Commit 2fb69c60 authored by Yi Liu's avatar Yi Liu Committed by Jason Gunthorpe
Browse files

iommufd: Support pasid attach/replace 

This extends the below APIs to support PASID. Device drivers to manage pasid
attach/replace/detach.

    int iommufd_device_attach(struct iommufd_device *idev,
			      ioasid_t pasid, u32 *pt_id);
    int iommufd_device_replace(struct iommufd_device *idev,
			       ioasid_t pasid, u32 *pt_id);
    void iommufd_device_detach(struct iommufd_device *idev,
			       ioasid_t pasid);

The pasid operations share underlying attach/replace/detach infrastructure
with the device operations, but still have some different implications:

 - no reserved region per pasid otherwise SVA architecture is already
   broken (CPU address space doesn't count device reserved regions);

 - accordingly no sw_msi trick;

Cache coherency enforcement is still applied to pasid operations since
it is about memory accesses post page table walking (no matter the walk
is per RID or per PASID).

Link: https://patch.msgid.link/r/20250321171940.7213-12-yi.l.liu@intel.com


Reviewed-by: default avatarJason Gunthorpe <jgg@nvidia.com>
Signed-off-by: default avatarKevin Tian <kevin.tian@intel.com>
Reviewed-by: default avatarNicolin Chen <nicolinc@nvidia.com>
Signed-off-by: default avatarYi Liu <yi.l.liu@intel.com>
Tested-by: default avatarNicolin Chen <nicolinc@nvidia.com>
Signed-off-by: default avatarJason Gunthorpe <jgg@nvidia.com>
parent ff3f014e

drivers/iommu/iommufd/device.c

+37 −22
Original line number Diff line number Diff line
@@ -428,9 +428,12 @@ static int iommufd_hwpt_attach_device(struct iommufd_hw_pagetable *hwpt, 
	}



	handle->idev = idev;

	WARN_ON(pasid != IOMMU_NO_PASID);

	if (pasid == IOMMU_NO_PASID)

		rc = iommu_attach_group_handle(hwpt->domain, idev->igroup->group,

					       &handle->handle);

	else

		rc = iommu_attach_device_pasid(hwpt->domain, idev->dev, pasid,

					       &handle->handle);

	if (rc)

		goto out_disable_iopf;
@@ -464,10 +467,12 @@ static void iommufd_hwpt_detach_device(struct iommufd_hw_pagetable *hwpt, 
{

	struct iommufd_attach_handle *handle;



	WARN_ON(pasid != IOMMU_NO_PASID);



	handle = iommufd_device_get_attach_handle(idev, pasid);

	if (pasid == IOMMU_NO_PASID)

		iommu_detach_group_handle(hwpt->domain, idev->igroup->group);

	else

		iommu_detach_device_pasid(hwpt->domain, idev->dev, pasid);



	if (hwpt->fault) {

		iommufd_auto_response_faults(hwpt, handle);

		iommufd_fault_iopf_disable(idev);
@@ -483,8 +488,6 @@ static int iommufd_hwpt_replace_device(struct iommufd_device *idev, 
	struct iommufd_attach_handle *handle, *old_handle;

	int rc;



	WARN_ON(pasid != IOMMU_NO_PASID);



	rc = iommufd_hwpt_pasid_compat(hwpt, idev, pasid);

	if (rc)

		return rc;
@@ -502,8 +505,12 @@ static int iommufd_hwpt_replace_device(struct iommufd_device *idev, 
	}



	handle->idev = idev;

	rc = iommu_replace_group_handle(idev->igroup->group, hwpt->domain,

					&handle->handle);

	if (pasid == IOMMU_NO_PASID)

		rc = iommu_replace_group_handle(idev->igroup->group,

						hwpt->domain, &handle->handle);

	else

		rc = iommu_replace_device_pasid(hwpt->domain, idev->dev,

						pasid, &handle->handle);

	if (rc)

		goto out_disable_iopf;
@@ -904,22 +911,25 @@ static int iommufd_device_change_pt(struct iommufd_device *idev, 
}



/**

 * iommufd_device_attach - Connect a device to an iommu_domain

 * iommufd_device_attach - Connect a device/pasid to an iommu_domain

 * @idev: device to attach

 * @pasid: pasid to attach

 * @pt_id: Input a IOMMUFD_OBJ_IOAS, or IOMMUFD_OBJ_HWPT_PAGING

 *         Output the IOMMUFD_OBJ_HWPT_PAGING ID

 *

 * This connects the device to an iommu_domain, either automatically or manually

 * selected. Once this completes the device could do DMA.

 * This connects the device/pasid to an iommu_domain, either automatically

 * or manually selected. Once this completes the device could do DMA with

 * @pasid. @pasid is IOMMU_NO_PASID if this attach is for no pasid usage.

 *

 * The caller should return the resulting pt_id back to userspace.

 * This function is undone by calling iommufd_device_detach().

 */

int iommufd_device_attach(struct iommufd_device *idev, u32 *pt_id)

int iommufd_device_attach(struct iommufd_device *idev, ioasid_t pasid,

			  u32 *pt_id)

{

	int rc;



	rc = iommufd_device_change_pt(idev, IOMMU_NO_PASID, pt_id,

	rc = iommufd_device_change_pt(idev, pasid, pt_id,

				      &iommufd_device_do_attach);

	if (rc)

		return rc;
@@ -934,8 +944,9 @@ int iommufd_device_attach(struct iommufd_device *idev, u32 *pt_id) 
EXPORT_SYMBOL_NS_GPL(iommufd_device_attach, "IOMMUFD");



/**

 * iommufd_device_replace - Change the device's iommu_domain

 * iommufd_device_replace - Change the device/pasid's iommu_domain

 * @idev: device to change

 * @pasid: pasid to change

 * @pt_id: Input a IOMMUFD_OBJ_IOAS, or IOMMUFD_OBJ_HWPT_PAGING

 *         Output the IOMMUFD_OBJ_HWPT_PAGING ID

 *
@@ -946,27 +957,31 @@ EXPORT_SYMBOL_NS_GPL(iommufd_device_attach, "IOMMUFD"); 
 *

 * If it fails then no change is made to the attachment. The iommu driver may

 * implement this so there is no disruption in translation. This can only be

 * called if iommufd_device_attach() has already succeeded.

 * called if iommufd_device_attach() has already succeeded. @pasid is

 * IOMMU_NO_PASID for no pasid usage.

 */

int iommufd_device_replace(struct iommufd_device *idev, u32 *pt_id)

int iommufd_device_replace(struct iommufd_device *idev, ioasid_t pasid,

			   u32 *pt_id)

{

	return iommufd_device_change_pt(idev, IOMMU_NO_PASID, pt_id,

	return iommufd_device_change_pt(idev, pasid, pt_id,

					&iommufd_device_do_replace);

}

EXPORT_SYMBOL_NS_GPL(iommufd_device_replace, "IOMMUFD");



/**

 * iommufd_device_detach - Disconnect a device to an iommu_domain

 * iommufd_device_detach - Disconnect a device/device to an iommu_domain

 * @idev: device to detach

 * @pasid: pasid to detach

 *

 * Undo iommufd_device_attach(). This disconnects the idev from the previously

 * attached pt_id. The device returns back to a blocked DMA translation.

 * @pasid is IOMMU_NO_PASID for no pasid usage.

 */

void iommufd_device_detach(struct iommufd_device *idev)

void iommufd_device_detach(struct iommufd_device *idev, ioasid_t pasid)

{

	struct iommufd_hw_pagetable *hwpt;



	hwpt = iommufd_hw_pagetable_detach(idev, IOMMU_NO_PASID);

	hwpt = iommufd_hw_pagetable_detach(idev, pasid);

	iommufd_hw_pagetable_put(idev->ictx, hwpt);

	refcount_dec(&idev->obj.users);

}

drivers/iommu/iommufd/selftest.c

+4 −4
Original line number Diff line number Diff line
@@ -945,7 +945,7 @@ static int iommufd_test_mock_domain(struct iommufd_ucmd *ucmd, 
	}

	sobj->idev.idev = idev;



	rc = iommufd_device_attach(idev, &pt_id);

	rc = iommufd_device_attach(idev, IOMMU_NO_PASID, &pt_id);

	if (rc)

		goto out_unbind;
@@ -960,7 +960,7 @@ static int iommufd_test_mock_domain(struct iommufd_ucmd *ucmd, 
	return 0;



out_detach:

	iommufd_device_detach(idev);

	iommufd_device_detach(idev, IOMMU_NO_PASID);

out_unbind:

	iommufd_device_unbind(idev);

out_mdev:
@@ -994,7 +994,7 @@ static int iommufd_test_mock_domain_replace(struct iommufd_ucmd *ucmd, 
		goto out_dev_obj;

	}



	rc = iommufd_device_replace(sobj->idev.idev, &pt_id);

	rc = iommufd_device_replace(sobj->idev.idev, IOMMU_NO_PASID, &pt_id);

	if (rc)

		goto out_dev_obj;
@@ -1655,7 +1655,7 @@ void iommufd_selftest_destroy(struct iommufd_object *obj) 


	switch (sobj->type) {

	case TYPE_IDEV:

		iommufd_device_detach(sobj->idev.idev);

		iommufd_device_detach(sobj->idev.idev, IOMMU_NO_PASID);

		iommufd_device_unbind(sobj->idev.idev);

		mock_dev_destroy(sobj->idev.mock_dev);

		break;

drivers/vfio/iommufd.c

+6 −4
Original line number Diff line number Diff line
@@ -128,7 +128,7 @@ void vfio_iommufd_physical_unbind(struct vfio_device *vdev) 
	lockdep_assert_held(&vdev->dev_set->lock);



	if (vdev->iommufd_attached) {

		iommufd_device_detach(vdev->iommufd_device);

		iommufd_device_detach(vdev->iommufd_device, IOMMU_NO_PASID);

		vdev->iommufd_attached = false;

	}

	iommufd_device_unbind(vdev->iommufd_device);
@@ -146,9 +146,11 @@ int vfio_iommufd_physical_attach_ioas(struct vfio_device *vdev, u32 *pt_id) 
		return -EINVAL;



	if (vdev->iommufd_attached)

		rc = iommufd_device_replace(vdev->iommufd_device, pt_id);

		rc = iommufd_device_replace(vdev->iommufd_device,

					    IOMMU_NO_PASID, pt_id);

	else

		rc = iommufd_device_attach(vdev->iommufd_device, pt_id);

		rc = iommufd_device_attach(vdev->iommufd_device,

					   IOMMU_NO_PASID, pt_id);

	if (rc)

		return rc;

	vdev->iommufd_attached = true;
@@ -163,7 +165,7 @@ void vfio_iommufd_physical_detach_ioas(struct vfio_device *vdev) 
	if (WARN_ON(!vdev->iommufd_device) || !vdev->iommufd_attached)

		return;



	iommufd_device_detach(vdev->iommufd_device);

	iommufd_device_detach(vdev->iommufd_device, IOMMU_NO_PASID);

	vdev->iommufd_attached = false;

}

EXPORT_SYMBOL_GPL(vfio_iommufd_physical_detach_ioas);

include/linux/iommufd.h

+6 −3
Original line number Diff line number Diff line
@@ -8,6 +8,7 @@ 


#include <linux/err.h>

#include <linux/errno.h>

#include <linux/iommu.h>

#include <linux/refcount.h>

#include <linux/types.h>

#include <linux/xarray.h>
@@ -54,9 +55,11 @@ struct iommufd_device *iommufd_device_bind(struct iommufd_ctx *ictx, 
					   struct device *dev, u32 *id);

void iommufd_device_unbind(struct iommufd_device *idev);



int iommufd_device_attach(struct iommufd_device *idev, u32 *pt_id);

int iommufd_device_replace(struct iommufd_device *idev, u32 *pt_id);

void iommufd_device_detach(struct iommufd_device *idev);

int iommufd_device_attach(struct iommufd_device *idev, ioasid_t pasid,

			  u32 *pt_id);

int iommufd_device_replace(struct iommufd_device *idev, ioasid_t pasid,

			   u32 *pt_id);

void iommufd_device_detach(struct iommufd_device *idev, ioasid_t pasid);



struct iommufd_ctx *iommufd_device_to_ictx(struct iommufd_device *idev);

u32 iommufd_device_to_id(struct iommufd_device *idev);