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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [SPAM] Re: [Xen-devel] [PATCH 02/11] xen/gntdev: allow usermode to map granted pages
On Wed, Dec 15, 2010 at 01:40:37PM +0000, stefano.stabellini@xxxxxxxxxxxxx
wrote:
> From: Gerd Hoffmann <kraxel@xxxxxxxxxx>
>
> The gntdev driver allows usermode to map granted pages from other
> domains. This is typically used to implement a Xen backend driver
> in user mode.
scripts/checkpatch.pl goes haywire on this patch. Any chance you can
make it cleaner? (or perhaps a subsequent patch to fix the checkpatch.pl
isseus?)
The issues are mainly the printk's can be converted to pr_debug..
>
> Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
> Signed-off-by: Stefano Stabellini <Stefano.Stabellini@xxxxxxxxxxxxx>
> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx>
> ---
> drivers/xen/Kconfig | 7 +
> drivers/xen/Makefile | 2 +
> drivers/xen/gntdev.c | 646
> ++++++++++++++++++++++++++++++++++++++++++++++++++
> include/xen/gntdev.h | 119 +++++++++
> 4 files changed, 774 insertions(+), 0 deletions(-)
> create mode 100644 drivers/xen/gntdev.c
> create mode 100644 include/xen/gntdev.h
>
> diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
> index 6e6180c..0c6d2a1 100644
> --- a/drivers/xen/Kconfig
> +++ b/drivers/xen/Kconfig
> @@ -62,6 +62,13 @@ config XEN_SYS_HYPERVISOR
> virtual environment, /sys/hypervisor will still be present,
> but will have no xen contents.
>
> +config XEN_GNTDEV
> + tristate "userspace grant access device driver"
> + depends on XEN
> + select MMU_NOTIFIER
> + help
> + Allows userspace processes use grants.
^^- "to"
> +
> config XEN_PLATFORM_PCI
> tristate "xen platform pci device driver"
> depends on XEN_PVHVM
> diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile
> index 533a199..674fdb5 100644
> --- a/drivers/xen/Makefile
> +++ b/drivers/xen/Makefile
> @@ -9,6 +9,7 @@ obj-$(CONFIG_HOTPLUG_CPU) += cpu_hotplug.o
> obj-$(CONFIG_XEN_XENCOMM) += xencomm.o
> obj-$(CONFIG_XEN_BALLOON) += balloon.o
> obj-$(CONFIG_XEN_DEV_EVTCHN) += xen-evtchn.o
> +obj-$(CONFIG_XEN_GNTDEV) += xen-gntdev.o
> obj-$(CONFIG_XENFS) += xenfs/
> obj-$(CONFIG_XEN_SYS_HYPERVISOR) += sys-hypervisor.o
> obj-$(CONFIG_XEN_PLATFORM_PCI) += platform-pci.o
> @@ -16,4 +17,5 @@ obj-$(CONFIG_SWIOTLB_XEN) += swiotlb-xen.o
> obj-$(CONFIG_XEN_DOM0) += pci.o
>
> xen-evtchn-y := evtchn.o
> +xen-gntdev-y := gntdev.o
>
> diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
> new file mode 100644
> index 0000000..45898d4
> --- /dev/null
> +++ b/drivers/xen/gntdev.c
> @@ -0,0 +1,646 @@
> +/******************************************************************************
> + * gntdev.c
> + *
> + * Device for accessing (in user-space) pages that have been granted by other
> + * domains.
> + *
> + * Copyright (c) 2006-2007, D G Murray.
> + * (c) 2009 Gerd Hoffmann <kraxel@xxxxxxxxxx>
> + *
> + * 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
> + */
> +
> +#include <linux/module.h>
> +#include <linux/kernel.h>
> +#include <linux/init.h>
> +#include <linux/miscdevice.h>
> +#include <linux/fs.h>
> +#include <linux/mm.h>
> +#include <linux/mman.h>
> +#include <linux/mmu_notifier.h>
> +#include <linux/types.h>
> +#include <linux/uaccess.h>
> +#include <linux/sched.h>
> +#include <linux/spinlock.h>
> +#include <linux/slab.h>
> +
> +#include <xen/xen.h>
> +#include <xen/grant_table.h>
> +#include <xen/gntdev.h>
> +#include <asm/xen/hypervisor.h>
> +#include <asm/xen/hypercall.h>
> +#include <asm/xen/page.h>
> +
> +MODULE_LICENSE("GPL");
> +MODULE_AUTHOR("Derek G. Murray <Derek.Murray@xxxxxxxxxxxx>, "
> + "Gerd Hoffmann <kraxel@xxxxxxxxxx>");
> +MODULE_DESCRIPTION("User-space granted page access driver");
> +
> +static int debug = 0;
> +module_param(debug, int, 0644);
You need to add:
MODULE_PARM_DESC
> +static int limit = 1024;
> +module_param(limit, int, 0644);
ditto
> +
> +struct gntdev_priv {
> + struct list_head maps;
> + uint32_t used;
> + uint32_t limit;
> + spinlock_t lock;
and some description about what the lock is protecting.
> + struct mm_struct *mm;
> + struct mmu_notifier mn;
> +};
> +
> +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;
> + struct ioctl_gntdev_grant_ref *grants;
> + struct gnttab_map_grant_ref *map_ops;
> + struct gnttab_unmap_grant_ref *unmap_ops;
> +};
> +
> +/* ------------------------------------------------------------------ */
> +
> +static void gntdev_print_maps(struct gntdev_priv *priv,
> + char *text, int text_index)
> +{
> + struct grant_map *map;
> +
> + printk("%s: maps list (priv %p, usage %d/%d)\n",
> + __FUNCTION__, priv, priv->used, priv->limit);
> + list_for_each_entry(map, &priv->maps, next)
> + printk(" index %2d, count %2d %s\n",
Use pr_debug.
> + map->index, map->count,
> + map->index == text_index && text ? text : "");
> +}
> +
> +static struct grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int
> count)
> +{
> + struct grant_map *add;
> +
> + add = kzalloc(sizeof(struct grant_map), GFP_KERNEL);
> + if (NULL == add)
> + return NULL;
> +
> + add->grants = kzalloc(sizeof(add->grants[0]) * count, GFP_KERNEL);
> + add->map_ops = kzalloc(sizeof(add->map_ops[0]) * count, GFP_KERNEL);
> + add->unmap_ops = kzalloc(sizeof(add->unmap_ops[0]) * count, GFP_KERNEL);
> + if (NULL == add->grants ||
> + NULL == add->map_ops ||
> + NULL == add->unmap_ops)
> + goto err;
> +
> + add->index = 0;
> + add->count = count;
> + add->priv = priv;
> +
> + if (add->count + priv->used > priv->limit)
> + goto err;
> +
> + return add;
> +
> +err:
> + kfree(add->grants);
> + kfree(add->map_ops);
> + kfree(add->unmap_ops);
> + kfree(add);
> + return NULL;
> +}
> +
> +static void gntdev_add_map(struct gntdev_priv *priv, struct grant_map *add)
> +{
> + struct grant_map *map;
> +
> + list_for_each_entry(map, &priv->maps, next) {
> + if (add->index + add->count < map->index) {
> + list_add_tail(&add->next, &map->next);
> + goto done;
> + }
> + add->index = map->index + map->count;
> + }
> + list_add_tail(&add->next, &priv->maps);
> +
> +done:
> + priv->used += add->count;
> + if (debug)
> + gntdev_print_maps(priv, "[new]", add->index);
> +}
> +
> +static struct grant_map *gntdev_find_map_index(struct gntdev_priv *priv, int
> index,
> + int count)
> +{
> + struct grant_map *map;
> +
> + list_for_each_entry(map, &priv->maps, next) {
> + if (map->index != index)
> + continue;
> + if (map->count != count)
> + continue;
> + return map;
> + }
> + return NULL;
> +}
> +
> +static struct grant_map *gntdev_find_map_vaddr(struct gntdev_priv *priv,
> + unsigned long vaddr)
> +{
> + 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)
> +{
> + if (!map)
> + return;
> + kfree(map->grants);
> + kfree(map->map_ops);
> + kfree(map->unmap_ops);
> + kfree(map);
> +}
> +
> +/* ------------------------------------------------------------------ */
> +
> +static int find_grant_ptes(pte_t *pte, pgtable_t token, unsigned long addr,
> void *data)
> +{
> + struct grant_map *map = data;
> + unsigned int pgnr = (addr - map->vma->vm_start) >> PAGE_SHIFT;
> + u64 pte_maddr;
> +
> + BUG_ON(pgnr >= map->count);
> + pte_maddr = (u64)pfn_to_mfn(page_to_pfn(token)) << PAGE_SHIFT;
> + pte_maddr += (unsigned long)pte & ~PAGE_MASK;
> + gnttab_set_map_op(&map->map_ops[pgnr], pte_maddr, map->flags,
> + map->grants[pgnr].ref,
> + map->grants[pgnr].domid);
> + gnttab_set_unmap_op(&map->unmap_ops[pgnr], pte_maddr, map->flags,
> + 0 /* handle */);
> + return 0;
> +}
> +
> +static int map_grant_pages(struct grant_map *map)
> +{
> + int i, err = 0;
> +
> + if (debug)
> + printk("%s: map %d+%d\n", __FUNCTION__, map->index, map->count);
pr_debug ought to do it.
> + err = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref,
> + map->map_ops, map->count);
> + if (WARN_ON(err))
> + return err;
> +
> + for (i = 0; i < map->count; i++) {
> + if (map->map_ops[i].status)
> + err = -EINVAL;
You WARN_ON earlier, but not here
> + map->unmap_ops[i].handle = map->map_ops[i].handle;
> + }
or here .. would it make sense to do it?
> + return err;
> +}
> +
> +static int unmap_grant_pages(struct grant_map *map, int offset, int pages)
> +{
> + int i, err = 0;
> +
> + if (debug)
> + printk("%s: map %d+%d [%d+%d]\n", __FUNCTION__,
> + map->index, map->count, offset, pages);
ditto.
> + err = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref,
> + map->unmap_ops + offset, pages);
> + if (WARN_ON(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;
> + }
> + return err;
> +}
> +
> +/* ------------------------------------------------------------------ */
> +
> +static void gntdev_vma_close(struct vm_area_struct *vma)
> +{
> + struct grant_map *map = vma->vm_private_data;
> +
> + if (debug)
> + printk("%s\n", __FUNCTION__);
> + 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)
> +{
> + if (debug)
> + printk("%s: vaddr %p, pgoff %ld (shouldn't happen)\n",
> + __FUNCTION__, vmf->virtual_address, vmf->pgoff);
> + vmf->flags = VM_FAULT_ERROR;
> + return 0;
> +}
> +
> +static struct vm_operations_struct gntdev_vmops = {
> + .close = gntdev_vma_close,
> + .fault = gntdev_vma_fault,
> +};
> +
> +/* ------------------------------------------------------------------ */
> +
> +static void mn_invl_range_start(struct mmu_notifier *mn,
> + struct mm_struct *mm,
> + unsigned long start, unsigned long end)
> +{
> + struct gntdev_priv *priv = container_of(mn, struct gntdev_priv, mn);
> + struct grant_map *map;
> + unsigned long mstart, mend;
> + int err;
> +
> + spin_lock(&priv->lock);
> + 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)
> + continue;
> + mstart = max(start, map->vma->vm_start);
> + mend = min(end, map->vma->vm_end);
> + if (debug)
> + printk("%s: map %d+%d (%lx %lx), range %lx %lx, mrange
> %lx %lx\n",
> + __FUNCTION__, map->index, map->count,
> + map->vma->vm_start, map->vma->vm_end,
> + start, end, mstart, mend);
> + err = unmap_grant_pages(map,
> + (mstart - map->vma->vm_start) >>
> PAGE_SHIFT,
> + (mend - mstart) >> PAGE_SHIFT);
> + WARN_ON(err);
Ah you WARN here.. so two WARN_ON in case the hypervisor call fails.
Maybe you just remove the WARN_ON in the unmap_grant_pages and let this
WARN_ON do the job?
> + }
> + spin_unlock(&priv->lock);
> +}
> +
> +static void mn_invl_page(struct mmu_notifier *mn,
> + struct mm_struct *mm,
> + unsigned long address)
> +{
> + mn_invl_range_start(mn, mm, address, address + PAGE_SIZE);
> +}
> +
> +static void mn_release(struct mmu_notifier *mn,
> + struct mm_struct *mm)
> +{
> + struct gntdev_priv *priv = container_of(mn, struct gntdev_priv, mn);
> + struct grant_map *map;
> + int err;
> +
> + spin_lock(&priv->lock);
> + list_for_each_entry(map, &priv->maps, next) {
> + if (!map->vma)
> + continue;
> + if (debug)
> + printk("%s: map %d+%d (%lx %lx)\n",
> + __FUNCTION__, map->index, map->count,
> + map->vma->vm_start, map->vma->vm_end);
> + err = unmap_grant_pages(map, 0, map->count);
Ok, so offset set to zero (might want a put /* offset */ comment in there.
> + WARN_ON(err);
> + }
> + spin_unlock(&priv->lock);
> +}
> +
> +struct mmu_notifier_ops gntdev_mmu_ops = {
> + .release = mn_release,
> + .invalidate_page = mn_invl_page,
> + .invalidate_range_start = mn_invl_range_start,
> +};
> +
> +/* ------------------------------------------------------------------ */
> +
> +static int gntdev_open(struct inode *inode, struct file *flip)
> +{
> + struct gntdev_priv *priv;
> +
> + priv = kzalloc(sizeof(*priv), GFP_KERNEL);
> + if (!priv)
> + return -ENOMEM;
> +
> + 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;
> + }
> + priv->mn.ops = &gntdev_mmu_ops;
> + mmu_notifier_register(&priv->mn, priv->mm);
You might want to check that this does not fail.
> + mmput(priv->mm);
> +
> + flip->private_data = priv;
> + if (debug)
> + printk("%s: priv %p\n", __FUNCTION__, priv);
> +
> + return 0;
> +}
> +
> +static int gntdev_release(struct inode *inode, struct file *flip)
> +{
> + struct gntdev_priv *priv = flip->private_data;
> + struct grant_map *map;
> + int err;
> +
> + if (debug)
> + printk("%s: priv %p\n", __FUNCTION__, 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))
Hmm, so if we fail (b/c we get -EBUSY) we free it? Would it be possible
to race with whoever is responsible for releasing this VMA (mn_release)
clearning this map while the holder of this map is trying to dereference
the map->unmap_ops ?
Oh wait, you and mn_release are both using a spinlock.. so, under what
conditions would this actually happend?
> + gntdev_free_map(map);
> +
> + }
> + spin_unlock(&priv->lock);
> +
> + mmu_notifier_unregister(&priv->mn, priv->mm);
> + kfree(priv);
> + return 0;
> +}
> +
> +static long gntdev_ioctl_map_grant_ref(struct gntdev_priv *priv,
The decleration is for 'long' but you return int. Looking at the
other ioctl (kvm ones) they all seem to return 'int' so this
decleration looks wrong.
> + struct ioctl_gntdev_map_grant_ref __user
> *u)
> +{
> + struct ioctl_gntdev_map_grant_ref op;
> + struct grant_map *map;
> + int err;
> +
> + if (copy_from_user(&op, u, sizeof(op)) != 0)
> + return -EFAULT;
> + if (debug)
> + printk("%s: priv %p, add %d\n", __FUNCTION__, 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 (copy_from_user(map->grants, &u->refs,
> + sizeof(map->grants[0]) * op.count) != 0) {
> + gntdev_free_map(map);
> + return err;
> + }
> +
> + spin_lock(&priv->lock);
> + gntdev_add_map(priv, map);
> + 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;
> + }
> + return 0;
> +}
> +
> +static long gntdev_ioctl_unmap_grant_ref(struct gntdev_priv *priv,
Same thing. Perhaps 'int' would be better suited.
> + struct ioctl_gntdev_unmap_grant_ref
> __user *u)
> +{
> + struct ioctl_gntdev_unmap_grant_ref op;
> + struct grant_map *map;
> + int err = -EINVAL;
Not -ENOENT? If you can't find the map .. well, the arguments are valid.
It is just that the map is not found. Or are the tools hard-coded to look
for -EINVAL?
> +
> + if (copy_from_user(&op, u, sizeof(op)) != 0)
> + return -EFAULT;
> + if (debug)
> + printk("%s: priv %p, del %d+%d\n", __FUNCTION__, priv,
> + (int)op.index, (int)op.count);
> +
> + spin_lock(&priv->lock);
> + map = gntdev_find_map_index(priv, op.index >> PAGE_SHIFT, op.count);
> + if (map)
> + err = gntdev_del_map(map);
> + spin_unlock(&priv->lock);
> + if (!err)
> + gntdev_free_map(map);
> + return err;
> +}
> +
> +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 grant_map *map;
> +
> + if (copy_from_user(&op, u, sizeof(op)) != 0)
> + return -EFAULT;
> + if (debug)
> + printk("%s: priv %p, offset for vaddr %lx\n", __FUNCTION__,
> 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);
> + 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)
> +{
> + struct ioctl_gntdev_set_max_grants op;
> +
> + if (copy_from_user(&op, u, sizeof(op)) != 0)
> + return -EFAULT;
> + if (debug)
> + printk("%s: priv %p, limit %d\n", __FUNCTION__, priv, op.count);
> + if (op.count > limit)
> + return -EINVAL;
Not -E2BIG?
> +
> + spin_lock(&priv->lock);
> + priv->limit = op.count;
> + spin_unlock(&priv->lock);
> + return 0;
> +}
> +
> +static long gntdev_ioctl(struct file *flip,
> + unsigned int cmd, unsigned long arg)
> +{
> + struct gntdev_priv *priv = flip->private_data;
> + void __user *ptr = (void __user *)arg;
> +
> + switch (cmd) {
> + case IOCTL_GNTDEV_MAP_GRANT_REF:
> + return gntdev_ioctl_map_grant_ref(priv, ptr);
> +
> + case IOCTL_GNTDEV_UNMAP_GRANT_REF:
> + return gntdev_ioctl_unmap_grant_ref(priv, ptr);
> +
> + 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);
> +
> + default:
> + if (debug)
> + printk("%s: priv %p, unknown cmd %x\n",
> + __FUNCTION__, priv, cmd);
> + return -ENOIOCTLCMD;
> + }
> +
> + return 0;
> +}
> +
> +static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma)
> +{
> + struct gntdev_priv *priv = flip->private_data;
> + int index = vma->vm_pgoff;
> + int count = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
> + struct grant_map *map;
> + int err = -EINVAL;
> +
> + if ((vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_SHARED))
> + return -EINVAL;
> +
> + if (debug)
> + printk("%s: map %d+%d at %lx (pgoff %lx)\n", __FUNCTION__,
> + index, count, vma->vm_start, vma->vm_pgoff);
> +
> + spin_lock(&priv->lock);
> + map = gntdev_find_map_index(priv, index, count);
> + if (!map)
> + goto unlock_out;
> + if (map->vma)
> + goto unlock_out;
> + if (priv->mm != vma->vm_mm) {
> + printk("%s: Huh? Other mm?\n", __FUNCTION__);
> + goto unlock_out;
> + }
> +
> + vma->vm_ops = &gntdev_vmops;
> +
> + vma->vm_flags |= VM_RESERVED;
> + vma->vm_flags |= VM_DONTCOPY;
> + vma->vm_flags |= VM_DONTEXPAND;
You can squish those.
> +
> + vma->vm_private_data = map;
> + map->vma = vma;
> +
> + map->flags = GNTMAP_host_map | GNTMAP_application_map |
> GNTMAP_contains_pte;
> + if (!(vma->vm_flags & VM_WRITE))
> + map->flags |= GNTMAP_readonly;
> +
> + err = apply_to_page_range(vma->vm_mm, vma->vm_start,
> + vma->vm_end - vma->vm_start,
> + find_grant_ptes, map);
> + if (err) {
> + goto unlock_out;
> + if (debug)
> + printk("%s: find_grant_ptes() failure.\n",
> __FUNCTION__);
Heh.. . You do a 'goto' and then 'if debug..' Swap them around.
> + }
> +
> + err = map_grant_pages(map);
> + if (err) {
> + goto unlock_out;
> + if (debug)
> + printk("%s: map_grant_pages() failure.\n",
> __FUNCTION__);
Ditto.
> + }
> + map->is_mapped = 1;
> +
> +unlock_out:
> + spin_unlock(&priv->lock);
> + return err;
> +}
> +
> +static const struct file_operations gntdev_fops = {
> + .owner = THIS_MODULE,
> + .open = gntdev_open,
> + .release = gntdev_release,
> + .mmap = gntdev_mmap,
> + .unlocked_ioctl = gntdev_ioctl
> +};
> +
> +static struct miscdevice gntdev_miscdev = {
> + .minor = MISC_DYNAMIC_MINOR,
> + .name = "xen/gntdev",
> + .fops = &gntdev_fops,
> +};
> +
> +/* ------------------------------------------------------------------ */
> +
> +static int __init gntdev_init(void)
> +{
> + int err;
> +
> + if (!xen_domain())
> + return -ENODEV;
> +
> + err = misc_register(&gntdev_miscdev);
> + if (err != 0) {
> + printk(KERN_ERR "Could not register gntdev device\n");
> + return err;
> + }
> + return 0;
> +}
> +
> +static void __exit gntdev_exit(void)
> +{
> + misc_deregister(&gntdev_miscdev);
> +}
> +
> +module_init(gntdev_init);
> +module_exit(gntdev_exit);
> +
> +/* ------------------------------------------------------------------ */
> diff --git a/include/xen/gntdev.h b/include/xen/gntdev.h
> new file mode 100644
> index 0000000..8bd1467
> --- /dev/null
> +++ b/include/xen/gntdev.h
> @@ -0,0 +1,119 @@
> +/******************************************************************************
> + * gntdev.h
> + *
> + * Interface to /dev/xen/gntdev.
> + *
> + * Copyright (c) 2007, D G Murray
> + *
> + * 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.
> + */
> +
> +#ifndef __LINUX_PUBLIC_GNTDEV_H__
> +#define __LINUX_PUBLIC_GNTDEV_H__
> +
> +struct ioctl_gntdev_grant_ref {
> + /* The domain ID of the grant to be mapped. */
> + uint32_t domid;
> + /* The grant reference of the grant to be mapped. */
> + uint32_t ref;
> +};
> +
> +/*
> + * Inserts the grant references into the mapping table of an instance
> + * of gntdev. N.B. This does not perform the mapping, which is deferred
> + * until mmap() is called with @index as the offset.
> + */
> +#define IOCTL_GNTDEV_MAP_GRANT_REF \
> +_IOC(_IOC_NONE, 'G', 0, sizeof(struct ioctl_gntdev_map_grant_ref))
> +struct ioctl_gntdev_map_grant_ref {
> + /* IN parameters */
> + /* The number of grants to be mapped. */
> + uint32_t count;
> + uint32_t pad;
> + /* OUT parameters */
> + /* The offset to be used on a subsequent call to mmap(). */
> + uint64_t index;
> + /* Variable IN parameter. */
> + /* Array of grant references, of size @count. */
> + struct ioctl_gntdev_grant_ref refs[1];
> +};
> +
> +/*
> + * Removes the grant references from the mapping table of an instance of
> + * of gntdev. N.B. munmap() must be called on the relevant virtual
> address(es)
> + * before this ioctl is called, or an error will result.
> + */
> +#define IOCTL_GNTDEV_UNMAP_GRANT_REF \
> +_IOC(_IOC_NONE, 'G', 1, sizeof(struct ioctl_gntdev_unmap_grant_ref))
> +struct ioctl_gntdev_unmap_grant_ref {
> + /* IN parameters */
> + /* The offset was returned by the corresponding map operation. */
> + uint64_t index;
> + /* The number of pages to be unmapped. */
> + uint32_t count;
> + uint32_t pad;
> +};
> +
> +/*
> + * Returns the offset in the driver's address space that corresponds
> + * to @vaddr. This can be used to perform a munmap(), followed by an
> + * UNMAP_GRANT_REF ioctl, where no state about the offset is retained by
> + * the caller. The number of pages that were allocated at the same time as
> + * @vaddr is returned in @count.
> + *
> + * N.B. Where more than one page has been mapped into a contiguous range, the
> + * supplied @vaddr must correspond to the start of the range; otherwise
> + * an error will result. It is only possible to munmap() the entire
> + * contiguously-allocated range at once, and not any subrange thereof.
> + */
> +#define IOCTL_GNTDEV_GET_OFFSET_FOR_VADDR \
> +_IOC(_IOC_NONE, 'G', 2, sizeof(struct ioctl_gntdev_get_offset_for_vaddr))
> +struct ioctl_gntdev_get_offset_for_vaddr {
> + /* IN parameters */
> + /* The virtual address of the first mapped page in a range. */
> + uint64_t vaddr;
> + /* OUT parameters */
> + /* The offset that was used in the initial mmap() operation. */
> + uint64_t offset;
> + /* The number of pages mapped in the VM area that begins at @vaddr. */
> + uint32_t count;
> + uint32_t pad;
> +};
> +
> +/*
> + * Sets the maximum number of grants that may mapped at once by this gntdev
> + * instance.
> + *
> + * N.B. This must be called before any other ioctl is performed on the
> device.
> + */
> +#define IOCTL_GNTDEV_SET_MAX_GRANTS \
> +_IOC(_IOC_NONE, 'G', 3, sizeof(struct ioctl_gntdev_set_max_grants))
> +struct ioctl_gntdev_set_max_grants {
> + /* IN parameter */
> + /* The maximum number of grants that may be mapped at once. */
> + uint32_t count;
> +};
> +
> +#endif /* __LINUX_PUBLIC_GNTDEV_H__ */
> --
> 1.5.6.5
>
>
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