[PATCH v1 05/16] iommufd/viommu: Add IOMMU_VIOMMU_SET/UNSET_VDEV_ID ioctl

7 Aug 2024

Introduce a pair of new ioctls to set/unset a per-viommu virtual device id
that should be linked to a physical device id via a struct device pointer.
Continue the support IOMMU_VIOMMU_TYPE_DEFAULT for a core-managed viommu.
Provide a lookup function for drivers to load device pointer by a virtual
device id.
Signed-off-by: Nicolin Chen nicolinc@nvidia.com
---
 drivers/iommu/iommufd/device.c          |   9 ++
 drivers/iommu/iommufd/iommufd_private.h |  20 ++++
 drivers/iommu/iommufd/main.c            |   6 ++
 drivers/iommu/iommufd/viommu.c          | 118 ++++++++++++++++++++++++
 include/uapi/linux/iommufd.h            |  40 ++++++++
 5 files changed, 193 insertions(+)

diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
index 5fd3dd420290..ed29bc606f5e 100644
--- a/drivers/iommu/iommufd/device.c
+++ b/drivers/iommu/iommufd/device.c
@@ -135,7 +135,14 @@ void iommufd_device_destroy(struct iommufd_object *obj)
 {
    struct iommufd_device *idev =
    	container_of(obj, struct iommufd_device, obj);
+	struct iommufd_vdev_id *vdev_id, *curr;
+	list_for_each_entry(vdev_id, &idev->vdev_id_list, idev_item) {
+		curr = xa_cmpxchg(&vdev_id->viommu->vdev_ids, vdev_id->vdev_id,
+				  vdev_id, NULL, GFP_KERNEL);
+		WARN_ON(curr != vdev_id);
+		kfree(vdev_id);
+	}
    iommu_device_release_dma_owner(idev->dev);
    iommufd_put_group(idev->igroup);
    if (!iommufd_selftest_is_mock_dev(idev->dev))
@@ -217,6 +224,8 @@ struct iommufd_device *iommufd_device_bind(struct iommufd_ctx *ictx,
    idev->igroup = igroup;
    mutex_init(&idev->iopf_lock);
+	INIT_LIST_HEAD(&idev->vdev_id_list);
+
    /*
     * If the caller fails after this success it must call
     * iommufd_unbind_device() which is safe since we hold this refcount.
diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h
index 443575fd3dd4..10c63972b9ab 100644
--- a/drivers/iommu/iommufd/iommufd_private.h
+++ b/drivers/iommu/iommufd/iommufd_private.h
@@ -417,6 +417,7 @@ struct iommufd_device {
    struct iommufd_ctx *ictx;
    struct iommufd_group *igroup;
    struct list_head group_item;
+	struct list_head vdev_id_list;
    /* always the physical device */
    struct device *dev;
    bool enforce_cache_coherency;
@@ -533,12 +534,31 @@ struct iommufd_viommu {
    struct iommufd_ctx *ictx;
    struct iommu_device *iommu_dev;
    struct iommufd_hwpt_paging *hwpt;
+	struct xarray vdev_ids;
unsigned int type;
 };
+struct iommufd_vdev_id {
+	struct iommufd_viommu *viommu;
+	struct device *dev;
+	u64 vdev_id;
+
+	struct list_head idev_item;
+};
+
+static inline struct iommufd_viommu *
+iommufd_get_viommu(struct iommufd_ucmd *ucmd, u32 id)
+{
+	return container_of(iommufd_get_object(ucmd->ictx, id,
+					       IOMMUFD_OBJ_VIOMMU),
+			    struct iommufd_viommu, obj);
+}
+
 int iommufd_viommu_alloc_ioctl(struct iommufd_ucmd *ucmd);
 void iommufd_viommu_destroy(struct iommufd_object *obj);
+int iommufd_viommu_set_vdev_id(struct iommufd_ucmd *ucmd);
+int iommufd_viommu_unset_vdev_id(struct iommufd_ucmd *ucmd);
#ifdef CONFIG_IOMMUFD_TEST
 int iommufd_test(struct iommufd_ucmd *ucmd);
diff --git a/drivers/iommu/iommufd/main.c b/drivers/iommu/iommufd/main.c
index 288ee51b6829..199ad90fa36b 100644
--- a/drivers/iommu/iommufd/main.c
+++ b/drivers/iommu/iommufd/main.c
@@ -334,6 +334,8 @@ union ucmd_buffer {
    struct iommu_option option;
    struct iommu_vfio_ioas vfio_ioas;
    struct iommu_viommu_alloc viommu;
+	struct iommu_viommu_set_vdev_id set_vdev_id;
+	struct iommu_viommu_unset_vdev_id unset_vdev_id;
 #ifdef CONFIG_IOMMUFD_TEST
    struct iommu_test_cmd test;
 #endif
@@ -387,6 +389,10 @@ static const struct iommufd_ioctl_op iommufd_ioctl_ops[] = {
    	 __reserved),
    IOCTL_OP(IOMMU_VIOMMU_ALLOC, iommufd_viommu_alloc_ioctl,
    	 struct iommu_viommu_alloc, out_viommu_id),
+	IOCTL_OP(IOMMU_VIOMMU_SET_VDEV_ID, iommufd_viommu_set_vdev_id,
+		 struct iommu_viommu_set_vdev_id, vdev_id),
+	IOCTL_OP(IOMMU_VIOMMU_UNSET_VDEV_ID, iommufd_viommu_unset_vdev_id,
+		 struct iommu_viommu_unset_vdev_id, vdev_id),
 #ifdef CONFIG_IOMMUFD_TEST
    IOCTL_OP(IOMMU_TEST_CMD, iommufd_test, struct iommu_test_cmd, last),
 #endif
diff --git a/drivers/iommu/iommufd/viommu.c b/drivers/iommu/iommufd/viommu.c
index 35ad6a77c9c1..05a688a471db 100644
--- a/drivers/iommu/iommufd/viommu.c
+++ b/drivers/iommu/iommufd/viommu.c
@@ -10,7 +10,14 @@ void iommufd_viommu_destroy(struct iommufd_object *obj)
 {
    struct iommufd_viommu *viommu =
    	container_of(obj, struct iommufd_viommu, obj);
+	struct iommufd_vdev_id *vdev_id;
+	unsigned long index;
+	xa_for_each(&viommu->vdev_ids, index, vdev_id) {
+		list_del(&vdev_id->idev_item);
+		kfree(vdev_id);
+	}
+	xa_destroy(&viommu->vdev_ids);
    refcount_dec(&viommu->hwpt->common.obj.users);
 }
@@ -73,3 +80,114 @@ int iommufd_viommu_alloc_ioctl(struct iommufd_ucmd *ucmd)
    iommufd_put_object(ucmd->ictx, &idev->obj);
    return rc;
 }
+
+int iommufd_viommu_set_vdev_id(struct iommufd_ucmd *ucmd)
+{
+	struct iommu_viommu_set_vdev_id *cmd = ucmd->cmd;
+	struct iommufd_hwpt_nested *hwpt_nested;
+	struct iommufd_vdev_id *vdev_id, *curr;
+	struct iommufd_hw_pagetable *hwpt;
+	struct iommufd_viommu *viommu;
+	struct iommufd_device *idev;
+	int rc = 0;
+
+	if (cmd->vdev_id > ULONG_MAX)
+		return -EINVAL;
+
+	idev = iommufd_get_device(ucmd, cmd->dev_id);
+	if (IS_ERR(idev))
+		return PTR_ERR(idev);
+	hwpt = idev->igroup->hwpt;
+
+	if (hwpt == NULL || hwpt->obj.type != IOMMUFD_OBJ_HWPT_NESTED) {
+		rc = -EINVAL;
+		goto out_put_idev;
+	}
+	hwpt_nested = container_of(hwpt, struct iommufd_hwpt_nested, common);
+
+	viommu = iommufd_get_viommu(ucmd, cmd->viommu_id);
+	if (IS_ERR(viommu)) {
+		rc = PTR_ERR(viommu);
+		goto out_put_idev;
+	}
+
+	if (hwpt_nested->viommu != viommu) {
+		rc = -EINVAL;
+		goto out_put_viommu;
+	}
+
+	vdev_id = kzalloc(sizeof(*vdev_id), GFP_KERNEL);
+	if (IS_ERR(vdev_id)) {
+		rc = PTR_ERR(vdev_id);
+		goto out_put_viommu;
+	}
+
+	vdev_id->viommu = viommu;
+	vdev_id->dev = idev->dev;
+	vdev_id->vdev_id = cmd->vdev_id;
+
+	curr = xa_cmpxchg(&viommu->vdev_ids, cmd->vdev_id,
+			  NULL, vdev_id, GFP_KERNEL);
+	if (curr) {
+		rc = xa_err(curr) ? : -EBUSY;
+		goto out_free_vdev_id;
+	}
+
+	list_add_tail(&vdev_id->idev_item, &idev->vdev_id_list);
+	goto out_put_viommu;
+
+out_free_vdev_id:
+	kfree(vdev_id);
+out_put_viommu:
+	iommufd_put_object(ucmd->ictx, &viommu->obj);
+out_put_idev:
+	iommufd_put_object(ucmd->ictx, &idev->obj);
+	return rc;
+}
+
+static struct device *
+iommufd_viommu_find_device(struct iommufd_viommu *viommu, u64 id)
+{
+	struct iommufd_vdev_id *vdev_id;
+
+	xa_lock(&viommu->vdev_ids);
+	vdev_id = xa_load(&viommu->vdev_ids, (unsigned long)id);
+	xa_unlock(&viommu->vdev_ids);
+	if (!vdev_id || vdev_id->vdev_id != id)
+		return NULL;
+	return vdev_id->dev;
+}
+
+int iommufd_viommu_unset_vdev_id(struct iommufd_ucmd *ucmd)
+{
+	struct iommu_viommu_unset_vdev_id *cmd = ucmd->cmd;
+	struct iommufd_vdev_id *vdev_id;
+	struct iommufd_viommu *viommu;
+	struct iommufd_device *idev;
+	int rc = 0;
+
+	idev = iommufd_get_device(ucmd, cmd->dev_id);
+	if (IS_ERR(idev))
+		return PTR_ERR(idev);
+
+	viommu = iommufd_get_viommu(ucmd, cmd->viommu_id);
+	if (IS_ERR(viommu)) {
+		rc = PTR_ERR(viommu);
+		goto out_put_idev;
+	}
+
+	if (idev->dev != iommufd_viommu_find_device(viommu, cmd->vdev_id)) {
+		rc = -EINVAL;
+		goto out_put_viommu;
+	}
+
+	vdev_id = xa_erase(&viommu->vdev_ids, cmd->vdev_id);
+	list_del(&vdev_id->idev_item);
+	kfree(vdev_id);
+
+out_put_viommu:
+	iommufd_put_object(ucmd->ictx, &viommu->obj);
+out_put_idev:
+	iommufd_put_object(ucmd->ictx, &idev->obj);
+	return rc;
+}
diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
index 0e384331a9c8..d5e72682ba57 100644
--- a/include/uapi/linux/iommufd.h
+++ b/include/uapi/linux/iommufd.h
@@ -52,6 +52,8 @@ enum {
    IOMMUFD_CMD_HWPT_INVALIDATE = 0x8d,
    IOMMUFD_CMD_FAULT_QUEUE_ALLOC = 0x8e,
    IOMMUFD_CMD_VIOMMU_ALLOC = 0x8f,
+	IOMMUFD_CMD_VIOMMU_SET_VDEV_ID = 0x90,
+	IOMMUFD_CMD_VIOMMU_UNSET_VDEV_ID = 0x91,
 };
/**
@@ -906,4 +908,42 @@ struct iommu_viommu_alloc {
    __u32 out_viommu_id;
 };
 #define IOMMU_VIOMMU_ALLOC _IO(IOMMUFD_TYPE, IOMMUFD_CMD_VIOMMU_ALLOC)
+
+/**
+ * struct iommu_viommu_set_vdev_id - ioctl(IOMMU_VIOMMU_SET_VDEV_ID)
+ * @size: sizeof(struct iommu_viommu_set_vdev_id)
+ * @viommu_id: viommu ID to associate with the device to store its virtual ID
+ * @dev_id: device ID to set its virtual ID
+ * @__reserved: Must be 0
+ * @vdev_id: Virtual device ID
+ *
+ * Set a viommu-specific virtual ID of a device
+ */
+struct iommu_viommu_set_vdev_id {
+	__u32 size;
+	__u32 viommu_id;
+	__u32 dev_id;
+	__u32 __reserved;
+	__aligned_u64 vdev_id;
+};
+#define IOMMU_VIOMMU_SET_VDEV_ID _IO(IOMMUFD_TYPE, IOMMUFD_CMD_VIOMMU_SET_VDEV_ID)
+
+/**
+ * struct iommu_viommu_unset_vdev_id - ioctl(IOMMU_VIOMMU_UNSET_VDEV_ID)
+ * @size: sizeof(struct iommu_viommu_unset_vdev_id)
+ * @viommu_id: viommu ID associated with the device to delete its virtual ID
+ * @dev_id: device ID to unset its virtual ID
+ * @__reserved: Must be 0
+ * @vdev_id: Virtual device ID (for verification)
+ *
+ * Unset a viommu-specific virtual ID of a device
+ */
+struct iommu_viommu_unset_vdev_id {
+	__u32 size;
+	__u32 viommu_id;
+	__u32 dev_id;
+	__u32 __reserved;
+	__aligned_u64 vdev_id;
+};
+#define IOMMU_VIOMMU_UNSET_VDEV_ID _IO(IOMMUFD_TYPE, IOMMUFD_CMD_VIOMMU_UNSET_VDEV_ID)
 #endif
-- 
2.43.0



    

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[PATCH v1 05/16] iommufd/viommu: Add IOMMU_VIOMMU_SET/UNSET_VDEV_ID ioctl