From: Sean Christopherson <[email protected]>
commit 97daa028f3f621adff2c4f7b15fe0874e5b5bd6c upstream.
Return the index of the last valid slot from gfn_to_memslot_approx() if
its binary search loop yielded an out-of-bounds index. The index can
be out-of-bounds if the specified gfn is less than the base of the
lowest memslot (which is also the last valid memslot).
Note, the sole caller, kvm_s390_get_cmma(), ensures used_slots is
non-zero.
Fixes: afdad61615cc3 ("KVM: s390: Fix storage attributes migration with memory
slots")
Cc: [email protected] # 4.19.x: 0774a964ef56: KVM: Fix out of range
accesses to memslots
Cc: [email protected] # 4.19.x
Signed-off-by: Sean Christopherson <[email protected]>
Message-Id: <[email protected]>
Reviewed-by: Cornelia Huck <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/s390/kvm/kvm-s390.c | 3 +++
1 file changed, 3 insertions(+)
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -1932,6 +1932,9 @@ static int gfn_to_memslot_approx(struct
start = slot + 1;
}
+ if (start >= slots->used_slots)
+ return slots->used_slots - 1;
+
if (gfn >= memslots[start].base_gfn &&
gfn < memslots[start].base_gfn + memslots[start].npages) {
atomic_set(&slots->lru_slot, start);
