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

Yi Liu
2023-02-09T04:35:16Z

From: Nicolin Chen <nicolinc@nvidia.com>

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@nvidia.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
---
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