From: Heiko Carstens <hca@linux.ibm.com>
Date: Tue, 24 Oct 2023 10:15:20 +0200
Subject: s390/cmma: fix handling of swapper_pg_dir and invalid_pg_dir
Git-commit: 84bb41d5df48868055d159d9247b80927f1f70f9
Patch-mainline: v6.7-rc1
References: LTC#203996 bsc#1217087
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: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Acked-by: Miroslav Franc <mfranc@suse.cz>
---
arch/s390/mm/page-states.c | 4 ++++
1 file changed, 4 insertions(+)
--- a/arch/s390/mm/page-states.c
+++ b/arch/s390/mm/page-states.c
@@ -179,11 +179,15 @@ void __init cmma_init_nodat(void)
struct memblock_region *reg;
struct page *page;
unsigned long start, end, ix;
+ int i;
if (cmma_flag < 2)
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);
/* Set all kernel pages not used for page tables to stable/no-dat */
for_each_memblock(memory, reg) {