[PATCH 6.1 081/107] s390/cmma: fix handling of swapper_pg_dir and invalid_pg_dir

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6.1-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Heiko Carstens <hca@xxxxxxxxxxxxx>

[ Upstream commit 84bb41d5df48868055d159d9247b80927f1f70f9 ]

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@xxxxxxxxxxxxxxx>
Reviewed-by: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx>
Signed-off-by: Heiko Carstens <hca@xxxxxxxxxxxxx>
Signed-off-by: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 arch/s390/mm/page-states.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/s390/mm/page-states.c b/arch/s390/mm/page-states.c
index 7bea3be8b8280..c112762e38015 100644
--- a/arch/s390/mm/page-states.c
+++ b/arch/s390/mm/page-states.c
@@ -192,6 +192,12 @@ 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) {
-- 
2.42.0







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