// 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/eventfd.h>
#include <linux/file.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/poll.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/srcu.h>
#include <linux/string.h>
#include <linux/workqueue.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 <linux/virtio_mmio.h>
#include <asm/xen/hypervisor.h>
#include <asm/xen/hypercall.h>
#include <xen/xen.h>
#include <xen/events.h>
#include <xen/privcmd.h>
#include <xen/interface/xen.h>
#include <xen/interface/memory.h>
#include <xen/interface/hvm/dm_op.h>
#include <xen/interface/hvm/ioreq.h>
#include <xen/features.h>
#include <xen/page.h>
#include <xen/xen-ops.h>
#include <xen/balloon.h>
#ifdef CONFIG_XEN_ACPI
#include <xen/acpi.h>
#endif
#include "privcmd.h"
MODULE_DESCRIPTION("Xen hypercall passthrough driver");
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 non-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 = vma_lookup(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 = kvcalloc(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);
kvfree(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, off = 0;
for (i = 0; i < num; ) {
unsigned int requested;
int page_count;
requested = DIV_ROUND_UP(
offset_in_page(kbufs[i].uptr) + kbufs[i].size,
PAGE_SIZE) - off;
if (requested > nr_pages)
return -ENOSPC;
page_count = pin_user_pages_fast(
(unsigned long)kbufs[i].uptr + off * PAGE_SIZE,
requested, FOLL_WRITE, pages);
if (page_count <= 0)
return page_count ? : -EFAULT;
*pinned += page_count;
nr_pages -= page_count;
pages += page_count;
off = (requested == page_count) ? 0 : off + page_count;
i += !off;
}
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)
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, pinned);
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,
struct privcmd_mmap_resource __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;
/* Both fields must be set or unset */
if (!!kdata.addr != !!kdata.num)
return -EINVAL;
xdata.domid = kdata.dom;
xdata.type = kdata.type;
xdata.id = kdata.id;
if (!kdata.addr && !kdata.num) {
/* Query the size of the resource. */
rc = HYPERVISOR_memory_op(XENMEM_acquire_resource, &xdata);
if (rc)
return rc;
return __put_user(xdata.nr_frames, &udata->num);
}
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 | __GFP_NOWARN);
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;
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, *errs = (int *)pfns;
BUILD_BUG_ON(sizeof(*errs) > sizeof(*pfns));
num = xen_remap_domain_mfn_array(vma,
kdata.addr & PAGE_MASK,
pfns, kdata.num, errs,
vma->vm_page_prot,
domid);
if (num < 0)
rc = num;
else if (num != kdata.num) {
unsigned int i;
for (i = 0; i < num; i++) {
rc = errs[i];
if (rc < 0)
break;
}
} else
rc = 0;
}
out:
mmap_write_unlock(mm);
kfree(pfns);
return rc;
}
static long privcmd_ioctl_pcidev_get_gsi(struct file *file, void __user *udata)
{
#if defined(CONFIG_XEN_ACPI)
int rc = -EINVAL;
struct privcmd_pcidev_get_gsi kdata;
if (copy_from_user(&kdata, udata, sizeof(kdata)))
return -EFAULT;
if (IS_REACHABLE(CONFIG_XEN_PCIDEV_BACKEND))
rc = pcistub_get_gsi_from_sbdf(kdata.sbdf);
if (rc < 0)
return rc;
kdata.gsi = rc;
if (copy_to_user(udata, &kdata, sizeof(kdata)))
return -EFAULT;
return 0;
#else
return -EINVAL;
#endif
}
#ifdef CONFIG_XEN_PRIVCMD_EVENTFD
/* Irqfd support */
static struct workqueue_struct *irqfd_cleanup_wq;
static DEFINE_SPINLOCK(irqfds_lock);
DEFINE_STATIC_SRCU(irqfds_srcu);
static LIST_HEAD(irqfds_list);
struct privcmd_kernel_irqfd {
struct xen_dm_op_buf xbufs;
domid_t dom;
bool error;
struct eventfd_ctx *eventfd;
struct work_struct shutdown;
wait_queue_entry_t wait;
struct list_head list;
poll_table pt;
};
static void irqfd_deactivate(struct privcmd_kernel_irqfd *kirqfd)
{
lockdep_assert_held(&irqfds_lock);
list_del_init(&kirqfd->list);
queue_work(irqfd_cleanup_wq, &kirqfd->shutdown);
}
static void irqfd_shutdown(struct work_struct *work)
{
struct privcmd_kernel_irqfd *kirqfd =
container_of(work, struct privcmd_kernel_irqfd, shutdown);
u64 cnt;
/* Make sure irqfd has been initialized in assign path */
synchronize_srcu(&irqfds_srcu);
eventfd_ctx_remove_wait_queue(kirqfd->eventfd, &kirqfd->wait, &cnt);
eventfd_ctx_put(kirqfd->eventfd);
kfree(kirqfd);
}
static void irqfd_inject(struct privcmd_kernel_irqfd *kirqfd)
{
u64 cnt;
long rc;
eventfd_ctx_do_read(kirqfd->eventfd, &cnt);
xen_preemptible_hcall_begin();
rc = HYPERVISOR_dm_op(kirqfd->dom, 1, &kirqfd->xbufs);
xen_preemptible_hcall_end();
/* Don't repeat the error message for consecutive failures */
if (rc && !kirqfd->error) {
pr_err("Failed to configure irq for guest domain: %d\n",
kirqfd->dom);
}
kirqfd->error = rc;
}
static int
irqfd_wakeup(wait_queue_entry_t *wait, unsigned int mode, int sync, void *key)
{
struct privcmd_kernel_irqfd *kirqfd =
container_of(wait, struct privcmd_kernel_irqfd, wait);
__poll_t flags = key_to_poll(key);
if (flags & EPOLLIN)
irqfd_inject(kirqfd);
if (flags & EPOLLHUP) {
unsigned long flags;
spin_lock_irqsave(&irqfds_lock, flags);
irqfd_deactivate(kirqfd);
spin_unlock_irqrestore(&irqfds_lock, flags);
}
return 0;
}
static void
irqfd_poll_func(struct file *file, wait_queue_head_t *wqh, poll_table *pt)
{
struct privcmd_kernel_irqfd *kirqfd =
container_of(pt, struct privcmd_kernel_irqfd, pt);
add_wait_queue_priority(wqh, &kirqfd->wait);
}
static int privcmd_irqfd_assign(struct privcmd_irqfd *irqfd)
{
struct privcmd_kernel_irqfd *kirqfd, *tmp;
unsigned long flags;
__poll_t events;
struct fd f;
void *dm_op;
int ret, idx;
kirqfd = kzalloc(sizeof(*kirqfd) + irqfd->size, GFP_KERNEL);
if (!kirqfd)
return -ENOMEM;
dm_op = kirqfd + 1;
if (copy_from_user(dm_op, u64_to_user_ptr(irqfd->dm_op), irqfd->size)) {
ret = -EFAULT;
goto error_kfree;
}
kirqfd->xbufs.size = irqfd->size;
set_xen_guest_handle(kirqfd->xbufs.h, dm_op);
kirqfd->dom = irqfd->dom;
INIT_WORK(&kirqfd->shutdown, irqfd_shutdown);
f = fdget(irqfd->fd);
if (!fd_file(f)) {
ret = -EBADF;
goto error_kfree;
}
kirqfd->eventfd = eventfd_ctx_fileget(fd_file(f));
if (IS_ERR(kirqfd->eventfd)) {
ret = PTR_ERR(kirqfd->eventfd);
goto error_fd_put;
}
/*
* Install our own custom wake-up handling so we are notified via a
* callback whenever someone signals the underlying eventfd.
*/
init_waitqueue_func_entry(&kirqfd->wait, irqfd_wakeup);
init_poll_funcptr(&kirqfd->pt, irqfd_poll_func);
spin_lock_irqsave(&irqfds_lock, flags);
list_for_each_entry(tmp, &irqfds_list, list) {
if (kirqfd->eventfd == tmp->eventfd) {
ret = -EBUSY;
spin_unlock_irqrestore(&irqfds_lock, flags);
goto error_eventfd;
}
}
idx = srcu_read_lock(&irqfds_srcu);
list_add_tail(&kirqfd->list, &irqfds_list);
spin_unlock_irqrestore(&irqfds_lock, flags);
/*
* Check if there was an event already pending on the eventfd before we
* registered, and trigger it as if we didn't miss it.
*/
events = vfs_poll(fd_file(f), &kirqfd->pt);
if (events & EPOLLIN)
irqfd_inject(kirqfd);
srcu_read_unlock(&irqfds_srcu, idx);
/*
* Do not drop the file until the kirqfd is fully initialized, otherwise
* we might race against the EPOLLHUP.
*/
fdput(f);
return 0;
error_eventfd:
eventfd_ctx_put(kirqfd->eventfd);
error_fd_put:
fdput(f);
error_kfree:
kfree(kirqfd);
return ret;
}
static int privcmd_irqfd_deassign(struct privcmd_irqfd *irqfd)
{
struct privcmd_kernel_irqfd *kirqfd;
struct eventfd_ctx *eventfd;
unsigned long flags;
eventfd = eventfd_ctx_fdget(irqfd->fd);
if (IS_ERR(eventfd))
return PTR_ERR(eventfd);
spin_lock_irqsave(&irqfds_lock, flags);
list_for_each_entry(kirqfd, &irqfds_list, list) {
if (kirqfd->eventfd == eventfd) {
irqfd_deactivate(kirqfd);
break;
}
}
spin_unlock_irqrestore(&irqfds_lock, flags);
eventfd_ctx_put(eventfd);
/*
* Block until we know all outstanding shutdown jobs have completed so
* that we guarantee there will not be any more interrupts once this
* deassign function returns.
*/
flush_workqueue(irqfd_cleanup_wq);
return 0;
}
static long privcmd_ioctl_irqfd(struct file *file, void __user *udata)
{
struct privcmd_data *data = file->private_data;
struct privcmd_irqfd irqfd;
if (copy_from_user(&irqfd, udata, sizeof(irqfd)))
return -EFAULT;
/* No other flags should be set */
if (irqfd.flags & ~PRIVCMD_IRQFD_FLAG_DEASSIGN)
return -EINVAL;
/* If restriction is in place, check the domid matches */
if (data->domid != DOMID_INVALID && data->domid != irqfd.dom)
return -EPERM;
if (irqfd.flags & PRIVCMD_IRQFD_FLAG_DEASSIGN)
return privcmd_irqfd_deassign(&irqfd);
return privcmd_irqfd_assign(&irqfd);
}
static int privcmd_irqfd_init(void)
{
irqfd_cleanup_wq = alloc_workqueue("privcmd-irqfd-cleanup", 0, 0);
if (!irqfd_cleanup_wq)
return -ENOMEM;
return 0;
}
static void privcmd_irqfd_exit(void)
{
struct privcmd_kernel_irqfd *kirqfd, *tmp;
unsigned long flags;
spin_lock_irqsave(&irqfds_lock, flags);
list_for_each_entry_safe(kirqfd, tmp, &irqfds_list, list)
irqfd_deactivate(kirqfd);
spin_unlock_irqrestore(&irqfds_lock, flags);
destroy_workqueue(irqfd_cleanup_wq);
}
/* Ioeventfd Support */
#define QUEUE_NOTIFY_VQ_MASK 0xFFFF
static DEFINE_MUTEX(ioreq_lock);
static LIST_HEAD(ioreq_list);
/* per-eventfd structure */
struct privcmd_kernel_ioeventfd {
struct eventfd_ctx *eventfd;
struct list_head list;
u64 addr;
unsigned int addr_len;
unsigned int vq;
};
/* per-guest CPU / port structure */
struct ioreq_port {
int vcpu;
unsigned int port;
struct privcmd_kernel_ioreq *kioreq;
};
/* per-guest structure */
struct privcmd_kernel_ioreq {
domid_t dom;
unsigned int vcpus;
u64 uioreq;
struct ioreq *ioreq;
spinlock_t lock; /* Protects ioeventfds list */
struct list_head ioeventfds;
struct list_head list;
struct ioreq_port ports[] __counted_by(vcpus);
};
static irqreturn_t ioeventfd_interrupt(int irq, void *dev_id)
{
struct ioreq_port *port = dev_id;
struct privcmd_kernel_ioreq *kioreq = port->kioreq;
struct ioreq *ioreq = &kioreq->ioreq[port->vcpu];
struct privcmd_kernel_ioeventfd *kioeventfd;
unsigned int state = STATE_IOREQ_READY;
if (ioreq->state != STATE_IOREQ_READY ||
ioreq->type != IOREQ_TYPE_COPY || ioreq->dir != IOREQ_WRITE)
return IRQ_NONE;
/*
* We need a barrier, smp_mb(), here to ensure reads are finished before
* `state` is updated. Since the lock implementation ensures that
* appropriate barrier will be added anyway, we can avoid adding
* explicit barrier here.
*
* Ideally we don't need to update `state` within the locks, but we do
* that here to avoid adding explicit barrier.
*/
spin_lock(&kioreq->lock);
ioreq->state = STATE_IOREQ_INPROCESS;
list_for_each_entry(kioeventfd, &kioreq->ioeventfds, list) {
if (ioreq->addr == kioeventfd->addr + VIRTIO_MMIO_QUEUE_NOTIFY &&
ioreq->size == kioeventfd->addr_len &&
(ioreq->data & QUEUE_NOTIFY_VQ_MASK) == kioeventfd->vq) {
eventfd_signal(kioeventfd->eventfd);
state = STATE_IORESP_READY;
break;
}
}
spin_unlock(&kioreq->lock);
/*
* We need a barrier, smp_mb(), here to ensure writes are finished
* before `state` is updated. Since the lock implementation ensures that
* appropriate barrier will be added anyway, we can avoid adding
* explicit barrier here.
*/
ioreq->state = state;
if (state == STATE_IORESP_READY) {
notify_remote_via_evtchn(port->port);
return IRQ_HANDLED;
}
return IRQ_NONE;
}
static void ioreq_free(struct privcmd_kernel_ioreq *kioreq)
{
struct ioreq_port *ports = kioreq->ports;
int i;
lockdep_assert_held(&ioreq_lock);
list_del(&kioreq->list);
for (i = kioreq->vcpus - 1; i >= 0; i--)
unbind_from_irqhandler(irq_from_evtchn(ports[i].port), &ports[i]);
kfree(kioreq);
}
static
struct privcmd_kernel_ioreq *alloc_ioreq(struct privcmd_ioeventfd *ioeventfd)
{
struct privcmd_kernel_ioreq *kioreq;
struct mm_struct *mm = current->mm;
struct vm_area_struct *vma;
struct page **pages;
unsigned int *ports;
int ret, size, i;
lockdep_assert_held(&ioreq_lock);
size = struct_size(kioreq, ports, ioeventfd->vcpus);
kioreq = kzalloc(size, GFP_KERNEL);
if (!kioreq)
return ERR_PTR(-ENOMEM);
kioreq->dom = ioeventfd->dom;
kioreq->vcpus = ioeventfd->vcpus;
kioreq->uioreq = ioeventfd->ioreq;
spin_lock_init(&kioreq->lock);
INIT_LIST_HEAD(&kioreq->ioeventfds);
/* The memory for ioreq server must have been mapped earlier */
mmap_write_lock(mm);
vma = find_vma(mm, (unsigned long)ioeventfd->ioreq);
if (!vma) {
pr_err("Failed to find vma for ioreq page!\n");
mmap_write_unlock(mm);
ret = -EFAULT;
goto error_kfree;
}
pages = vma->vm_private_data;
kioreq->ioreq = (struct ioreq *)(page_to_virt(pages[0]));
mmap_write_unlock(mm);
ports = memdup_array_user(u64_to_user_ptr(ioeventfd->ports),
kioreq->vcpus, sizeof(*ports));
if (IS_ERR(ports)) {
ret = PTR_ERR(ports);
goto error_kfree;
}
for (i = 0; i < kioreq->vcpus; i++) {
kioreq->ports[i].vcpu = i;
kioreq->ports[i].port = ports[i];
kioreq->ports[i].kioreq = kioreq;
ret = bind_evtchn_to_irqhandler_lateeoi(ports[i],
ioeventfd_interrupt, IRQF_SHARED, "ioeventfd",
&kioreq->ports[i]);
if (ret < 0)
goto error_unbind;
}
kfree(ports);
list_add_tail(&kioreq->list, &ioreq_list);
return kioreq;
error_unbind:
while (--i >= 0)
unbind_from_irqhandler(irq_from_evtchn(ports[i]), &kioreq->ports[i]);
kfree(ports);
error_kfree:
kfree(kioreq);
return ERR_PTR(ret);
}
static struct privcmd_kernel_ioreq *
get_ioreq(struct privcmd_ioeventfd *ioeventfd, struct eventfd_ctx *eventfd)
{
struct privcmd_kernel_ioreq *kioreq;
unsigned long flags;
list_for_each_entry(kioreq, &ioreq_list, list) {
struct privcmd_kernel_ioeventfd *kioeventfd;
/*
* kioreq fields can be accessed here without a lock as they are
* never updated after being added to the ioreq_list.
*/
if (kioreq->uioreq != ioeventfd->ioreq) {
continue;
} else if (kioreq->dom != ioeventfd->dom ||
kioreq->vcpus != ioeventfd->vcpus) {
pr_err("Invalid ioeventfd configuration mismatch, dom (%u vs %u), vcpus (%u vs %u)\n",
kioreq->dom, ioeventfd->dom, kioreq->vcpus,
ioeventfd->vcpus);
return ERR_PTR(-EINVAL);
}
/* Look for a duplicate eventfd for the same guest */
spin_lock_irqsave(&kioreq->lock, flags);
list_for_each_entry(kioeventfd, &kioreq->ioeventfds, list) {
if (eventfd == kioeventfd->eventfd) {
spin_unlock_irqrestore(&kioreq->lock, flags);
return ERR_PTR(-EBUSY);
}
}
spin_unlock_irqrestore(&kioreq->lock, flags);
return kioreq;
}
/* Matching kioreq isn't found, allocate a new one */
return alloc_ioreq(ioeventfd);
}
static void ioeventfd_free(struct privcmd_kernel_ioeventfd *kioeventfd)
{
list_del(&kioeventfd->list);
eventfd_ctx_put(kioeventfd->eventfd);
kfree(kioeventfd);
}
static int privcmd_ioeventfd_assign(struct privcmd_ioeventfd *ioeventfd)
{
struct privcmd_kernel_ioeventfd *kioeventfd;
struct privcmd_kernel_ioreq *kioreq;
unsigned long flags;
struct fd f;
int ret;
/* Check for range overflow */
if (ioeventfd->addr + ioeventfd->addr_len < ioeventfd->addr)
return -EINVAL;
/* Vhost requires us to support length 1, 2, 4, and 8 */
if (!(ioeventfd->addr_len == 1 || ioeventfd->addr_len == 2 ||
ioeventfd->addr_len == 4 || ioeventfd->addr_len == 8))
return -EINVAL;
/* 4096 vcpus limit enough ? */
if (!ioeventfd->vcpus || ioeventfd->vcpus > 4096)
return -EINVAL;
kioeventfd = kzalloc(sizeof(*kioeventfd), GFP_KERNEL);
if (!kioeventfd)
return -ENOMEM;
f = fdget(ioeventfd->event_fd);
if (!fd_file(f)) {
ret = -EBADF;
goto error_kfree;
}
kioeventfd->eventfd = eventfd_ctx_fileget(fd_file(f));
fdput(f);
if (IS_ERR(kioeventfd->eventfd)) {
ret = PTR_ERR(kioeventfd->eventfd);
goto error_kfree;
}
kioeventfd->addr = ioeventfd->addr;
kioeventfd->addr_len = ioeventfd->addr_len;
kioeventfd->vq = ioeventfd->vq;
mutex_lock(&ioreq_lock);
kioreq = get_ioreq(ioeventfd, kioeventfd->eventfd);
if (IS_ERR(kioreq)) {
mutex_unlock(&ioreq_lock);
ret = PTR_ERR(kioreq);
goto error_eventfd;
}
spin_lock_irqsave(&kioreq->lock, flags);
list_add_tail(&kioeventfd->list, &kioreq->ioeventfds);
spin_unlock_irqrestore(&kioreq->lock, flags);
mutex_unlock(&ioreq_lock);
return 0;
error_eventfd:
eventfd_ctx_put(kioeventfd->eventfd);
error_kfree:
kfree(kioeventfd);
return ret;
}
static int privcmd_ioeventfd_deassign(struct privcmd_ioeventfd *ioeventfd)
{
struct privcmd_kernel_ioreq *kioreq, *tkioreq;
struct eventfd_ctx *eventfd;
unsigned long flags;
int ret = 0;
eventfd = eventfd_ctx_fdget(ioeventfd->event_fd);
if (IS_ERR(eventfd))
return PTR_ERR(eventfd);
mutex_lock(&ioreq_lock);
list_for_each_entry_safe(kioreq, tkioreq, &ioreq_list, list) {
struct privcmd_kernel_ioeventfd *kioeventfd, *tmp;
/*
* kioreq fields can be accessed here without a lock as they are
* never updated after being added to the ioreq_list.
*/
if (kioreq->dom != ioeventfd->dom ||
kioreq->uioreq != ioeventfd->ioreq ||
kioreq->vcpus != ioeventfd->vcpus)
continue;
spin_lock_irqsave(&kioreq->lock, flags);
list_for_each_entry_safe(kioeventfd, tmp, &kioreq->ioeventfds, list) {
if (eventfd == kioeventfd->eventfd) {
ioeventfd_free(kioeventfd);
spin_unlock_irqrestore(&kioreq->lock, flags);
if (list_empty(&kioreq->ioeventfds))
ioreq_free(kioreq);
goto unlock;
}
}
spin_unlock_irqrestore(&kioreq->lock, flags);
break;
}
pr_err("Ioeventfd isn't already assigned, dom: %u, addr: %llu\n",
ioeventfd->dom, ioeventfd->addr);
ret = -ENODEV;
unlock:
mutex_unlock(&ioreq_lock);
eventfd_ctx_put(eventfd);
return ret;
}
static long privcmd_ioctl_ioeventfd(struct file *file, void __user *udata)
{
struct privcmd_data *data = file->private_data;
struct privcmd_ioeventfd ioeventfd;
if (copy_from_user(&ioeventfd, udata, sizeof(ioeventfd)))
return -EFAULT;
/* No other flags should be set */
if (ioeventfd.flags & ~PRIVCMD_IOEVENTFD_FLAG_DEASSIGN)
return -EINVAL;
/* If restriction is in place, check the domid matches */
if (data->domid != DOMID_INVALID && data->domid != ioeventfd.dom)
return -EPERM;
if (ioeventfd.flags & PRIVCMD_IOEVENTFD_FLAG_DEASSIGN)
return privcmd_ioeventfd_deassign(&ioeventfd);
return privcmd_ioeventfd_assign(&ioeventfd);
}
static void privcmd_ioeventfd_exit(void)
{
struct privcmd_kernel_ioreq *kioreq, *tmp;
unsigned long flags;
mutex_lock(&ioreq_lock);
list_for_each_entry_safe(kioreq, tmp, &ioreq_list, list) {
struct privcmd_kernel_ioeventfd *kioeventfd, *tmp;
spin_lock_irqsave(&kioreq->lock, flags);
list_for_each_entry_safe(kioeventfd, tmp, &kioreq->ioeventfds, list)
ioeventfd_free(kioeventfd);
spin_unlock_irqrestore(&kioreq->lock, flags);
ioreq_free(kioreq);
}
mutex_unlock(&ioreq_lock);
}
#else
static inline long privcmd_ioctl_irqfd(struct file *file, void __user *udata)
{
return -EOPNOTSUPP;
}
static inline int privcmd_irqfd_init(void)
{
return 0;
}
static inline void privcmd_irqfd_exit(void)
{
}
static inline long privcmd_ioctl_ioeventfd(struct file *file, void __user *udata)
{
return -EOPNOTSUPP;
}
static inline void privcmd_ioeventfd_exit(void)
{
}
#endif /* CONFIG_XEN_PRIVCMD_EVENTFD */
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;
case IOCTL_PRIVCMD_IRQFD:
ret = privcmd_ioctl_irqfd(file, udata);
break;
case IOCTL_PRIVCMD_IOEVENTFD:
ret = privcmd_ioctl_ioeventfd(file, udata);
break;
case IOCTL_PRIVCMD_PCIDEV_GET_GSI:
ret = privcmd_ioctl_pcidev_get_gsi(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);
kvfree(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 */
vm_flags_set(vma, 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(ptep_get(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");
goto err_privcmdbuf;
}
err = privcmd_irqfd_init();
if (err != 0) {
pr_err("irqfd init failed\n");
goto err_irqfd;
}
return 0;
err_irqfd:
misc_deregister(&xen_privcmdbuf_dev);
err_privcmdbuf:
misc_deregister(&privcmd_dev);
return err;
}
static void __exit privcmd_exit(void)
{
privcmd_ioeventfd_exit();
privcmd_irqfd_exit();
misc_deregister(&privcmd_dev);
misc_deregister(&xen_privcmdbuf_dev);
}
module_init(privcmd_init);
module_exit(privcmd_exit);
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