[PATCH v10 20/22] vfio: Add VFIO_DEVICE_[AT|DE]TACH_IOMMUFD_PT

Yi Liu
2023-04-26T15:04:59Z

This adds ioctl for userspace to attach device cdev fd to and detach
from IOAS/hw_pagetable managed by iommufd.

VFIO_DEVICE_ATTACH_IOMMUFD_PT: attach vfio device to IOAS, hw_pagetable
managed by iommufd. Attach can be
undo by VFIO_DEVICE_DETACH_IOMMUFD_PT
or device fd close.
VFIO_DEVICE_DETACH_IOMMUFD_PT: detach vfio device from the current attached
IOAS or hw_pagetable managed by iommufd.

Signed-off-by: Yi Liu <yi.l.liu@intel.com>
---
drivers/vfio/device_cdev.c | 66 ++++++++++++++++++++++++++++++++++++++
drivers/vfio/iommufd.c | 20 ++++++++++++
drivers/vfio/vfio.h | 18 +++++++++++
drivers/vfio/vfio_main.c | 8 +++++
include/uapi/linux/vfio.h | 52 ++++++++++++++++++++++++++++++
5 files changed, 164 insertions(+)

diff --git a/drivers/vfio/device_cdev.c b/drivers/vfio/device_cdev.c
index 004217e6f758..6d7f50ee535d 100644
--- a/drivers/vfio/device_cdev.c
+++ b/drivers/vfio/device_cdev.c
@@ -174,6 +174,72 @@ long vfio_device_ioctl_bind_iommufd(struct vfio_device_file *df,
return ret;
}

+int vfio_ioctl_device_attach(struct vfio_device_file *df,
+ struct vfio_device_attach_iommufd_pt __user *arg)
+{
+ struct vfio_device *device = df->device;
+ struct vfio_device_attach_iommufd_pt attach;
+ unsigned long minsz;
+ int ret;
+
+ minsz = offsetofend(struct vfio_device_attach_iommufd_pt, pt_id);
+
+ if (copy_from_user(&attach, arg, minsz))
+ return -EFAULT;
+
+ if (attach.argsz < minsz || attach.flags)
+ return -EINVAL;
+
+ /* ATTACH only allowed for cdev fds */
+ if (df->group)
+ return -EINVAL;
+
+ mutex_lock(&device->dev_set->lock);
+ ret = vfio_iommufd_attach(device, &attach.pt_id);
+ if (ret)
+ goto out_unlock;
+
+ ret = copy_to_user(&arg->pt_id, &attach.pt_id,
+ sizeof(attach.pt_id)) ? -EFAULT : 0;
+ if (ret)
+ goto out_detach;
+ mutex_unlock(&device->dev_set->lock);
+
+ return 0;
+
+out_detach:
+ vfio_iommufd_detach(device);
+out_unlock:
+ mutex_unlock(&device->dev_set->lock);
+ return ret;
+}
+
+int vfio_ioctl_device_detach(struct vfio_device_file *df,
+ struct vfio_device_detach_iommufd_pt __user *arg)
+{
+ struct vfio_device *device = df->device;
+ struct vfio_device_detach_iommufd_pt detach;
+ unsigned long minsz;
+
+ minsz = offsetofend(struct vfio_device_detach_iommufd_pt, flags);
+
+ if (copy_from_user(&detach, arg, minsz))
+ return -EFAULT;
+
+ if (detach.argsz < minsz || detach.flags)
+ return -EINVAL;
+
+ /* DETACH only allowed for cdev fds */
+ if (df->group)
+ return -EINVAL;
+
+ mutex_lock(&device->dev_set->lock);
+ vfio_iommufd_detach(device);
+ mutex_unlock(&device->dev_set->lock);
+
+ return 0;
+}
+
static char *vfio_device_devnode(const struct device *dev, umode_t *mode)
{
return kasprintf(GFP_KERNEL, "vfio/devices/%s", dev_name(dev));
diff --git a/drivers/vfio/iommufd.c b/drivers/vfio/iommufd.c
index 49dc1182dea8..00c14821bfa5 100644
--- a/drivers/vfio/iommufd.c
+++ b/drivers/vfio/iommufd.c
@@ -76,6 +76,26 @@ void vfio_iommufd_unbind(struct vfio_device_file *df)
vdev->ops->unbind_iommufd(vdev);
}

+int vfio_iommufd_attach(struct vfio_device *vdev, u32 *pt_id)
+{
+ lockdep_assert_held(&vdev->dev_set->lock);
+
+ if (vdev->noiommu)
+ return vfio_iommufd_emulated_attach_ioas(vdev, pt_id);
+
+ return vdev->ops->attach_ioas(vdev, pt_id);
+}
+
+void vfio_iommufd_detach(struct vfio_device *vdev)
+{
+ lockdep_assert_held(&vdev->dev_set->lock);
+
+ if (vdev->noiommu)
+ vfio_iommufd_emulated_detach_ioas(vdev);
+ else
+ vdev->ops->detach_ioas(vdev);
+}
+
struct iommufd_ctx *vfio_iommufd_physical_ictx(struct vfio_device *vdev)
{
if (vdev->iommufd_device)
diff --git a/drivers/vfio/vfio.h b/drivers/vfio/vfio.h
index c38ee0e0cd54..c8579d63b2b9 100644
--- a/drivers/vfio/vfio.h
+++ b/drivers/vfio/vfio.h
@@ -242,6 +242,8 @@ int vfio_iommufd_bind(struct vfio_device_file *df);
void vfio_iommufd_unbind(struct vfio_device_file *df);
int vfio_iommufd_compat_attach_ioas(struct vfio_device *device,
struct iommufd_ctx *ictx);
+int vfio_iommufd_attach(struct vfio_device *vdev, u32 *pt_id);
+void vfio_iommufd_detach(struct vfio_device *vdev);
#else
static inline int
vfio_iommufd_compat_probe_noiommu(struct vfio_device *device,
@@ -283,6 +285,10 @@ int vfio_device_fops_cdev_open(struct inode *inode, struct file *filep);
void vfio_device_cdev_close(struct vfio_device_file *df);
long vfio_device_ioctl_bind_iommufd(struct vfio_device_file *df,
struct vfio_device_bind_iommufd __user *arg);
+int vfio_ioctl_device_attach(struct vfio_device_file *df,
+ struct vfio_device_attach_iommufd_pt __user *arg);
+int vfio_ioctl_device_detach(struct vfio_device_file *df,
+ struct vfio_device_detach_iommufd_pt __user *arg);
int vfio_cdev_init(struct class *device_class);
void vfio_cdev_cleanup(void);
#else
@@ -316,6 +322,18 @@ static inline long vfio_device_ioctl_bind_iommufd(struct vfio_device_file *df,
return -EOPNOTSUPP;
}

+static inline int vfio_ioctl_device_attach(struct vfio_device_file *df,
+ struct vfio_device_attach_iommufd_pt __user *arg)
+{
+ return -EOPNOTSUPP;
+}
+
+static inline int vfio_ioctl_device_detach(struct vfio_device_file *df,
+ struct vfio_device_detach_iommufd_pt __user *arg)
+{
+ return -EOPNOTSUPP;
+}
+
static inline int vfio_cdev_init(struct class *device_class)
{
return 0;
diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c
index e9ee5ab7257b..1004863efc14 100644
--- a/drivers/vfio/vfio_main.c
+++ b/drivers/vfio/vfio_main.c
@@ -1154,6 +1154,14 @@ static long vfio_device_fops_unl_ioctl(struct file *filep,
ret = vfio_ioctl_device_feature(device, (void __user *)arg);
break;

+ case VFIO_DEVICE_ATTACH_IOMMUFD_PT:
+ ret = vfio_ioctl_device_attach(df, (void __user *)arg);
+ break;
+
+ case VFIO_DEVICE_DETACH_IOMMUFD_PT:
+ ret = vfio_ioctl_device_detach(df, (void __user *)arg);
+ break;
+
default:
if (unlikely(!device->ops->ioctl))
ret = -EINVAL;
diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index 43b1b9f8cd24..62bd41c214fd 100644
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -222,6 +222,58 @@ struct vfio_device_bind_iommufd {

#define VFIO_DEVICE_BIND_IOMMUFD _IO(VFIO_TYPE, VFIO_BASE + 19)

+/*
+ * VFIO_DEVICE_ATTACH_IOMMUFD_PT - _IOW(VFIO_TYPE, VFIO_BASE + 20,
+ * struct vfio_device_attach_iommufd_pt)
+ *
+ * Attach a vfio device to an iommufd address space specified by IOAS
+ * id or hw_pagetable (hwpt) id.
+ *
+ * Available only after a device has been bound to iommufd via
+ * VFIO_DEVICE_BIND_IOMMUFD
+ *
+ * Undo by VFIO_DEVICE_DETACH_IOMMUFD_PT or device fd close.
+ *
+ * @argsz: user filled size of this data.
+ * @flags: must be 0.
+ * @pt_id: Input the target id which can represent an ioas or a hwpt
+ * allocated via iommufd subsystem.
+ * Output the input ioas id or the attached hwpt id which could
+ * be the specified hwpt itself or a hwpt automatically created
+ * for the specified ioas by kernel during the attachment.
+ *
+ * Return: 0 on success, -errno on failure.
+ */
+struct vfio_device_attach_iommufd_pt {
+ __u32 argsz;
+ __u32 flags;
+ __u32 pt_id;
+};
+
+#define VFIO_DEVICE_ATTACH_IOMMUFD_PT _IO(VFIO_TYPE, VFIO_BASE + 20)
+
+/*
+ * VFIO_DEVICE_DETACH_IOMMUFD_PT - _IOW(VFIO_TYPE, VFIO_BASE + 21,
+ * struct vfio_device_detach_iommufd_pt)
+ *
+ * Detach a vfio device from the iommufd address space it has been
+ * attached to. After it, device should be in a blocking DMA state.
+ *
+ * Available only after a device has been bound to iommufd via
+ * VFIO_DEVICE_BIND_IOMMUFD.
+ *
+ * @argsz: user filled size of this data.
+ * @flags: must be 0.
+ *
+ * Return: 0 on success, -errno on failure.
+ */
+struct vfio_device_detach_iommufd_pt {
+ __u32 argsz;
+ __u32 flags;
+};
+
+#define VFIO_DEVICE_DETACH_IOMMUFD_PT _IO(VFIO_TYPE, VFIO_BASE + 21)
+
/**
* VFIO_DEVICE_GET_INFO - _IOR(VFIO_TYPE, VFIO_BASE + 7,
* struct vfio_device_info)
--
2.34.1