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Commit 0ea22f07 authored by Daniel De Graaf's avatar Daniel De Graaf Committed by Konrad Rzeszutek Wilk
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xen-gntdev: Fix unmap notify on PV domains 



In paravirtualized guests, the struct page* for mappings is only a
placeholder, and cannot be used to access the granted memory. Use the
userspace mapping that we have set up in order to implement
UNMAP_NOTIFY_CLEAR_BYTE.

Signed-off-by: default avatarDaniel De Graaf <dgdegra@tycho.nsa.gov>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
parent 90b6f305

drivers/xen/gntdev.c

+7 −2
Original line number Diff line number Diff line
@@ -289,7 +289,12 @@ static int unmap_grant_pages(struct grant_map *map, int offset, int pages) 


	if (map->notify.flags & UNMAP_NOTIFY_CLEAR_BYTE) {

		int pgno = (map->notify.addr >> PAGE_SHIFT);

		if (pgno >= offset && pgno < offset + pages) {

		if (pgno >= offset && pgno < offset + pages && use_ptemod) {

			void __user *tmp;

			tmp = map->vma->vm_start + map->notify.addr;

			copy_to_user(tmp, &err, 1);

			map->notify.flags &= ~UNMAP_NOTIFY_CLEAR_BYTE;

		} else if (pgno >= offset && pgno < offset + pages) {

			uint8_t *tmp = kmap(map->pages[pgno]);

			tmp[map->notify.addr & (PAGE_SIZE-1)] = 0;

			kunmap(map->pages[pgno]);
@@ -298,7 +303,7 @@ static int unmap_grant_pages(struct grant_map *map, int offset, int pages) 
	}



	pr_debug("map %d+%d [%d+%d]\n", map->index, map->count, offset, pages);

	err = gnttab_unmap_refs(map->unmap_ops + offset, map->pages, pages);

	err = gnttab_unmap_refs(map->unmap_ops + offset, map->pages + offset, pages);

	if (err)

		return err;