Commit 84bb41d5 authored by Heiko Carstens's avatar Heiko Carstens Committed by Vasily Gorbik
Browse files

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: <stable@vger.kernel.org>
Reviewed-by: default avatarClaudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
Signed-off-by: default avatarVasily Gorbik <gor@linux.ibm.com>
parent 44d93045

arch/s390/mm/page-states.c

+6 −0
Original line number Diff line number Diff line
@@ -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) {