xen/gntdev: Add initial support for dma-buf UAPI (932d6562) · Commits · e / devices / android_kernel_fairphone_FP4

drivers/xen/Kconfig

+10 −0

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		@@ -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

drivers/xen/Makefile

+1 −0

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		@@ -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

drivers/xen/gntdev-common.h

+6 −0

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		@@ -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 {

drivers/xen/gntdev-dmabuf.c

0 → 100644

+177 −0

Original line number	Diff line number	Diff line
		// 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);
		}

drivers/xen/gntdev-dmabuf.h

0 → 100644

+33 −0

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		/* 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