[RFC 1/7] vhost/iommufd: Add the functions support iommufd

[Cindy Lu <lulu@redhat.com>]

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 <lulu@redhat.com>
---
 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,
+	.unmap = vdpa_emulated_unmap,
+};
+
+int vdpa_iommufd_emulated_bind(struct vdpa_device *vdpa,
+			       struct iommufd_ctx *ictx, u32 *out_device_id)
+{
+	vhost_vdpa_lockdep_assert_held(vdpa);
+
+	vdpa->iommufd_ictx = ictx;
+	iommufd_ctx_get(ictx);
+	struct iommufd_device *idev;
+
+	idev = iommufd_device_bind(ictx, vdpa->dma_dev, out_device_id);
+
+	if (IS_ERR(idev))
+		return PTR_ERR(idev);
+	vdpa->iommufd_device = idev;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(vdpa_iommufd_emulated_bind);
+
+void vdpa_iommufd_emulated_unbind(struct vdpa_device *vdpa)
+{
+	vhost_vdpa_lockdep_assert_held(vdpa);
+
+	if (vdpa->iommufd_access) {
+		iommufd_access_destroy(vdpa->iommufd_access);
+		vdpa->iommufd_access = NULL;
+	}
+	iommufd_ctx_put(vdpa->iommufd_ictx);
+	vdpa->iommufd_ictx = NULL;
+}
+EXPORT_SYMBOL_GPL(vdpa_iommufd_emulated_unbind);
+
+int vdpa_iommufd_emulated_attach_ioas(struct vdpa_device *vdpa, u32 *pt_id)
+{
+	struct iommufd_access *user;
+
+	vhost_vdpa_lockdep_assert_held(vdpa);
+
+	user = iommufd_access_create(vdpa->iommufd_ictx, *pt_id, &vdpa_user_ops,
+				     vdpa);
+	if (IS_ERR(user))
+		return PTR_ERR(user);
+	vdpa->iommufd_access = user;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(vdpa_iommufd_emulated_attach_ioas);
+int vdpa_iommufd_emulated_detach_ioas(struct vdpa_device *vdpa)
+{
+	vhost_vdpa_lockdep_assert_held(vdpa);
+
+	if (!vdpa->iommufd_ictx || !vdpa->iommufd_access)
+		return -1;
+
+	iommufd_access_destroy(vdpa->iommufd_access);
+	vdpa->iommufd_access = NULL;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(vdpa_iommufd_emulated_detach_ioas);
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index 790b296271f1..c470a5596d9c 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -291,6 +291,27 @@ static inline bool vhost_is_little_endian(struct vhost_virtqueue *vq)
 }
 #endif
 
+struct iommufd_ctx;
+struct vdpa_device;
+void vhost_vdpa_lockdep_assert_held(struct vdpa_device *vdpa);
+
+#if IS_ENABLED(CONFIG_IOMMUFD)
+int vdpa_iommufd_bind(struct vdpa_device *vdpa, struct iommufd_ctx *ictx,
+		      u32 *ioas_id, u32 *device_id);
+void vdpa_iommufd_unbind(struct vdpa_device *vdpa);
+#else
+static inline int vdpa_iommufd_bind(struct vdpa_device *vdpa,
+				    struct iommufd_ctx *ictx, u32 *ioas_id,
+				    u32 *device_id)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline void vdpa_iommufd_unbind(struct vdpa_device *vdpa)
+{
+}
+#endif
+
 /* Memory accessors */
 static inline u16 vhost16_to_cpu(struct vhost_virtqueue *vq, __virtio16 val)
 {
-- 
2.34.3