Introduce a new IOMMUFD_OBJ_VDEVICE to represent a physical device, i.e.
iommufd_device (idev) object, against an iommufd_viommu (vIOMMU) object in
the VM. This vDEVICE object (and its structure) holds all the information
and attributes in a VM, regarding the device related to the vIOMMU.
As an initial patch, add a per-vIOMMU virtual ID. This can be:
- Virtual StreamID on a nested ARM SMMUv3, an index to a Stream Table
- Virtual DeviceID on a nested AMD IOMMU, an index to a Device Table
- Virtual ID on a nested Intel VT-D IOMMU, an index to a Context Table
Potentially, this vDEVICE structure would hold some vData for Confidential
Compute Architecture (CCA). Use this virtual ID to index an "vdevs" xarray
that belongs to a vIOMMU object.
Add a new ioctl for vDEVICE allocations. Since a vDEVICE is a connection
of an iommufd_device object and an iommufd_viommu object, require both as
the ioctl inputs and take refcounts in the ioctl handler.
Then, let the idev structure hold the allocated vdev pointer with a proper
locking protection.
Signed-off-by: Nicolin Chen <nicol...@nvidia.com>
---
drivers/iommu/iommufd/iommufd_private.h | 20 +++++
include/linux/iommufd.h | 3 +
include/uapi/linux/iommufd.h | 26 ++++++
drivers/iommu/iommufd/device.c | 11 +++
drivers/iommu/iommufd/main.c | 7 ++
drivers/iommu/iommufd/viommu.c | 101 ++++++++++++++++++++++++
6 files changed, 168 insertions(+)
diff --git a/drivers/iommu/iommufd/iommufd_private.h
b/drivers/iommu/iommufd/iommufd_private.h
index 8c9ab35eaea5..365cf5a56cdf 100644
--- a/drivers/iommu/iommufd/iommufd_private.h
+++ b/drivers/iommu/iommufd/iommufd_private.h
@@ -391,6 +391,7 @@ struct iommufd_device {
struct iommufd_object obj;
struct iommufd_ctx *ictx;
struct iommufd_group *igroup;
+ struct iommufd_vdevice *vdev;
struct list_head group_item;
/* always the physical device */
struct device *dev;
@@ -505,8 +506,27 @@ static inline int iommufd_hwpt_replace_device(struct
iommufd_device *idev,
return iommu_group_replace_domain(idev->igroup->group, hwpt->domain);
}
+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_vdevice_alloc_ioctl(struct iommufd_ucmd *ucmd);
+void iommufd_vdevice_destroy(struct iommufd_object *obj);
+void iommufd_vdevice_abort(struct iommufd_object *obj);
+
+struct iommufd_vdevice {
+ struct iommufd_object obj;
+ struct iommufd_ctx *ictx;
+ struct iommufd_device *idev;
+ struct iommufd_viommu *viommu;
+ u64 id; /* per-vIOMMU virtual ID */
+};
#ifdef CONFIG_IOMMUFD_TEST
int iommufd_test(struct iommufd_ucmd *ucmd);
diff --git a/include/linux/iommufd.h b/include/linux/iommufd.h
index 083ceb209704..e6cd288e8b83 100644
--- a/include/linux/iommufd.h
+++ b/include/linux/iommufd.h
@@ -31,6 +31,7 @@ enum iommufd_object_type {
IOMMUFD_OBJ_ACCESS,
IOMMUFD_OBJ_FAULT,
IOMMUFD_OBJ_VIOMMU,
+ IOMMUFD_OBJ_VDEVICE,
#ifdef CONFIG_IOMMUFD_TEST
IOMMUFD_OBJ_SELFTEST,
#endif
@@ -89,6 +90,8 @@ struct iommufd_viommu {
const struct iommufd_viommu_ops *ops;
+ struct xarray vdevs;
+
unsigned int type;
};
diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
index 56c742106a45..b699ecb7aa9c 100644
--- a/include/uapi/linux/iommufd.h
+++ b/include/uapi/linux/iommufd.h
@@ -52,6 +52,7 @@ enum {
IOMMUFD_CMD_HWPT_INVALIDATE = 0x8d,
IOMMUFD_CMD_FAULT_QUEUE_ALLOC = 0x8e,
IOMMUFD_CMD_VIOMMU_ALLOC = 0x8f,
+ IOMMUFD_CMD_VDEVICE_ALLOC = 0x90,
};
/**
@@ -896,4 +897,29 @@ struct iommu_viommu_alloc {
__u32 out_viommu_id;
};
#define IOMMU_VIOMMU_ALLOC _IO(IOMMUFD_TYPE, IOMMUFD_CMD_VIOMMU_ALLOC)
+
+/**
+ * struct iommu_vdevice_alloc - ioctl(IOMMU_VDEVICE_ALLOC)
+ * @size: sizeof(struct iommu_vdevice_alloc)
+ * @viommu_id: vIOMMU ID to associate with the virtual device
+ * @dev_id: The pyhsical device to allocate a virtual instance on the vIOMMU
+ * @__reserved: Must be 0
+ * @virt_id: Virtual device ID per vIOMMU, e.g. vSID of ARM SMMUv3, vDeviceID
+ * of AMD IOMMU, and vID of a nested Intel VT-d to a Context Table.
+ * @out_vdevice_id: Output virtual instance ID for the allocated object
+ * @__reserved2: Must be 0
+ *
+ * Allocate a virtual device instance (for a physical device) against a vIOMMU.
+ * This instance holds the device's information (related to its vIOMMU) in a
VM.
+ */
+struct iommu_vdevice_alloc {
+ __u32 size;
+ __u32 viommu_id;
+ __u32 dev_id;
+ __u32 __reserved;
+ __aligned_u64 virt_id;
+ __u32 out_vdevice_id;
+ __u32 __reserved2;
+};
+#define IOMMU_VDEVICE_ALLOC _IO(IOMMUFD_TYPE, IOMMUFD_CMD_VDEVICE_ALLOC)
#endif
diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
index 5fd3dd420290..e50113305a9c 100644
--- a/drivers/iommu/iommufd/device.c
+++ b/drivers/iommu/iommufd/device.c
@@ -277,6 +277,17 @@ EXPORT_SYMBOL_NS_GPL(iommufd_ctx_has_group, IOMMUFD);
*/
void iommufd_device_unbind(struct iommufd_device *idev)
{
+ u32 vdev_id = 0;
+
+ /* idev->vdev object should be destroyed prior, yet just in case.. */
+ mutex_lock(&idev->igroup->lock);
+ if (idev->vdev)
+ vdev_id = idev->vdev->obj.id;
+ mutex_unlock(&idev->igroup->lock);
+ /* Relying on xa_lock against a race with iommufd_destroy() */
+ if (vdev_id)
+ iommufd_object_remove(idev->ictx, NULL, vdev_id, 0);
+
iommufd_object_destroy_user(idev->ictx, &idev->obj);
}
EXPORT_SYMBOL_NS_GPL(iommufd_device_unbind, IOMMUFD);
diff --git a/drivers/iommu/iommufd/main.c b/drivers/iommu/iommufd/main.c
index ab5ee325d809..696ac9e0e74b 100644
--- a/drivers/iommu/iommufd/main.c
+++ b/drivers/iommu/iommufd/main.c
@@ -322,6 +322,7 @@ union ucmd_buffer {
struct iommu_option option;
struct iommu_vfio_ioas vfio_ioas;
struct iommu_viommu_alloc viommu;
+ struct iommu_vdevice_alloc vdev;
#ifdef CONFIG_IOMMUFD_TEST
struct iommu_test_cmd test;
#endif
@@ -375,6 +376,8 @@ 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_VDEVICE_ALLOC, iommufd_vdevice_alloc_ioctl,
+ struct iommu_vdevice_alloc, __reserved2),
#ifdef CONFIG_IOMMUFD_TEST
IOCTL_OP(IOMMU_TEST_CMD, iommufd_test, struct iommu_test_cmd, last),
#endif
@@ -513,6 +516,10 @@ static const struct iommufd_object_ops
iommufd_object_ops[] = {
[IOMMUFD_OBJ_VIOMMU] = {
.destroy = iommufd_viommu_destroy,
},
+ [IOMMUFD_OBJ_VDEVICE] = {
+ .destroy = iommufd_vdevice_destroy,
+ .abort = iommufd_vdevice_abort,
+ },
#ifdef CONFIG_IOMMUFD_TEST
[IOMMUFD_OBJ_SELFTEST] = {
.destroy = iommufd_selftest_destroy,
diff --git a/drivers/iommu/iommufd/viommu.c b/drivers/iommu/iommufd/viommu.c
index eb41e15ebab1..2b9a9a80298d 100644
--- a/drivers/iommu/iommufd/viommu.c
+++ b/drivers/iommu/iommufd/viommu.c
@@ -12,6 +12,7 @@ void iommufd_viommu_destroy(struct iommufd_object *obj)
if (viommu->ops && viommu->ops->free)
viommu->ops->free(viommu);
refcount_dec(&viommu->hwpt->common.obj.users);
+ xa_destroy(&viommu->vdevs);
}
int iommufd_viommu_alloc_ioctl(struct iommufd_ucmd *ucmd)
@@ -70,6 +71,7 @@ int iommufd_viommu_alloc_ioctl(struct iommufd_ucmd *ucmd)
*/
viommu->iommu_dev = __iommu_get_iommu_dev(idev->dev);
+ xa_init(&viommu->vdevs);
refcount_inc(&viommu->hwpt->common.obj.users);
cmd->out_viommu_id = viommu->obj.id;
@@ -87,3 +89,102 @@ int iommufd_viommu_alloc_ioctl(struct iommufd_ucmd *ucmd)
iommufd_put_object(ucmd->ictx, &idev->obj);
return rc;
}
+
+void iommufd_vdevice_abort(struct iommufd_object *obj)
+{
+ struct iommufd_vdevice *old,
+ *vdev = container_of(obj, struct iommufd_vdevice, obj);
+ struct iommufd_viommu *viommu = vdev->viommu;
+ struct iommufd_device *idev = vdev->idev;
+
+ lockdep_assert_held(&idev->igroup->lock);
+
+ old = xa_cmpxchg(&viommu->vdevs, vdev->id, vdev, NULL, GFP_KERNEL);
+ if (old)
+ WARN_ON(old != vdev);
+
+ refcount_dec(&viommu->obj.users);
+ refcount_dec(&idev->obj.users);
+ idev->vdev = NULL;
+}
+
+void iommufd_vdevice_destroy(struct iommufd_object *obj)
+{
+ struct iommufd_vdevice *vdev =
+ container_of(obj, struct iommufd_vdevice, obj);
+
+ mutex_lock(&vdev->idev->igroup->lock);
+ iommufd_vdevice_abort(obj);
+ mutex_unlock(&vdev->idev->igroup->lock);
+}
+
+int iommufd_vdevice_alloc_ioctl(struct iommufd_ucmd *ucmd)
+{
+ struct iommu_vdevice_alloc *cmd = ucmd->cmd;
+ struct iommufd_vdevice *vdev, *curr;
+ struct iommufd_viommu *viommu;
+ struct iommufd_device *idev;
+ u64 virt_id = cmd->virt_id;
+ int rc = 0;
+
+ if (virt_id > ULONG_MAX)
+ return -EINVAL;
+
+ viommu = iommufd_get_viommu(ucmd, cmd->viommu_id);
+ if (IS_ERR(viommu))
+ return PTR_ERR(viommu);
+
+ idev = iommufd_get_device(ucmd, cmd->dev_id);
+ if (IS_ERR(idev)) {
+ rc = PTR_ERR(idev);
+ goto out_put_viommu;
+ }
+
+ mutex_lock(&idev->igroup->lock);
+ if (idev->vdev) {
+ rc = -EEXIST;
+ goto out_unlock_igroup;
+ }
+
+ vdev = iommufd_object_alloc(ucmd->ictx, vdev, IOMMUFD_OBJ_VDEVICE);
+ if (IS_ERR(vdev)) {
+ rc = PTR_ERR(vdev);
+ goto out_unlock_igroup;
+ }
+
+ rc = iommufd_verify_unfinalized_object(ucmd->ictx, &vdev->obj);
+ if (rc) {
+ kfree(vdev);
+ goto out_unlock_igroup;
+ }
+
+ vdev->idev = idev;
+ vdev->id = virt_id;
+ vdev->viommu = viommu;
+
+ idev->vdev = vdev;
+ refcount_inc(&idev->obj.users);
+ refcount_inc(&viommu->obj.users);
+
+ curr = xa_cmpxchg(&viommu->vdevs, virt_id, NULL, vdev, GFP_KERNEL);
+ if (curr) {
+ rc = xa_err(curr) ?: -EBUSY;
+ goto out_abort;
+ }
+
+ cmd->out_vdevice_id = vdev->obj.id;
+ rc = iommufd_ucmd_respond(ucmd, sizeof(*cmd));
+ if (rc)
+ goto out_abort;
+ iommufd_object_finalize(ucmd->ictx, &vdev->obj);
+ goto out_unlock_igroup;
+
+out_abort:
+ iommufd_object_abort_and_destroy(ucmd->ictx, &vdev->obj);
+out_unlock_igroup:
+ mutex_unlock(&idev->igroup->lock);
+ iommufd_put_object(ucmd->ictx, &idev->obj);
+out_put_viommu:
+ iommufd_put_object(ucmd->ictx, &viommu->obj);
+ return rc;
+}
--
2.43.0
