[RFC 4/7] iommufd: Support attach/replace for SIOV virtual device {dev, pasid}

Yi Liu
2023-10-09T08:52:08Z

From: Kevin Tian <kevin.tian@intel.com>

SIOV devices allows driver to tag different PASIDs for the virtual devices
within it. Such driver should call iommufd_device_bind_pasid() to connect
the pasid of the device to iommufd, and then driver is able to attach the
virtual device to IOAS/HWPT with the iommufd_device_attach() API.

Unlike physical devices, for SIOV virtual devices, iommufd_device_attach()
eventually uses the idev->default_pasid when the virtual device is attached
to an IOAS/HWPT. Also, there is no need to do immediate_attach per iommu
domain allocation in the attach/replace path if any iommu domain allocation
happens since the attach/replace is eventually pasid attach/replace.

Signed-off-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
---
drivers/iommu/iommufd/device.c | 21 +++++++++++++++++----
1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
index 35c1419ee96b..4882e3106b2e 100644
--- a/drivers/iommu/iommufd/device.c
+++ b/drivers/iommu/iommufd/device.c
@@ -841,7 +841,11 @@ int iommufd_device_attach(struct iommufd_device *idev, u32 *pt_id)
.pasid = IOMMU_PASID_INVALID
};

- rc = iommufd_device_change_pt(idev, pt_id, &data);
+ if (idev->igroup)
+ rc = iommufd_device_change_pt(idev, pt_id, &data);
+ else
+ /* SIOV device follows generic pasid attach flow */
+ rc = iommufd_device_pasid_attach(idev, idev->default_pasid, pt_id);
if (rc)
return rc;

@@ -876,7 +880,12 @@ int iommufd_device_replace(struct iommufd_device *idev, u32 *pt_id)
.pasid = IOMMU_PASID_INVALID
};

- return iommufd_device_change_pt(idev, pt_id, &data);
+ if (idev->igroup) {
+ return iommufd_device_change_pt(idev, pt_id, &data);
+ } else {
+ /* SIOV device follows generic pasid replace flow */
+ return iommufd_device_pasid_replace(idev, idev->default_pasid, pt_id);
+ }
}
EXPORT_SYMBOL_NS_GPL(iommufd_device_replace, IOMMUFD);

@@ -891,8 +900,12 @@ void iommufd_device_detach(struct iommufd_device *idev)
{
struct iommufd_hw_pagetable *hwpt;

- hwpt = iommufd_hw_pagetable_detach(idev);
- iommufd_hw_pagetable_put(idev->ictx, hwpt);
+ if (idev->igroup) {
+ hwpt = iommufd_hw_pagetable_detach(idev);
+ iommufd_hw_pagetable_put(idev->ictx, hwpt);
+ } else {
+ iommufd_device_pasid_detach(idev, idev->default_pasid);
+ }
refcount_dec(&idev->obj.users);
}
EXPORT_SYMBOL_NS_GPL(iommufd_device_detach, IOMMUFD);
--
2.34.1