Add a new file vhost/iommufd.c to support the function of
iommufd, This file contains iommufd function of emulated device and
the physical device.

Signed-off-by: Cindy Lu <redacted>
---
 drivers/vhost/iommufd.c | 151 ++++++++++++++++++++++++++++++++++++++++
 drivers/vhost/vhost.h   |  21 ++++++
 2 files changed, 172 insertions(+)
 create mode 100644 drivers/vhost/iommufd.c

diff --git a/drivers/vhost/iommufd.c b/drivers/vhost/iommufd.c
new file mode 100644
index 000000000000..080858f76fd5
--- /dev/null
+++ b/drivers/vhost/iommufd.c

@@ -0,0 +1,151 @@
+#include <linux/vdpa.h>
+#include <linux/iommufd.h>
+
+#include "vhost.h"
+
+MODULE_IMPORT_NS(IOMMUFD);
+
+int vdpa_iommufd_bind(struct vdpa_device *vdpa, struct iommufd_ctx *ictx,
+                     u32 *ioas_id, u32 *device_id)
+{
+       int ret;
+
+       vhost_vdpa_lockdep_assert_held(vdpa);
+
+       /*
+        * If the driver doesn't provide this op then it means the device does
+        * not do DMA at all. So nothing to do.
+        */
+       if (!vdpa->config->bind_iommufd)
+               return 0;
+
+       ret = vdpa->config->bind_iommufd(vdpa, ictx, device_id);
+       if (ret)
+               return ret;
+
+       ret = vdpa->config->attach_ioas(vdpa, ioas_id);
+       if (ret)
+               goto err_unbind;
+       vdpa->iommufd_attached = true;
+
+       return 0;
+
+err_unbind:
+       if (vdpa->config->unbind_iommufd)
+               vdpa->config->unbind_iommufd(vdpa);
+       return ret;
+}
+
+void vdpa_iommufd_unbind(struct vdpa_device *vdpa)
+{
+       vhost_vdpa_lockdep_assert_held(vdpa);
+
+       if (vdpa->config->unbind_iommufd)
+               vdpa->config->unbind_iommufd(vdpa);
+}
+
+int vdpa_iommufd_physical_bind(struct vdpa_device *vdpa,
+                              struct iommufd_ctx *ictx, u32 *out_device_id)
+{
+       struct device *dma_dev = vdpa_get_dma_dev(vdpa);
+       struct iommufd_device *idev;
+
+       idev = iommufd_device_bind(ictx, dma_dev, out_device_id);
+       if (IS_ERR(idev))
+               return PTR_ERR(idev);
+       vdpa->iommufd_device = idev;
+       return 0;
+}
+EXPORT_SYMBOL_GPL(vdpa_iommufd_physical_bind);
+
+void vdpa_iommufd_physical_unbind(struct vdpa_device *vdpa)
+{
+       vhost_vdpa_lockdep_assert_held(vdpa);
+
+       if (vdpa->iommufd_attached) {
+               iommufd_device_detach(vdpa->iommufd_device);
+               vdpa->iommufd_attached = false;
+       }
+       iommufd_device_unbind(vdpa->iommufd_device);
+       vdpa->iommufd_device = NULL;
+}
+EXPORT_SYMBOL_GPL(vdpa_iommufd_physical_unbind);
+
+int vdpa_iommufd_physical_attach_ioas(struct vdpa_device *vdpa, u32 *pt_id)
+{
+       unsigned int flags = 0;
+
+       return iommufd_device_attach(vdpa->iommufd_device, pt_id);
+}
+EXPORT_SYMBOL_GPL(vdpa_iommufd_physical_attach_ioas);
+
+static void vdpa_emulated_unmap(void *data, unsigned long iova,
+                               unsigned long length)
+{
+       struct vdpa_device *vdpa = data;
+
+       vdpa->config->dma_unmap(vdpa, 0, iova, length);
+}
+
+static const struct iommufd_access_ops vdpa_user_ops = {
+       .needs_pin_pages = 1,