vfio: Add VFIO_DEVICE_[AT|DE]TACH_IOMMUFD_PT

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 or 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.

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Tested-by: Nicolin Chen <nicolinc@nvidia.com>
Tested-by: Matthew Rosato <mjrosato@linux.ibm.com>
Tested-by: Yanting Jiang <yanting.jiang@intel.com>
Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Tested-by: Terrence Xu <terrence.xu@intel.com>
Tested-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
Link: https://lore.kernel.org/r/20230718135551.6592-24-yi.l.liu@intel.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

diff --git a/drivers/vfio/device_cdev.c b/drivers/vfio/device_cdev.c
index f40784d..e75da0a 100644 (file)
--- a/drivers/vfio/device_cdev.c
+++ b/drivers/vfio/device_cdev.c
@@ -152,6 +152,64 @@ void vfio_df_unbind_iommufd(struct vfio_device_file *df)
        vfio_device_unblock_group(device);
 }
 
+int vfio_df_ioctl_attach_pt(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;
+
+       mutex_lock(&device->dev_set->lock);
+       ret = device->ops->attach_ioas(device, &attach.pt_id);
+       if (ret)
+               goto out_unlock;
+
+       if (copy_to_user(&arg->pt_id, &attach.pt_id, sizeof(attach.pt_id))) {
+               ret = -EFAULT;
+               goto out_detach;
+       }
+       mutex_unlock(&device->dev_set->lock);
+
+       return 0;
+
+out_detach:
+       device->ops->detach_ioas(device);
+out_unlock:
+       mutex_unlock(&device->dev_set->lock);
+       return ret;
+}
+
+int vfio_df_ioctl_detach_pt(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;
+
+       mutex_lock(&device->dev_set->lock);
+       device->ops->detach_ioas(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/vfio.h b/drivers/vfio/vfio.h
index b6d4ba1..8353774 100644 (file)
--- a/drivers/vfio/vfio.h
+++ b/drivers/vfio/vfio.h
@@ -266,6 +266,11 @@ vfio_iommufd_compat_attach_ioas(struct vfio_device *device,
 }
 #endif
 
+int vfio_df_ioctl_attach_pt(struct vfio_device_file *df,
+                           struct vfio_device_attach_iommufd_pt __user *arg);
+int vfio_df_ioctl_detach_pt(struct vfio_device_file *df,
+                           struct vfio_device_detach_iommufd_pt __user *arg);
+
 #if IS_ENABLED(CONFIG_VFIO_DEVICE_CDEV)
 void vfio_init_device_cdev(struct vfio_device *device);
 

diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c
index 9fdf93f..ba1d84a 100644 (file)
--- a/drivers/vfio/vfio_main.c
+++ b/drivers/vfio/vfio_main.c
@@ -1162,6 +1162,19 @@ static long vfio_device_fops_unl_ioctl(struct file *filep,
        if (ret)
                return ret;
 
+       /* cdev only ioctls */
+       if (IS_ENABLED(CONFIG_VFIO_DEVICE_CDEV) && !df->group) {
+               switch (cmd) {
+               case VFIO_DEVICE_ATTACH_IOMMUFD_PT:
+                       ret = vfio_df_ioctl_attach_pt(df, uptr);
+                       goto out;
+
+               case VFIO_DEVICE_DETACH_IOMMUFD_PT:
+                       ret = vfio_df_ioctl_detach_pt(df, uptr);
+                       goto out;
+               }
+       }
+
        switch (cmd) {
        case VFIO_DEVICE_FEATURE:
                ret = vfio_ioctl_device_feature(device, uptr);
@@ -1174,7 +1187,7 @@ static long vfio_device_fops_unl_ioctl(struct file *filep,
                        ret = device->ops->ioctl(device, cmd, arg);
                break;
        }
-
+out:
        vfio_device_pm_runtime_put(device);
        return ret;
 }

diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
index 098946b..fa06e3e 100644 (file)
--- a/include/uapi/linux/vfio.h
+++ b/include/uapi/linux/vfio.h
@@ -925,6 +925,50 @@ struct vfio_device_bind_iommufd {
 #define VFIO_DEVICE_BIND_IOMMUFD       _IO(VFIO_TYPE, VFIO_BASE + 18)
 
 /*
+ * VFIO_DEVICE_ATTACH_IOMMUFD_PT - _IOW(VFIO_TYPE, VFIO_BASE + 19,
+ *                                     struct vfio_device_attach_iommufd_pt)
+ * @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.
+ *
+ * Associate the device with an address space within the bound iommufd.
+ * Undo by VFIO_DEVICE_DETACH_IOMMUFD_PT or device fd close.  This is only
+ * allowed on cdev fds.
+ *
+ * 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 + 19)
+
+/*
+ * VFIO_DEVICE_DETACH_IOMMUFD_PT - _IOW(VFIO_TYPE, VFIO_BASE + 20,
+ *                                     struct vfio_device_detach_iommufd_pt)
+ * @argsz:     User filled size of this data.
+ * @flags:     Must be 0.
+ *
+ * Remove the association of the device and its current associated address
+ * space.  After it, the device should be in a blocking DMA state.  This is only
+ * allowed on cdev fds.
+ *
+ * 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 + 20)
+
+/*
  * Provide support for setting a PCI VF Token, which is used as a shared
  * secret between PF and VF drivers.  This feature may only be set on a
  * PCI SR-IOV PF when SR-IOV is enabled on the PF and there are no existing