![Michel Lespinasse](/assets/img/avatar_default.png)
Convert comments that reference mmap_sem to reference mmap_lock instead. [akpm@linux-foundation.org: fix up linux-next leftovers] [akpm@linux-foundation.org: s/lockaphore/lock/, per Vlastimil] [akpm@linux-foundation.org: more linux-next fixups, per Michel] Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-13-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1121 lines
27 KiB
C
1121 lines
27 KiB
C
/******************************************************************************
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* gntdev.c
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*
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* Device for accessing (in user-space) pages that have been granted by other
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* domains.
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*
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* Copyright (c) 2006-2007, D G Murray.
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* (c) 2009 Gerd Hoffmann <kraxel@redhat.com>
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* (c) 2018 Oleksandr Andrushchenko, EPAM Systems Inc.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#undef DEBUG
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#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
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#include <linux/dma-mapping.h>
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/miscdevice.h>
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#include <linux/fs.h>
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#include <linux/uaccess.h>
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#include <linux/sched.h>
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#include <linux/sched/mm.h>
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#include <linux/spinlock.h>
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#include <linux/slab.h>
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#include <linux/highmem.h>
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#include <linux/refcount.h>
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#include <xen/xen.h>
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#include <xen/grant_table.h>
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#include <xen/balloon.h>
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#include <xen/gntdev.h>
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#include <xen/events.h>
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#include <xen/page.h>
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#include <asm/xen/hypervisor.h>
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#include <asm/xen/hypercall.h>
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#include "gntdev-common.h"
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#ifdef CONFIG_XEN_GNTDEV_DMABUF
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#include "gntdev-dmabuf.h"
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#endif
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Derek G. Murray <Derek.Murray@cl.cam.ac.uk>, "
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"Gerd Hoffmann <kraxel@redhat.com>");
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MODULE_DESCRIPTION("User-space granted page access driver");
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static unsigned int limit = 64*1024;
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module_param(limit, uint, 0644);
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MODULE_PARM_DESC(limit,
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"Maximum number of grants that may be mapped by one mapping request");
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static int use_ptemod;
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static int unmap_grant_pages(struct gntdev_grant_map *map,
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int offset, int pages);
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static struct miscdevice gntdev_miscdev;
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/* ------------------------------------------------------------------ */
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bool gntdev_test_page_count(unsigned int count)
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{
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return !count || count > limit;
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}
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static void gntdev_print_maps(struct gntdev_priv *priv,
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char *text, int text_index)
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{
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#ifdef DEBUG
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struct gntdev_grant_map *map;
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pr_debug("%s: maps list (priv %p)\n", __func__, priv);
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list_for_each_entry(map, &priv->maps, next)
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pr_debug(" index %2d, count %2d %s\n",
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map->index, map->count,
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map->index == text_index && text ? text : "");
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#endif
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}
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static void gntdev_free_map(struct gntdev_grant_map *map)
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{
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if (map == NULL)
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return;
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#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
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if (map->dma_vaddr) {
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struct gnttab_dma_alloc_args args;
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args.dev = map->dma_dev;
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args.coherent = !!(map->dma_flags & GNTDEV_DMA_FLAG_COHERENT);
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args.nr_pages = map->count;
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args.pages = map->pages;
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args.frames = map->frames;
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args.vaddr = map->dma_vaddr;
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args.dev_bus_addr = map->dma_bus_addr;
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gnttab_dma_free_pages(&args);
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} else
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#endif
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if (map->pages)
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gnttab_free_pages(map->count, map->pages);
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#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
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kvfree(map->frames);
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#endif
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kvfree(map->pages);
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kvfree(map->grants);
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kvfree(map->map_ops);
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kvfree(map->unmap_ops);
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kvfree(map->kmap_ops);
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kvfree(map->kunmap_ops);
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kfree(map);
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}
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struct gntdev_grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int count,
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int dma_flags)
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{
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struct gntdev_grant_map *add;
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int i;
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add = kzalloc(sizeof(*add), GFP_KERNEL);
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if (NULL == add)
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return NULL;
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add->grants = kvcalloc(count, sizeof(add->grants[0]), GFP_KERNEL);
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add->map_ops = kvcalloc(count, sizeof(add->map_ops[0]), GFP_KERNEL);
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add->unmap_ops = kvcalloc(count, sizeof(add->unmap_ops[0]), GFP_KERNEL);
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add->kmap_ops = kvcalloc(count, sizeof(add->kmap_ops[0]), GFP_KERNEL);
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add->kunmap_ops = kvcalloc(count,
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sizeof(add->kunmap_ops[0]), GFP_KERNEL);
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add->pages = kvcalloc(count, sizeof(add->pages[0]), GFP_KERNEL);
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if (NULL == add->grants ||
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NULL == add->map_ops ||
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NULL == add->unmap_ops ||
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NULL == add->kmap_ops ||
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NULL == add->kunmap_ops ||
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NULL == add->pages)
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goto err;
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#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
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add->dma_flags = dma_flags;
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/*
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* Check if this mapping is requested to be backed
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* by a DMA buffer.
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*/
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if (dma_flags & (GNTDEV_DMA_FLAG_WC | GNTDEV_DMA_FLAG_COHERENT)) {
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struct gnttab_dma_alloc_args args;
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add->frames = kvcalloc(count, sizeof(add->frames[0]),
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GFP_KERNEL);
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if (!add->frames)
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goto err;
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/* Remember the device, so we can free DMA memory. */
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add->dma_dev = priv->dma_dev;
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args.dev = priv->dma_dev;
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args.coherent = !!(dma_flags & GNTDEV_DMA_FLAG_COHERENT);
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args.nr_pages = count;
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args.pages = add->pages;
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args.frames = add->frames;
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if (gnttab_dma_alloc_pages(&args))
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goto err;
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add->dma_vaddr = args.vaddr;
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add->dma_bus_addr = args.dev_bus_addr;
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} else
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#endif
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if (gnttab_alloc_pages(count, add->pages))
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goto err;
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for (i = 0; i < count; i++) {
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add->map_ops[i].handle = -1;
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add->unmap_ops[i].handle = -1;
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add->kmap_ops[i].handle = -1;
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add->kunmap_ops[i].handle = -1;
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}
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add->index = 0;
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add->count = count;
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refcount_set(&add->users, 1);
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return add;
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err:
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gntdev_free_map(add);
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return NULL;
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}
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void gntdev_add_map(struct gntdev_priv *priv, struct gntdev_grant_map *add)
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{
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struct gntdev_grant_map *map;
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list_for_each_entry(map, &priv->maps, next) {
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if (add->index + add->count < map->index) {
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list_add_tail(&add->next, &map->next);
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goto done;
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}
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add->index = map->index + map->count;
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}
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list_add_tail(&add->next, &priv->maps);
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done:
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gntdev_print_maps(priv, "[new]", add->index);
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}
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static struct gntdev_grant_map *gntdev_find_map_index(struct gntdev_priv *priv,
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int index, int count)
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{
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struct gntdev_grant_map *map;
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list_for_each_entry(map, &priv->maps, next) {
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if (map->index != index)
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continue;
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if (count && map->count != count)
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continue;
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return map;
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}
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return NULL;
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}
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void gntdev_put_map(struct gntdev_priv *priv, struct gntdev_grant_map *map)
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{
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if (!map)
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return;
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if (!refcount_dec_and_test(&map->users))
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return;
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if (map->notify.flags & UNMAP_NOTIFY_SEND_EVENT) {
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notify_remote_via_evtchn(map->notify.event);
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evtchn_put(map->notify.event);
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}
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if (map->pages && !use_ptemod)
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unmap_grant_pages(map, 0, map->count);
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gntdev_free_map(map);
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}
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/* ------------------------------------------------------------------ */
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static int find_grant_ptes(pte_t *pte, unsigned long addr, void *data)
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{
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struct gntdev_grant_map *map = data;
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unsigned int pgnr = (addr - map->vma->vm_start) >> PAGE_SHIFT;
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int flags = map->flags | GNTMAP_application_map | GNTMAP_contains_pte;
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u64 pte_maddr;
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BUG_ON(pgnr >= map->count);
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pte_maddr = arbitrary_virt_to_machine(pte).maddr;
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/*
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* Set the PTE as special to force get_user_pages_fast() fall
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* back to the slow path. If this is not supported as part of
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* the grant map, it will be done afterwards.
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*/
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if (xen_feature(XENFEAT_gnttab_map_avail_bits))
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flags |= (1 << _GNTMAP_guest_avail0);
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gnttab_set_map_op(&map->map_ops[pgnr], pte_maddr, flags,
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map->grants[pgnr].ref,
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map->grants[pgnr].domid);
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gnttab_set_unmap_op(&map->unmap_ops[pgnr], pte_maddr, flags,
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-1 /* handle */);
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return 0;
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}
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#ifdef CONFIG_X86
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static int set_grant_ptes_as_special(pte_t *pte, unsigned long addr, void *data)
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{
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set_pte_at(current->mm, addr, pte, pte_mkspecial(*pte));
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return 0;
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}
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#endif
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int gntdev_map_grant_pages(struct gntdev_grant_map *map)
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{
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int i, err = 0;
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if (!use_ptemod) {
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/* Note: it could already be mapped */
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if (map->map_ops[0].handle != -1)
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return 0;
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for (i = 0; i < map->count; i++) {
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unsigned long addr = (unsigned long)
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pfn_to_kaddr(page_to_pfn(map->pages[i]));
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gnttab_set_map_op(&map->map_ops[i], addr, map->flags,
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map->grants[i].ref,
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map->grants[i].domid);
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gnttab_set_unmap_op(&map->unmap_ops[i], addr,
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map->flags, -1 /* handle */);
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}
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} else {
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/*
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* Setup the map_ops corresponding to the pte entries pointing
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* to the kernel linear addresses of the struct pages.
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* These ptes are completely different from the user ptes dealt
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* with find_grant_ptes.
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*/
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for (i = 0; i < map->count; i++) {
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unsigned long address = (unsigned long)
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pfn_to_kaddr(page_to_pfn(map->pages[i]));
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BUG_ON(PageHighMem(map->pages[i]));
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gnttab_set_map_op(&map->kmap_ops[i], address,
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map->flags | GNTMAP_host_map,
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map->grants[i].ref,
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map->grants[i].domid);
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gnttab_set_unmap_op(&map->kunmap_ops[i], address,
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map->flags | GNTMAP_host_map, -1);
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}
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}
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pr_debug("map %d+%d\n", map->index, map->count);
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err = gnttab_map_refs(map->map_ops, use_ptemod ? map->kmap_ops : NULL,
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map->pages, map->count);
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if (err)
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return err;
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for (i = 0; i < map->count; i++) {
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if (map->map_ops[i].status) {
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err = -EINVAL;
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continue;
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}
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map->unmap_ops[i].handle = map->map_ops[i].handle;
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if (use_ptemod)
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map->kunmap_ops[i].handle = map->kmap_ops[i].handle;
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#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
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else if (map->dma_vaddr) {
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unsigned long bfn;
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bfn = pfn_to_bfn(page_to_pfn(map->pages[i]));
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map->unmap_ops[i].dev_bus_addr = __pfn_to_phys(bfn);
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}
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#endif
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}
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return err;
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}
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static int __unmap_grant_pages(struct gntdev_grant_map *map, int offset,
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int pages)
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{
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int i, err = 0;
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struct gntab_unmap_queue_data unmap_data;
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if (map->notify.flags & UNMAP_NOTIFY_CLEAR_BYTE) {
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int pgno = (map->notify.addr >> PAGE_SHIFT);
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if (pgno >= offset && pgno < offset + pages) {
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/* No need for kmap, pages are in lowmem */
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uint8_t *tmp = pfn_to_kaddr(page_to_pfn(map->pages[pgno]));
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tmp[map->notify.addr & (PAGE_SIZE-1)] = 0;
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map->notify.flags &= ~UNMAP_NOTIFY_CLEAR_BYTE;
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}
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}
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unmap_data.unmap_ops = map->unmap_ops + offset;
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unmap_data.kunmap_ops = use_ptemod ? map->kunmap_ops + offset : NULL;
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unmap_data.pages = map->pages + offset;
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unmap_data.count = pages;
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err = gnttab_unmap_refs_sync(&unmap_data);
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if (err)
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return err;
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for (i = 0; i < pages; i++) {
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if (map->unmap_ops[offset+i].status)
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err = -EINVAL;
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pr_debug("unmap handle=%d st=%d\n",
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map->unmap_ops[offset+i].handle,
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map->unmap_ops[offset+i].status);
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map->unmap_ops[offset+i].handle = -1;
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}
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return err;
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}
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static int unmap_grant_pages(struct gntdev_grant_map *map, int offset,
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int pages)
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{
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int range, err = 0;
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pr_debug("unmap %d+%d [%d+%d]\n", map->index, map->count, offset, pages);
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/* It is possible the requested range will have a "hole" where we
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* already unmapped some of the grants. Only unmap valid ranges.
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*/
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while (pages && !err) {
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while (pages && map->unmap_ops[offset].handle == -1) {
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offset++;
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pages--;
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}
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range = 0;
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while (range < pages) {
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if (map->unmap_ops[offset+range].handle == -1)
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break;
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range++;
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}
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err = __unmap_grant_pages(map, offset, range);
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offset += range;
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pages -= range;
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}
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return err;
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}
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/* ------------------------------------------------------------------ */
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static void gntdev_vma_open(struct vm_area_struct *vma)
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{
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struct gntdev_grant_map *map = vma->vm_private_data;
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pr_debug("gntdev_vma_open %p\n", vma);
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refcount_inc(&map->users);
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}
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static void gntdev_vma_close(struct vm_area_struct *vma)
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{
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struct gntdev_grant_map *map = vma->vm_private_data;
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struct file *file = vma->vm_file;
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struct gntdev_priv *priv = file->private_data;
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pr_debug("gntdev_vma_close %p\n", vma);
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if (use_ptemod) {
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WARN_ON(map->vma != vma);
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mmu_interval_notifier_remove(&map->notifier);
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map->vma = NULL;
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}
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vma->vm_private_data = NULL;
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gntdev_put_map(priv, map);
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}
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|
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static struct page *gntdev_vma_find_special_page(struct vm_area_struct *vma,
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unsigned long addr)
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{
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struct gntdev_grant_map *map = vma->vm_private_data;
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return map->pages[(addr - map->pages_vm_start) >> PAGE_SHIFT];
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}
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|
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static const struct vm_operations_struct gntdev_vmops = {
|
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.open = gntdev_vma_open,
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.close = gntdev_vma_close,
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.find_special_page = gntdev_vma_find_special_page,
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};
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|
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/* ------------------------------------------------------------------ */
|
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|
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static bool gntdev_invalidate(struct mmu_interval_notifier *mn,
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const struct mmu_notifier_range *range,
|
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unsigned long cur_seq)
|
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{
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struct gntdev_grant_map *map =
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container_of(mn, struct gntdev_grant_map, notifier);
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unsigned long mstart, mend;
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int err;
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|
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if (!mmu_notifier_range_blockable(range))
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return false;
|
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|
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/*
|
|
* If the VMA is split or otherwise changed the notifier is not
|
|
* updated, but we don't want to process VA's outside the modified
|
|
* VMA. FIXME: It would be much more understandable to just prevent
|
|
* modifying the VMA in the first place.
|
|
*/
|
|
if (map->vma->vm_start >= range->end ||
|
|
map->vma->vm_end <= range->start)
|
|
return true;
|
|
|
|
mstart = max(range->start, map->vma->vm_start);
|
|
mend = min(range->end, map->vma->vm_end);
|
|
pr_debug("map %d+%d (%lx %lx), range %lx %lx, mrange %lx %lx\n",
|
|
map->index, map->count,
|
|
map->vma->vm_start, map->vma->vm_end,
|
|
range->start, range->end, mstart, mend);
|
|
err = unmap_grant_pages(map,
|
|
(mstart - map->vma->vm_start) >> PAGE_SHIFT,
|
|
(mend - mstart) >> PAGE_SHIFT);
|
|
WARN_ON(err);
|
|
|
|
return true;
|
|
}
|
|
|
|
static const struct mmu_interval_notifier_ops gntdev_mmu_ops = {
|
|
.invalidate = gntdev_invalidate,
|
|
};
|
|
|
|
/* ------------------------------------------------------------------ */
|
|
|
|
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);
|
|
mutex_init(&priv->lock);
|
|
|
|
#ifdef CONFIG_XEN_GNTDEV_DMABUF
|
|
priv->dmabuf_priv = gntdev_dmabuf_init(flip);
|
|
if (IS_ERR(priv->dmabuf_priv)) {
|
|
int ret = PTR_ERR(priv->dmabuf_priv);
|
|
|
|
kfree(priv);
|
|
return ret;
|
|
}
|
|
#endif
|
|
|
|
flip->private_data = priv;
|
|
#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
|
|
priv->dma_dev = gntdev_miscdev.this_device;
|
|
dma_coerce_mask_and_coherent(priv->dma_dev, DMA_BIT_MASK(64));
|
|
#endif
|
|
pr_debug("priv %p\n", priv);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int gntdev_release(struct inode *inode, struct file *flip)
|
|
{
|
|
struct gntdev_priv *priv = flip->private_data;
|
|
struct gntdev_grant_map *map;
|
|
|
|
pr_debug("priv %p\n", priv);
|
|
|
|
mutex_lock(&priv->lock);
|
|
while (!list_empty(&priv->maps)) {
|
|
map = list_entry(priv->maps.next,
|
|
struct gntdev_grant_map, next);
|
|
list_del(&map->next);
|
|
gntdev_put_map(NULL /* already removed */, map);
|
|
}
|
|
mutex_unlock(&priv->lock);
|
|
|
|
#ifdef CONFIG_XEN_GNTDEV_DMABUF
|
|
gntdev_dmabuf_fini(priv->dmabuf_priv);
|
|
#endif
|
|
|
|
kfree(priv);
|
|
return 0;
|
|
}
|
|
|
|
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 gntdev_grant_map *map;
|
|
int err;
|
|
|
|
if (copy_from_user(&op, u, sizeof(op)) != 0)
|
|
return -EFAULT;
|
|
pr_debug("priv %p, add %d\n", priv, op.count);
|
|
if (unlikely(gntdev_test_page_count(op.count)))
|
|
return -EINVAL;
|
|
|
|
err = -ENOMEM;
|
|
map = gntdev_alloc_map(priv, op.count, 0 /* This is not a dma-buf. */);
|
|
if (!map)
|
|
return err;
|
|
|
|
if (copy_from_user(map->grants, &u->refs,
|
|
sizeof(map->grants[0]) * op.count) != 0) {
|
|
gntdev_put_map(NULL, map);
|
|
return -EFAULT;
|
|
}
|
|
|
|
mutex_lock(&priv->lock);
|
|
gntdev_add_map(priv, map);
|
|
op.index = map->index << PAGE_SHIFT;
|
|
mutex_unlock(&priv->lock);
|
|
|
|
if (copy_to_user(u, &op, sizeof(op)) != 0)
|
|
return -EFAULT;
|
|
|
|
return 0;
|
|
}
|
|
|
|
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 gntdev_grant_map *map;
|
|
int err = -ENOENT;
|
|
|
|
if (copy_from_user(&op, u, sizeof(op)) != 0)
|
|
return -EFAULT;
|
|
pr_debug("priv %p, del %d+%d\n", priv, (int)op.index, (int)op.count);
|
|
|
|
mutex_lock(&priv->lock);
|
|
map = gntdev_find_map_index(priv, op.index >> PAGE_SHIFT, op.count);
|
|
if (map) {
|
|
list_del(&map->next);
|
|
err = 0;
|
|
}
|
|
mutex_unlock(&priv->lock);
|
|
if (map)
|
|
gntdev_put_map(priv, 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 gntdev_grant_map *map;
|
|
int rv = -EINVAL;
|
|
|
|
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);
|
|
|
|
mmap_read_lock(current->mm);
|
|
vma = find_vma(current->mm, op.vaddr);
|
|
if (!vma || vma->vm_ops != &gntdev_vmops)
|
|
goto out_unlock;
|
|
|
|
map = vma->vm_private_data;
|
|
if (!map)
|
|
goto out_unlock;
|
|
|
|
op.offset = map->index << PAGE_SHIFT;
|
|
op.count = map->count;
|
|
rv = 0;
|
|
|
|
out_unlock:
|
|
mmap_read_unlock(current->mm);
|
|
|
|
if (rv == 0 && copy_to_user(u, &op, sizeof(op)) != 0)
|
|
return -EFAULT;
|
|
return rv;
|
|
}
|
|
|
|
static long gntdev_ioctl_notify(struct gntdev_priv *priv, void __user *u)
|
|
{
|
|
struct ioctl_gntdev_unmap_notify op;
|
|
struct gntdev_grant_map *map;
|
|
int rc;
|
|
int out_flags;
|
|
evtchn_port_t out_event;
|
|
|
|
if (copy_from_user(&op, u, sizeof(op)))
|
|
return -EFAULT;
|
|
|
|
if (op.action & ~(UNMAP_NOTIFY_CLEAR_BYTE|UNMAP_NOTIFY_SEND_EVENT))
|
|
return -EINVAL;
|
|
|
|
/* We need to grab a reference to the event channel we are going to use
|
|
* to send the notify before releasing the reference we may already have
|
|
* (if someone has called this ioctl twice). This is required so that
|
|
* it is possible to change the clear_byte part of the notification
|
|
* without disturbing the event channel part, which may now be the last
|
|
* reference to that event channel.
|
|
*/
|
|
if (op.action & UNMAP_NOTIFY_SEND_EVENT) {
|
|
if (evtchn_get(op.event_channel_port))
|
|
return -EINVAL;
|
|
}
|
|
|
|
out_flags = op.action;
|
|
out_event = op.event_channel_port;
|
|
|
|
mutex_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:
|
|
if ((op.action & UNMAP_NOTIFY_CLEAR_BYTE) &&
|
|
(map->flags & GNTMAP_readonly)) {
|
|
rc = -EINVAL;
|
|
goto unlock_out;
|
|
}
|
|
|
|
out_flags = map->notify.flags;
|
|
out_event = map->notify.event;
|
|
|
|
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:
|
|
mutex_unlock(&priv->lock);
|
|
|
|
/* Drop the reference to the event channel we did not save in the map */
|
|
if (out_flags & UNMAP_NOTIFY_SEND_EVENT)
|
|
evtchn_put(out_event);
|
|
|
|
return rc;
|
|
}
|
|
|
|
#define GNTDEV_COPY_BATCH 16
|
|
|
|
struct gntdev_copy_batch {
|
|
struct gnttab_copy ops[GNTDEV_COPY_BATCH];
|
|
struct page *pages[GNTDEV_COPY_BATCH];
|
|
s16 __user *status[GNTDEV_COPY_BATCH];
|
|
unsigned int nr_ops;
|
|
unsigned int nr_pages;
|
|
};
|
|
|
|
static int gntdev_get_page(struct gntdev_copy_batch *batch, void __user *virt,
|
|
bool writeable, unsigned long *gfn)
|
|
{
|
|
unsigned long addr = (unsigned long)virt;
|
|
struct page *page;
|
|
unsigned long xen_pfn;
|
|
int ret;
|
|
|
|
ret = get_user_pages_fast(addr, 1, writeable ? FOLL_WRITE : 0, &page);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
batch->pages[batch->nr_pages++] = page;
|
|
|
|
xen_pfn = page_to_xen_pfn(page) + XEN_PFN_DOWN(addr & ~PAGE_MASK);
|
|
*gfn = pfn_to_gfn(xen_pfn);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void gntdev_put_pages(struct gntdev_copy_batch *batch)
|
|
{
|
|
unsigned int i;
|
|
|
|
for (i = 0; i < batch->nr_pages; i++)
|
|
put_page(batch->pages[i]);
|
|
batch->nr_pages = 0;
|
|
}
|
|
|
|
static int gntdev_copy(struct gntdev_copy_batch *batch)
|
|
{
|
|
unsigned int i;
|
|
|
|
gnttab_batch_copy(batch->ops, batch->nr_ops);
|
|
gntdev_put_pages(batch);
|
|
|
|
/*
|
|
* For each completed op, update the status if the op failed
|
|
* and all previous ops for the segment were successful.
|
|
*/
|
|
for (i = 0; i < batch->nr_ops; i++) {
|
|
s16 status = batch->ops[i].status;
|
|
s16 old_status;
|
|
|
|
if (status == GNTST_okay)
|
|
continue;
|
|
|
|
if (__get_user(old_status, batch->status[i]))
|
|
return -EFAULT;
|
|
|
|
if (old_status != GNTST_okay)
|
|
continue;
|
|
|
|
if (__put_user(status, batch->status[i]))
|
|
return -EFAULT;
|
|
}
|
|
|
|
batch->nr_ops = 0;
|
|
return 0;
|
|
}
|
|
|
|
static int gntdev_grant_copy_seg(struct gntdev_copy_batch *batch,
|
|
struct gntdev_grant_copy_segment *seg,
|
|
s16 __user *status)
|
|
{
|
|
uint16_t copied = 0;
|
|
|
|
/*
|
|
* Disallow local -> local copies since there is only space in
|
|
* batch->pages for one page per-op and this would be a very
|
|
* expensive memcpy().
|
|
*/
|
|
if (!(seg->flags & (GNTCOPY_source_gref | GNTCOPY_dest_gref)))
|
|
return -EINVAL;
|
|
|
|
/* Can't cross page if source/dest is a grant ref. */
|
|
if (seg->flags & GNTCOPY_source_gref) {
|
|
if (seg->source.foreign.offset + seg->len > XEN_PAGE_SIZE)
|
|
return -EINVAL;
|
|
}
|
|
if (seg->flags & GNTCOPY_dest_gref) {
|
|
if (seg->dest.foreign.offset + seg->len > XEN_PAGE_SIZE)
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (put_user(GNTST_okay, status))
|
|
return -EFAULT;
|
|
|
|
while (copied < seg->len) {
|
|
struct gnttab_copy *op;
|
|
void __user *virt;
|
|
size_t len, off;
|
|
unsigned long gfn;
|
|
int ret;
|
|
|
|
if (batch->nr_ops >= GNTDEV_COPY_BATCH) {
|
|
ret = gntdev_copy(batch);
|
|
if (ret < 0)
|
|
return ret;
|
|
}
|
|
|
|
len = seg->len - copied;
|
|
|
|
op = &batch->ops[batch->nr_ops];
|
|
op->flags = 0;
|
|
|
|
if (seg->flags & GNTCOPY_source_gref) {
|
|
op->source.u.ref = seg->source.foreign.ref;
|
|
op->source.domid = seg->source.foreign.domid;
|
|
op->source.offset = seg->source.foreign.offset + copied;
|
|
op->flags |= GNTCOPY_source_gref;
|
|
} else {
|
|
virt = seg->source.virt + copied;
|
|
off = (unsigned long)virt & ~XEN_PAGE_MASK;
|
|
len = min(len, (size_t)XEN_PAGE_SIZE - off);
|
|
|
|
ret = gntdev_get_page(batch, virt, false, &gfn);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
op->source.u.gmfn = gfn;
|
|
op->source.domid = DOMID_SELF;
|
|
op->source.offset = off;
|
|
}
|
|
|
|
if (seg->flags & GNTCOPY_dest_gref) {
|
|
op->dest.u.ref = seg->dest.foreign.ref;
|
|
op->dest.domid = seg->dest.foreign.domid;
|
|
op->dest.offset = seg->dest.foreign.offset + copied;
|
|
op->flags |= GNTCOPY_dest_gref;
|
|
} else {
|
|
virt = seg->dest.virt + copied;
|
|
off = (unsigned long)virt & ~XEN_PAGE_MASK;
|
|
len = min(len, (size_t)XEN_PAGE_SIZE - off);
|
|
|
|
ret = gntdev_get_page(batch, virt, true, &gfn);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
op->dest.u.gmfn = gfn;
|
|
op->dest.domid = DOMID_SELF;
|
|
op->dest.offset = off;
|
|
}
|
|
|
|
op->len = len;
|
|
copied += len;
|
|
|
|
batch->status[batch->nr_ops] = status;
|
|
batch->nr_ops++;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static long gntdev_ioctl_grant_copy(struct gntdev_priv *priv, void __user *u)
|
|
{
|
|
struct ioctl_gntdev_grant_copy copy;
|
|
struct gntdev_copy_batch batch;
|
|
unsigned int i;
|
|
int ret = 0;
|
|
|
|
if (copy_from_user(©, u, sizeof(copy)))
|
|
return -EFAULT;
|
|
|
|
batch.nr_ops = 0;
|
|
batch.nr_pages = 0;
|
|
|
|
for (i = 0; i < copy.count; i++) {
|
|
struct gntdev_grant_copy_segment seg;
|
|
|
|
if (copy_from_user(&seg, ©.segments[i], sizeof(seg))) {
|
|
ret = -EFAULT;
|
|
goto out;
|
|
}
|
|
|
|
ret = gntdev_grant_copy_seg(&batch, &seg, ©.segments[i].status);
|
|
if (ret < 0)
|
|
goto out;
|
|
|
|
cond_resched();
|
|
}
|
|
if (batch.nr_ops)
|
|
ret = gntdev_copy(&batch);
|
|
return ret;
|
|
|
|
out:
|
|
gntdev_put_pages(&batch);
|
|
return ret;
|
|
}
|
|
|
|
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_UNMAP_NOTIFY:
|
|
return gntdev_ioctl_notify(priv, ptr);
|
|
|
|
case IOCTL_GNTDEV_GRANT_COPY:
|
|
return gntdev_ioctl_grant_copy(priv, ptr);
|
|
|
|
#ifdef CONFIG_XEN_GNTDEV_DMABUF
|
|
case IOCTL_GNTDEV_DMABUF_EXP_FROM_REFS:
|
|
return gntdev_ioctl_dmabuf_exp_from_refs(priv, use_ptemod, ptr);
|
|
|
|
case IOCTL_GNTDEV_DMABUF_EXP_WAIT_RELEASED:
|
|
return gntdev_ioctl_dmabuf_exp_wait_released(priv, ptr);
|
|
|
|
case IOCTL_GNTDEV_DMABUF_IMP_TO_REFS:
|
|
return gntdev_ioctl_dmabuf_imp_to_refs(priv, ptr);
|
|
|
|
case IOCTL_GNTDEV_DMABUF_IMP_RELEASE:
|
|
return gntdev_ioctl_dmabuf_imp_release(priv, ptr);
|
|
#endif
|
|
|
|
default:
|
|
pr_debug("priv %p, unknown cmd %x\n", 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_pages(vma);
|
|
struct gntdev_grant_map *map;
|
|
int err = -EINVAL;
|
|
|
|
if ((vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_SHARED))
|
|
return -EINVAL;
|
|
|
|
pr_debug("map %d+%d at %lx (pgoff %lx)\n",
|
|
index, count, vma->vm_start, vma->vm_pgoff);
|
|
|
|
mutex_lock(&priv->lock);
|
|
map = gntdev_find_map_index(priv, index, count);
|
|
if (!map)
|
|
goto unlock_out;
|
|
if (use_ptemod && map->vma)
|
|
goto unlock_out;
|
|
refcount_inc(&map->users);
|
|
|
|
vma->vm_ops = &gntdev_vmops;
|
|
|
|
vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP | VM_MIXEDMAP;
|
|
|
|
if (use_ptemod)
|
|
vma->vm_flags |= VM_DONTCOPY;
|
|
|
|
vma->vm_private_data = map;
|
|
if (map->flags) {
|
|
if ((vma->vm_flags & VM_WRITE) &&
|
|
(map->flags & GNTMAP_readonly))
|
|
goto out_unlock_put;
|
|
} else {
|
|
map->flags = GNTMAP_host_map;
|
|
if (!(vma->vm_flags & VM_WRITE))
|
|
map->flags |= GNTMAP_readonly;
|
|
}
|
|
|
|
if (use_ptemod) {
|
|
map->vma = vma;
|
|
err = mmu_interval_notifier_insert_locked(
|
|
&map->notifier, vma->vm_mm, vma->vm_start,
|
|
vma->vm_end - vma->vm_start, &gntdev_mmu_ops);
|
|
if (err)
|
|
goto out_unlock_put;
|
|
}
|
|
mutex_unlock(&priv->lock);
|
|
|
|
if (use_ptemod) {
|
|
/*
|
|
* gntdev takes the address of the PTE in find_grant_ptes() and
|
|
* passes it to the hypervisor in gntdev_map_grant_pages(). The
|
|
* purpose of the notifier is to prevent the hypervisor pointer
|
|
* to the PTE from going stale.
|
|
*
|
|
* Since this vma's mappings can't be touched without the
|
|
* mmap_lock, and we are holding it now, there is no need for
|
|
* the notifier_range locking pattern.
|
|
*/
|
|
mmu_interval_read_begin(&map->notifier);
|
|
|
|
map->pages_vm_start = vma->vm_start;
|
|
err = apply_to_page_range(vma->vm_mm, vma->vm_start,
|
|
vma->vm_end - vma->vm_start,
|
|
find_grant_ptes, map);
|
|
if (err) {
|
|
pr_warn("find_grant_ptes() failure.\n");
|
|
goto out_put_map;
|
|
}
|
|
}
|
|
|
|
err = gntdev_map_grant_pages(map);
|
|
if (err)
|
|
goto out_put_map;
|
|
|
|
if (!use_ptemod) {
|
|
err = vm_map_pages_zero(vma, map->pages, map->count);
|
|
if (err)
|
|
goto out_put_map;
|
|
} else {
|
|
#ifdef CONFIG_X86
|
|
/*
|
|
* If the PTEs were not made special by the grant map
|
|
* hypercall, do so here.
|
|
*
|
|
* This is racy since the mapping is already visible
|
|
* to userspace but userspace should be well-behaved
|
|
* enough to not touch it until the mmap() call
|
|
* returns.
|
|
*/
|
|
if (!xen_feature(XENFEAT_gnttab_map_avail_bits)) {
|
|
apply_to_page_range(vma->vm_mm, vma->vm_start,
|
|
vma->vm_end - vma->vm_start,
|
|
set_grant_ptes_as_special, NULL);
|
|
}
|
|
#endif
|
|
}
|
|
|
|
return 0;
|
|
|
|
unlock_out:
|
|
mutex_unlock(&priv->lock);
|
|
return err;
|
|
|
|
out_unlock_put:
|
|
mutex_unlock(&priv->lock);
|
|
out_put_map:
|
|
if (use_ptemod) {
|
|
unmap_grant_pages(map, 0, map->count);
|
|
if (map->vma) {
|
|
mmu_interval_notifier_remove(&map->notifier);
|
|
map->vma = NULL;
|
|
}
|
|
}
|
|
gntdev_put_map(priv, map);
|
|
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;
|
|
|
|
use_ptemod = !xen_feature(XENFEAT_auto_translated_physmap);
|
|
|
|
err = misc_register(&gntdev_miscdev);
|
|
if (err != 0) {
|
|
pr_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);
|
|
|
|
/* ------------------------------------------------------------------ */
|