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authorJanosch Frank <frankja@linux.ibm.com>2019-07-16 13:08:37 +0200
committerChristian Borntraeger <borntraeger@de.ibm.com>2020-02-27 19:47:11 +0100
commitfa0c5eabbdd33012b369cf75d6a39389cc9ae707 (patch)
tree7456128145b210018c8acc80d98c8125d5a7cef7 /arch/s390/mm
parent29b40f105ec8d555984c1f72dc9133b122e51903 (diff)
KVM: s390: protvirt: Secure memory is not mergeable
KSM will not work on secure pages, because when the kernel reads a secure page, it will be encrypted and hence no two pages will look the same. Let's mark the guest pages as unmergeable when we transition to secure mode. Signed-off-by: Janosch Frank <frankja@linux.ibm.com> Reviewed-by: Thomas Huth <thuth@redhat.com> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Cornelia Huck <cohuck@redhat.com> [borntraeger@de.ibm.com: patch merging, splitting, fixing] Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Diffstat (limited to 'arch/s390/mm')
-rw-r--r--arch/s390/mm/gmap.c30
1 files changed, 20 insertions, 10 deletions
diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c
index edcdca97e85e..7291452fe5f0 100644
--- a/arch/s390/mm/gmap.c
+++ b/arch/s390/mm/gmap.c
@@ -2548,6 +2548,22 @@ int s390_enable_sie(void)
}
EXPORT_SYMBOL_GPL(s390_enable_sie);
+int gmap_mark_unmergeable(void)
+{
+ struct mm_struct *mm = current->mm;
+ struct vm_area_struct *vma;
+
+ for (vma = mm->mmap; vma; vma = vma->vm_next) {
+ if (ksm_madvise(vma, vma->vm_start, vma->vm_end,
+ MADV_UNMERGEABLE, &vma->vm_flags)) {
+ return -ENOMEM;
+ }
+ }
+ mm->def_flags &= ~VM_MERGEABLE;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(gmap_mark_unmergeable);
+
/*
* Enable storage key handling from now on and initialize the storage
* keys with the default key.
@@ -2593,7 +2609,6 @@ static const struct mm_walk_ops enable_skey_walk_ops = {
int s390_enable_skey(void)
{
struct mm_struct *mm = current->mm;
- struct vm_area_struct *vma;
int rc = 0;
down_write(&mm->mmap_sem);
@@ -2601,16 +2616,11 @@ int s390_enable_skey(void)
goto out_up;
mm->context.uses_skeys = 1;
- for (vma = mm->mmap; vma; vma = vma->vm_next) {
- if (ksm_madvise(vma, vma->vm_start, vma->vm_end,
- MADV_UNMERGEABLE, &vma->vm_flags)) {
- mm->context.uses_skeys = 0;
- rc = -ENOMEM;
- goto out_up;
- }
+ rc = gmap_mark_unmergeable();
+ if (rc) {
+ mm->context.uses_skeys = 0;
+ goto out_up;
}
- mm->def_flags &= ~VM_MERGEABLE;
-
walk_page_range(mm, 0, TASK_SIZE, &enable_skey_walk_ops, NULL);
out_up: