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/******************************************************************************
* privcmd.c
*
* Interface to privileged domain-0 commands.
*
* Copyright (c) 2002-2004, K A Fraser, B Dragovic
*/
#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/uaccess.h>
#include <linux/swap.h>
#include <linux/highmem.h>
#include <linux/pagemap.h>
#include <linux/seq_file.h>
#include <linux/miscdevice.h>
#include <asm/pgalloc.h>
#include <asm/pgtable.h>
#include <asm/tlb.h>
#include <asm/xen/hypervisor.h>
#include <asm/xen/hypercall.h>
#include <xen/xen.h>
#include <xen/privcmd.h>
#include <xen/interface/xen.h>
#include <xen/features.h>
#include <xen/page.h>
#include <xen/xen-ops.h>
#include <xen/balloon.h>
#include "privcmd.h"
MODULE_LICENSE("GPL");
#define PRIV_VMA_LOCKED ((void *)1)
static int privcmd_vma_range_is_mapped(
struct vm_area_struct *vma,
unsigned long addr,
unsigned long nr_pages);
static long privcmd_ioctl_hypercall(void __user *udata)
{
struct privcmd_hypercall hypercall;
long ret;
if (copy_from_user(&hypercall, udata, sizeof(hypercall)))
return -EFAULT;
ret = privcmd_call(hypercall.op,
hypercall.arg[0], hypercall.arg[1],
hypercall.arg[2], hypercall.arg[3],
hypercall.arg[4]);
return ret;
}
static void free_page_list(struct list_head *pages)
{
struct page *p, *n;
list_for_each_entry_safe(p, n, pages, lru)
__free_page(p);
INIT_LIST_HEAD(pages);
}
/*
* Given an array of items in userspace, return a list of pages
* containing the data. If copying fails, either because of memory
* allocation failure or a problem reading user memory, return an
* error code; its up to the caller to dispose of any partial list.
*/
static int gather_array(struct list_head *pagelist,
unsigned nelem, size_t size,
const void __user *data)
{
unsigned pageidx;
void *pagedata;
int ret;
if (size > PAGE_SIZE)
return 0;
pageidx = PAGE_SIZE;
pagedata = NULL; /* quiet, gcc */
while (nelem--) {
if (pageidx > PAGE_SIZE-size) {
struct page *page = alloc_page(GFP_KERNEL);
ret = -ENOMEM;
if (page == NULL)
goto fail;
pagedata = page_address(page);
list_add_tail(&page->lru, pagelist);
pageidx = 0;
}
ret = -EFAULT;
if (copy_from_user(pagedata + pageidx, data, size))
goto fail;
data += size;
pageidx += size;
}
ret = 0;
fail:
return ret;
}
/*
* Call function "fn" on each element of the array fragmented
* over a list of pages.
*/
static int traverse_pages(unsigned nelem, size_t size,
struct list_head *pos,
int (*fn)(void *data, void *state),
void *state)
{
void *pagedata;
unsigned pageidx;
int ret = 0;
BUG_ON(size > PAGE_SIZE);
pageidx = PAGE_SIZE;
pagedata = NULL; /* hush, gcc */
while (nelem--) {
if (pageidx > PAGE_SIZE-size) {
struct page *page;
pos = pos->next;
page = list_entry(pos, struct page, lru);
pagedata = page_address(page);
pageidx = 0;
}
ret = (*fn)(pagedata + pageidx, state);
if (ret)
break;
pageidx += size;
}
return ret;
}
struct mmap_mfn_state {
unsigned long va;
struct vm_area_struct *vma;
domid_t domain;
};
static int mmap_mfn_range(void *data, void *state)
{
struct privcmd_mmap_entry *msg = data;
struct mmap_mfn_state *st = state;
struct vm_area_struct *vma = st->vma;
int rc;
/* Do not allow range to wrap the address space. */
if ((msg->npages > (LONG_MAX >> PAGE_SHIFT)) ||
((unsigned long)(msg->npages << PAGE_SHIFT) >= -st->va))
return -EINVAL;
/* Range chunks must be contiguous in va space. */
if ((msg->va != st->va) ||
((msg->va+(msg->npages<<PAGE_SHIFT)) > vma->vm_end))
return -EINVAL;
rc = xen_remap_domain_mfn_range(vma,
msg->va & PAGE_MASK,
msg->mfn, msg->npages,
vma->vm_page_prot,
st->domain, NULL);
if (rc < 0)
return rc;
st->va += msg->npages << PAGE_SHIFT;
return 0;
}
static long privcmd_ioctl_mmap(void __user *udata)
{
struct privcmd_mmap mmapcmd;
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
int rc;
LIST_HEAD(pagelist);
struct mmap_mfn_state state;
/* We only support privcmd_ioctl_mmap_batch for auto translated. */
if (xen_feature(XENFEAT_auto_translated_physmap))
return -ENOSYS;
if (copy_from_user(&mmapcmd, udata, sizeof(mmapcmd)))
return -EFAULT;
rc = gather_array(&pagelist,
mmapcmd.num, sizeof(struct privcmd_mmap_entry),
mmapcmd.entry);
if (rc || list_empty(&pagelist))
goto out;
down_write(&mm->mmap_sem);
{
struct page *page = list_first_entry(&pagelist,
struct page, lru);
struct privcmd_mmap_entry *msg = page_address(page);
vma = find_vma(mm, msg->va);
rc = -EINVAL;
if (!vma || (msg->va != vma->vm_start) || vma->vm_private_data)
goto out_up;
vma->vm_private_data = PRIV_VMA_LOCKED;
}
state.va = vma->vm_start;
state.vma = vma;
state.domain = mmapcmd.dom;
rc = traverse_pages(mmapcmd.num, sizeof(struct privcmd_mmap_entry),
&pagelist,
mmap_mfn_range, &state);
out_up:
up_write(&mm->mmap_sem);
out:
|