s390/cmma: fix handling of swapper_pg_dir and invalid_pg_dir

If the cmma no-dat feature is available the kernel page tables are walked
to identify and mark all pages which are used for address translation (all
region, segment, and page tables). In a subsequent loop all other pages are
marked as "no-dat" pages with the ESSA instruction.

This information is visible to the hypervisor, so that the hypervisor can
optimize purging of guest TLB entries. All pages used for swapper_pg_dir
and invalid_pg_dir are incorrectly marked as no-dat, which in turn can
result in incorrect guest TLB flushes.

Fix this by marking those pages correctly as being used for DAT.

Cc: <[email protected]>
Reviewed-by: Claudio Imbrenda <[email protected]>
Signed-off-by: Heiko Carstens <[email protected]>
Signed-off-by: Vasily Gorbik <[email protected]>

Author: hcahca

arch/s390/mm/page-states.c

@@ -188,6 +188,12 @@ void __init cmma_init_nodat(void)
 		return;
 	/* Mark pages used in kernel page tables */
 	mark_kernel_pgd();
+	page = virt_to_page(&swapper_pg_dir);
+	for (i = 0; i < 4; i++)
+		set_bit(PG_arch_1, &page[i].flags);
+	page = virt_to_page(&invalid_pg_dir);
+	for (i = 0; i < 4; i++)
+		set_bit(PG_arch_1, &page[i].flags);
 
 	/* Set all kernel pages not used for page tables to stable/no-dat */
 	for_each_mem_pfn_range(i, MAX_NUMNODES, &start, &end, NULL) {