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authorTakuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>2011-11-14 18:23:34 +0900
committerAvi Kivity <avi@redhat.com>2011-12-27 11:17:19 +0200
commit7850ac5420803996e2960d15b924021f28e0dffc (patch)
treedc4ed43a8e5ffcfbf45b48c8d78228ffe9762efa
parent9b9b1492364758de82c19c36f07baa9ae162c7e5 (diff)
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>
-rw-r--r--arch/x86/kvm/x86.c9
-rw-r--r--include/linux/kvm_host.h1
-rw-r--r--virt/kvm/kvm_main.c4
3 files changed, 7 insertions, 7 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index a3b25a524c9b..220c83b0fbda 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3466,10 +3466,9 @@ static int kvm_vm_ioctl_reinject(struct kvm *kvm,
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 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
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 @@ int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
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;
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index c6a2ec925846..7c654aa46b6c 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -181,6 +181,7 @@ struct kvm_memory_slot {
unsigned long *rmap;
unsigned long *dirty_bitmap;
unsigned long *dirty_bitmap_head;
+ unsigned long nr_dirty_pages;
struct kvm_lpage_info *lpage_info[KVM_NR_PAGE_SIZES - 1];
unsigned long userspace_addr;
int user_alloc;
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 4c5b9a239674..af5c988cafcc 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -625,6 +625,7 @@ static int kvm_create_dirty_bitmap(struct kvm_memory_slot *memslot)
return -ENOMEM;
memslot->dirty_bitmap_head = memslot->dirty_bitmap;
+ memslot->nr_dirty_pages = 0;
return 0;
}
#endif /* !CONFIG_S390 */
@@ -1491,7 +1492,8 @@ void mark_page_dirty_in_slot(struct kvm *kvm, struct kvm_memory_slot *memslot,
if (memslot && memslot->dirty_bitmap) {
unsigned long rel_gfn = gfn - memslot->base_gfn;
- __set_bit_le(rel_gfn, memslot->dirty_bitmap);
+ if (!__test_and_set_bit_le(rel_gfn, memslot->dirty_bitmap))
+ memslot->nr_dirty_pages++;
}
}