Re: [v7] Add udmabuf misc device
From: Yann Droneaud <hidden>
Date: 2018-09-11 20:47:37
Also in:
dri-devel, linux-doc, linux-kselftest, linux-media, lkml
Hi, Le lundi 27 août 2018 à 11:34 +0200, Gerd Hoffmann a écrit :
quoted hunk
A driver to let userspace turn memfd regions into dma-bufs. Use case: Allows qemu create dmabufs for the vga framebuffer or virtio-gpu ressources. Then they can be passed around to display those guest things on the host. To spice client for classic full framebuffer display, and hopefully some day to wayland server for seamless guest window display. qemu test branch: https://git.kraxel.org/cgit/qemu/log/?h=sirius/udmabuf Cc: David Airlie <redacted> Cc: Tomeu Vizoso <redacted> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Cc: Daniel Vetter <redacted> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com> Acked-by: Daniel Vetter <redacted> --- Documentation/ioctl/ioctl-number.txt | 1 + include/uapi/linux/udmabuf.h | 33 +++ drivers/dma-buf/udmabuf.c | 287 ++++++++++++++++++++++ tools/testing/selftests/drivers/dma-buf/udmabuf.c | 96 ++++++++ MAINTAINERS | 16 ++ drivers/dma-buf/Kconfig | 8 + drivers/dma-buf/Makefile | 1 + tools/testing/selftests/drivers/dma-buf/Makefile | 5 + 8 files changed, 447 insertions(+) create mode 100644 include/uapi/linux/udmabuf.h create mode 100644 drivers/dma-buf/udmabuf.c create mode 100644 tools/testing/selftests/drivers/dma-buf/udmabuf.c create mode 100644 tools/testing/selftests/drivers/dma-buf/Makefilediff --git a/include/uapi/linux/udmabuf.hb/include/uapi/linux/udmabuf.h new file mode 100644 index 0000000000..46b6532ed8--- /dev/null +++ b/include/uapi/linux/udmabuf.h@@ -0,0 +1,33 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +#ifndef _UAPI_LINUX_UDMABUF_H +#define _UAPI_LINUX_UDMABUF_H + +#include <linux/types.h> +#include <linux/ioctl.h> + +#define UDMABUF_FLAGS_CLOEXEC 0x01 + +struct udmabuf_create { + __u32 memfd; + __u32 flags; + __u64 offset; + __u64 size; +}; + +struct udmabuf_create_item { + __u32 memfd; + __u32 __pad; + __u64 offset; + __u64 size; +}; + +struct udmabuf_create_list { + __u32 flags; + __u32 count; + struct udmabuf_create_item list[]; +}; + +#define UDMABUF_CREATE _IOW('u', 0x42, struct udmabuf_create) +#define UDMABUF_CREATE_LIST _IOW('u', 0x43, structudmabuf_create_list) + +#endif /* _UAPI_LINUX_UDMABUF_H */diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c new file mode 100644 index 0000000000..8e24204526 --- /dev/null +++ b/drivers/dma-buf/udmabuf.c +static long udmabuf_create(struct udmabuf_create_list *head, + struct udmabuf_create_item *list) +{ + DEFINE_DMA_BUF_EXPORT_INFO(exp_info); + struct file *memfd = NULL; + struct udmabuf *ubuf; + struct dma_buf *buf; + pgoff_t pgoff, pgcnt, pgidx, pgbuf; + struct page *page; + int seals, ret = -EINVAL; + u32 i, flags; + + ubuf = kzalloc(sizeof(struct udmabuf), GFP_KERNEL); + if (!ubuf) + return -ENOMEM; + + for (i = 0; i < head->count; i++) {
You need to check .__pad for unsupported value:
if (list[i].__pad) {
ret = -EINVAL;
goto err_free_ubuf;
}
+ if (!IS_ALIGNED(list[i].offset, PAGE_SIZE))
+ goto err_free_ubuf;
+ if (!IS_ALIGNED(list[i].size, PAGE_SIZE))
+ goto err_free_ubuf;
+ ubuf->pagecount += list[i].size >> PAGE_SHIFT;
+ }
+ ubuf->pages = kmalloc_array(ubuf->pagecount, sizeof(struct page
*),
+ GFP_KERNEL);
+ if (!ubuf->pages) {
+ ret = -ENOMEM;
+ goto err_free_ubuf;
+ }
+
+ pgbuf = 0;
+ for (i = 0; i < head->count; i++) {
+ memfd = fget(list[i].memfd);
+ if (!memfd)
+ goto err_put_pages;
+ if (!shmem_mapping(file_inode(memfd)->i_mapping))
+ goto err_put_pages;
+ seals = memfd_fcntl(memfd, F_GET_SEALS, 0);
+ if (seals == -EINVAL ||
+ (seals & SEALS_WANTED) != SEALS_WANTED ||
+ (seals & SEALS_DENIED) != 0)
+ goto err_put_pages;
+ pgoff = list[i].offset >> PAGE_SHIFT;
+ pgcnt = list[i].size >> PAGE_SHIFT;
+ for (pgidx = 0; pgidx < pgcnt; pgidx++) {
+ page = shmem_read_mapping_page(
+ file_inode(memfd)->i_mapping, pgoff +
pgidx);
+ if (IS_ERR(page)) {
+ ret = PTR_ERR(page);
+ goto err_put_pages;
+ }
+ ubuf->pages[pgbuf++] = page;
+ }
+ fput(memfd);
+ }
+ memfd = NULL;
+
+ exp_info.ops = &udmabuf_ops;
+ exp_info.size = ubuf->pagecount << PAGE_SHIFT;
+ exp_info.priv = ubuf;
+
+ buf = dma_buf_export(&exp_info);
+ if (IS_ERR(buf)) {
+ ret = PTR_ERR(buf);
+ goto err_put_pages;
+ }
+
+ flags = 0;
You need to check .flags for unsupported value:
if (head->flags & ~UDMABUF_FLAGS_CLOEXEC)
return -EINVAL;
(at the beginning of the function, of course).
+ if (head->flags & UDMABUF_FLAGS_CLOEXEC) + flags |= O_CLOEXEC; + return dma_buf_fd(buf, flags); + +err_put_pages: + while (pgbuf > 0) + put_page(ubuf->pages[--pgbuf]); +err_free_ubuf: + fput(memfd); + kfree(ubuf->pages); + kfree(ubuf); + return ret; +} +
Regards -- Yann Droneaud OPTEYA