This is a note to let you know that I've just added the patch titled
s390/cmma: fix handling of swapper_pg_dir and invalid_pg_dir
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
s390-cmma-fix-handling-of-swapper_pg_dir-and-invalid.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit f351ad21a347721c35701459a28e5803e11f8c71
Author: Heiko Carstens <hca@xxxxxxxxxxxxx>
Date: Tue Oct 24 10:15:20 2023 +0200
s390/cmma: fix handling of swapper_pg_dir and invalid_pg_dir
[ 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>
diff --git a/arch/s390/mm/page-states.c b/arch/s390/mm/page-states.c
index 00e7b0876dc50..79a037f49f707 100644
--- a/arch/s390/mm/page-states.c
+++ b/arch/s390/mm/page-states.c
@@ -181,6 +181,12 @@ 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) {
