5.4-stable review patch. If anyone has any objections, please let me know.
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From: Heiko Carstens hca@linux.ibm.com
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@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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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) {