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xen-gntdev: Fix unmap notify on PV domains

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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: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This commit is contained in:
Daniel De Graaf 2011-02-08 09:14:06 -05:00 committed by Konrad Rzeszutek Wilk
parent 90b6f30548
commit 0ea22f072f
1 changed files with 7 additions and 2 deletions
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9
drivers/xen/gntdev.c
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@ -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;