diff mbox series

[RFC,v3,2/4] iommufd: Add IOMMUFD_CMD_DEVICE_SET_DATA and IOMMUFD_CMD_DEVICE_UNSET_DATA

Message ID 08604f9f4835d5a6b0d2d75de69722194abf7747.1682234302.git.nicolinc@nvidia.com
State New
Headers
Series Add set_dev_data and unset_dev_data support |

Commit Message

Nicolin Chen April 23, 2023, 7:40 a.m. UTC 
  Add a new pair of ioctls to allow user space to set and unset its iommu-
specific device data for a passthrough device that's behind the iommu.

On platforms with SMMUv3, this new uAPIs will be used to forward a user
space virtual Stream ID of a passthrough device to link to its physical
Stream ID and log into a lookup table, in order for the host kernel to
later run sanity on ATC invalidation requests from the user space, with
ATC_INV commands that have SID fields (virtual Stream IDs).

Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
 drivers/iommu/iommufd/device.c          | 81 +++++++++++++++++++++++++
 drivers/iommu/iommufd/iommufd_private.h |  3 +
 drivers/iommu/iommufd/main.c            |  4 ++
 include/uapi/linux/iommufd.h            | 32 ++++++++++
 4 files changed, 120 insertions(+)

Comments

Baolu Lu April 24, 2023, 2:44 a.m. UTC | #1 
On 4/23/23 3:40 PM, Nicolin Chen wrote:
> Add a new pair of ioctls to allow user space to set and unset its iommu-
> specific device data for a passthrough device that's behind the iommu.
> 
> On platforms with SMMUv3, this new uAPIs will be used to forward a user
> space virtual Stream ID of a passthrough device to link to its physical
> Stream ID and log into a lookup table, in order for the host kernel to
> later run sanity on ATC invalidation requests from the user space, with
> ATC_INV commands that have SID fields (virtual Stream IDs).
> 
> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
> ---
>   drivers/iommu/iommufd/device.c          | 81 +++++++++++++++++++++++++
>   drivers/iommu/iommufd/iommufd_private.h |  3 +
>   drivers/iommu/iommufd/main.c            |  4 ++
>   include/uapi/linux/iommufd.h            | 32 ++++++++++
>   4 files changed, 120 insertions(+)
> 
> diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
> index c649a3403797..9480cd36a8bd 100644
> --- a/drivers/iommu/iommufd/device.c
> +++ b/drivers/iommu/iommufd/device.c
> @@ -136,6 +136,8 @@ void iommufd_device_destroy(struct iommufd_object *obj)
>   	struct iommufd_device *idev =
>   		container_of(obj, struct iommufd_device, obj);
>   
> +	if (WARN_ON(idev->has_user_data))
> +		dev_iommu_ops(idev->dev)->unset_dev_user_data(idev->dev);

Do you really need this WARN_ON()? The user space application can easily
trigger this kernel WARN() by setting the user data and forgetting to
unset it.

Best regards,
baolu
Nicolin Chen April 24, 2023, 6:50 p.m. UTC | #2 
Hi Baolu,

On Mon, Apr 24, 2023 at 10:44:08AM +0800, Baolu Lu wrote:

> On 4/23/23 3:40 PM, Nicolin Chen wrote:
> > Add a new pair of ioctls to allow user space to set and unset its iommu-
> > specific device data for a passthrough device that's behind the iommu.
> > 
> > On platforms with SMMUv3, this new uAPIs will be used to forward a user
> > space virtual Stream ID of a passthrough device to link to its physical
> > Stream ID and log into a lookup table, in order for the host kernel to
> > later run sanity on ATC invalidation requests from the user space, with
> > ATC_INV commands that have SID fields (virtual Stream IDs).
> > 
> > Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
> > ---
> >   drivers/iommu/iommufd/device.c          | 81 +++++++++++++++++++++++++
> >   drivers/iommu/iommufd/iommufd_private.h |  3 +
> >   drivers/iommu/iommufd/main.c            |  4 ++
> >   include/uapi/linux/iommufd.h            | 32 ++++++++++
> >   4 files changed, 120 insertions(+)
> > 
> > diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
> > index c649a3403797..9480cd36a8bd 100644
> > --- a/drivers/iommu/iommufd/device.c
> > +++ b/drivers/iommu/iommufd/device.c
> > @@ -136,6 +136,8 @@ void iommufd_device_destroy(struct iommufd_object *obj)
> >       struct iommufd_device *idev =
> >               container_of(obj, struct iommufd_device, obj);
> > 
> > +     if (WARN_ON(idev->has_user_data))
> > +             dev_iommu_ops(idev->dev)->unset_dev_user_data(idev->dev);
> 
> Do you really need this WARN_ON()? The user space application can easily
> trigger this kernel WARN() by setting the user data and forgetting to
> unset it.

I can drop that, since it's a user triggerable one.

Thanks
Nic
diff mbox series

Patch

diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
index c649a3403797..9480cd36a8bd 100644
--- a/drivers/iommu/iommufd/device.c
+++ b/drivers/iommu/iommufd/device.c
@@ -136,6 +136,8 @@  void iommufd_device_destroy(struct iommufd_object *obj)
 	struct iommufd_device *idev =
 		container_of(obj, struct iommufd_device, obj);
 
+	if (WARN_ON(idev->has_user_data))
+		dev_iommu_ops(idev->dev)->unset_dev_user_data(idev->dev);
 	iommu_device_release_dma_owner(idev->dev);
 	iommufd_put_group(idev->igroup);
 	if (!iommufd_selftest_is_mock_dev(idev->dev))
@@ -726,6 +728,85 @@  void iommufd_device_detach(struct iommufd_device *idev)
 }
 EXPORT_SYMBOL_NS_GPL(iommufd_device_detach, IOMMUFD);
 
+int iommufd_device_set_data(struct iommufd_ucmd *ucmd)
+{
+	struct iommu_device_set_data *cmd = ucmd->cmd;
+	struct iommufd_device *idev;
+	const struct iommu_ops *ops;
+	void *data = NULL;
+	int rc;
+
+	if (!cmd->data_uptr || !cmd->data_len)
+		return -EINVAL;
+
+	idev = iommufd_get_device(ucmd, cmd->dev_id);
+	if (IS_ERR(idev))
+		return PTR_ERR(idev);
+
+	mutex_lock(&idev->igroup->lock);
+	if (idev->has_user_data) {
+		rc = -EEXIST;
+		goto out_unlock;
+	}
+
+	ops = dev_iommu_ops(idev->dev);
+	if (!ops->dev_user_data_len ||
+	    !ops->set_dev_user_data ||
+	    !ops->unset_dev_user_data) {
+		rc = -EOPNOTSUPP;
+		goto out_unlock;
+	}
+
+	data = kzalloc(ops->dev_user_data_len, GFP_KERNEL);
+	if (!data) {
+		rc = -ENOMEM;
+		goto out_unlock;
+	}
+
+	if (copy_struct_from_user(data, ops->dev_user_data_len,
+				  u64_to_user_ptr(cmd->data_uptr),
+				  cmd->data_len)) {
+		rc = -EFAULT;
+		goto out_free_data;
+	}
+
+	rc = ops->set_dev_user_data(idev->dev, data);
+	if (rc)
+		goto out_free_data;
+
+	idev->has_user_data = true;
+out_free_data:
+	kfree(data);
+out_unlock:
+	mutex_unlock(&idev->igroup->lock);
+	iommufd_put_object(&idev->obj);
+	return rc;
+}
+
+int iommufd_device_unset_data(struct iommufd_ucmd *ucmd)
+{
+	struct iommu_device_unset_data *cmd = ucmd->cmd;
+	struct iommufd_device *idev;
+	int rc = 0;
+
+	idev = iommufd_get_device(ucmd, cmd->dev_id);
+	if (IS_ERR(idev))
+		return PTR_ERR(idev);
+
+	mutex_lock(&idev->igroup->lock);
+	if (!idev->has_user_data) {
+		rc = -ENOENT;
+		goto out_unlock;
+	}
+
+	dev_iommu_ops(idev->dev)->unset_dev_user_data(idev->dev);
+	idev->has_user_data = false;
+out_unlock:
+	mutex_unlock(&idev->igroup->lock);
+	iommufd_put_object(&idev->obj);
+	return rc;
+}
+
 void iommufd_access_destroy_object(struct iommufd_object *obj)
 {
 	struct iommufd_access *access =
diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h
index 35d1294b2f06..98eaef9c41d3 100644
--- a/drivers/iommu/iommufd/iommufd_private.h
+++ b/drivers/iommu/iommufd/iommufd_private.h
@@ -309,6 +309,7 @@  struct iommufd_device {
 	/* always the physical device */
 	struct device *dev;
 	bool enforce_cache_coherency;
+	bool has_user_data;
 };
 
 static inline struct iommufd_device *
@@ -321,6 +322,8 @@  iommufd_get_device(struct iommufd_ucmd *ucmd, u32 id)
 
 void iommufd_device_destroy(struct iommufd_object *obj);
 int iommufd_device_get_hw_info(struct iommufd_ucmd *ucmd);
+int iommufd_device_set_data(struct iommufd_ucmd *ucmd);
+int iommufd_device_unset_data(struct iommufd_ucmd *ucmd);
 
 struct iommufd_access {
 	struct iommufd_object obj;
diff --git a/drivers/iommu/iommufd/main.c b/drivers/iommu/iommufd/main.c
index b84b22487b7d..bd4753512990 100644
--- a/drivers/iommu/iommufd/main.c
+++ b/drivers/iommu/iommufd/main.c
@@ -326,6 +326,10 @@  static const struct iommufd_ioctl_op iommufd_ioctl_ops[] = {
 		 val64),
 	IOCTL_OP(IOMMU_VFIO_IOAS, iommufd_vfio_ioas, struct iommu_vfio_ioas,
 		 __reserved),
+	IOCTL_OP(IOMMU_DEVICE_SET_DATA, iommufd_device_set_data,
+		 struct iommu_device_set_data, data_len),
+	IOCTL_OP(IOMMU_DEVICE_UNSET_DATA, iommufd_device_unset_data,
+		 struct iommu_device_unset_data, dev_id),
 #ifdef CONFIG_IOMMUFD_TEST
 	IOCTL_OP(IOMMU_TEST_CMD, iommufd_test, struct iommu_test_cmd, last),
 #endif
diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
index ac023ea6040a..b39b0e2e46b1 100644
--- a/include/uapi/linux/iommufd.h
+++ b/include/uapi/linux/iommufd.h
@@ -51,6 +51,8 @@  enum {
 	IOMMUFD_CMD_HWPT_ALLOC,
 	IOMMUFD_CMD_DEVICE_GET_HW_INFO,
 	IOMMUFD_CMD_HWPT_INVALIDATE,
+	IOMMUFD_CMD_DEVICE_SET_DATA,
+	IOMMUFD_CMD_DEVICE_UNSET_DATA,
 };
 
 /**
@@ -626,4 +628,34 @@  struct iommu_hwpt_invalidate {
 	__aligned_u64 data_uptr;
 };
 #define IOMMU_HWPT_INVALIDATE _IO(IOMMUFD_TYPE, IOMMUFD_CMD_HWPT_INVALIDATE)
+
+/**
+ * struct iommu_device_set_data - ioctl(IOMMU_DEVICE_SET_DATA)
+ * @size: sizeof(struct iommu_device_set_data)
+ * @dev_id: The device to set an iommu specific device data
+ * @data_uptr: User pointer of the device user data
+ * @data_len: Length of the device user data
+ *
+ * The device data must be unset using ioctl(IOMMU_DEVICE_UNSET_DATA), before
+ * another ioctl(IOMMU_DEVICE_SET_DATA) call or before the device itself gets
+ * unbind'd from the iommufd context.
+ */
+struct iommu_device_set_data {
+	__u32 size;
+	__u32 dev_id;
+	__aligned_u64 data_uptr;
+	__u32 data_len;
+};
+#define IOMMU_DEVICE_SET_DATA _IO(IOMMUFD_TYPE, IOMMUFD_CMD_DEVICE_SET_DATA)
+
+/**
+ * struct iommu_device_unset_data - ioctl(IOMMU_DEVICE_UNSET_DATA)
+ * @size: sizeof(struct iommu_device_unset_data)
+ * @dev_id: The device to unset its device user data
+ */
+struct iommu_device_unset_data {
+	__u32 size;
+	__u32 dev_id;
+};
+#define IOMMU_DEVICE_UNSET_DATA _IO(IOMMUFD_TYPE, IOMMUFD_CMD_DEVICE_UNSET_DATA)
 #endif