1// SPDX-License-Identifier: GPL-2.0
2#include <linux/slab.h>
3#include <linux/types.h>
4#include <linux/mm.h>
5#include <linux/fs.h>
6
7#include <xen/page.h>
8#include <xen/xenbus.h>
9
10#include "xenfs.h"
11
12static ssize_t xsd_read(struct file *file, char __user *buf,
13 size_t size, loff_t *off)
14{
15 const char *str = (const char *)file->private_data;
16 return simple_read_from_buffer(to: buf, count: size, ppos: off, from: str, strlen(str));
17}
18
19static int xsd_release(struct inode *inode, struct file *file)
20{
21 kfree(objp: file->private_data);
22 return 0;
23}
24
25static int xsd_kva_open(struct inode *inode, struct file *file)
26{
27 file->private_data = (void *)kasprintf(GFP_KERNEL, fmt: "0x%p",
28 xen_store_interface);
29 if (!file->private_data)
30 return -ENOMEM;
31 return 0;
32}
33
34static int xsd_kva_mmap(struct file *file, struct vm_area_struct *vma)
35{
36 size_t size = vma->vm_end - vma->vm_start;
37
38 if ((size > PAGE_SIZE) || (vma->vm_pgoff != 0))
39 return -EINVAL;
40
41 if (remap_pfn_range(vma, addr: vma->vm_start,
42 pfn: virt_to_pfn(v: xen_store_interface),
43 size, vma->vm_page_prot))
44 return -EAGAIN;
45
46 return 0;
47}
48
49const struct file_operations xsd_kva_file_ops = {
50 .open = xsd_kva_open,
51 .mmap = xsd_kva_mmap,
52 .read = xsd_read,
53 .release = xsd_release,
54};
55
56static int xsd_port_open(struct inode *inode, struct file *file)
57{
58 file->private_data = (void *)kasprintf(GFP_KERNEL, fmt: "%d",
59 xen_store_evtchn);
60 if (!file->private_data)
61 return -ENOMEM;
62 return 0;
63}
64
65const struct file_operations xsd_port_file_ops = {
66 .open = xsd_port_open,
67 .read = xsd_read,
68 .release = xsd_release,
69};
70

source code of linux/drivers/xen/xenfs/xenstored.c