diff options
Diffstat (limited to 'drivers/xen/grant-table.c')
| -rw-r--r-- | drivers/xen/grant-table.c | 31 |
1 files changed, 24 insertions, 7 deletions
diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c index 3745a318def..fd725cde6ad 100644 --- a/drivers/xen/grant-table.c +++ b/drivers/xen/grant-table.c @@ -466,13 +466,30 @@ int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops, if (map_ops[i].status) continue; - /* 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)) + + if (map_ops[i].flags & GNTMAP_contains_pte) { + pte = (pte_t *) (mfn_to_virt(PFN_DOWN(map_ops[i].host_addr)) + (map_ops[i].host_addr & ~PAGE_MASK)); - mfn = pte_mfn(*pte); - ret = m2p_add_override(mfn, pages[i]); + mfn = pte_mfn(*pte); + } else { + /* If you really wanted to do this: + * mfn = PFN_DOWN(map_ops[i].dev_bus_addr); + * + * The reason we do not implement it is b/c on the + * unmap path (gnttab_unmap_refs) we have no means of + * checking whether the page is !GNTMAP_contains_pte. + * + * That is without some extra data-structure to carry + * the struct page, bool clear_pte, and list_head next + * tuples and deal with allocation/delallocation, etc. + * + * The users of this API set the GNTMAP_contains_pte + * flag so lets just return not supported until it + * becomes neccessary to implement. + */ + return -EOPNOTSUPP; + } + ret = m2p_add_override(mfn, pages[i], + map_ops[i].flags & GNTMAP_contains_pte); if (ret) return ret; } @@ -494,7 +511,7 @@ int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops, return ret; for (i = 0; i < count; i++) { - ret = m2p_remove_override(pages[i]); + ret = m2p_remove_override(pages[i], true /* clear the PTE */); if (ret) return ret; } |