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Merge branches 'stable/hvc-console', 'stable/gntalloc.v6' and 'stable/balloon' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen 

* 'stable/hvc-console' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
  xen/hvc: Disable probe_irq_on/off from poking the hvc-console IRQ line.

* 'stable/gntalloc.v6' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
  xen: gntdev: fix build warning
  xen/p2m/m2p/gnttab: do not add failed grant maps to m2p override
  xen-gntdev: Add cast to pointer
  xen-gntdev: Fix incorrect use of zero handle
  xen: change xen/[gntdev/gntalloc] to default m
  xen-gntdev: prevent using UNMAP_NOTIFY_CLEAR_BYTE on read-only mappings
  xen-gntdev: Avoid double-mapping memory
  xen-gntdev: Avoid unmapping ranges twice
  xen-gntdev: Use map->vma for checking map validity
  xen-gntdev: Fix unmap notify on PV domains
  xen-gntdev: Fix memory leak when mmap fails
  xen/gntalloc,gntdev: Add unmap notify ioctl
  xen-gntalloc: Userspace grant allocation driver
  xen-gntdev: Support mapping in HVM domains
  xen-gntdev: Add reference counting to maps
  xen-gntdev: Use find_vma rather than iterating our vma list manually
  xen-gntdev: Change page limit to be global instead of per-open

* 'stable/balloon' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen: (24 commits)
  xen-gntdev: Use ballooned pages for grant mappings
  xen-balloon: Add interface to retrieve ballooned pages
  xen-balloon: Move core balloon functionality out of module
  xen/balloon: Remove pr_info's and don't alter retry_count
  xen/balloon: Protect against CPU exhaust by event/x process
  xen/balloon: Migration from mod_timer() to schedule_delayed_work()
  xen/balloon: Removal of driver_pages
This commit is contained in:
Linus Torvalds 2011-03-17 18:16:36 -07:00
parent c55d267de2 bbd5a762b4 ca47ceaa2c
commit 514af9f790
12 changed files with 1328 additions and 389 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
arch/x86/xen/mmu.c
View File

@ -79,8 +79,7 @@
/*
* Protects atomic reservation decrease/increase against concurrent increases.
* Also protects non-atomic updates of current_pages and driver_pages, and
* balloon lists.
* Also protects non-atomic updates of current_pages and balloon lists.
*/
DEFINE_SPINLOCK(xen_reservation_lock);

2
drivers/tty/hvc/hvc_xen.c
View File

@ -177,6 +177,8 @@ static int __init xen_hvc_init(void)
}
if (xencons_irq < 0)
xencons_irq = 0; /* NO_IRQ */
else
set_irq_noprobe(xencons_irq);
hp = hvc_alloc(HVC_COOKIE, xencons_irq, ops, 256);
if (IS_ERR(hp))

10
drivers/xen/Kconfig
View File

@ -76,10 +76,20 @@ config XEN_XENBUS_FRONTEND
config XEN_GNTDEV
tristate "userspace grant access device driver"
depends on XEN
default m
select MMU_NOTIFIER
help
Allows userspace processes to use grants.
config XEN_GRANT_DEV_ALLOC
tristate "User-space grant reference allocator driver"
depends on XEN
default m
help
Allows userspace processes to create pages with access granted
to other domains. This can be used to implement frontend drivers
or as part of an inter-domain shared memory channel.
config XEN_PLATFORM_PCI
tristate "xen platform pci device driver"
depends on XEN_PVHVM && PCI

6
drivers/xen/Makefile
View File

@ -1,4 +1,4 @@
obj-y += grant-table.o features.o events.o manage.o
obj-y += grant-table.o features.o events.o manage.o balloon.o
obj-y += xenbus/
nostackp := $(call cc-option, -fno-stack-protector)
@ -7,9 +7,10 @@ CFLAGS_features.o := $(nostackp)
obj-$(CONFIG_BLOCK) += biomerge.o
obj-$(CONFIG_HOTPLUG_CPU) += cpu_hotplug.o
obj-$(CONFIG_XEN_XENCOMM) += xencomm.o
obj-$(CONFIG_XEN_BALLOON) += balloon.o
obj-$(CONFIG_XEN_BALLOON) += xen-balloon.o
obj-$(CONFIG_XEN_DEV_EVTCHN) += xen-evtchn.o
obj-$(CONFIG_XEN_GNTDEV) += xen-gntdev.o
obj-$(CONFIG_XEN_GRANT_DEV_ALLOC) += xen-gntalloc.o
obj-$(CONFIG_XENFS) += xenfs/
obj-$(CONFIG_XEN_SYS_HYPERVISOR) += sys-hypervisor.o
obj-$(CONFIG_XEN_PLATFORM_PCI) += xen-platform-pci.o
@ -18,5 +19,6 @@ obj-$(CONFIG_XEN_DOM0) += pci.o
xen-evtchn-y := evtchn.o
xen-gntdev-y := gntdev.o
xen-gntalloc-y := gntalloc.o
xen-platform-pci-y := platform-pci.o

361
drivers/xen/balloon.c
View File

@ -1,6 +1,4 @@
/******************************************************************************
* balloon.c
*
* Xen balloon driver - enables returning/claiming memory to/from Xen.
*
* Copyright (c) 2003, B Dragovic
@ -33,7 +31,6 @@
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/mm.h>
@ -42,13 +39,11 @@
#include <linux/highmem.h>
#include <linux/mutex.h>
#include <linux/list.h>
#include <linux/sysdev.h>
#include <linux/gfp.h>
#include <asm/page.h>
#include <asm/pgalloc.h>
#include <asm/pgtable.h>
#include <asm/uaccess.h>
#include <asm/tlb.h>
#include <asm/e820.h>
@ -58,35 +53,29 @@
#include <xen/xen.h>
#include <xen/interface/xen.h>
#include <xen/interface/memory.h>
#include <xen/xenbus.h>
#include <xen/balloon.h>
#include <xen/features.h>
#include <xen/page.h>
#define PAGES2KB(_p) ((_p)<<(PAGE_SHIFT-10))
/*
* balloon_process() state:
*
* BP_DONE: done or nothing to do,
* BP_EAGAIN: error, go to sleep,
* BP_ECANCELED: error, balloon operation canceled.
*/
#define BALLOON_CLASS_NAME "xen_memory"
struct balloon_stats {
/* We aim for 'current allocation' == 'target allocation'. */
unsigned long current_pages;
unsigned long target_pages;
/*
* Drivers may alter the memory reservation independently, but they
* must inform the balloon driver so we avoid hitting the hard limit.
*/
unsigned long driver_pages;
/* Number of pages in high- and low-memory balloons. */
unsigned long balloon_low;
unsigned long balloon_high;
enum bp_state {
BP_DONE,
BP_EAGAIN,
BP_ECANCELED
};
static DEFINE_MUTEX(balloon_mutex);
static struct sys_device balloon_sysdev;
static int register_balloon(struct sys_device *sysdev);
static struct balloon_stats balloon_stats;
struct balloon_stats balloon_stats;
EXPORT_SYMBOL_GPL(balloon_stats);
/* We increase/decrease in batches which fit in a page */
static unsigned long frame_list[PAGE_SIZE / sizeof(unsigned long)];
@ -104,8 +93,7 @@ static LIST_HEAD(ballooned_pages);
/* Main work function, always executed in process context. */
static void balloon_process(struct work_struct *work);
static DECLARE_WORK(balloon_worker, balloon_process);
static struct timer_list balloon_timer;
static DECLARE_DELAYED_WORK(balloon_worker, balloon_process);
/* When ballooning out (allocating memory to return to Xen) we don't really
want the kernel to try too hard since that can trigger the oom killer. */
@ -140,14 +128,17 @@ static void balloon_append(struct page *page)
}
/* balloon_retrieve: rescue a page from the balloon, if it is not empty. */
static struct page *balloon_retrieve(void)
static struct page *balloon_retrieve(bool prefer_highmem)
{
struct page *page;
if (list_empty(&ballooned_pages))
return NULL;
page = list_entry(ballooned_pages.next, struct page, lru);
if (prefer_highmem)
page = list_entry(ballooned_pages.prev, struct page, lru);
else
page = list_entry(ballooned_pages.next, struct page, lru);
list_del(&page->lru);
if (PageHighMem(page)) {
@ -177,9 +168,29 @@ static struct page *balloon_next_page(struct page *page)
return list_entry(next, struct page, lru);
}
static void balloon_alarm(unsigned long unused)
static enum bp_state update_schedule(enum bp_state state)
{
schedule_work(&balloon_worker);
if (state == BP_DONE) {
balloon_stats.schedule_delay = 1;
balloon_stats.retry_count = 1;
return BP_DONE;
}
++balloon_stats.retry_count;
if (balloon_stats.max_retry_count != RETRY_UNLIMITED &&
balloon_stats.retry_count > balloon_stats.max_retry_count) {
balloon_stats.schedule_delay = 1;
balloon_stats.retry_count = 1;
return BP_ECANCELED;
}
balloon_stats.schedule_delay <<= 1;
if (balloon_stats.schedule_delay > balloon_stats.max_schedule_delay)
balloon_stats.schedule_delay = balloon_stats.max_schedule_delay;
return BP_EAGAIN;
}
static unsigned long current_target(void)
@ -194,11 +205,11 @@ static unsigned long current_target(void)
return target;
}
static int increase_reservation(unsigned long nr_pages)
static enum bp_state increase_reservation(unsigned long nr_pages)
{
int rc;
unsigned long pfn, i;
struct page *page;
long rc;
struct xen_memory_reservation reservation = {
.address_bits = 0,
.extent_order = 0,
@ -210,7 +221,10 @@ static int increase_reservation(unsigned long nr_pages)
page = balloon_first_page();
for (i = 0; i < nr_pages; i++) {
BUG_ON(page == NULL);
if (!page) {
nr_pages = i;
break;
}
frame_list[i] = page_to_pfn(page);
page = balloon_next_page(page);
}
@ -218,11 +232,11 @@ static int increase_reservation(unsigned long nr_pages)
set_xen_guest_handle(reservation.extent_start, frame_list);
reservation.nr_extents = nr_pages;
rc = HYPERVISOR_memory_op(XENMEM_populate_physmap, &reservation);
if (rc < 0)
goto out;
if (rc <= 0)
return BP_EAGAIN;
for (i = 0; i < rc; i++) {
page = balloon_retrieve();
page = balloon_retrieve(false);
BUG_ON(page == NULL);
pfn = page_to_pfn(page);
@ -249,15 +263,14 @@ static int increase_reservation(unsigned long nr_pages)
balloon_stats.current_pages += rc;
out:
return rc < 0 ? rc : rc != nr_pages;
return BP_DONE;
}
static int decrease_reservation(unsigned long nr_pages)
static enum bp_state decrease_reservation(unsigned long nr_pages, gfp_t gfp)
{
enum bp_state state = BP_DONE;
unsigned long pfn, i;
struct page *page;
int need_sleep = 0;
int ret;
struct xen_memory_reservation reservation = {
.address_bits = 0,
@ -269,9 +282,9 @@ static int decrease_reservation(unsigned long nr_pages)
nr_pages = ARRAY_SIZE(frame_list);
for (i = 0; i < nr_pages; i++) {
if ((page = alloc_page(GFP_BALLOON)) == NULL) {
if ((page = alloc_page(gfp)) == NULL) {
nr_pages = i;
need_sleep = 1;
state = BP_EAGAIN;
break;
}
@ -307,7 +320,7 @@ static int decrease_reservation(unsigned long nr_pages)
balloon_stats.current_pages -= nr_pages;
return need_sleep;
return state;
}
/*
@ -318,77 +331,101 @@ static int decrease_reservation(unsigned long nr_pages)
*/
static void balloon_process(struct work_struct *work)
{
int need_sleep = 0;
enum bp_state state = BP_DONE;
long credit;
mutex_lock(&balloon_mutex);
do {
credit = current_target() - balloon_stats.current_pages;
if (credit > 0)
need_sleep = (increase_reservation(credit) != 0);
state = increase_reservation(credit);
if (credit < 0)
need_sleep = (decrease_reservation(-credit) != 0);
state = decrease_reservation(-credit, GFP_BALLOON);
state = update_schedule(state);
#ifndef CONFIG_PREEMPT
if (need_resched())
schedule();
#endif
} while ((credit != 0) && !need_sleep);
} while (credit && state == BP_DONE);
/* Schedule more work if there is some still to be done. */
if (current_target() != balloon_stats.current_pages)
mod_timer(&balloon_timer, jiffies + HZ);
if (state == BP_EAGAIN)
schedule_delayed_work(&balloon_worker, balloon_stats.schedule_delay * HZ);
mutex_unlock(&balloon_mutex);
}
/* Resets the Xen limit, sets new target, and kicks off processing. */
static void balloon_set_new_target(unsigned long target)
void balloon_set_new_target(unsigned long target)
{
/* No need for lock. Not read-modify-write updates. */
balloon_stats.target_pages = target;
schedule_work(&balloon_worker);
schedule_delayed_work(&balloon_worker, 0);
}
EXPORT_SYMBOL_GPL(balloon_set_new_target);
static struct xenbus_watch target_watch =
/**
* alloc_xenballooned_pages - get pages that have been ballooned out
* @nr_pages: Number of pages to get
* @pages: pages returned
* @return 0 on success, error otherwise
*/
int alloc_xenballooned_pages(int nr_pages, struct page** pages)
{
.node = "memory/target"
};
int pgno = 0;
struct page* page;
mutex_lock(&balloon_mutex);
while (pgno < nr_pages) {
page = balloon_retrieve(true);
if (page) {
pages[pgno++] = page;
} else {
enum bp_state st;
st = decrease_reservation(nr_pages - pgno, GFP_HIGHUSER);
if (st != BP_DONE)
goto out_undo;
}
}
mutex_unlock(&balloon_mutex);
return 0;
out_undo:
while (pgno)
balloon_append(pages[--pgno]);
/* Free the memory back to the kernel soon */
schedule_delayed_work(&balloon_worker, 0);
mutex_unlock(&balloon_mutex);
return -ENOMEM;
}
EXPORT_SYMBOL(alloc_xenballooned_pages);
/* React to a change in the target key */
static void watch_target(struct xenbus_watch *watch,
const char **vec, unsigned int len)
/**
* free_xenballooned_pages - return pages retrieved with get_ballooned_pages
* @nr_pages: Number of pages
* @pages: pages to return
*/
void free_xenballooned_pages(int nr_pages, struct page** pages)
{
unsigned long long new_target;
int err;
int i;
err = xenbus_scanf(XBT_NIL, "memory", "target", "%llu", &new_target);
if (err != 1) {
/* This is ok (for domain0 at least) - so just return */
return;
mutex_lock(&balloon_mutex);
for (i = 0; i < nr_pages; i++) {
if (pages[i])
balloon_append(pages[i]);
}
/* The given memory/target value is in KiB, so it needs converting to
* pages. PAGE_SHIFT converts bytes to pages, hence PAGE_SHIFT - 10.
*/
balloon_set_new_target(new_target >> (PAGE_SHIFT - 10));
/* The balloon may be too large now. Shrink it if needed. */
if (current_target() != balloon_stats.current_pages)
schedule_delayed_work(&balloon_worker, 0);
mutex_unlock(&balloon_mutex);
}
static int balloon_init_watcher(struct notifier_block *notifier,
unsigned long event,
void *data)
{
int err;
err = register_xenbus_watch(&target_watch);
if (err)
printk(KERN_ERR "Failed to set balloon watcher\n");
return NOTIFY_DONE;
}
static struct notifier_block xenstore_notifier;
EXPORT_SYMBOL(free_xenballooned_pages);
static int __init balloon_init(void)
{
@ -398,7 +435,7 @@ static int __init balloon_init(void)
if (!xen_domain())
return -ENODEV;
pr_info("xen_balloon: Initialising balloon driver.\n");
pr_info("xen/balloon: Initialising balloon driver.\n");
if (xen_pv_domain())
nr_pages = xen_start_info->nr_pages;
@ -408,13 +445,11 @@ static int __init balloon_init(void)
balloon_stats.target_pages = balloon_stats.current_pages;
balloon_stats.balloon_low = 0;
balloon_stats.balloon_high = 0;
balloon_stats.driver_pages = 0UL;
init_timer(&balloon_timer);
balloon_timer.data = 0;
balloon_timer.function = balloon_alarm;
register_balloon(&balloon_sysdev);
balloon_stats.schedule_delay = 1;
balloon_stats.max_schedule_delay = 32;
balloon_stats.retry_count = 1;
balloon_stats.max_retry_count = RETRY_UNLIMITED;
/*
* Initialise the balloon with excess memory space. We need
@ -436,153 +471,9 @@ static int __init balloon_init(void)
__balloon_append(page);
}
target_watch.callback = watch_target;
xenstore_notifier.notifier_call = balloon_init_watcher;
register_xenstore_notifier(&xenstore_notifier);
return 0;
}
subsys_initcall(balloon_init);
static void balloon_exit(void)
{
/* XXX - release balloon here */
return;
}
module_exit(balloon_exit);
#define BALLOON_SHOW(name, format, args...) \
static ssize_t show_##name(struct sys_device *dev, \
struct sysdev_attribute *attr, \
char *buf) \
{ \
return sprintf(buf, format, ##args); \
} \
static SYSDEV_ATTR(name, S_IRUGO, show_##name, NULL)
BALLOON_SHOW(current_kb, "%lu\n", PAGES2KB(balloon_stats.current_pages));
BALLOON_SHOW(low_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_low));
BALLOON_SHOW(high_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_high));
BALLOON_SHOW(driver_kb, "%lu\n", PAGES2KB(balloon_stats.driver_pages));
static ssize_t show_target_kb(struct sys_device *dev, struct sysdev_attribute *attr,
char *buf)
{
return sprintf(buf, "%lu\n", PAGES2KB(balloon_stats.target_pages));
}
static ssize_t store_target_kb(struct sys_device *dev,
struct sysdev_attribute *attr,
const char *buf,
size_t count)
{
char *endchar;
unsigned long long target_bytes;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
target_bytes = simple_strtoull(buf, &endchar, 0) * 1024;
balloon_set_new_target(target_bytes >> PAGE_SHIFT);
return count;
}
static SYSDEV_ATTR(target_kb, S_IRUGO | S_IWUSR,
show_target_kb, store_target_kb);
static ssize_t show_target(struct sys_device *dev, struct sysdev_attribute *attr,
char *buf)
{
return sprintf(buf, "%llu\n",
(unsigned long long)balloon_stats.target_pages
<< PAGE_SHIFT);
}
static ssize_t store_target(struct sys_device *dev,
struct sysdev_attribute *attr,
const char *buf,
size_t count)
{
char *endchar;
unsigned long long target_bytes;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
target_bytes = memparse(buf, &endchar);
balloon_set_new_target(target_bytes >> PAGE_SHIFT);
return count;
}
static SYSDEV_ATTR(target, S_IRUGO | S_IWUSR,
show_target, store_target);
static struct sysdev_attribute *balloon_attrs[] = {
&attr_target_kb,
&attr_target,
};
static struct attribute *balloon_info_attrs[] = {
&attr_current_kb.attr,
&attr_low_kb.attr,
&attr_high_kb.attr,
&attr_driver_kb.attr,
NULL
};
static struct attribute_group balloon_info_group = {
.name = "info",
.attrs = balloon_info_attrs,
};
static struct sysdev_class balloon_sysdev_class = {
.name = BALLOON_CLASS_NAME,
};
static int register_balloon(struct sys_device *sysdev)
{
int i, error;
error = sysdev_class_register(&balloon_sysdev_class);
if (error)
return error;
sysdev->id = 0;
sysdev->cls = &balloon_sysdev_class;
error = sysdev_register(sysdev);
if (error) {
sysdev_class_unregister(&balloon_sysdev_class);
return error;
}
for (i = 0; i < ARRAY_SIZE(balloon_attrs); i++) {
error = sysdev_create_file(sysdev, balloon_attrs[i]);
if (error)
goto fail;
}
error = sysfs_create_group(&sysdev->kobj, &balloon_info_group);
if (error)
goto fail;
return 0;
fail:
while (--i >= 0)
sysdev_remove_file(sysdev, balloon_attrs[i]);
sysdev_unregister(sysdev);
sysdev_class_unregister(&balloon_sysdev_class);
return error;
}
MODULE_LICENSE("GPL");

545
drivers/xen/gntalloc.c Normal file
View File

@ -0,0 +1,545 @@
/******************************************************************************
* gntalloc.c
*
* Device for creating grant references (in user-space) that may be shared
* with other domains.
*
* 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/*
* This driver exists to allow userspace programs in Linux to allocate kernel
* memory that will later be shared with another domain. Without this device,
* Linux userspace programs cannot create grant references.
*
* How this stuff works:
* X -> granting a page to Y
* Y -> mapping the grant from X
*
* 1. X uses the gntalloc device to allocate a page of kernel memory, P.
* 2. X creates an entry in the grant table that says domid(Y) can access P.
* This is done without a hypercall unless the grant table needs expansion.
* 3. X gives the grant reference identifier, GREF, to Y.
* 4. Y maps the page, either directly into kernel memory for use in a backend
* driver, or via a the gntdev device to map into the address space of an
* application running in Y. This is the first point at which Xen does any
* tracking of the page.
* 5. A program in X mmap()s a segment of the gntalloc device that corresponds
* to the shared page, and can now communicate with Y over the shared page.
*
*
* NOTE TO USERSPACE LIBRARIES:
* The grant allocation and mmap()ing are, naturally, two separate operations.
* You set up the sharing by calling the create ioctl() and then the mmap().
* Teardown requires munmap() and either close() or ioctl().
*
* WARNING: Since Xen does not allow a guest to forcibly end the use of a grant
* reference, this device can be used to consume kernel memory by leaving grant
* references mapped by another domain when an application exits. Therefore,
* there is a global limit on the number of pages that can be allocated. When
* all references to the page are unmapped, it will be freed during the next
* grant operation.
*/
#include <linux/atomic.h>
#include <linux/module.h>
#include <linux/miscdevice.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/device.h>
#include <linux/mm.h>
#include <linux/uaccess.h>
#include <linux/types.h>
#include <linux/list.h>
#include <linux/highmem.h>
#include <xen/xen.h>
#include <xen/page.h>
#include <xen/grant_table.h>
#include <xen/gntalloc.h>
#include <xen/events.h>
static int limit = 1024;
module_param(limit, int, 0644);
MODULE_PARM_DESC(limit, "Maximum number of grants that may be allocated by "
"the gntalloc device");
static LIST_HEAD(gref_list);
static DEFINE_SPINLOCK(gref_lock);
static int gref_size;
struct notify_info {
uint16_t pgoff:12; /* Bits 0-11: Offset of the byte to clear */
uint16_t flags:2; /* Bits 12-13: Unmap notification flags */
int event; /* Port (event channel) to notify */
};
/* Metadata on a grant reference. */
struct gntalloc_gref {
struct list_head next_gref; /* list entry gref_list */
struct list_head next_file; /* list entry file->list, if open */
struct page *page; /* The shared page */
uint64_t file_index; /* File offset for mmap() */
unsigned int users; /* Use count - when zero, waiting on Xen */
grant_ref_t gref_id; /* The grant reference number */
struct notify_info notify; /* Unmap notification */
};
struct gntalloc_file_private_data {
struct list_head list;
uint64_t index;
};
static void __del_gref(struct gntalloc_gref *gref);
static void do_cleanup(void)
{
struct gntalloc_gref *gref, *n;
list_for_each_entry_safe(gref, n, &gref_list, next_gref) {
if (!gref->users)
__del_gref(gref);
}
}
static int add_grefs(struct ioctl_gntalloc_alloc_gref *op,
uint32_t *gref_ids, struct gntalloc_file_private_data *priv)
{
int i, rc, readonly;
LIST_HEAD(queue_gref);
LIST_HEAD(queue_file);
struct gntalloc_gref *gref;
readonly = !(op->flags & GNTALLOC_FLAG_WRITABLE);
rc = -ENOMEM;
for (i = 0; i < op->count; i++) {
gref = kzalloc(sizeof(*gref), GFP_KERNEL);
if (!gref)
goto undo;
list_add_tail(&gref->next_gref, &queue_gref);
list_add_tail(&gref->next_file, &queue_file);
gref->users = 1;
gref->file_index = op->index + i * PAGE_SIZE;
gref->page = alloc_page(GFP_KERNEL|__GFP_ZERO);
if (!gref->page)
goto undo;
/* Grant foreign access to the page. */
gref->gref_id = gnttab_grant_foreign_access(op->domid,
pfn_to_mfn(page_to_pfn(gref->page)), readonly);
if (gref->gref_id < 0) {
rc = gref->gref_id;
goto undo;
}
gref_ids[i] = gref->gref_id;
}
/* Add to gref lists. */
spin_lock(&gref_lock);
list_splice_tail(&queue_gref, &gref_list);
list_splice_tail(&queue_file, &priv->list);
spin_unlock(&gref_lock);
return 0;
undo:
spin_lock(&gref_lock);
gref_size -= (op->count - i);
list_for_each_entry(gref, &queue_file, next_file) {
/* __del_gref does not remove from queue_file */
__del_gref(gref);
}
/* It's possible for the target domain to map the just-allocated grant
* references by blindly guessing their IDs; if this is done, then
* __del_gref will leave them in the queue_gref list. They need to be
* added to the global list so that we can free them when they are no
* longer referenced.
*/
if (unlikely(!list_empty(&queue_gref)))
list_splice_tail(&queue_gref, &gref_list);
spin_unlock(&gref_lock);
return rc;
}
static void __del_gref(struct gntalloc_gref *gref)
{
if (gref->notify.flags & UNMAP_NOTIFY_CLEAR_BYTE) {
uint8_t *tmp = kmap(gref->page);
tmp[gref->notify.pgoff] = 0;
kunmap(gref->page);
}
if (gref->notify.flags & UNMAP_NOTIFY_SEND_EVENT)
notify_remote_via_evtchn(gref->notify.event);
gref->notify.flags = 0;
if (gref->gref_id > 0) {
if (gnttab_query_foreign_access(gref->gref_id))
return;
if (!gnttab_end_foreign_access_ref(gref->gref_id, 0))
return;
}
gref_size--;
list_del(&gref->next_gref);
if (gref->page)
__free_page(gref->page);
kfree(gref);
}
/* finds contiguous grant references in a file, returns the first */
static struct gntalloc_gref *find_grefs(struct gntalloc_file_private_data *priv,
uint64_t index, uint32_t count)
{
struct gntalloc_gref *rv = NULL, *gref;
list_for_each_entry(gref, &priv->list, next_file) {
if (gref->file_index == index && !rv)
rv = gref;
if (rv) {
if (gref->file_index != index)
return NULL;
index += PAGE_SIZE;
count--;
if (count == 0)
return rv;
}
}
return NULL;
}
/*
* -------------------------------------
* File operations.
* -------------------------------------
*/
static int gntalloc_open(struct inode *inode, struct file *filp)
{
struct gntalloc_file_private_data *priv;
priv = kzalloc(sizeof(*priv), GFP_KERNEL);
if (!priv)
goto out_nomem;
INIT_LIST_HEAD(&priv->list);
filp->private_data = priv;
pr_debug("%s: priv %p\n", __func__, priv);
return 0;
out_nomem:
return -ENOMEM;
}
static int gntalloc_release(struct inode *inode, struct file *filp)
{
struct gntalloc_file_private_data *priv = filp->private_data;
struct gntalloc_gref *gref;
pr_debug("%s: priv %p\n", __func__, priv);
spin_lock(&gref_lock);
while (!list_empty(&priv->list)) {
gref = list_entry(priv->list.next,
struct gntalloc_gref, next_file);
list_del(&gref->next_file);
gref->users--;
if (gref->users == 0)
__del_gref(gref);
}
kfree(priv);
spin_unlock(&gref_lock);
return 0;
}
static long gntalloc_ioctl_alloc(struct gntalloc_file_private_data *priv,
struct ioctl_gntalloc_alloc_gref __user *arg)
{
int rc = 0;
struct ioctl_gntalloc_alloc_gref op;
uint32_t *gref_ids;
pr_debug("%s: priv %p\n", __func__, priv);
if (copy_from_user(&op, arg, sizeof(op))) {
rc = -EFAULT;
goto out;
}
gref_ids = kzalloc(sizeof(gref_ids[0]) * op.count, GFP_TEMPORARY);
if (!gref_ids) {
rc = -ENOMEM;
goto out;
}
spin_lock(&gref_lock);
/* Clean up pages that were at zero (local) users but were still mapped
* by remote domains. Since those pages count towards the limit that we
* are about to enforce, removing them here is a good idea.
*/
do_cleanup();
if (gref_size + op.count > limit) {
spin_unlock(&gref_lock);
rc = -ENOSPC;
goto out_free;
}
gref_size += op.count;
op.index = priv->index;
priv->index += op.count * PAGE_SIZE;
spin_unlock(&gref_lock);
rc = add_grefs(&op, gref_ids, priv);
if (rc < 0)
goto out_free;
/* Once we finish add_grefs, it is unsafe to touch the new reference,
* since it is possible for a concurrent ioctl to remove it (by guessing
* its index). If the userspace application doesn't provide valid memory
* to write the IDs to, then it will need to close the file in order to
* release - which it will do by segfaulting when it tries to access the
* IDs to close them.
*/
if (copy_to_user(arg, &op, sizeof(op))) {
rc = -EFAULT;
goto out_free;
}
if (copy_to_user(arg->gref_ids, gref_ids,
sizeof(gref_ids[0]) * op.count)) {
rc = -EFAULT;
goto out_free;
}
out_free:
kfree(gref_ids);
out:
return rc;
}
static long gntalloc_ioctl_dealloc(struct gntalloc_file_private_data *priv,
void __user *arg)
{
int i, rc = 0;
struct ioctl_gntalloc_dealloc_gref op;
struct gntalloc_gref *gref, *n;
pr_debug("%s: priv %p\n", __func__, priv);
if (copy_from_user(&op, arg, sizeof(op))) {
rc = -EFAULT;
goto dealloc_grant_out;
}
spin_lock(&gref_lock);
gref = find_grefs(priv, op.index, op.count);
if (gref) {
/* Remove from the file list only, and decrease reference count.
* The later call to do_cleanup() will remove from gref_list and
* free the memory if the pages aren't mapped anywhere.
*/
for (i = 0; i < op.count; i++) {
n = list_entry(gref->next_file.next,
struct gntalloc_gref, next_file);
list_del(&gref->next_file);
gref->users--;
gref = n;
}
} else {
rc = -EINVAL;
}
do_cleanup();
spin_unlock(&gref_lock);
dealloc_grant_out:
return rc;
}
static long gntalloc_ioctl_unmap_notify(struct gntalloc_file_private_data *priv,
void __user *arg)
{
struct ioctl_gntalloc_unmap_notify op;
struct gntalloc_gref *gref;
uint64_t index;
int pgoff;
int rc;
if (copy_from_user(&op, arg, sizeof(op)))
return -EFAULT;
index = op.index & ~(PAGE_SIZE - 1);
pgoff = op.index & (PAGE_SIZE - 1);
spin_lock(&gref_lock);
gref = find_grefs(priv, index, 1);
if (!gref) {
rc = -ENOENT;
goto unlock_out;
}
if (op.action & ~(UNMAP_NOTIFY_CLEAR_BYTE|UNMAP_NOTIFY_SEND_EVENT)) {
rc = -EINVAL;
goto unlock_out;
}
gref->notify.flags = op.action;
gref->notify.pgoff = pgoff;
gref->notify.event = op.event_channel_port;
rc = 0;
unlock_out:
spin_unlock(&gref_lock);
return rc;
}
static long gntalloc_ioctl(struct file *filp, unsigned int cmd,
unsigned long arg)
{
struct gntalloc_file_private_data *priv = filp->private_data;
switch (cmd) {
case IOCTL_GNTALLOC_ALLOC_GREF:
return gntalloc_ioctl_alloc(priv, (void __user *)arg);
case IOCTL_GNTALLOC_DEALLOC_GREF:
return gntalloc_ioctl_dealloc(priv, (void __user *)arg);
case IOCTL_GNTALLOC_SET_UNMAP_NOTIFY:
return gntalloc_ioctl_unmap_notify(priv, (void __user *)arg);
default:
return -ENOIOCTLCMD;
}
return 0;
}
static void gntalloc_vma_close(struct vm_area_struct *vma)
{
struct gntalloc_gref *gref = vma->vm_private_data;
if (!gref)
return;
spin_lock(&gref_lock);
gref->users--;
if (gref->users == 0)
__del_gref(gref);
spin_unlock(&gref_lock);
}
static struct vm_operations_struct gntalloc_vmops = {
.close = gntalloc_vma_close,
};
static int gntalloc_mmap(struct file *filp, struct vm_area_struct *vma)
{
struct gntalloc_file_private_data *priv = filp->private_data;
struct gntalloc_gref *gref;
int count = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
int rv, i;
pr_debug("%s: priv %p, page %lu+%d\n", __func__,
priv, vma->vm_pgoff, count);
if (!(vma->vm_flags & VM_SHARED)) {
printk(KERN_ERR "%s: Mapping must be shared.\n", __func__);
return -EINVAL;
}
spin_lock(&gref_lock);
gref = find_grefs(priv, vma->vm_pgoff << PAGE_SHIFT, count);
if (gref == NULL) {
rv = -ENOENT;
pr_debug("%s: Could not find grant reference",
__func__);
goto out_unlock;
}
vma->vm_private_data = gref;
vma->vm_flags |= VM_RESERVED;
vma->vm_flags |= VM_DONTCOPY;
vma->vm_flags |= VM_PFNMAP | VM_PFN_AT_MMAP;
vma->vm_ops = &gntalloc_vmops;
for (i = 0; i < count; i++) {
gref->users++;
rv = vm_insert_page(vma, vma->vm_start + i * PAGE_SIZE,
gref->page);
if (rv)
goto out_unlock;
gref = list_entry(gref->next_file.next,
struct gntalloc_gref, next_file);
}
rv = 0;
out_unlock:
spin_unlock(&gref_lock);
return rv;
}
static const struct file_operations gntalloc_fops = {
.owner = THIS_MODULE,
.open = gntalloc_open,
.release = gntalloc_release,
.unlocked_ioctl = gntalloc_ioctl,
.mmap = gntalloc_mmap
};
/*
* -------------------------------------
* Module creation/destruction.
* -------------------------------------
*/
static struct miscdevice gntalloc_miscdev = {
.minor = MISC_DYNAMIC_MINOR,
.name = "xen/gntalloc",
.fops = &gntalloc_fops,
};
static int __init gntalloc_init(void)
{
int err;
if (!xen_domain())
return -ENODEV;
err = misc_register(&gntalloc_miscdev);
if (err != 0) {
printk(KERN_ERR "Could not register misc gntalloc device\n");
return err;
}
pr_debug("Created grant allocation device at %d,%d\n",
MISC_MAJOR, gntalloc_miscdev.minor);
return 0;
}
static void __exit gntalloc_exit(void)
{
misc_deregister(&gntalloc_miscdev);
}
module_init(gntalloc_init);
module_exit(gntalloc_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Carter Weatherly <carter.weatherly@jhuapl.edu>, "
"Daniel De Graaf <dgdegra@tycho.nsa.gov>");
MODULE_DESCRIPTION("User-space grant reference allocator driver");

386
drivers/xen/gntdev.c
View File

@ -32,10 +32,13 @@
#include <linux/sched.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/highmem.h>
#include <xen/xen.h>
#include <xen/grant_table.h>
#include <xen/balloon.h>
#include <xen/gntdev.h>
#include <xen/events.h>
#include <asm/xen/hypervisor.h>
#include <asm/xen/hypercall.h>
#include <asm/xen/page.h>
@ -45,35 +48,46 @@ MODULE_AUTHOR("Derek G. Murray <Derek.Murray@cl.cam.ac.uk>, "
"Gerd Hoffmann <kraxel@redhat.com>");
MODULE_DESCRIPTION("User-space granted page access driver");
static int limit = 1024;
static int limit = 1024*1024;
module_param(limit, int, 0644);
MODULE_PARM_DESC(limit, "Maximum number of grants that may be mapped at "
"once by a gntdev instance");
MODULE_PARM_DESC(limit, "Maximum number of grants that may be mapped by "
"the gntdev device");
static atomic_t pages_mapped = ATOMIC_INIT(0);
static int use_ptemod;
struct gntdev_priv {
struct list_head maps;
uint32_t used;
uint32_t limit;
/* lock protects maps from concurrent changes */
spinlock_t lock;
struct mm_struct *mm;
struct mmu_notifier mn;
};
struct unmap_notify {
int flags;
/* Address relative to the start of the grant_map */
int addr;
int event;
};
struct grant_map {
struct list_head next;
struct gntdev_priv *priv;
struct vm_area_struct *vma;
int index;
int count;
int flags;
int is_mapped;
atomic_t users;
struct unmap_notify notify;
struct ioctl_gntdev_grant_ref *grants;
struct gnttab_map_grant_ref *map_ops;
struct gnttab_unmap_grant_ref *unmap_ops;
struct page **pages;
};
static int unmap_grant_pages(struct grant_map *map, int offset, int pages);
/* ------------------------------------------------------------------ */
static void gntdev_print_maps(struct gntdev_priv *priv,
@ -82,9 +96,7 @@ static void gntdev_print_maps(struct gntdev_priv *priv,
#ifdef DEBUG
struct grant_map *map;
pr_debug("maps list (priv %p, usage %d/%d)\n",
priv, priv->used, priv->limit);
pr_debug("%s: maps list (priv %p)\n", __func__, priv);
list_for_each_entry(map, &priv->maps, next)
pr_debug(" index %2d, count %2d %s\n",
map->index, map->count,
@ -111,27 +123,21 @@ static struct grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int count)
NULL == add->pages)
goto err;
if (alloc_xenballooned_pages(count, add->pages))
goto err;
for (i = 0; i < count; i++) {
add->pages[i] = alloc_page(GFP_KERNEL | __GFP_HIGHMEM);
if (add->pages[i] == NULL)
goto err;
add->map_ops[i].handle = -1;
add->unmap_ops[i].handle = -1;
}
add->index = 0;
add->count = count;
add->priv = priv;
if (add->count + priv->used > priv->limit)
goto err;
atomic_set(&add->users, 1);
return add;
err:
if (add->pages)
for (i = 0; i < count; i++) {
if (add->pages[i])
__free_page(add->pages[i]);
}
kfree(add->pages);
kfree(add->grants);
kfree(add->map_ops);
@ -154,7 +160,6 @@ static void gntdev_add_map(struct gntdev_priv *priv, struct grant_map *add)
list_add_tail(&add->next, &priv->maps);
done:
priv->used += add->count;
gntdev_print_maps(priv, "[new]", add->index);
}
@ -166,57 +171,33 @@ static struct grant_map *gntdev_find_map_index(struct gntdev_priv *priv,
list_for_each_entry(map, &priv->maps, next) {
if (map->index != index)
continue;
if (map->count != count)
if (count && map->count != count)
continue;
return map;
}
return NULL;
}
static struct grant_map *gntdev_find_map_vaddr(struct gntdev_priv *priv,
unsigned long vaddr)
static void gntdev_put_map(struct grant_map *map)
{
struct grant_map *map;
list_for_each_entry(map, &priv->maps, next) {
if (!map->vma)
continue;
if (vaddr < map->vma->vm_start)
continue;
if (vaddr >= map->vma->vm_end)
continue;
return map;
}
return NULL;
}
static int gntdev_del_map(struct grant_map *map)
{
int i;
if (map->vma)
return -EBUSY;
for (i = 0; i < map->count; i++)
if (map->unmap_ops[i].handle)
return -EBUSY;
map->priv->used -= map->count;
list_del(&map->next);
return 0;
}
static void gntdev_free_map(struct grant_map *map)
{
int i;
if (!map)
return;
if (map->pages)
for (i = 0; i < map->count; i++) {
if (map->pages[i])
__free_page(map->pages[i]);
}
if (!atomic_dec_and_test(&map->users))
return;
atomic_sub(map->count, &pages_mapped);
if (map->notify.flags & UNMAP_NOTIFY_SEND_EVENT) {
notify_remote_via_evtchn(map->notify.event);
}
if (map->pages) {
if (!use_ptemod)
unmap_grant_pages(map, 0, map->count);
free_xenballooned_pages(map->count, map->pages);
}
kfree(map->pages);
kfree(map->grants);
kfree(map->map_ops);
@ -231,18 +212,17 @@ static int find_grant_ptes(pte_t *pte, pgtable_t token,
{
struct grant_map *map = data;
unsigned int pgnr = (addr - map->vma->vm_start) >> PAGE_SHIFT;
int flags = map->flags | GNTMAP_application_map | GNTMAP_contains_pte;
u64 pte_maddr;
BUG_ON(pgnr >= map->count);
pte_maddr = arbitrary_virt_to_machine(pte).maddr;
gnttab_set_map_op(&map->map_ops[pgnr], pte_maddr,
GNTMAP_contains_pte | map->flags,
gnttab_set_map_op(&map->map_ops[pgnr], pte_maddr, flags,
map->grants[pgnr].ref,
map->grants[pgnr].domid);
gnttab_set_unmap_op(&map->unmap_ops[pgnr], pte_maddr,
GNTMAP_contains_pte | map->flags,
0 /* handle */);
gnttab_set_unmap_op(&map->unmap_ops[pgnr], pte_maddr, flags,
-1 /* handle */);
return 0;
}
@ -250,6 +230,21 @@ static int map_grant_pages(struct grant_map *map)
{
int i, err = 0;
if (!use_ptemod) {
/* Note: it could already be mapped */
if (map->map_ops[0].handle != -1)
return 0;
for (i = 0; i < map->count; i++) {
unsigned long addr = (unsigned long)
pfn_to_kaddr(page_to_pfn(map->pages[i]));
gnttab_set_map_op(&map->map_ops[i], addr, map->flags,
map->grants[i].ref,
map->grants[i].domid);
gnttab_set_unmap_op(&map->unmap_ops[i], addr,
map->flags, -1 /* handle */);
}
}
pr_debug("map %d+%d\n", map->index, map->count);
err = gnttab_map_refs(map->map_ops, map->pages, map->count);
if (err)
@ -258,28 +253,81 @@ static int map_grant_pages(struct grant_map *map)
for (i = 0; i < map->count; i++) {
if (map->map_ops[i].status)
err = -EINVAL;
map->unmap_ops[i].handle = map->map_ops[i].handle;
else {
BUG_ON(map->map_ops[i].handle == -1);
map->unmap_ops[i].handle = map->map_ops[i].handle;
pr_debug("map handle=%d\n", map->map_ops[i].handle);
}
}
return err;
}
static int unmap_grant_pages(struct grant_map *map, int offset, int pages)
static int __unmap_grant_pages(struct grant_map *map, int offset, int pages)
{
int i, err = 0;
pr_debug("map %d+%d [%d+%d]\n", map->index, map->count, offset, pages);
err = gnttab_unmap_refs(map->unmap_ops + offset, map->pages, pages);
if (map->notify.flags & UNMAP_NOTIFY_CLEAR_BYTE) {
int pgno = (map->notify.addr >> PAGE_SHIFT);
if (pgno >= offset && pgno < offset + pages && use_ptemod) {
void __user *tmp = (void __user *)
map->vma->vm_start + map->notify.addr;
err = copy_to_user(tmp, &err, 1);
if (err)
return err;
map->notify.flags &= ~UNMAP_NOTIFY_CLEAR_BYTE;
} else if (pgno >= offset && pgno < offset + pages) {
uint8_t *tmp = kmap(map->pages[pgno]);
tmp[map->notify.addr & (PAGE_SIZE-1)] = 0;
kunmap(map->pages[pgno]);
map->notify.flags &= ~UNMAP_NOTIFY_CLEAR_BYTE;
}
}
err = gnttab_unmap_refs(map->unmap_ops + offset, map->pages + offset, pages);
if (err)
return err;
for (i = 0; i < pages; i++) {
if (map->unmap_ops[offset+i].status)
err = -EINVAL;
map->unmap_ops[offset+i].handle = 0;
pr_debug("unmap handle=%d st=%d\n",
map->unmap_ops[offset+i].handle,
map->unmap_ops[offset+i].status);
map->unmap_ops[offset+i].handle = -1;
}
return err;
}
static int unmap_grant_pages(struct grant_map *map, int offset, int pages)
{
int range, err = 0;
pr_debug("unmap %d+%d [%d+%d]\n", map->index, map->count, offset, pages);
/* It is possible the requested range will have a "hole" where we
* already unmapped some of the grants. Only unmap valid ranges.
*/
while (pages && !err) {
while (pages && map->unmap_ops[offset].handle == -1) {
offset++;
pages--;
}
range = 0;
while (range < pages) {
if (map->unmap_ops[offset+range].handle == -1) {
range--;
break;
}
range++;
}
err = __unmap_grant_pages(map, offset, range);
offset += range;
pages -= range;
}
return err;
}
/* ------------------------------------------------------------------ */
static void gntdev_vma_close(struct vm_area_struct *vma)
@ -287,22 +335,13 @@ static void gntdev_vma_close(struct vm_area_struct *vma)
struct grant_map *map = vma->vm_private_data;
pr_debug("close %p\n", vma);
map->is_mapped = 0;
map->vma = NULL;
vma->vm_private_data = NULL;
}
static int gntdev_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
pr_debug("vaddr %p, pgoff %ld (shouldn't happen)\n",
vmf->virtual_address, vmf->pgoff);
vmf->flags = VM_FAULT_ERROR;
return 0;
gntdev_put_map(map);
}
static struct vm_operations_struct gntdev_vmops = {
.close = gntdev_vma_close,
.fault = gntdev_vma_fault,
};
/* ------------------------------------------------------------------ */
@ -320,8 +359,6 @@ static void mn_invl_range_start(struct mmu_notifier *mn,
list_for_each_entry(map, &priv->maps, next) {
if (!map->vma)
continue;
if (!map->is_mapped)
continue;
if (map->vma->vm_start >= end)
continue;
if (map->vma->vm_end <= start)
@ -386,16 +423,17 @@ static int gntdev_open(struct inode *inode, struct file *flip)
INIT_LIST_HEAD(&priv->maps);
spin_lock_init(&priv->lock);
priv->limit = limit;
priv->mm = get_task_mm(current);
if (!priv->mm) {
kfree(priv);
return -ENOMEM;
if (use_ptemod) {
priv->mm = get_task_mm(current);
if (!priv->mm) {
kfree(priv);
return -ENOMEM;
}
priv->mn.ops = &gntdev_mmu_ops;
ret = mmu_notifier_register(&priv->mn, priv->mm);
mmput(priv->mm);
}
priv->mn.ops = &gntdev_mmu_ops;
ret = mmu_notifier_register(&priv->mn, priv->mm);
mmput(priv->mm);
if (ret) {
kfree(priv);
@ -412,21 +450,19 @@ static int gntdev_release(struct inode *inode, struct file *flip)
{
struct gntdev_priv *priv = flip->private_data;
struct grant_map *map;
int err;
pr_debug("priv %p\n", priv);
spin_lock(&priv->lock);
while (!list_empty(&priv->maps)) {
map = list_entry(priv->maps.next, struct grant_map, next);
err = gntdev_del_map(map);
if (WARN_ON(err))
gntdev_free_map(map);
list_del(&map->next);
gntdev_put_map(map);
}
spin_unlock(&priv->lock);
mmu_notifier_unregister(&priv->mn, priv->mm);
if (use_ptemod)
mmu_notifier_unregister(&priv->mn, priv->mm);
kfree(priv);
return 0;
}
@ -443,16 +479,21 @@ static long gntdev_ioctl_map_grant_ref(struct gntdev_priv *priv,
pr_debug("priv %p, add %d\n", priv, op.count);
if (unlikely(op.count <= 0))
return -EINVAL;
if (unlikely(op.count > priv->limit))
return -EINVAL;
err = -ENOMEM;
map = gntdev_alloc_map(priv, op.count);
if (!map)
return err;
if (unlikely(atomic_add_return(op.count, &pages_mapped) > limit)) {
pr_debug("can't map: over limit\n");
gntdev_put_map(map);
return err;
}
if (copy_from_user(map->grants, &u->refs,
sizeof(map->grants[0]) * op.count) != 0) {
gntdev_free_map(map);
gntdev_put_map(map);
return err;
}
@ -461,13 +502,9 @@ static long gntdev_ioctl_map_grant_ref(struct gntdev_priv *priv,
op.index = map->index << PAGE_SHIFT;
spin_unlock(&priv->lock);
if (copy_to_user(u, &op, sizeof(op)) != 0) {
spin_lock(&priv->lock);
gntdev_del_map(map);
spin_unlock(&priv->lock);
gntdev_free_map(map);
return err;
}
if (copy_to_user(u, &op, sizeof(op)) != 0)
return -EFAULT;
return 0;
}
@ -484,11 +521,12 @@ static long gntdev_ioctl_unmap_grant_ref(struct gntdev_priv *priv,
spin_lock(&priv->lock);
map = gntdev_find_map_index(priv, op.index >> PAGE_SHIFT, op.count);
if (map)
err = gntdev_del_map(map);
if (map) {
list_del(&map->next);
gntdev_put_map(map);
err = 0;
}
spin_unlock(&priv->lock);
if (!err)
gntdev_free_map(map);
return err;
}
@ -496,43 +534,66 @@ static long gntdev_ioctl_get_offset_for_vaddr(struct gntdev_priv *priv,
struct ioctl_gntdev_get_offset_for_vaddr __user *u)
{
struct ioctl_gntdev_get_offset_for_vaddr op;
struct vm_area_struct *vma;
struct grant_map *map;
if (copy_from_user(&op, u, sizeof(op)) != 0)
return -EFAULT;
pr_debug("priv %p, offset for vaddr %lx\n", priv, (unsigned long)op.vaddr);
spin_lock(&priv->lock);
map = gntdev_find_map_vaddr(priv, op.vaddr);
if (map == NULL ||
map->vma->vm_start != op.vaddr) {
spin_unlock(&priv->lock);
vma = find_vma(current->mm, op.vaddr);
if (!vma || vma->vm_ops != &gntdev_vmops)
return -EINVAL;
}
map = vma->vm_private_data;
if (!map)
return -EINVAL;
op.offset = map->index << PAGE_SHIFT;
op.count = map->count;
spin_unlock(&priv->lock);
if (copy_to_user(u, &op, sizeof(op)) != 0)
return -EFAULT;
return 0;
}
static long gntdev_ioctl_set_max_grants(struct gntdev_priv *priv,
struct ioctl_gntdev_set_max_grants __user *u)
static long gntdev_ioctl_notify(struct gntdev_priv *priv, void __user *u)
{
struct ioctl_gntdev_set_max_grants op;
struct ioctl_gntdev_unmap_notify op;
struct grant_map *map;
int rc;
if (copy_from_user(&op, u, sizeof(op)) != 0)
if (copy_from_user(&op, u, sizeof(op)))
return -EFAULT;
pr_debug("priv %p, limit %d\n", priv, op.count);
if (op.count > limit)
return -E2BIG;
if (op.action & ~(UNMAP_NOTIFY_CLEAR_BYTE|UNMAP_NOTIFY_SEND_EVENT))
return -EINVAL;
spin_lock(&priv->lock);
priv->limit = op.count;
list_for_each_entry(map, &priv->maps, next) {
uint64_t begin = map->index << PAGE_SHIFT;
uint64_t end = (map->index + map->count) << PAGE_SHIFT;
if (op.index >= begin && op.index < end)
goto found;
}
rc = -ENOENT;
goto unlock_out;
found:
if ((op.action & UNMAP_NOTIFY_CLEAR_BYTE) &&
(map->flags & GNTMAP_readonly)) {
rc = -EINVAL;
goto unlock_out;
}
map->notify.flags = op.action;
map->notify.addr = op.index - (map->index << PAGE_SHIFT);
map->notify.event = op.event_channel_port;
rc = 0;
unlock_out:
spin_unlock(&priv->lock);
return 0;
return rc;
}
static long gntdev_ioctl(struct file *flip,
@ -551,8 +612,8 @@ static long gntdev_ioctl(struct file *flip,
case IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR:
return gntdev_ioctl_get_offset_for_vaddr(priv, ptr);
case IOCTL_GNTDEV_SET_MAX_GRANTS:
return gntdev_ioctl_set_max_grants(priv, ptr);
case IOCTL_GNTDEV_SET_UNMAP_NOTIFY:
return gntdev_ioctl_notify(priv, ptr);
default:
pr_debug("priv %p, unknown cmd %x\n", priv, cmd);
@ -568,7 +629,7 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma)
int index = vma->vm_pgoff;
int count = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
struct grant_map *map;
int err = -EINVAL;
int i, err = -EINVAL;
if ((vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_SHARED))
return -EINVAL;
@ -580,47 +641,70 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma)
map = gntdev_find_map_index(priv, index, count);
if (!map)
goto unlock_out;
if (map->vma)
if (use_ptemod && map->vma)
goto unlock_out;
if (priv->mm != vma->vm_mm) {
if (use_ptemod && priv->mm != vma->vm_mm) {
printk(KERN_WARNING "Huh? Other mm?\n");
goto unlock_out;
}
atomic_inc(&map->users);
vma->vm_ops = &gntdev_vmops;
vma->vm_flags |= VM_RESERVED|VM_DONTCOPY|VM_DONTEXPAND|VM_PFNMAP;
vma->vm_private_data = map;
map->vma = vma;
map->flags = GNTMAP_host_map | GNTMAP_application_map;
if (!(vma->vm_flags & VM_WRITE))
map->flags |= GNTMAP_readonly;
if (use_ptemod)
map->vma = vma;
if (map->flags) {
if ((vma->vm_flags & VM_WRITE) &&
(map->flags & GNTMAP_readonly))
return -EINVAL;
} else {
map->flags = GNTMAP_host_map;
if (!(vma->vm_flags & VM_WRITE))
map->flags |= GNTMAP_readonly;
}
spin_unlock(&priv->lock);
err = apply_to_page_range(vma->vm_mm, vma->vm_start,
vma->vm_end - vma->vm_start,
find_grant_ptes, map);
if (err) {
printk(KERN_WARNING "find_grant_ptes() failure.\n");
return err;
if (use_ptemod) {
err = apply_to_page_range(vma->vm_mm, vma->vm_start,
vma->vm_end - vma->vm_start,
find_grant_ptes, map);
if (err) {
printk(KERN_WARNING "find_grant_ptes() failure.\n");
goto out_put_map;
}
}
err = map_grant_pages(map);
if (err) {
printk(KERN_WARNING "map_grant_pages() failure.\n");
return err;
}
if (err)
goto out_put_map;
map->is_mapped = 1;
if (!use_ptemod) {
for (i = 0; i < count; i++) {
err = vm_insert_page(vma, vma->vm_start + i*PAGE_SIZE,
map->pages[i]);
if (err)
goto out_put_map;
}
}
return 0;
unlock_out:
spin_unlock(&priv->lock);
return err;
out_put_map:
if (use_ptemod)
map->vma = NULL;
gntdev_put_map(map);
return err;
}
static const struct file_operations gntdev_fops = {
@ -646,6 +730,8 @@ static int __init gntdev_init(void)
if (!xen_domain())
return -ENODEV;
use_ptemod = xen_pv_domain();
err = misc_register(&gntdev_miscdev);
if (err != 0) {
printk(KERN_ERR "Could not register gntdev device\n");

10
drivers/xen/grant-table.c
View File

@ -458,7 +458,14 @@ int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
if (ret)
return ret;
if (xen_feature(XENFEAT_auto_translated_physmap))
return ret;
for (i = 0; i < count; i++) {
/* Do not add to override if the map failed. */
if (map_ops[i].status)
continue;
/* m2p override only supported for GNTMAP_contains_pte mappings */
if (!(map_ops[i].flags & GNTMAP_contains_pte))
continue;
@ -483,6 +490,9 @@ int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
if (ret)
return ret;
if (xen_feature(XENFEAT_auto_translated_physmap))
return ret;
for (i = 0; i < count; i++) {
ret = m2p_remove_override(pages[i]);
if (ret)

256
drivers/xen/xen-balloon.c Normal file
View File

@ -0,0 +1,256 @@
/******************************************************************************
* Xen balloon driver - enables returning/claiming memory to/from Xen.
*
* Copyright (c) 2003, B Dragovic
* Copyright (c) 2003-2004, M Williamson, K Fraser
* Copyright (c) 2005 Dan M. Smith, IBM Corporation
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation; or, when distributed
* separately from the Linux kernel or incorporated into other
* software packages, subject to the following license:
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this source file (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use, copy, modify,
* merge, publish, distribute, sublicense, and/or sell copies of the Software,
* and to permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/sysdev.h>
#include <linux/capability.h>
#include <xen/xen.h>
#include <xen/interface/xen.h>
#include <xen/balloon.h>
#include <xen/xenbus.h>
#include <xen/features.h>
#include <xen/page.h>
#define PAGES2KB(_p) ((_p)<<(PAGE_SHIFT-10))
#define BALLOON_CLASS_NAME "xen_memory"
static struct sys_device balloon_sysdev;
static int register_balloon(struct sys_device *sysdev);
static struct xenbus_watch target_watch =
{
.node = "memory/target"
};
/* React to a change in the target key */
static void watch_target(struct xenbus_watch *watch,
const char **vec, unsigned int len)
{
unsigned long long new_target;
int err;
err = xenbus_scanf(XBT_NIL, "memory", "target", "%llu", &new_target);
if (err != 1) {
/* This is ok (for domain0 at least) - so just return */
return;
}
/* The given memory/target value is in KiB, so it needs converting to
* pages. PAGE_SHIFT converts bytes to pages, hence PAGE_SHIFT - 10.
*/
balloon_set_new_target(new_target >> (PAGE_SHIFT - 10));
}
static int balloon_init_watcher(struct notifier_block *notifier,
unsigned long event,
void *data)
{
int err;
err = register_xenbus_watch(&target_watch);
if (err)
printk(KERN_ERR "Failed to set balloon watcher\n");
return NOTIFY_DONE;
}
static struct notifier_block xenstore_notifier;
static int __init balloon_init(void)
{
if (!xen_domain())
return -ENODEV;
pr_info("xen-balloon: Initialising balloon driver.\n");
register_balloon(&balloon_sysdev);
target_watch.callback = watch_target;
xenstore_notifier.notifier_call = balloon_init_watcher;
register_xenstore_notifier(&xenstore_notifier);
return 0;
}
subsys_initcall(balloon_init);
static void balloon_exit(void)
{
/* XXX - release balloon here */
return;
}
module_exit(balloon_exit);
#define BALLOON_SHOW(name, format, args...) \
static ssize_t show_##name(struct sys_device *dev, \
struct sysdev_attribute *attr, \
char *buf) \
{ \
return sprintf(buf, format, ##args); \
} \
static SYSDEV_ATTR(name, S_IRUGO, show_##name, NULL)
BALLOON_SHOW(current_kb, "%lu\n", PAGES2KB(balloon_stats.current_pages));
BALLOON_SHOW(low_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_low));
BALLOON_SHOW(high_kb, "%lu\n", PAGES2KB(balloon_stats.balloon_high));
static SYSDEV_ULONG_ATTR(schedule_delay, 0444, balloon_stats.schedule_delay);
static SYSDEV_ULONG_ATTR(max_schedule_delay, 0644, balloon_stats.max_schedule_delay);
static SYSDEV_ULONG_ATTR(retry_count, 0444, balloon_stats.retry_count);
static SYSDEV_ULONG_ATTR(max_retry_count, 0644, balloon_stats.max_retry_count);
static ssize_t show_target_kb(struct sys_device *dev, struct sysdev_attribute *attr,
char *buf)
{
return sprintf(buf, "%lu\n", PAGES2KB(balloon_stats.target_pages));
}
static ssize_t store_target_kb(struct sys_device *dev,
struct sysdev_attribute *attr,
const char *buf,
size_t count)
{
char *endchar;
unsigned long long target_bytes;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
target_bytes = simple_strtoull(buf, &endchar, 0) * 1024;
balloon_set_new_target(target_bytes >> PAGE_SHIFT);
return count;
}
static SYSDEV_ATTR(target_kb, S_IRUGO | S_IWUSR,
show_target_kb, store_target_kb);
static ssize_t show_target(struct sys_device *dev, struct sysdev_attribute *attr,
char *buf)
{
return sprintf(buf, "%llu\n",
(unsigned long long)balloon_stats.target_pages
<< PAGE_SHIFT);
}
static ssize_t store_target(struct sys_device *dev,
struct sysdev_attribute *attr,
const char *buf,
size_t count)
{
char *endchar;
unsigned long long target_bytes;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
target_bytes = memparse(buf, &endchar);
balloon_set_new_target(target_bytes >> PAGE_SHIFT);
return count;
}
static SYSDEV_ATTR(target, S_IRUGO | S_IWUSR,
show_target, store_target);
static struct sysdev_attribute *balloon_attrs[] = {
&attr_target_kb,
&attr_target,
&attr_schedule_delay.attr,
&attr_max_schedule_delay.attr,
&attr_retry_count.attr,
&attr_max_retry_count.attr
};
static struct attribute *balloon_info_attrs[] = {
&attr_current_kb.attr,
&attr_low_kb.attr,
&attr_high_kb.attr,
NULL
};
static struct attribute_group balloon_info_group = {
.name = "info",
.attrs = balloon_info_attrs
};
static struct sysdev_class balloon_sysdev_class = {
.name = BALLOON_CLASS_NAME
};
static int register_balloon(struct sys_device *sysdev)
{
int i, error;
error = sysdev_class_register(&balloon_sysdev_class);
if (error)
return error;
sysdev->id = 0;
sysdev->cls = &balloon_sysdev_class;
error = sysdev_register(sysdev);
if (error) {
sysdev_class_unregister(&balloon_sysdev_class);
return error;
}
for (i = 0; i < ARRAY_SIZE(balloon_attrs); i++) {
error = sysdev_create_file(sysdev, balloon_attrs[i]);
if (error)
goto fail;
}
error = sysfs_create_group(&sysdev->kobj, &balloon_info_group);
if (error)
goto fail;
return 0;
fail:
while (--i >= 0)
sysdev_remove_file(sysdev, balloon_attrs[i]);
sysdev_unregister(sysdev);
sysdev_class_unregister(&balloon_sysdev_class);
return error;
}
MODULE_LICENSE("GPL");

25
include/xen/balloon.h Normal file
View File

@ -0,0 +1,25 @@
/******************************************************************************
* Xen balloon functionality
*/
#define RETRY_UNLIMITED 0
struct balloon_stats {
/* We aim for 'current allocation' == 'target allocation'. */
unsigned long current_pages;
unsigned long target_pages;
/* Number of pages in high- and low-memory balloons. */
unsigned long balloon_low;
unsigned long balloon_high;
unsigned long schedule_delay;
unsigned long max_schedule_delay;
unsigned long retry_count;
unsigned long max_retry_count;
};
extern struct balloon_stats balloon_stats;
void balloon_set_new_target(unsigned long target);
int alloc_xenballooned_pages(int nr_pages, struct page** pages);
void free_xenballooned_pages(int nr_pages, struct page** pages);

82
include/xen/gntalloc.h Normal file
View File

@ -0,0 +1,82 @@
/******************************************************************************
* gntalloc.h
*
* Interface to /dev/xen/gntalloc.
*
* Author: Daniel De Graaf <dgdegra@tycho.nsa.gov>
*
* This file is in the public domain.
*/
#ifndef __LINUX_PUBLIC_GNTALLOC_H__
#define __LINUX_PUBLIC_GNTALLOC_H__
/*
* Allocates a new page and creates a new grant reference.
*/
#define IOCTL_GNTALLOC_ALLOC_GREF \
_IOC(_IOC_NONE, 'G', 5, sizeof(struct ioctl_gntalloc_alloc_gref))
struct ioctl_gntalloc_alloc_gref {
/* IN parameters */
/* The ID of the domain to be given access to the grants. */
uint16_t domid;
/* Flags for this mapping */
uint16_t flags;
/* Number of pages to map */
uint32_t count;
/* OUT parameters */
/* The offset to be used on a subsequent call to mmap(). */
uint64_t index;
/* The grant references of the newly created grant, one per page */
/* Variable size, depending on count */
uint32_t gref_ids[1];
};
#define GNTALLOC_FLAG_WRITABLE 1
/*
* Deallocates the grant reference, allowing the associated page to be freed if
* no other domains are using it.
*/
#define IOCTL_GNTALLOC_DEALLOC_GREF \
_IOC(_IOC_NONE, 'G', 6, sizeof(struct ioctl_gntalloc_dealloc_gref))
struct ioctl_gntalloc_dealloc_gref {
/* IN parameters */
/* The offset returned in the map operation */
uint64_t index;
/* Number of references to unmap */
uint32_t count;
};
/*
* Sets up an unmap notification within the page, so that the other side can do
* cleanup if this side crashes. Required to implement cross-domain robust
* mutexes or close notification on communication channels.
*
* Each mapped page only supports one notification; multiple calls referring to
* the same page overwrite the previous notification. You must clear the
* notification prior to the IOCTL_GNTALLOC_DEALLOC_GREF if you do not want it
* to occur.
*/
#define IOCTL_GNTALLOC_SET_UNMAP_NOTIFY \
_IOC(_IOC_NONE, 'G', 7, sizeof(struct ioctl_gntalloc_unmap_notify))
struct ioctl_gntalloc_unmap_notify {
/* IN parameters */
/* Offset in the file descriptor for a byte within the page (same as
* used in mmap). If using UNMAP_NOTIFY_CLEAR_BYTE, this is the byte to
* be cleared. Otherwise, it can be any byte in the page whose
* notification we are adjusting.
*/
uint64_t index;
/* Action(s) to take on unmap */
uint32_t action;
/* Event channel to notify */
uint32_t event_channel_port;
};
/* Clear (set to zero) the byte specified by index */
#define UNMAP_NOTIFY_CLEAR_BYTE 0x1
/* Send an interrupt on the indicated event channel */
#define UNMAP_NOTIFY_SEND_EVENT 0x2
#endif /* __LINUX_PUBLIC_GNTALLOC_H__ */

31
include/xen/gntdev.h
View File

@ -116,4 +116,35 @@ struct ioctl_gntdev_set_max_grants {
uint32_t count;
};
/*
* Sets up an unmap notification within the page, so that the other side can do
* cleanup if this side crashes. Required to implement cross-domain robust
* mutexes or close notification on communication channels.
*
* Each mapped page only supports one notification; multiple calls referring to
* the same page overwrite the previous notification. You must clear the
* notification prior to the IOCTL_GNTALLOC_DEALLOC_GREF if you do not want it
* to occur.
*/
#define IOCTL_GNTDEV_SET_UNMAP_NOTIFY \
_IOC(_IOC_NONE, 'G', 7, sizeof(struct ioctl_gntdev_unmap_notify))
struct ioctl_gntdev_unmap_notify {
/* IN parameters */
/* Offset in the file descriptor for a byte within the page (same as
* used in mmap). If using UNMAP_NOTIFY_CLEAR_BYTE, this is the byte to
* be cleared. Otherwise, it can be any byte in the page whose
* notification we are adjusting.
*/
uint64_t index;
/* Action(s) to take on unmap */
uint32_t action;
/* Event channel to notify */
uint32_t event_channel_port;
};
/* Clear (set to zero) the byte specified by index */
#define UNMAP_NOTIFY_CLEAR_BYTE 0x1
/* Send an interrupt on the indicated event channel */
#define UNMAP_NOTIFY_SEND_EVENT 0x2
#endif /* __LINUX_PUBLIC_GNTDEV_H__ */