From: David Hildenbrand <david@xxxxxxxxxx> We already optimize get_guest_storage_key() to assume that if we don't have a PTE table and don't have a huge page mapped that the storage key is 0. Similarly, optimize reset_guest_reference_bit() to simply do nothing if there is no PTE table and no huge page mapped. Signed-off-by: David Hildenbrand <david@xxxxxxxxxx> Reviewed-by: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx> Acked-by: Heiko Carstens <hca@xxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20210909162248.14969-10-david@xxxxxxxxxx Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx> --- arch/s390/mm/pgtable.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c index 1c9aeb361f8d..c16232cd0ec5 100644 --- a/arch/s390/mm/pgtable.c +++ b/arch/s390/mm/pgtable.c @@ -901,13 +901,23 @@ int reset_guest_reference_bit(struct mm_struct *mm, unsigned long addr) pte_t *ptep; int cc = 0; - if (pmd_lookup(mm, addr, &pmdp)) + /* + * If we don't have a PTE table and if there is no huge page mapped, + * the storage key is 0 and there is nothing for us to do. + */ + switch (pmd_lookup(mm, addr, &pmdp)) { + case -ENOENT: + return 0; + case 0: + break; + default: return -EFAULT; + } ptl = pmd_lock(mm, pmdp); if (!pmd_present(*pmdp)) { spin_unlock(ptl); - return -EFAULT; + return 0; } if (pmd_large(*pmdp)) { -- 2.31.1
