From: Oleksandr Andrushchenko
Add UAPI and IOCTLs for dma-buf grant device driver extension:
the extension allows userspace processes and kernel modules to
use Xen backed dma-buf implementation. With this extension grant
references to the pages of an imported dma-buf can be exported
for other domain use and grant references coming from a foreign
domain can be converted into a local dma-buf for local export.
Implement basic initialization and stubs for Xen DMA buffers'
support.
Signed-off-by: Oleksandr Andrushchenko
---
drivers/xen/Kconfig | 10 +++
drivers/xen/Makefile| 1 +
drivers/xen/gntdev-common.h | 6 ++
drivers/xen/gntdev-dmabuf.c | 72
drivers/xen/gntdev-dmabuf.h | 39 +++
drivers/xen/gntdev.c| 132
include/uapi/xen/gntdev.h | 91 +
7 files changed, 351 insertions(+)
create mode 100644 drivers/xen/gntdev-dmabuf.c
create mode 100644 drivers/xen/gntdev-dmabuf.h
diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
index 39536ddfbce4..52d64e4b6b81 100644
--- a/drivers/xen/Kconfig
+++ b/drivers/xen/Kconfig
@@ -152,6 +152,16 @@ config XEN_GNTDEV
help
Allows userspace processes to use grants.
+config XEN_GNTDEV_DMABUF
+ bool "Add support for dma-buf grant access device driver extension"
+ depends on XEN_GNTDEV && XEN_GRANT_DMA_ALLOC && DMA_SHARED_BUFFER
+ help
+ Allows userspace processes and kernel modules to use Xen backed
+ dma-buf implementation. With this extension grant references to
+ the pages of an imported dma-buf can be exported for other domain
+ use and grant references coming from a foreign domain can be
+ converted into a local dma-buf for local export.
+
config XEN_GRANT_DEV_ALLOC
tristate "User-space grant reference allocator driver"
depends on XEN
diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile
index 3c87b0c3aca6..33afb7b2b227 100644
--- a/drivers/xen/Makefile
+++ b/drivers/xen/Makefile
@@ -41,5 +41,6 @@ obj-$(CONFIG_XEN_PVCALLS_BACKEND) += pvcalls-back.o
obj-$(CONFIG_XEN_PVCALLS_FRONTEND) += pvcalls-front.o
xen-evtchn-y := evtchn.o
xen-gntdev-y := gntdev.o
+xen-gntdev-$(CONFIG_XEN_GNTDEV_DMABUF) += gntdev-dmabuf.o
xen-gntalloc-y := gntalloc.o
xen-privcmd-y := privcmd.o
diff --git a/drivers/xen/gntdev-common.h b/drivers/xen/gntdev-common.h
index 7a9845a6bee9..a3408fd39b07 100644
--- a/drivers/xen/gntdev-common.h
+++ b/drivers/xen/gntdev-common.h
@@ -16,6 +16,8 @@
#include
#include
+struct gntdev_dmabuf_priv;
+
struct gntdev_priv {
/* maps with visible offsets in the file descriptor */
struct list_head maps;
@@ -31,6 +33,10 @@ struct gntdev_priv {
/* Device for which DMA memory is allocated. */
struct device *dma_dev;
#endif
+
+#ifdef CONFIG_XEN_GNTDEV_DMABUF
+ struct gntdev_dmabuf_priv *dmabuf_priv;
+#endif
};
struct gntdev_unmap_notify {
diff --git a/drivers/xen/gntdev-dmabuf.c b/drivers/xen/gntdev-dmabuf.c
new file mode 100644
index ..dc57c6a25525
--- /dev/null
+++ b/drivers/xen/gntdev-dmabuf.c
@@ -0,0 +1,72 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Xen dma-buf functionality for gntdev.
+ *
+ * Copyright (c) 2018 Oleksandr Andrushchenko, EPAM Systems Inc.
+ */
+
+#include
+
+#include "gntdev-dmabuf.h"
+
+struct gntdev_dmabuf_priv {
+ /* List of exported DMA buffers. */
+ struct list_head exp_list;
+ /* List of wait objects. */
+ struct list_head exp_wait_list;
+ /* This is the lock which protects dma_buf_xxx lists. */
+ struct mutex lock;
+};
+
+/* DMA buffer export support. */
+
+/* Implementation of wait for exported DMA buffer to be released. */
+
+int gntdev_dmabuf_exp_wait_released(struct gntdev_dmabuf_priv *priv, int fd,
+ int wait_to_ms)
+{
+ return -EINVAL;
+}
+
+int gntdev_dmabuf_exp_from_refs(struct gntdev_priv *priv, int flags,
+ int count, u32 domid, u32 *refs, u32 *fd)
+{
+ *fd = -1;
+ return -EINVAL;
+}
+
+/* DMA buffer import support. */
+
+struct gntdev_dmabuf *
+gntdev_dmabuf_imp_to_refs(struct gntdev_dmabuf_priv *priv, struct device *dev,
+ int fd, int count, int domid)
+{
+ return ERR_PTR(-ENOMEM);
+}
+
+u32 *gntdev_dmabuf_imp_get_refs(struct gntdev_dmabuf *gntdev_dmabuf)
+{
+ return NULL;
+}
+
+int gntdev_dmabuf_imp_release(struct gntdev_dmabuf_priv *priv, u32 fd)
+{
+ return -EINVAL;
+}
+
+struct gntdev_dmabuf_priv *gntdev_dmabuf_init(void)
+{
+ struct gntdev_dmabuf_priv *priv;
+
+ priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return ERR_PTR(-ENOMEM);
+
+ return priv;
+}
+
+void gntdev_dmabuf_fini(struct gntdev_dmabuf_priv *priv)
+{
+
