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From: Claudio Imbrenda <imbrenda@linux.ibm.com>
To: linux-s390@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, frankja@linux.ibm.com, nrb@linux.ibm.com,
        nsg@linux.ibm.com, borntraeger@de.ibm.com, hca@linux.ibm.com,
        gerald.schaefer@linux.ibm.com, david@redhat.com
Subject: [PATCH v1 1/2] s390/mm: fix storage key clearing for guest huge pages
Date: Tue, 16 Apr 2024 13:42:19 +0200
Message-ID: <20240416114220.28489-2-imbrenda@linux.ibm.com>
In-Reply-To: <20240416114220.28489-1-imbrenda@linux.ibm.com>
References: <20240416114220.28489-1-imbrenda@linux.ibm.com>
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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")
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
---
 arch/s390/mm/gmap.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c
index 094b43b121cd..12d22a7fa32f 100644
--- a/arch/s390/mm/gmap.c
+++ b/arch/s390/mm/gmap.c
@@ -2661,7 +2661,7 @@ 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();
-- 
2.44.0