xen: introduce gnttab_map_refs and gnttab_unmap_refs
gnttab_map_refs maps some grant refs and uses the new m2p override to
set a proper m2p mapping for the granted pages.
gnttab_unmap_refs unmaps the granted refs and removes th mappings from
the m2p override.
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index 6c45318..1afd569 100644
--- a/drivers/xen/grant-table.c
+++ b/drivers/xen/grant-table.c
@@ -447,6 +447,42 @@
}
EXPORT_SYMBOL_GPL(gnttab_max_grant_frames);
+int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
+ struct page **pages, unsigned int count)
+{
+ int i, ret;
+ pte_t *pte;
+ unsigned long mfn;
+
+ ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map_ops, count);
+
+ for (i = 0; i < count; i++) {
+ /* m2p override only supported for GNTMAP_contains_pte mappings */
+ if (!(map_ops[i].flags & GNTMAP_contains_pte))
+ continue;
+ pte = (pte_t *) (mfn_to_virt(PFN_DOWN(map_ops[i].host_addr)) +
+ (map_ops[i].host_addr & ~PAGE_MASK));
+ mfn = pte_mfn(*pte);
+ m2p_add_override(mfn, pages[i]);
+ }
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(gnttab_map_refs);
+
+int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
+ struct page **pages, unsigned int count)
+{
+ int i, ret;
+
+ ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap_ops, count);
+ for (i = 0; i < count; i++)
+ m2p_remove_override(pages[i]);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(gnttab_unmap_refs);
+
static int gnttab_map(unsigned int start_idx, unsigned int end_idx)
{
struct gnttab_setup_table setup;