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 5.4-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_pg_dir.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 84bb41d5df48868055d159d9247b80927f1f70f9 Mon Sep 17 00:00:00 2001
From: Heiko Carstens <hca@xxxxxxxxxxxxx>
Date: Tue, 24 Oct 2023 10:15:20 +0200
Subject: s390/cmma: fix handling of swapper_pg_dir and invalid_pg_dir
From: Heiko Carstens <hca@xxxxxxxxxxxxx>
commit 84bb41d5df48868055d159d9247b80927f1f70f9 upstream.
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: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/s390/mm/page-states.c | 6 ++++++
1 file changed, 6 insertions(+)
--- a/arch/s390/mm/page-states.c
+++ b/arch/s390/mm/page-states.c
@@ -198,6 +198,12 @@ 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_memblock(memory, reg) {
Patches currently in stable-queue which might be from hca@xxxxxxxxxxxxx are
queue-5.4/s390-cmma-fix-initial-kernel-address-space-page-table-walk.patch
queue-5.4/s390-cmma-fix-handling-of-swapper_pg_dir-and-invalid_pg_dir.patch
