KVM: Count the number of dirty pages for dirty logging
Needed for the next patch which uses this number to decide how to write
protect a slot.
Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index a3b25a5..220c83b 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3466,10 +3466,9 @@
int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
struct kvm_dirty_log *log)
{
- int r, i;
+ int r;
struct kvm_memory_slot *memslot;
unsigned long n;
- unsigned long is_dirty = 0;
mutex_lock(&kvm->slots_lock);
@@ -3484,11 +3483,8 @@
n = kvm_dirty_bitmap_bytes(memslot);
- for (i = 0; !is_dirty && i < n/sizeof(long); i++)
- is_dirty = memslot->dirty_bitmap[i];
-
/* If nothing is dirty, don't bother messing with page tables. */
- if (is_dirty) {
+ if (memslot->nr_dirty_pages) {
struct kvm_memslots *slots, *old_slots;
unsigned long *dirty_bitmap;
@@ -3503,6 +3499,7 @@
goto out;
memcpy(slots, kvm->memslots, sizeof(struct kvm_memslots));
slots->memslots[log->slot].dirty_bitmap = dirty_bitmap;
+ slots->memslots[log->slot].nr_dirty_pages = 0;
slots->generation++;
old_slots = kvm->memslots;