#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);
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 */
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 {
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;
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)
{
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;
}
#include <xen/xen.h>
#include <xen/grant_table.h>
#include <xen/gntdev.h>
+#include <xen/events.h>
#include <asm/xen/hypervisor.h>
#include <asm/xen/hypercall.h>
#include <asm/xen/page.h>
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 vm_area_struct *vma;
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;
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;
}
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);
{
int i, err = 0;
+ if (map->notify.flags & UNMAP_NOTIFY_CLEAR_BYTE) {
+ int pgno = (map->notify.addr >> PAGE_SHIFT);
+ 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;
+ }
+ }
+
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 (err)
return 0;
}
+static long gntdev_ioctl_notify(struct gntdev_priv *priv, void __user *u)
+{
+ struct ioctl_gntdev_unmap_notify op;
+ struct grant_map *map;
+ int rc;
+
+ if (copy_from_user(&op, u, sizeof(op)))
+ return -EFAULT;
+
+ if (op.action & ~(UNMAP_NOTIFY_CLEAR_BYTE|UNMAP_NOTIFY_SEND_EVENT))
+ return -EINVAL;
+
+ spin_lock(&priv->lock);
+
+ 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:
+ 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 rc;
+}
+
static long gntdev_ioctl(struct file *flip,
unsigned int cmd, unsigned long arg)
{
case IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR:
return gntdev_ioctl_get_offset_for_vaddr(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);
return -ENOIOCTLCMD;
/* 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__ */
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__ */
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