From 87f1d40a706bdebdc8f959b9ac291d0d8fdfcc7e Mon Sep 17 00:00:00 2001 From: Jeremy Fitzhardinge Date: Mon, 13 Dec 2010 14:42:30 +0000 Subject: xen p2m: clear the old pte when adding a page to m2p_override When adding a page to m2p_override we change the p2m of the page so we need to also clear the old pte of the kernel linear mapping because it doesn't correspond anymore. When we remove the page from m2p_override we restore the original p2m of the page and we also restore the old pte of the kernel linear mapping. Before changing the p2m mappings in m2p_add_override and m2p_remove_override, check that the page passed as argument is valid and return an error if it is not. Signed-off-by: Jeremy Fitzhardinge Signed-off-by: Stefano Stabellini Signed-off-by: Konrad Rzeszutek Wilk --- drivers/xen/grant-table.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) (limited to 'drivers/xen/grant-table.c') diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c index 1afd5690858..9ef54ebc119 100644 --- a/drivers/xen/grant-table.c +++ b/drivers/xen/grant-table.c @@ -455,6 +455,8 @@ int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops, unsigned long mfn; ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map_ops, count); + if (ret) + return ret; for (i = 0; i < count; i++) { /* m2p override only supported for GNTMAP_contains_pte mappings */ @@ -463,7 +465,9 @@ int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops, 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]); + ret = m2p_add_override(mfn, pages[i]); + if (ret) + return ret; } return ret; @@ -476,8 +480,14 @@ int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops, 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]); + if (ret) + return ret; + + for (i = 0; i < count; i++) { + ret = m2p_remove_override(pages[i]); + if (ret) + return ret; + } return ret; } -- cgit v1.2.3-18-g5258