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
[ Upstream commit 44d93045247661acbd50b1629e62f415f2747577 ]
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. The initial loop however is incorrect: only the first three of the four pages which belong to segment and region tables will be marked as being used for DAT. The last page is incorrectly marked as no-dat.
This can result in incorrect guest TLB flushes.
Fix this by simply marking all four pages.
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: Sasha Levin sashal@kernel.org --- arch/s390/mm/page-states.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/s390/mm/page-states.c b/arch/s390/mm/page-states.c index 10d81deef330f..bef7e07da98ef 100644 --- a/arch/s390/mm/page-states.c +++ b/arch/s390/mm/page-states.c @@ -131,7 +131,7 @@ static void mark_kernel_pud(p4d_t *p4d, unsigned long addr, unsigned long end) continue; if (!pud_folded(*pud)) { page = phys_to_page(pud_val(*pud)); - for (i = 0; i < 3; i++) + for (i = 0; i < 4; i++) set_bit(PG_arch_1, &page[i].flags); } mark_kernel_pmd(pud, addr, next); @@ -152,7 +152,7 @@ static void mark_kernel_p4d(pgd_t *pgd, unsigned long addr, unsigned long end) continue; if (!p4d_folded(*p4d)) { page = phys_to_page(p4d_val(*p4d)); - for (i = 0; i < 3; i++) + for (i = 0; i < 4; i++) set_bit(PG_arch_1, &page[i].flags); } mark_kernel_pud(p4d, addr, next); @@ -174,7 +174,7 @@ static void mark_kernel_pgd(void) continue; if (!pgd_folded(*pgd)) { page = phys_to_page(pgd_val(*pgd)); - for (i = 0; i < 3; i++) + for (i = 0; i < 4; i++) set_bit(PG_arch_1, &page[i].flags); } mark_kernel_p4d(pgd, addr, next);