s390/mm: Fix storage key clearing for guest huge pages

[ Upstream commit 843c3280686fc1a83d89ee1e0b5599c9f6b09d0c ]

The function __storage_key_init_range() expects the end address to be
the first byte outside the range to be initialized. I.e. end - start
should be the size of the area to be initialized.

The current code works because __storage_key_init_range() will still loop
over every page in the range, but it is slower than using sske_frame().

Fixes: 964c2c05c9f3 ("s390/mm: Clear huge page storage keys on enable_skey")
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Link: https://lore.kernel.org/r/20240416114220.28489-2-imbrenda@linux.ibm.com
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c
index 08a7eca03daf78277f603b29fb86afef8cc80e29..41a4a60c5e651dd3e5dd23274e24fab06035012d 100644 (file)
--- a/arch/s390/mm/gmap.c
+++ b/arch/s390/mm/gmap.c
@@ -2659,7 +2659,7 @@ static int __s390_enable_skey_hugetlb(pte_t *pte, unsigned long addr,
                return 0;
 
        start = pmd_val(*pmd) & HPAGE_MASK;
-       end = start + HPAGE_SIZE - 1;
+       end = start + HPAGE_SIZE;
        __storage_key_init_range(start, end);
        set_bit(PG_arch_1, &page->flags);
        cond_resched();