On 20.07.2018 10:58, Martin Schwidefsky wrote:
> On Fri, 20 Jul 2018 09:44:48 +0100
> Janosch Frank <frankja@xxxxxxxxxxxxx> wrote:
>
>> Similarly to the pte skey handling, where we set the storage key to
>> the default key for each newly mapped pte, we have to also do that for
>> huge pmds.
>>
>> With the PG_arch_1 flag we keep track if the area has already been
>> cleared of its skeys.
>>
>> Signed-off-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
>> ---
>> arch/s390/mm/gmap.c | 2 ++
>> arch/s390/mm/hugetlbpage.c | 24 ++++++++++++++++++++++++
>> 2 files changed, 26 insertions(+)
>>
>> diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c
>> index 6194a8a62aa0..409bc8f9d5b6 100644
>> --- a/arch/s390/mm/gmap.c
>> +++ b/arch/s390/mm/gmap.c
>> @@ -2554,6 +2554,7 @@ static int __s390_enable_skey_hugetlb(pte_t *pte, unsigned long addr,
>> {
>> pmd_t *pmd = (pmd_t *)pte;
>> unsigned long start, end;
>> + struct page *page = pmd_page(*pmd);
>>
>> /*
>> * The write check makes sure we do not set a key on shared
>> @@ -2568,6 +2569,7 @@ static int __s390_enable_skey_hugetlb(pte_t *pte, unsigned long addr,
>> start = pmd_val(*pmd) & HPAGE_MASK;
>> end = start + HPAGE_SIZE - 1;
>> __storage_key_init_range(start, end);
>> + set_bit(PG_arch_1, &page->flags);
>> return 0;
>> }
>>
>> diff --git a/arch/s390/mm/hugetlbpage.c b/arch/s390/mm/hugetlbpage.c
>> index e804090f4470..b0246c705a19 100644
>> --- a/arch/s390/mm/hugetlbpage.c
>> +++ b/arch/s390/mm/hugetlbpage.c
>> @@ -123,6 +123,29 @@ static inline pte_t __rste_to_pte(unsigned long rste)
>> return pte;
>> }
>>
>> +static void clear_huge_pte_skeys(struct mm_struct *mm, unsigned long rste)
>> +{
>> + struct page *page;
>> + unsigned long size, paddr;
>> +
>> + if (!mm_uses_skeys(mm) ||
>> + rste & _SEGMENT_ENTRY_INVALID)
>> + return;
>> +
>> + if ((rste & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3) {
>> + page = pud_page(__pud(rste));
>> + size = PUD_SIZE;
>> + paddr = rste & PUD_MASK;
>> + } else {
>> + page = pmd_page(__pmd(rste));
>> + size = PMD_SIZE;
>> + paddr = rste & PMD_MASK;
>> + }
>> +
>> + if (!test_and_set_bit(PG_arch_1, &page->flags))
>> + __storage_key_init_range(paddr, paddr + size - 1);
>> +}
>> +
>> void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
>> pte_t *ptep, pte_t pte)
>> {
>> @@ -137,6 +160,7 @@ void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
>> rste |= _REGION_ENTRY_TYPE_R3 | _REGION3_ENTRY_LARGE;
>> else
>> rste |= _SEGMENT_ENTRY_LARGE;
>> + clear_huge_pte_skeys(mm, rste);
>> pte_val(*ptep) = rste;
>> }
>>
>
> That looks promising but I miss the hunk for arch_clear_hugepage_flags() to reset
> the PG_arch_1 bit again when the huge page is freed.
>
Yes, missing this:
diff --git i/arch/s390/include/asm/hugetlb.h
w/arch/s390/include/asm/hugetlb.h
index 9c5fc50204dd..2d1afa58a4b6 100644
--- i/arch/s390/include/asm/hugetlb.h
+++ w/arch/s390/include/asm/hugetlb.h
@@ -37,7 +37,10 @@ static inline int prepare_hugepage_range(struct file
*file,
return 0;
}
-#define arch_clear_hugepage_flags(page) do { } while (0)
+static inline void arch_clear_hugepage_flags(struct page *page)
+{
+ clear_bit(PG_arch_1, &page->flags);
+}
Attachment:
signature.asc
Description: OpenPGP digital signature
