HVM does not allow direct PTE modification, so guest pages must be
allocated and used for grant mappings. If Xen does not provide an
auto-translated physmap, the existing direct PTE modification is more
efficient.
Signed-off-by: Daniel De Graaf <dgdegra@xxxxxxxxxxxxx>
---
drivers/xen/Makefile | 2 +
drivers/xen/gntdev-hvm.c | 601 ++++++++++++++++++++++++++++++++++++++++++++++
drivers/xen/gntdev.c | 3 +
3 files changed, 606 insertions(+), 0 deletions(-)
create mode 100644 drivers/xen/gntdev-hvm.c
diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile
index 9814c1d..ab0e6eb 100644
--- a/drivers/xen/Makefile
+++ b/drivers/xen/Makefile
@@ -10,6 +10,7 @@ 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-$(CONFIG_XEN_GNTDEV) += xen-gntdev-hvm.o
obj-$(CONFIG_XEN_GRANT_DEV_ALLOC) += xen-gntalloc.o
obj-$(CONFIG_XEN_PCIDEV_BACKEND) += pciback/
obj-$(CONFIG_XEN_BLKDEV_BACKEND) += blkback/
@@ -26,4 +27,5 @@ obj-$(CONFIG_XEN_PLATFORM_PCI) += platform-pci.o
xen-evtchn-y := evtchn.o
xen-gntdev-y := gntdev.o
+xen-gntdev-hvm-y := gntdev-hvm.o
xen-gntalloc-y := gntalloc.o
diff --git a/drivers/xen/gntdev-hvm.c b/drivers/xen/gntdev-hvm.c
new file mode 100644
index 0000000..331d5af
--- /dev/null
+++ b/drivers/xen/gntdev-hvm.c
@@ -0,0 +1,601 @@
+/******************************************************************************
+ * 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/types.h>
+#include <linux/uaccess.h>
+#include <linux/sched.h>
+#include <linux/spinlock.h>
+#include <linux/vmalloc.h>
+
+#include <xen/xen.h>
+#include <xen/grant_table.h>
+#include <xen/gntdev.h>
+#include <xen/interface/memory.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);
+static int limit = 1024*1024;
+module_param(limit, int, 0644);
+static atomic_t pages_mapped = ATOMIC_INIT(0);
+
+struct gntdev_priv {
+ struct list_head maps;
+ spinlock_t lock;
+};
+
+struct granted_page {
+ struct page* page;
+ union {
+ struct ioctl_gntdev_grant_ref target;
+ grant_handle_t handle;
+ };
+};
+
+struct grant_map {
+ struct list_head next;
+ int index;
+ int count;
+ atomic_t users;
+ int is_mapped:1;
+ int is_ro:1;
+ struct granted_page pages[0];
+};
+
+static struct vm_operations_struct gntdev_vmops;
+
+/* ------------------------------------------------------------------ */
+
+static void gntdev_print_maps(struct gntdev_priv *priv,
+ char *text, int text_index)
+{
+ struct grant_map *map;
+
+ printk("%s: maps list (priv %p)\n", __FUNCTION__, priv);
+ list_for_each_entry(map, &priv->maps, next) {
+ printk(" %p: %2d+%2d, r%c, %s %d,%d %s\n", map,
+ map->index, map->count, map->is_ro ? 'o' : 'w',
+ map->is_mapped ? "use,hnd" : "dom,ref",
+ map->is_mapped ? atomic_read(&map->users)
+ : map->pages[0].target.domid,
+ map->is_mapped ? map->pages[0].handle
+ : map->pages[0].target.ref,
+ map->index == text_index && text ? text : "");
+ }
+}
+
+static struct grant_map *gntdev_alloc_map(int count,
+ struct ioctl_gntdev_grant_ref* grants)
+{
+ struct grant_map *add;
+ int i;
+
+ add = kzalloc(sizeof(*add) + sizeof(add->pages[0])*count, GFP_KERNEL);
+ if (!add)
+ return NULL;
+
+ atomic_set(&add->users, 1);
+ add->count = count;
+
+ for(i = 0; i < count; i++)
+ add->pages[i].target = grants[i];
+
+ return add;
+}
+
+static void gntdev_add_map(struct gntdev_priv *priv, struct grant_map *add)
+{
+ struct grant_map *map;
+
+ spin_lock(&priv->lock);
+
+ 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:
+ if (debug)
+ gntdev_print_maps(priv, "[new]", add->index);
+
+ spin_unlock(&priv->lock);
+}
+
+static void __gntdev_del_map(struct gntdev_priv *priv, struct grant_map *map)
+{
+ list_del(&map->next);
+}
+
+static void gntdev_del_map(struct gntdev_priv *priv, struct grant_map *map)
+{
+ spin_lock(&priv->lock);
+ __gntdev_del_map(priv, map);
+ spin_unlock(&priv->lock);
+}
+
+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 void gntdev_unmap_fast(struct grant_map *map,
+ struct gnttab_unmap_grant_ref *unmap_ops)
+{
+ int err, flags, i, unmap_size = 0;
+ unsigned long pfn;
+ phys_addr_t mfn;
+
+ flags = GNTMAP_host_map;
+ if (map->is_ro)
+ flags |= GNTMAP_readonly;
+
+ for (i=0; i < map->count; i++) {
+ if (!map->pages[i].page)
+ continue;
+ pfn = page_to_pfn(map->pages[i].page);
+ mfn = (phys_addr_t)pfn_to_kaddr(pfn);
+ gnttab_set_unmap_op(&unmap_ops[unmap_size], mfn, flags,
+ map->pages[i].handle);
+ unmap_size++;
+ }
+
+ err = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref,
+ unmap_ops, unmap_size);
+ WARN_ON(err);
+
+ for (i = 0; i < unmap_size; i++)
+ WARN_ON(unmap_ops[i].status);
+}
+
+// for the out-of-memory case
+static void gntdev_unmap_slow(struct grant_map *map)
+{
+ int err, flags, i;
+ unsigned long pfn;
+ phys_addr_t mfn;
+ struct gnttab_unmap_grant_ref unmap_op;
+
+ flags = GNTMAP_host_map;
+ if (map->is_ro)
+ flags |= GNTMAP_readonly;
+
+ for (i=0; i < map->count; i++) {
+ if (!map->pages[i].page)
+ continue;
+
+ pfn = page_to_pfn(map->pages[i].page);
+ mfn = (phys_addr_t)pfn_to_kaddr(pfn);
+ gnttab_set_unmap_op(&unmap_op, mfn, flags,
map->pages[i].handle);
+ err = HYPERVISOR_grant_table_op(
+ GNTTABOP_unmap_grant_ref, &unmap_op, 1);
+ WARN_ON(err);
+ WARN_ON(unmap_op.status);
+ }
+}
+
+static void gntdev_put_map(struct grant_map *map)
+{
+ struct gnttab_unmap_grant_ref *unmap_ops;
+ int i;
+ if (!map)
+ return;
+ if (!atomic_dec_and_test(&map->users))
+ return;
+ if (debug)
+ printk("%s: unmap %p (%d pages)\n", __FUNCTION__, map,
map->count);
+ if (map->is_mapped) {
+ unmap_ops = kzalloc(sizeof(unmap_ops[0]) * map->count,
+ GFP_TEMPORARY);
+ if (likely(unmap_ops)) {
+ gntdev_unmap_fast(map, unmap_ops);
+ kfree(unmap_ops);
+ } else {
+ gntdev_unmap_slow(map);
+ }
+
+ atomic_sub(map->count, &pages_mapped);
+ }
+ for (i=0; i < map->count; i++)
+ if (map->pages[i].page)
+ __free_page(map->pages[i].page);
+ kfree(map);
+}
+
+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);
+
+ 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;
+
+ if (debug) {
+ printk("%s: priv %p\n", __FUNCTION__, priv);
+ gntdev_print_maps(priv, NULL, 0);
+ }
+
+ spin_lock(&priv->lock);
+ while (!list_empty(&priv->maps)) {
+ map = list_entry(priv->maps.next, struct grant_map, next);
+ list_del(&map->next);
+ gntdev_put_map(map);
+ }
+ spin_unlock(&priv->lock);
+
+ kfree(priv);
+ return 0;
+}
+
+static int gntdev_do_map(struct grant_map *map)
+{
+ int err, flags, i;
+ struct page* page;
+ phys_addr_t mfn;
+ struct gnttab_map_grant_ref* map_ops;
+
+ flags = GNTMAP_host_map;
+ if (map->is_ro)
+ flags |= GNTMAP_readonly;
+
+ err = -ENOMEM;
+
+ if (unlikely(atomic_add_return(map->count, &pages_mapped) > limit)) {
+ if (debug)
+ printk("%s: maps full\n", __FUNCTION__);
+ goto out;
+ }
+
+ map_ops = kzalloc(sizeof(map_ops[0]) * map->count, GFP_TEMPORARY);
+ if (!map_ops)
+ goto out;
+
+ for (i = 0; i < map->count; i++) {
+ page = alloc_page(GFP_KERNEL|__GFP_HIGHMEM|__GFP_ZERO);
+ if (unlikely(!page))
+ goto out_free;
+ map->pages[i].page = page;
+ mfn = (phys_addr_t)pfn_to_kaddr(page_to_pfn(page));
+ gnttab_set_map_op(&map_ops[i], mfn, flags,
+ map->pages[i].target.ref,
+ map->pages[i].target.domid);
+ }
+ err = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref,
+ map_ops, map->count);
+ if (WARN_ON(err))
+ goto out_free;
+
+ if (debug && map->count)
+ printk("%s: mapped first at gfn=%lx mfn=%lx\n", __func__,
+ page_to_pfn(map->pages[0].page),
pfn_to_mfn(page_to_pfn(map->pages[0].page)));
+
+ map->is_mapped = 1;
+
+ for (i = 0; i < map->count; i++) {
+ if (map_ops[i].status) {
+ if (debug)
+ printk("%s: failed map at page %d: stat=%d\n",
+ __FUNCTION__, i, map_ops[i].status);
+ __free_page(map->pages[i].page);
+ map->pages[i].page = NULL;
+ err = -EINVAL;
+ } else {
+ map->pages[i].handle = map_ops[i].handle;
+ }
+ }
+
+out_free:
+ kfree(map_ops);
+out:
+ if (!map->is_mapped)
+ atomic_sub(map->count, &pages_mapped);
+ return err;
+}
+
+static long gntdev_ioctl_map_grant_ref(struct gntdev_priv *priv,
+ struct ioctl_gntdev_map_grant_ref __user
*u)
+{
+ struct ioctl_gntdev_map_grant_ref op;
+ struct grant_map *map;
+ struct ioctl_gntdev_grant_ref* grants;
+ 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;
+
+ err = -ENOMEM;
+ grants = kmalloc(sizeof(grants[0]) * op.count, GFP_TEMPORARY);
+ if (!grants)
+ goto out_fail;
+
+ err = -EFAULT;
+ if (copy_from_user(grants, u->refs, sizeof(grants[0]) * op.count))
+ goto out_free;
+
+ map = gntdev_alloc_map(op.count, grants);
+ if (!map)
+ goto out_free;
+
+ gntdev_add_map(priv, map);
+
+ op.index = map->index << PAGE_SHIFT;
+
+ err = -EFAULT;
+ if (copy_to_user(u, &op, sizeof(op)) != 0)
+ goto out_remove;
+
+ err = 0;
+
+out_free:
+ kfree(grants);
+out_fail:
+ return err;
+
+out_remove:
+ gntdev_del_map(priv, map);
+ gntdev_put_map(map);
+ goto out_free;
+}
+
+static long gntdev_ioctl_unmap_grant_ref(struct gntdev_priv *priv,
+ struct ioctl_gntdev_unmap_grant_ref
__user *u)
+{
+ struct ioctl_gntdev_unmap_grant_ref op;
+ struct grant_map *map;
+ int err = 0;
+
+ if (copy_from_user(&op, u, sizeof(op)) != 0)
+ return -EFAULT;
+
+ spin_lock(&priv->lock);
+ map = gntdev_find_map_index(priv, op.index >> PAGE_SHIFT, op.count);
+ if (map) {
+ __gntdev_del_map(priv, map);
+ } else
+ err = -EINVAL;
+ spin_unlock(&priv->lock);
+
+ if (debug)
+ printk("%s: priv %p, del %d+%d = %p\n", __FUNCTION__, priv,
+ (int)op.index, (int)op.count, map);
+
+ gntdev_put_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 vm_area_struct *vma;
+ 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);
+
+ vma = find_vma(current->mm, op.vaddr);
+ if (!vma)
+ return -EINVAL;
+
+ map = vma->vm_private_data;
+ if (vma->vm_ops != &gntdev_vmops || !map)
+ return -EINVAL;
+
+ op.offset = map->index << PAGE_SHIFT;
+ op.count = map->count;
+
+ if (copy_to_user(u, &op, sizeof(op)) != 0)
+ return -EFAULT;
+ 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);
+
+ default:
+ if (debug)
+ printk("%s: priv %p, unknown cmd %x\n",
+ __FUNCTION__, priv, cmd);
+ return -ENOIOCTLCMD;
+ }
+
+ return 0;
+}
+
+static int gntdev_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+ struct grant_map *map = vma->vm_private_data;
+ pgoff_t pgoff = vmf->pgoff - vma->vm_pgoff;
+
+ if (!map || !map->is_mapped || pgoff < 0 || pgoff > map->count) {
+ if (debug)
+ printk("%s: vaddr %p, pgoff %ld (shouldn't happen)\n",
+ __FUNCTION__, vmf->virtual_address, pgoff);
+ return VM_FAULT_SIGBUS;
+ }
+
+ vmf->page = map->pages[pgoff].page;
+ get_page(vmf->page);
+ return 0;
+}
+
+static void gntdev_vma_close(struct vm_area_struct *vma)
+{
+ struct grant_map *map = vma->vm_private_data;
+ gntdev_put_map(map);
+}
+
+static struct vm_operations_struct gntdev_vmops = {
+ .fault = gntdev_vma_fault,
+ .close = gntdev_vma_close,
+};
+
+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_SHARED))
+ return -EINVAL;
+
+ spin_lock(&priv->lock);
+ map = gntdev_find_map_index(priv, index, count);
+
+ if (debug)
+ printk("%s: map %d+%d at %lx (priv %p, map %p)\n", __func__,
+ index, count, vma->vm_start, priv, map);
+
+ if (!map)
+ goto unlock_out;
+
+ if (!map->is_mapped) {
+ map->is_ro = !(vma->vm_flags & VM_WRITE);
+ err = gntdev_do_map(map);
+ if (err)
+ goto unlock_out;
+ }
+
+ if ((vma->vm_flags & VM_WRITE) && map->is_ro)
+ goto unlock_out;
+
+ err = 0;
+ vma->vm_ops = &gntdev_vmops;
+
+ vma->vm_flags |= VM_RESERVED;
+ vma->vm_flags |= VM_DONTEXPAND;
+ vma->vm_flags |= VM_IO;
+
+ vma->vm_private_data = map;
+
+ atomic_inc(&map->users);
+
+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;
+
+ if (!xen_feature(XENFEAT_auto_translated_physmap))
+ 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/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index a73f07c..f6b98c0 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -626,6 +626,9 @@ static int __init gntdev_init(void)
if (!xen_domain())
return -ENODEV;
+ if (xen_feature(XENFEAT_auto_translated_physmap))
+ return -ENODEV;
+
err = misc_register(&gntdev_miscdev);
if (err != 0) {
printk(KERN_ERR "Could not register gntdev device\n");
--
1.7.2.3
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