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

Cindy Lu
2023-09-23T17:06:47Z

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