qubes-linux-utils/kernel-modules/u2mfn/u2mfn.c
Marek Marczykowski-Górecki 0c4c2323c0 Add VM kernel related files as qubes-core-vm-kernel-support package
This is preparation for pvgrub support, where all VM kernel files will
be installed inside of VM instead of dom0.
But also the same could be used to prepare VM kernel image from any dom0
kernel.
2015-03-25 23:25:33 +01:00

173 lines
4.1 KiB
C

/*
* The Qubes OS Project, http://www.qubes-os.org
*
* Copyright (C) 2010 Rafal Wojtczuk <rafal@invisiblethingslab.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
*/
#include <linux/module.h>
#include <linux/version.h>
#include <linux/proc_fs.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/sched.h>
#ifndef FOREIGN_FRAME_BIT
#include <xen/page.h>
#endif
#include <linux/highmem.h>
/* copy of /usr/include/u2mfn-kernel.h, to reduce requirements */
#include <linux/ioctl.h>
#define U2MFN_MAGIC 0xf5
#define U2MFN_GET_MFN_FOR_PAGE _IOW(U2MFN_MAGIC, 1, int)
#define U2MFN_GET_LAST_MFN _IO(U2MFN_MAGIC, 2)
#if LINUX_VERSION_CODE < KERNEL_VERSION(3,0,0)
static inline unsigned long virt_to_phys(volatile void *address)
{
return __pa((unsigned long) address);
}
#endif
#ifdef virt_to_mfn
#define VIRT_TO_MFN virt_to_mfn
#else
extern unsigned long *phys_to_machine_mapping;
static inline unsigned long VIRT_TO_MFN(void *addr)
{
unsigned int pfn = virt_to_phys(addr) >> PAGE_SHIFT;
return phys_to_machine_mapping[pfn] & ~FOREIGN_FRAME_BIT;
}
#endif
/// User virtual address to mfn translator
/**
\param cmd ignored
\param data the user-specified address
\return mfn corresponding to "data" argument, or -1 on error
*/
static long u2mfn_ioctl(struct file *f, unsigned int cmd,
unsigned long data)
{
struct page *user_page;
void *kaddr;
int ret;
if (_IOC_TYPE(cmd) != U2MFN_MAGIC) {
printk("Qubes u2mfn: wrong IOCTL magic");
return -ENOTTY;
}
switch (cmd) {
case U2MFN_GET_MFN_FOR_PAGE:
down_read(&current->mm->mmap_sem);
ret = get_user_pages
(current, current->mm, data, 1, 1, 0, &user_page, 0);
up_read(&current->mm->mmap_sem);
if (ret != 1) {
printk("U2MFN_GET_MFN_FOR_PAGE: get_user_pages failed, ret=0x%x\n", ret);
return -1;
}
kaddr = kmap(user_page);
ret = VIRT_TO_MFN(kaddr);
kunmap(user_page);
put_page(user_page);
break;
case U2MFN_GET_LAST_MFN:
if (f->private_data)
ret = VIRT_TO_MFN(f->private_data);
else
ret = 0;
break;
default:
printk("Qubes u2mfn: wrong ioctl passed!\n");
return -ENOTTY;
}
return ret;
}
static int u2mfn_mmap(struct file *f, struct vm_area_struct *vma)
{
int ret;
char *kbuf;
long length = vma->vm_end - vma->vm_start;
printk("u2mfn_mmap: entering, private=%p\n", f->private_data);
if (f->private_data)
return -EBUSY;
if (length != PAGE_SIZE)
return -EINVAL;
kbuf = (char *) __get_free_page(GFP_KERNEL);
if (!kbuf)
return -ENOMEM;
f->private_data = kbuf;
ret = remap_pfn_range(vma, vma->vm_start,
virt_to_phys(kbuf) >> PAGE_SHIFT,
length, vma->vm_page_prot);
printk("u2mfn_mmap: calling remap return %d\n", ret);
if (ret)
return ret;
return 0;
}
static int u2mfn_release(struct inode *i, struct file *f)
{
printk("u2mfn_release, priv=%p\n", f->private_data);
if (f->private_data)
__free_page(f->private_data);
f->private_data = NULL;
return 0;
}
static struct file_operations u2mfn_fops = {
.unlocked_ioctl = u2mfn_ioctl,
.mmap = u2mfn_mmap,
.release = u2mfn_release
};
/// u2mfn module registration
/**
tries to register "/proc/u2mfn" pseudofile
*/
static int u2mfn_init(void)
{
struct proc_dir_entry *u2mfn_node =
proc_create_data("u2mfn", 0666, NULL,
&u2mfn_fops, 0);
if (!u2mfn_node)
return -1;
return 0;
}
static void u2mfn_exit(void)
{
remove_proc_entry("u2mfn", 0);
}
module_init(u2mfn_init);
module_exit(u2mfn_exit);
MODULE_LICENSE("GPL");