From 97ca7bfc19605bc08e9183441b8b8545e84032d6 Mon Sep 17 00:00:00 2001 From: Christian Borntraeger <borntraeger@de.ibm.com> Date: Thu, 6 Jul 2017 10:12:58 +0200 Subject: [PATCH] s390/mm: set change and reference bit on lazy key enablement When we enable storage keys for a guest lazily, we reset the ACC and F values. That is correct assuming that these are 0 on a clear reset and the guest obviously has not used any key setting instruction. We also zero out the change and reference bit. This is not correct as the architecture prefers over-indication instead of under-indication for the keyless->keyed transition. This patch fixes the behaviour and always sets guest change and guest reference for all guest storage keys on the keyless -> keyed switch. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Reviewed-by: Claudio Imbrenda <imbrenda@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> --- arch/s390/mm/pgtable.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c index d4d409ba206b2..4a1f7366b17ae 100644 --- a/arch/s390/mm/pgtable.c +++ b/arch/s390/mm/pgtable.c @@ -591,11 +591,11 @@ void ptep_zap_key(struct mm_struct *mm, unsigned long addr, pte_t *ptep) unsigned long ptev; pgste_t pgste; - /* Clear storage key */ + /* Clear storage key ACC and F, but set R/C */ preempt_disable(); pgste = pgste_get_lock(ptep); - pgste_val(pgste) &= ~(PGSTE_ACC_BITS | PGSTE_FP_BIT | - PGSTE_GR_BIT | PGSTE_GC_BIT); + pgste_val(pgste) &= ~(PGSTE_ACC_BITS | PGSTE_FP_BIT); + pgste_val(pgste) |= PGSTE_GR_BIT | PGSTE_GC_BIT; ptev = pte_val(*ptep); if (!(ptev & _PAGE_INVALID) && (ptev & _PAGE_WRITE)) page_set_storage_key(ptev & PAGE_MASK, PAGE_DEFAULT_KEY, 1); -- GitLab