diff options
| author | Claudio Imbrenda <imbrenda@linux.ibm.com> | 2025-11-04 16:40:48 +0100 |
|---|---|---|
| committer | Heiko Carstens <hca@linux.ibm.com> | 2025-12-08 13:06:14 +0100 |
| commit | 2f393c228cc519ddf19b8c6c05bf15723241aa96 (patch) | |
| tree | 278c0cb064cab8d205d86c78e3120f8de7164e9b | |
| parent | f770950a4709af290f314e691897ec0003fbd8ae (diff) | |
KVM: s390: Fix gmap_helper_zap_one_page() again
A few checks were missing in gmap_helper_zap_one_page(), which can lead
to memory corruption in the guest under specific circumstances.
Add the missing checks.
Fixes: 5deafa27d9ae ("KVM: s390: Fix to clear PTE when discarding a swapped page")
Cc: stable@vger.kernel.org
Reported-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Tested-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
| -rw-r--r-- | arch/s390/mm/gmap_helpers.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/arch/s390/mm/gmap_helpers.c b/arch/s390/mm/gmap_helpers.c index 549f14ad08af..d41b19925a5a 100644 --- a/arch/s390/mm/gmap_helpers.c +++ b/arch/s390/mm/gmap_helpers.c @@ -47,6 +47,7 @@ static void ptep_zap_softleaf_entry(struct mm_struct *mm, softleaf_t entry) void gmap_helper_zap_one_page(struct mm_struct *mm, unsigned long vmaddr) { struct vm_area_struct *vma; + unsigned long pgstev; spinlock_t *ptl; pgste_t pgste; pte_t *ptep; @@ -65,9 +66,13 @@ void gmap_helper_zap_one_page(struct mm_struct *mm, unsigned long vmaddr) if (pte_swap(*ptep)) { preempt_disable(); pgste = pgste_get_lock(ptep); + pgstev = pgste_val(pgste); - ptep_zap_softleaf_entry(mm, softleaf_from_pte(*ptep)); - pte_clear(mm, vmaddr, ptep); + if ((pgstev & _PGSTE_GPS_USAGE_MASK) == _PGSTE_GPS_USAGE_UNUSED || + (pgstev & _PGSTE_GPS_ZERO)) { + ptep_zap_softleaf_entry(mm, softleaf_from_pte(*ptep)); + pte_clear(mm, vmaddr, ptep); + } pgste_set_unlock(ptep, pgste); preempt_enable(); |