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| author | Stefano Stabellini <stefano.stabellini@eu.citrix.com> | 2013-07-23 21:23:54 +0400 |
|---|---|---|
| committer | Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> | 2013-08-20 18:25:35 +0400 |
| commit | ee0726407feaf504dff304fb603652fb2d778b42 (patch) | |
| tree | 408473642b805ba2e56b94766f877fcb8518f24b /drivers/xen/gntdev.c | |
| parent | 072b2064b88f709c53a83c6ec1f1cb17bf7c0abf (diff) | |
| download | linux-ee0726407feaf504dff304fb603652fb2d778b42.tar.xz | |
xen/m2p: use GNTTABOP_unmap_and_replace to reinstate the original mapping
GNTTABOP_unmap_grant_ref unmaps a grant and replaces it with a 0
mapping instead of reinstating the original mapping.
Doing so separately would be racy.
To unmap a grant and reinstate the original mapping atomically we use
GNTTABOP_unmap_and_replace.
GNTTABOP_unmap_and_replace doesn't work with GNTMAP_contains_pte, so
don't use it for kmaps. GNTTABOP_unmap_and_replace zeroes the mapping
passed in new_addr so we have to reinstate it, however that is a
per-cpu mapping only used for balloon scratch pages, so we can be sure that
it's not going to be accessed while the mapping is not valid.
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
CC: alex@alex.org.uk
CC: dcrisan@flexiant.com
[v1: Konrad fixed up the conflicts]
Conflicts:
arch/x86/xen/p2m.c
Diffstat (limited to 'drivers/xen/gntdev.c')
| -rw-r--r-- | drivers/xen/gntdev.c | 11 |
1 files changed, 2 insertions, 9 deletions
diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c index eab5427c75f5..e41c79c986ea 100644 --- a/drivers/xen/gntdev.c +++ b/drivers/xen/gntdev.c @@ -272,19 +272,12 @@ static int map_grant_pages(struct grant_map *map) * with find_grant_ptes. */ for (i = 0; i < map->count; i++) { - unsigned level; unsigned long address = (unsigned long) pfn_to_kaddr(page_to_pfn(map->pages[i])); - pte_t *ptep; - u64 pte_maddr = 0; BUG_ON(PageHighMem(map->pages[i])); - ptep = lookup_address(address, &level); - pte_maddr = arbitrary_virt_to_machine(ptep).maddr; - gnttab_set_map_op(&map->kmap_ops[i], pte_maddr, - map->flags | - GNTMAP_host_map | - GNTMAP_contains_pte, + gnttab_set_map_op(&map->kmap_ops[i], address, + map->flags | GNTMAP_host_map, map->grants[i].ref, map->grants[i].domid); } |