/******************************************************************************
* privcmd.c
*
* Interface to privileged domain-0 commands.
*
* Copyright (c) 2002-2004, K A Fraser, B Dragovic
*/
#include <linux/kernel.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/smp_lock.h>
#include <linux/highmem.h>
#include <linux/pagemap.h>
#include <linux/seq_file.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>
#ifndef HAVE_ARCH_PRIVCMD_MMAP
static int privcmd_enforce_singleshot_mapping(struct vm_area_struct *vma);
#endif
struct remap_data {
unsigned long mfn;
unsigned domid;
pgprot_t prot;
};
static int remap_area_mfn_pte_fn(pte_t *ptep, pgtable_t token,
unsigned long addr, void *data)
{
struct remap_data *rmd = data;
pte_t pte = pte_mkspecial(pfn_pte(rmd->mfn++, rmd->prot));
xen_set_domain_pte(ptep, pte, rmd->domid);
return 0;
}
int remap_domain_mfn_range(struct vm_area_struct *vma, unsigned long addr,
unsigned long mfn, unsigned long size,
pgprot_t prot, unsigned domid)
{
struct remap_data rmd;
int err;
prot = __pgprot(pgprot_val(prot) | _PAGE_IOMAP);
vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP;
rmd.mfn = mfn;
rmd.prot = prot;
rmd.domid = domid;
err = apply_to_page_range(vma->vm_mm, addr, size,
remap_area_mfn_pte_fn, &rmd);
return err;
}
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,
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;
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 = remap_domain_mfn_range(vma,
msg->va & PAGE_MASK,
msg->mfn,
msg->npages << PAGE_SHIFT,
vma->vm_page_prot,
st->domain);
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;
if (!xen_initial_domain())
return -EPERM;
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) ||
!privcmd_enforce_singleshot_mapping(vma))
goto out_up;
}
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:
free_page_list(&pagelist);
return rc;
}
struct mmap_batch_state {
domid_t domain;
unsigned long va;
struct vm_area_struct *vma;
int err;
xen_pfn_t __user *user;
};
static int mmap_batch_fn(void *data, void *state)
{
xen_pfn_t *mfnp = data;
struct mmap_batch_state *st = state;
if (remap_domain_mfn_range(st->vma, st->va & PAGE_MASK,
*mfnp, PAGE_SIZE,
st->vma->vm_page_prot, st->domain) < 0) {
*mfnp |= 0xf0000000U;
st->err++;
}
st->va += PAGE_SIZE;
return 0;
}
static int mmap_return_errors(void *data, void *state)
{
xen_pfn_t *mfnp = data;
struct mmap_batch_state *st = state;
put_user(*mfnp, st->user++);
return 0;
}
static long privcmd_ioctl_mmap_batch(void __user *udata)
{
int ret;
struct privcmd_mmapbatch m;
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
unsigned long nr_pages;
LIST_HEAD(pagelist);
struct mmap_batch_state state;
if (!xen_initial_domain())
return -EPERM;
if (copy_from_user(&m, udata, sizeof(m)))
return -EFAULT;
nr_pages = m.num;
if ((m.num <= 0) || (nr_pages > (LONG_MAX >> PAGE_SHIFT)))
return -EINVAL;
ret = gather_array(&pagelist, m.num, sizeof(xen_pfn_t),
m.arr);
if (ret || list_empty(&pagelist))
goto out;
down_write(&mm->mmap_sem);
vma = find_vma(mm, m.addr);
ret = -EINVAL;
if (!vma ||
(m.addr != vma->vm_start) ||
((m.addr + (nr_pages << PAGE_SHIFT)) != vma->vm_end) ||
!privcmd_enforce_singleshot_mapping(vma)) {
up_write(&mm->mmap_sem);
goto out;
}
state.domain = m.dom;
state.vma = vma;
state.va = m.addr;
state.err = 0;
ret = traverse_pages(m.num, sizeof(xen_pfn_t),
&pagelist, mmap_batch_fn, &state);
up_write(&mm->mmap_sem);
if (state.err > 0) {
ret = state.err;
state.user = udata;
traverse_pages(m.num, sizeof(xen_pfn_t),
&pagelist,
mmap_return_errors, &state);
}
out:
free_page_list(&pagelist);
return ret;
}
static long privcmd_ioctl(struct file *file,
unsigned int cmd, unsigned long data)
{
int ret = -ENOSYS;
void __user *udata = (void __user *) data;
switch (cmd) {
case IOCTL_PRIVCMD_HYPERCALL:
ret = privcmd_ioctl_hypercall(udata);
break;
case IOCTL_PRIVCMD_MMAP:
ret = privcmd_ioctl_mmap(udata);
break;
case IOCTL_PRIVCMD_MMAPBATCH:
ret = privcmd_ioctl_mmap_batch(udata);
break;
default:
ret = -EINVAL;
break;
}
return ret;
}
#ifndef HAVE_ARCH_PRIVCMD_MMAP
static int privcmd_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
return VM_FAULT_SIGBUS;
}
static struct vm_operations_struct privcmd_vm_ops = {
.fault = privcmd_fault
};
static int privcmd_mmap(struct file *file, struct vm_area_struct *vma)
{
/* Unsupported for auto-translate guests. */
if (xen_feature(XENFEAT_auto_translated_physmap))
return -ENOSYS;
/* DONTCOPY is essential for Xen as copy_page_range is broken. */
vma->vm_flags |= VM_RESERVED | VM_IO | VM_DONTCOPY;
vma->vm_ops = &privcmd_vm_ops;
vma->vm_private_data = NULL;
return 0;
}
static int privcmd_enforce_singleshot_mapping(struct vm_area_struct *vma)
{
return (xchg(&vma->vm_private_data, (void *)1) == NULL);
}
#endif
const struct file_operations privcmd_file_ops = {
.unlocked_ioctl = privcmd_ioctl,
.mmap = privcmd_mmap,
};
