_ioas) {
 		mutex_lock(&hwpt->ioas->mutex);
-		iopt_remove_reserved_iova(&hwpt->ioas->iopt, idev->dev);
+		iommufd_device_detach_ioas(idev, hwpt);
 		mutex_unlock(&hwpt->ioas->mutex);
 	}
 	mutex_unlock(&hwpt->devices_lock);
@@ -342,7 +372,6 @@ static int iommufd_device_do_attach(struct iommufd_device *idev,
 				    struct iommufd_hw_pagetable *hwpt)
 {
 	struct iommufd_hw_pagetable *cur_hwpt = idev->hwpt;
-	phys_addr_t sw_msi_start = PHYS_ADDR_MAX;
 	int rc;
 
 	lockdep_assert_held(&hwpt->ioas->mutex);
@@ -367,15 +396,10 @@ static int iommufd_device_do_attach(struct iommufd_device *idev,
 		}
 	}
 
-	rc = iopt_table_enforce_group_resv_regions(&hwpt->ioas->iopt, idev->dev,
-						   idev->group, &sw_msi_start);
+	rc = iommufd_device_attach_ioas(idev, hwpt);
 	if (rc)
 		goto out_unlock;
 
-	rc = iommufd_device_setup_msi(idev, hwpt, sw_msi_start);
-	if (rc)
-		goto out_iova;
-
 	/*
 	 * FIXME: Hack around missing a device-centric iommu api, only attach to
 	 * the group once for the first device that is in the group.
-- 
2.34.1