linux/drivers/xen/privcmd.c
Linus Torvalds 68beef5710 xen: branch for v5.9-rc4
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Merge tag 'for-linus-5.9-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull xen updates from Juergen Gross:
 "A small series for fixing a problem with Xen PVH guests when running
  as backends (e.g. as dom0).

  Mapping other guests' memory is now working via ZONE_DEVICE, thus not
  requiring to abuse the memory hotplug functionality for that purpose"

* tag 'for-linus-5.9-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen: add helpers to allocate unpopulated memory
  memremap: rename MEMORY_DEVICE_DEVDAX to MEMORY_DEVICE_GENERIC
  xen/balloon: add header guard
2020-09-06 09:59:27 -07:00

996 lines
22 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/******************************************************************************
* 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 <linux/moduleparam.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/interface/memory.h>
#include <xen/interface/hvm/dm_op.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 unsigned int privcmd_dm_op_max_num = 16;
module_param_named(dm_op_max_nr_bufs, privcmd_dm_op_max_num, uint, 0644);
MODULE_PARM_DESC(dm_op_max_nr_bufs,
"Maximum number of buffers per dm_op hypercall");
static unsigned int privcmd_dm_op_buf_max_size = 4096;
module_param_named(dm_op_buf_max_size, privcmd_dm_op_buf_max_size, uint,
0644);
MODULE_PARM_DESC(dm_op_buf_max_size,
"Maximum size of a dm_op hypercall buffer");
struct privcmd_data {
domid_t domid;
};
static int privcmd_vma_range_is_mapped(
struct vm_area_struct *vma,
unsigned long addr,
unsigned long nr_pages);
static long privcmd_ioctl_hypercall(struct file *file, void __user *udata)
{
struct privcmd_data *data = file->private_data;
struct privcmd_hypercall hypercall;
long ret;
/* Disallow arbitrary hypercalls if restricted */
if (data->domid != DOMID_INVALID)
return -EPERM;
if (copy_from_user(&hypercall, udata, sizeof(hypercall)))
return -EFAULT;
xen_preemptible_hcall_begin();
ret = privcmd_call(hypercall.op,
hypercall.arg[0], hypercall.arg[1],
hypercall.arg[2], hypercall.arg[3],
hypercall.arg[4]);
xen_preemptible_hcall_end();
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;
}
/*
* Similar to traverse_pages, but use each page as a "block" of
* data to be processed as one unit.
*/
static int traverse_pages_block(unsigned nelem, size_t size,
struct list_head *pos,
int (*fn)(void *data, int nr, void *state),
void *state)
{
void *pagedata;
int ret = 0;
BUG_ON(size > PAGE_SIZE);
while (nelem) {
int nr = (PAGE_SIZE/size);
struct page *page;
if (nr > nelem)
nr = nelem;
pos = pos->next;
page = list_entry(pos, struct page, lru);
pagedata = page_address(page);
ret = (*fn)(pagedata, nr, state);
if (ret)
break;
nelem -= nr;
}
return ret;
}
struct mmap_gfn_state {
unsigned long va;
struct vm_area_struct *vma;
domid_t domain;
};
static int mmap_gfn_range(void *data, void *state)
{
struct privcmd_mmap_entry *msg = data;
struct mmap_gfn_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_gfn_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(struct file *file, void __user *udata)
{
struct privcmd_data *data = file->private_data;
struct privcmd_mmap mmapcmd;
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
int rc;
LIST_HEAD(pagelist);
struct mmap_gfn_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;
/* If restriction is in place, check the domid matches */
if (data->domid != DOMID_INVALID && data->domid != mmapcmd.dom)
return -EPERM;
rc = gather_array(&pagelist,
mmapcmd.num, sizeof(struct privcmd_mmap_entry),
mmapcmd.entry);
if (rc || list_empty(&pagelist))
goto out;
mmap_write_lock(mm);
{
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_gfn_range, &state);
out_up:
mmap_write_unlock(mm);
out:
free_page_list(&pagelist);
return rc;
}
struct mmap_batch_state {
domid_t domain;
unsigned long va;
struct vm_area_struct *vma;
int index;
/* A tristate:
* 0 for no errors
* 1 if at least one error has happened (and no
* -ENOENT errors have happened)
* -ENOENT if at least 1 -ENOENT has happened.
*/
int global_error;
int version;
/* User-space gfn array to store errors in the second pass for V1. */
xen_pfn_t __user *user_gfn;
/* User-space int array to store errors in the second pass for V2. */
int __user *user_err;
};
/* auto translated dom0 note: if domU being created is PV, then gfn is
* mfn(addr on bus). If it's auto xlated, then gfn is pfn (input to HAP).
*/
static int mmap_batch_fn(void *data, int nr, void *state)
{
xen_pfn_t *gfnp = data;
struct mmap_batch_state *st = state;
struct vm_area_struct *vma = st->vma;
struct page **pages = vma->vm_private_data;
struct page **cur_pages = NULL;
int ret;
if (xen_feature(XENFEAT_auto_translated_physmap))
cur_pages = &pages[st->index];
BUG_ON(nr < 0);
ret = xen_remap_domain_gfn_array(st->vma, st->va & PAGE_MASK, gfnp, nr,
(int *)gfnp, st->vma->vm_page_prot,
st->domain, cur_pages);
/* Adjust the global_error? */
if (ret != nr) {
if (ret == -ENOENT)
st->global_error = -ENOENT;
else {
/* Record that at least one error has happened. */
if (st->global_error == 0)
st->global_error = 1;
}
}
st->va += XEN_PAGE_SIZE * nr;
st->index += nr / XEN_PFN_PER_PAGE;
return 0;
}
static int mmap_return_error(int err, struct mmap_batch_state *st)
{
int ret;
if (st->version == 1) {
if (err) {
xen_pfn_t gfn;
ret = get_user(gfn, st->user_gfn);
if (ret < 0)
return ret;
/*
* V1 encodes the error codes in the 32bit top
* nibble of the gfn (with its known
* limitations vis-a-vis 64 bit callers).
*/
gfn |= (err == -ENOENT) ?
PRIVCMD_MMAPBATCH_PAGED_ERROR :
PRIVCMD_MMAPBATCH_MFN_ERROR;
return __put_user(gfn, st->user_gfn++);
} else
st->user_gfn++;
} else { /* st->version == 2 */
if (err)
return __put_user(err, st->user_err++);
else
st->user_err++;
}
return 0;
}
static int mmap_return_errors(void *data, int nr, void *state)
{
struct mmap_batch_state *st = state;
int *errs = data;
int i;
int ret;
for (i = 0; i < nr; i++) {
ret = mmap_return_error(errs[i], st);
if (ret < 0)
return ret;
}
return 0;
}
/* Allocate pfns that are then mapped with gfns from foreign domid. Update
* the vma with the page info to use later.
* Returns: 0 if success, otherwise -errno
*/
static int alloc_empty_pages(struct vm_area_struct *vma, int numpgs)
{
int rc;
struct page **pages;
pages = kcalloc(numpgs, sizeof(pages[0]), GFP_KERNEL);
if (pages == NULL)
return -ENOMEM;
rc = xen_alloc_unpopulated_pages(numpgs, pages);
if (rc != 0) {
pr_warn("%s Could not alloc %d pfns rc:%d\n", __func__,
numpgs, rc);
kfree(pages);
return -ENOMEM;
}
BUG_ON(vma->vm_private_data != NULL);
vma->vm_private_data = pages;
return 0;
}
static const struct vm_operations_struct privcmd_vm_ops;
static long privcmd_ioctl_mmap_batch(
struct file *file, void __user *udata, int version)
{
struct privcmd_data *data = file->private_data;
int ret;
struct privcmd_mmapbatch_v2 m;
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
unsigned long nr_pages;
LIST_HEAD(pagelist);
struct mmap_batch_state state;
switch (version) {
case 1:
if (copy_from_user(&m, udata, sizeof(struct privcmd_mmapbatch)))
return -EFAULT;
/* Returns per-frame error in m.arr. */
m.err = NULL;
if (!access_ok(m.arr, m.num * sizeof(*m.arr)))
return -EFAULT;
break;
case 2:
if (copy_from_user(&m, udata, sizeof(struct privcmd_mmapbatch_v2)))
return -EFAULT;
/* Returns per-frame error code in m.err. */
if (!access_ok(m.err, m.num * (sizeof(*m.err))))
return -EFAULT;
break;
default:
return -EINVAL;
}
/* If restriction is in place, check the domid matches */
if (data->domid != DOMID_INVALID && data->domid != m.dom)
return -EPERM;
nr_pages = DIV_ROUND_UP(m.num, XEN_PFN_PER_PAGE);
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)
goto out;
if (list_empty(&pagelist)) {
ret = -EINVAL;
goto out;
}
if (version == 2) {
/* Zero error array now to only copy back actual errors. */
if (clear_user(m.err, sizeof(int) * m.num)) {
ret = -EFAULT;
goto out;
}
}
mmap_write_lock(mm);
vma = find_vma(mm, m.addr);
if (!vma ||
vma->vm_ops != &privcmd_vm_ops) {
ret = -EINVAL;
goto out_unlock;
}
/*
* Caller must either:
*
* Map the whole VMA range, which will also allocate all the
* pages required for the auto_translated_physmap case.
*
* Or
*
* Map unmapped holes left from a previous map attempt (e.g.,
* because those foreign frames were previously paged out).
*/
if (vma->vm_private_data == NULL) {
if (m.addr != vma->vm_start ||
m.addr + (nr_pages << PAGE_SHIFT) != vma->vm_end) {
ret = -EINVAL;
goto out_unlock;
}
if (xen_feature(XENFEAT_auto_translated_physmap)) {
ret = alloc_empty_pages(vma, nr_pages);
if (ret < 0)
goto out_unlock;
} else
vma->vm_private_data = PRIV_VMA_LOCKED;
} else {
if (m.addr < vma->vm_start ||
m.addr + (nr_pages << PAGE_SHIFT) > vma->vm_end) {
ret = -EINVAL;
goto out_unlock;
}
if (privcmd_vma_range_is_mapped(vma, m.addr, nr_pages)) {
ret = -EINVAL;
goto out_unlock;
}
}
state.domain = m.dom;
state.vma = vma;
state.va = m.addr;
state.index = 0;
state.global_error = 0;
state.version = version;
BUILD_BUG_ON(((PAGE_SIZE / sizeof(xen_pfn_t)) % XEN_PFN_PER_PAGE) != 0);
/* mmap_batch_fn guarantees ret == 0 */
BUG_ON(traverse_pages_block(m.num, sizeof(xen_pfn_t),
&pagelist, mmap_batch_fn, &state));
mmap_write_unlock(mm);
if (state.global_error) {
/* Write back errors in second pass. */
state.user_gfn = (xen_pfn_t *)m.arr;
state.user_err = m.err;
ret = traverse_pages_block(m.num, sizeof(xen_pfn_t),
&pagelist, mmap_return_errors, &state);
} else
ret = 0;
/* If we have not had any EFAULT-like global errors then set the global
* error to -ENOENT if necessary. */
if ((ret == 0) && (state.global_error == -ENOENT))
ret = -ENOENT;
out:
free_page_list(&pagelist);
return ret;
out_unlock:
mmap_write_unlock(mm);
goto out;
}
static int lock_pages(
struct privcmd_dm_op_buf kbufs[], unsigned int num,
struct page *pages[], unsigned int nr_pages, unsigned int *pinned)
{
unsigned int i;
for (i = 0; i < num; i++) {
unsigned int requested;
int page_count;
requested = DIV_ROUND_UP(
offset_in_page(kbufs[i].uptr) + kbufs[i].size,
PAGE_SIZE);
if (requested > nr_pages)
return -ENOSPC;
page_count = pin_user_pages_fast(
(unsigned long) kbufs[i].uptr,
requested, FOLL_WRITE, pages);
if (page_count < 0)
return page_count;
*pinned += page_count;
nr_pages -= page_count;
pages += page_count;
}
return 0;
}
static void unlock_pages(struct page *pages[], unsigned int nr_pages)
{
unpin_user_pages_dirty_lock(pages, nr_pages, true);
}
static long privcmd_ioctl_dm_op(struct file *file, void __user *udata)
{
struct privcmd_data *data = file->private_data;
struct privcmd_dm_op kdata;
struct privcmd_dm_op_buf *kbufs;
unsigned int nr_pages = 0;
struct page **pages = NULL;
struct xen_dm_op_buf *xbufs = NULL;
unsigned int i;
long rc;
unsigned int pinned = 0;
if (copy_from_user(&kdata, udata, sizeof(kdata)))
return -EFAULT;
/* If restriction is in place, check the domid matches */
if (data->domid != DOMID_INVALID && data->domid != kdata.dom)
return -EPERM;
if (kdata.num == 0)
return 0;
if (kdata.num > privcmd_dm_op_max_num)
return -E2BIG;
kbufs = kcalloc(kdata.num, sizeof(*kbufs), GFP_KERNEL);
if (!kbufs)
return -ENOMEM;
if (copy_from_user(kbufs, kdata.ubufs,
sizeof(*kbufs) * kdata.num)) {
rc = -EFAULT;
goto out;
}
for (i = 0; i < kdata.num; i++) {
if (kbufs[i].size > privcmd_dm_op_buf_max_size) {
rc = -E2BIG;
goto out;
}
if (!access_ok(kbufs[i].uptr,
kbufs[i].size)) {
rc = -EFAULT;
goto out;
}
nr_pages += DIV_ROUND_UP(
offset_in_page(kbufs[i].uptr) + kbufs[i].size,
PAGE_SIZE);
}
pages = kcalloc(nr_pages, sizeof(*pages), GFP_KERNEL);
if (!pages) {
rc = -ENOMEM;
goto out;
}
xbufs = kcalloc(kdata.num, sizeof(*xbufs), GFP_KERNEL);
if (!xbufs) {
rc = -ENOMEM;
goto out;
}
rc = lock_pages(kbufs, kdata.num, pages, nr_pages, &pinned);
if (rc < 0) {
nr_pages = pinned;
goto out;
}
for (i = 0; i < kdata.num; i++) {
set_xen_guest_handle(xbufs[i].h, kbufs[i].uptr);
xbufs[i].size = kbufs[i].size;
}
xen_preemptible_hcall_begin();
rc = HYPERVISOR_dm_op(kdata.dom, kdata.num, xbufs);
xen_preemptible_hcall_end();
out:
unlock_pages(pages, nr_pages);
kfree(xbufs);
kfree(pages);
kfree(kbufs);
return rc;
}
static long privcmd_ioctl_restrict(struct file *file, void __user *udata)
{
struct privcmd_data *data = file->private_data;
domid_t dom;
if (copy_from_user(&dom, udata, sizeof(dom)))
return -EFAULT;
/* Set restriction to the specified domain, or check it matches */
if (data->domid == DOMID_INVALID)
data->domid = dom;
else if (data->domid != dom)
return -EINVAL;
return 0;
}
static long privcmd_ioctl_mmap_resource(struct file *file, void __user *udata)
{
struct privcmd_data *data = file->private_data;
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
struct privcmd_mmap_resource kdata;
xen_pfn_t *pfns = NULL;
struct xen_mem_acquire_resource xdata;
int rc;
if (copy_from_user(&kdata, udata, sizeof(kdata)))
return -EFAULT;
/* If restriction is in place, check the domid matches */
if (data->domid != DOMID_INVALID && data->domid != kdata.dom)
return -EPERM;
mmap_write_lock(mm);
vma = find_vma(mm, kdata.addr);
if (!vma || vma->vm_ops != &privcmd_vm_ops) {
rc = -EINVAL;
goto out;
}
pfns = kcalloc(kdata.num, sizeof(*pfns), GFP_KERNEL);
if (!pfns) {
rc = -ENOMEM;
goto out;
}
if (IS_ENABLED(CONFIG_XEN_AUTO_XLATE) &&
xen_feature(XENFEAT_auto_translated_physmap)) {
unsigned int nr = DIV_ROUND_UP(kdata.num, XEN_PFN_PER_PAGE);
struct page **pages;
unsigned int i;
rc = alloc_empty_pages(vma, nr);
if (rc < 0)
goto out;
pages = vma->vm_private_data;
for (i = 0; i < kdata.num; i++) {
xen_pfn_t pfn =
page_to_xen_pfn(pages[i / XEN_PFN_PER_PAGE]);
pfns[i] = pfn + (i % XEN_PFN_PER_PAGE);
}
} else
vma->vm_private_data = PRIV_VMA_LOCKED;
memset(&xdata, 0, sizeof(xdata));
xdata.domid = kdata.dom;
xdata.type = kdata.type;
xdata.id = kdata.id;
xdata.frame = kdata.idx;
xdata.nr_frames = kdata.num;
set_xen_guest_handle(xdata.frame_list, pfns);
xen_preemptible_hcall_begin();
rc = HYPERVISOR_memory_op(XENMEM_acquire_resource, &xdata);
xen_preemptible_hcall_end();
if (rc)
goto out;
if (IS_ENABLED(CONFIG_XEN_AUTO_XLATE) &&
xen_feature(XENFEAT_auto_translated_physmap)) {
rc = xen_remap_vma_range(vma, kdata.addr, kdata.num << PAGE_SHIFT);
} else {
unsigned int domid =
(xdata.flags & XENMEM_rsrc_acq_caller_owned) ?
DOMID_SELF : kdata.dom;
int num;
num = xen_remap_domain_mfn_array(vma,
kdata.addr & PAGE_MASK,
pfns, kdata.num, (int *)pfns,
vma->vm_page_prot,
domid,
vma->vm_private_data);
if (num < 0)
rc = num;
else if (num != kdata.num) {
unsigned int i;
for (i = 0; i < num; i++) {
rc = pfns[i];
if (rc < 0)
break;
}
} else
rc = 0;
}
out:
mmap_write_unlock(mm);
kfree(pfns);
return rc;
}
static long privcmd_ioctl(struct file *file,
unsigned int cmd, unsigned long data)
{
int ret = -ENOTTY;
void __user *udata = (void __user *) data;
switch (cmd) {
case IOCTL_PRIVCMD_HYPERCALL:
ret = privcmd_ioctl_hypercall(file, udata);
break;
case IOCTL_PRIVCMD_MMAP:
ret = privcmd_ioctl_mmap(file, udata);
break;
case IOCTL_PRIVCMD_MMAPBATCH:
ret = privcmd_ioctl_mmap_batch(file, udata, 1);
break;
case IOCTL_PRIVCMD_MMAPBATCH_V2:
ret = privcmd_ioctl_mmap_batch(file, udata, 2);
break;
case IOCTL_PRIVCMD_DM_OP:
ret = privcmd_ioctl_dm_op(file, udata);
break;
case IOCTL_PRIVCMD_RESTRICT:
ret = privcmd_ioctl_restrict(file, udata);
break;
case IOCTL_PRIVCMD_MMAP_RESOURCE:
ret = privcmd_ioctl_mmap_resource(file, udata);
break;
default:
break;
}
return ret;
}
static int privcmd_open(struct inode *ino, struct file *file)
{
struct privcmd_data *data = kzalloc(sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
/* DOMID_INVALID implies no restriction */
data->domid = DOMID_INVALID;
file->private_data = data;
return 0;
}
static int privcmd_release(struct inode *ino, struct file *file)
{
struct privcmd_data *data = file->private_data;
kfree(data);
return 0;
}
static void privcmd_close(struct vm_area_struct *vma)
{
struct page **pages = vma->vm_private_data;
int numpgs = vma_pages(vma);
int numgfns = (vma->vm_end - vma->vm_start) >> XEN_PAGE_SHIFT;
int rc;
if (!xen_feature(XENFEAT_auto_translated_physmap) || !numpgs || !pages)
return;
rc = xen_unmap_domain_gfn_range(vma, numgfns, pages);
if (rc == 0)
xen_free_unpopulated_pages(numpgs, pages);
else
pr_crit("unable to unmap MFN range: leaking %d pages. rc=%d\n",
numpgs, rc);
kfree(pages);
}
static vm_fault_t privcmd_fault(struct vm_fault *vmf)
{
printk(KERN_DEBUG "privcmd_fault: vma=%p %lx-%lx, pgoff=%lx, uv=%p\n",
vmf->vma, vmf->vma->vm_start, vmf->vma->vm_end,
vmf->pgoff, (void *)vmf->address);
return VM_FAULT_SIGBUS;
}
static const struct vm_operations_struct privcmd_vm_ops = {
.close = privcmd_close,
.fault = privcmd_fault
};
static int privcmd_mmap(struct file *file, struct vm_area_struct *vma)
{
/* DONTCOPY is essential for Xen because copy_page_range doesn't know
* how to recreate these mappings */
vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTCOPY |
VM_DONTEXPAND | VM_DONTDUMP;
vma->vm_ops = &privcmd_vm_ops;
vma->vm_private_data = NULL;
return 0;
}
/*
* For MMAPBATCH*. This allows asserting the singleshot mapping
* on a per pfn/pte basis. Mapping calls that fail with ENOENT
* can be then retried until success.
*/
static int is_mapped_fn(pte_t *pte, unsigned long addr, void *data)
{
return pte_none(*pte) ? 0 : -EBUSY;
}
static int privcmd_vma_range_is_mapped(
struct vm_area_struct *vma,
unsigned long addr,
unsigned long nr_pages)
{
return apply_to_page_range(vma->vm_mm, addr, nr_pages << PAGE_SHIFT,
is_mapped_fn, NULL) != 0;
}
const struct file_operations xen_privcmd_fops = {
.owner = THIS_MODULE,
.unlocked_ioctl = privcmd_ioctl,
.open = privcmd_open,
.release = privcmd_release,
.mmap = privcmd_mmap,
};
EXPORT_SYMBOL_GPL(xen_privcmd_fops);
static struct miscdevice privcmd_dev = {
.minor = MISC_DYNAMIC_MINOR,
.name = "xen/privcmd",
.fops = &xen_privcmd_fops,
};
static int __init privcmd_init(void)
{
int err;
if (!xen_domain())
return -ENODEV;
err = misc_register(&privcmd_dev);
if (err != 0) {
pr_err("Could not register Xen privcmd device\n");
return err;
}
err = misc_register(&xen_privcmdbuf_dev);
if (err != 0) {
pr_err("Could not register Xen hypercall-buf device\n");
misc_deregister(&privcmd_dev);
return err;
}
return 0;
}
static void __exit privcmd_exit(void)
{
misc_deregister(&privcmd_dev);
misc_deregister(&xen_privcmdbuf_dev);
}
module_init(privcmd_init);
module_exit(privcmd_exit);