From 53eac7a8f8cf3d7dc5ecac1946f31442f5eee5f3 Mon Sep 17 00:00:00 2001
From: Peter Xu <peterx@redhat.com>
Date: Wed, 8 May 2019 17:15:46 +0800
Subject: [PATCH] KVM: Fix kvm_clear_dirty_log_protect off-by-(minus-)one
Just imaging the case where num_pages < BITS_PER_LONG, then the loop
will be skipped while it shouldn't.
Signed-off-by: Peter Xu <peterx@redhat.com>
Fixes: 2a31b9db153530df4aa02dac8c32837bf5f47019
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
virt/kvm/kvm_main.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index ad39c57de82d8..7883e0ad07fe8 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1264,8 +1264,8 @@ int kvm_clear_dirty_log_protect(struct kvm *kvm,
return -EFAULT;
spin_lock(&kvm->mmu_lock);
- for (offset = log->first_page,
- i = offset / BITS_PER_LONG, n = log->num_pages / BITS_PER_LONG; n--;
+ for (offset = log->first_page, i = offset / BITS_PER_LONG,
+ n = DIV_ROUND_UP(log->num_pages, BITS_PER_LONG); n--;
i++, offset += BITS_PER_LONG) {
unsigned long mask = *dirty_bitmap_buffer++;
atomic_long_t *p = (atomic_long_t *) &dirty_bitmap[i];
--
GitLab