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authorOleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>2018-07-20 11:01:48 +0200
committerBoris Ostrovsky <boris.ostrovsky@oracle.com>2018-07-27 05:05:14 +0200
commit932d6562179efe8e2460a0343dbe0fcacf288a9e (patch)
treeedaf27dad5042f971a9f098ca7c6217132e4d08c /drivers/xen
parentxen/gntdev: Make private routines/structures accessible (diff)
downloadlinux-932d6562179efe8e2460a0343dbe0fcacf288a9e.tar.xz
linux-932d6562179efe8e2460a0343dbe0fcacf288a9e.zip
xen/gntdev: Add initial support for dma-buf UAPI
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 <oleksandr_andrushchenko@epam.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Diffstat (limited to 'drivers/xen')
-rw-r--r--drivers/xen/Kconfig10
-rw-r--r--drivers/xen/Makefile1
-rw-r--r--drivers/xen/gntdev-common.h6
-rw-r--r--drivers/xen/gntdev-dmabuf.c177
-rw-r--r--drivers/xen/gntdev-dmabuf.h33
-rw-r--r--drivers/xen/gntdev.c31
6 files changed, 258 insertions, 0 deletions
diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
index 75e5c40f80a5..b459edfacff3 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 129dd1cc1b83..3e542f60f29f 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 privcmd-buf.o
diff --git a/drivers/xen/gntdev-common.h b/drivers/xen/gntdev-common.h
index 2346c198f72e..2f8b949c3eeb 100644
--- a/drivers/xen/gntdev-common.h
+++ b/drivers/xen/gntdev-common.h
@@ -16,6 +16,8 @@
#include <linux/mmu_notifier.h>
#include <linux/types.h>
+struct gntdev_dmabuf_priv;
+
struct gntdev_priv {
/* Maps with visible offsets in the file descriptor. */
struct list_head maps;
@@ -33,6 +35,10 @@ 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 000000000000..af782c0a8a19
--- /dev/null
+++ b/drivers/xen/gntdev-dmabuf.c
@@ -0,0 +1,177 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Xen dma-buf functionality for gntdev.
+ *
+ * Copyright (c) 2018 Oleksandr Andrushchenko, EPAM Systems Inc.
+ */
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/uaccess.h>
+
+#include <xen/xen.h>
+#include <xen/grant_table.h>
+
+#include "gntdev-common.h"
+#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. */
+
+static int dmabuf_exp_wait_released(struct gntdev_dmabuf_priv *priv, int fd,
+ int wait_to_ms)
+{
+ return -EINVAL;
+}
+
+static int 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. */
+
+static struct gntdev_dmabuf *
+dmabuf_imp_to_refs(struct gntdev_dmabuf_priv *priv, struct device *dev,
+ int fd, int count, int domid)
+{
+ return ERR_PTR(-ENOMEM);
+}
+
+static u32 *dmabuf_imp_get_refs(struct gntdev_dmabuf *gntdev_dmabuf)
+{
+ return NULL;
+}
+
+static int dmabuf_imp_release(struct gntdev_dmabuf_priv *priv, u32 fd)
+{
+ return -EINVAL;
+}
+
+/* DMA buffer IOCTL support. */
+
+long gntdev_ioctl_dmabuf_exp_from_refs(struct gntdev_priv *priv, int use_ptemod,
+ struct ioctl_gntdev_dmabuf_exp_from_refs __user *u)
+{
+ struct ioctl_gntdev_dmabuf_exp_from_refs op;
+ u32 *refs;
+ long ret;
+
+ if (use_ptemod) {
+ pr_debug("Cannot provide dma-buf: use_ptemode %d\n",
+ use_ptemod);
+ return -EINVAL;
+ }
+
+ if (copy_from_user(&op, u, sizeof(op)) != 0)
+ return -EFAULT;
+
+ if (unlikely(op.count <= 0))
+ return -EINVAL;
+
+ refs = kcalloc(op.count, sizeof(*refs), GFP_KERNEL);
+ if (!refs)
+ return -ENOMEM;
+
+ if (copy_from_user(refs, u->refs, sizeof(*refs) * op.count) != 0) {
+ ret = -EFAULT;
+ goto out;
+ }
+
+ ret = dmabuf_exp_from_refs(priv, op.flags, op.count,
+ op.domid, refs, &op.fd);
+ if (ret)
+ goto out;
+
+ if (copy_to_user(u, &op, sizeof(op)) != 0)
+ ret = -EFAULT;
+
+out:
+ kfree(refs);
+ return ret;
+}
+
+long gntdev_ioctl_dmabuf_exp_wait_released(struct gntdev_priv *priv,
+ struct ioctl_gntdev_dmabuf_exp_wait_released __user *u)
+{
+ struct ioctl_gntdev_dmabuf_exp_wait_released op;
+
+ if (copy_from_user(&op, u, sizeof(op)) != 0)
+ return -EFAULT;
+
+ return dmabuf_exp_wait_released(priv->dmabuf_priv, op.fd,
+ op.wait_to_ms);
+}
+
+long gntdev_ioctl_dmabuf_imp_to_refs(struct gntdev_priv *priv,
+ struct ioctl_gntdev_dmabuf_imp_to_refs __user *u)
+{
+ struct ioctl_gntdev_dmabuf_imp_to_refs op;
+ struct gntdev_dmabuf *gntdev_dmabuf;
+ long ret;
+
+ if (copy_from_user(&op, u, sizeof(op)) != 0)
+ return -EFAULT;
+
+ if (unlikely(op.count <= 0))
+ return -EINVAL;
+
+ gntdev_dmabuf = dmabuf_imp_to_refs(priv->dmabuf_priv,
+ priv->dma_dev, op.fd,
+ op.count, op.domid);
+ if (IS_ERR(gntdev_dmabuf))
+ return PTR_ERR(gntdev_dmabuf);
+
+ if (copy_to_user(u->refs, dmabuf_imp_get_refs(gntdev_dmabuf),
+ sizeof(*u->refs) * op.count) != 0) {
+ ret = -EFAULT;
+ goto out_release;
+ }
+ return 0;
+
+out_release:
+ dmabuf_imp_release(priv->dmabuf_priv, op.fd);
+ return ret;
+}
+
+long gntdev_ioctl_dmabuf_imp_release(struct gntdev_priv *priv,
+ struct ioctl_gntdev_dmabuf_imp_release __user *u)
+{
+ struct ioctl_gntdev_dmabuf_imp_release op;
+
+ if (copy_from_user(&op, u, sizeof(op)) != 0)
+ return -EFAULT;
+
+ return dmabuf_imp_release(priv->dmabuf_priv, op.fd);
+}
+
+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)
+{
+ kfree(priv);
+}
diff --git a/drivers/xen/gntdev-dmabuf.h b/drivers/xen/gntdev-dmabuf.h
new file mode 100644
index 000000000000..7220a53d0fc5
--- /dev/null
+++ b/drivers/xen/gntdev-dmabuf.h
@@ -0,0 +1,33 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+/*
+ * Xen dma-buf functionality for gntdev.
+ *
+ * Copyright (c) 2018 Oleksandr Andrushchenko, EPAM Systems Inc.
+ */
+
+#ifndef _GNTDEV_DMABUF_H
+#define _GNTDEV_DMABUF_H
+
+#include <xen/gntdev.h>
+
+struct gntdev_dmabuf_priv;
+struct gntdev_priv;
+
+struct gntdev_dmabuf_priv *gntdev_dmabuf_init(void);
+
+void gntdev_dmabuf_fini(struct gntdev_dmabuf_priv *priv);
+
+long gntdev_ioctl_dmabuf_exp_from_refs(struct gntdev_priv *priv, int use_ptemod,
+ struct ioctl_gntdev_dmabuf_exp_from_refs __user *u);
+
+long gntdev_ioctl_dmabuf_exp_wait_released(struct gntdev_priv *priv,
+ struct ioctl_gntdev_dmabuf_exp_wait_released __user *u);
+
+long gntdev_ioctl_dmabuf_imp_to_refs(struct gntdev_priv *priv,
+ struct ioctl_gntdev_dmabuf_imp_to_refs __user *u);
+
+long gntdev_ioctl_dmabuf_imp_release(struct gntdev_priv *priv,
+ struct ioctl_gntdev_dmabuf_imp_release __user *u);
+
+#endif
diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index e03f50052f3e..c866a62f766d 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -48,6 +48,9 @@
#include <asm/xen/hypercall.h>
#include "gntdev-common.h"
+#ifdef CONFIG_XEN_GNTDEV_DMABUF
+#include "gntdev-dmabuf.h"
+#endif
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Derek G. Murray <Derek.Murray@cl.cam.ac.uk>, "
@@ -566,6 +569,15 @@ static int gntdev_open(struct inode *inode, struct file *flip)
INIT_LIST_HEAD(&priv->freeable_maps);
mutex_init(&priv->lock);
+#ifdef CONFIG_XEN_GNTDEV_DMABUF
+ priv->dmabuf_priv = gntdev_dmabuf_init();
+ if (IS_ERR(priv->dmabuf_priv)) {
+ ret = PTR_ERR(priv->dmabuf_priv);
+ kfree(priv);
+ return ret;
+ }
+#endif
+
if (use_ptemod) {
priv->mm = get_task_mm(current);
if (!priv->mm) {
@@ -616,8 +628,13 @@ static int gntdev_release(struct inode *inode, struct file *flip)
WARN_ON(!list_empty(&priv->freeable_maps));
mutex_unlock(&priv->lock);
+#ifdef CONFIG_XEN_GNTDEV_DMABUF
+ gntdev_dmabuf_fini(priv->dmabuf_priv);
+#endif
+
if (use_ptemod)
mmu_notifier_unregister(&priv->mn, priv->mm);
+
kfree(priv);
return 0;
}
@@ -1009,6 +1026,20 @@ static long gntdev_ioctl(struct file *flip,
case IOCTL_GNTDEV_GRANT_COPY:
return gntdev_ioctl_grant_copy(priv, ptr);
+#ifdef CONFIG_XEN_GNTDEV_DMABUF
+ case IOCTL_GNTDEV_DMABUF_EXP_FROM_REFS:
+ return gntdev_ioctl_dmabuf_exp_from_refs(priv, use_ptemod, ptr);
+
+ case IOCTL_GNTDEV_DMABUF_EXP_WAIT_RELEASED:
+ return gntdev_ioctl_dmabuf_exp_wait_released(priv, ptr);
+
+ case IOCTL_GNTDEV_DMABUF_IMP_TO_REFS:
+ return gntdev_ioctl_dmabuf_imp_to_refs(priv, ptr);
+
+ case IOCTL_GNTDEV_DMABUF_IMP_RELEASE:
+ return gntdev_ioctl_dmabuf_imp_release(priv, ptr);
+#endif
+
default:
pr_debug("priv %p, unknown cmd %x\n", priv, cmd);
return -ENOIOCTLCMD;