KVM: fix the handling of dirty bitmaps to avoid overflows
Int is not long enough to store the size of a dirty bitmap.
This patch fixes this problem with the introduction of a wrapper
function to calculate the sizes of dirty bitmaps.
Note: in mark_page_dirty(), we have to consider the fact that
__set_bit() takes the offset as int, not long.
Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
diff --git a/arch/ia64/kvm/kvm-ia64.c b/arch/ia64/kvm/kvm-ia64.c
index 73c5c2b..7f3c0a2 100644
--- a/arch/ia64/kvm/kvm-ia64.c
+++ b/arch/ia64/kvm/kvm-ia64.c
@@ -1802,7 +1802,8 @@
{
struct kvm_memory_slot *memslot;
int r, i;
- long n, base;
+ long base;
+ unsigned long n;
unsigned long *dirty_bitmap = (unsigned long *)(kvm->arch.vm_base +
offsetof(struct kvm_vm_data, kvm_mem_dirty_log));
@@ -1815,7 +1816,7 @@
if (!memslot->dirty_bitmap)
goto out;
- n = ALIGN(memslot->npages, BITS_PER_LONG) / 8;
+ n = kvm_dirty_bitmap_bytes(memslot);
base = memslot->base_gfn / BITS_PER_LONG;
for (i = 0; i < n/sizeof(long); ++i) {
@@ -1831,7 +1832,7 @@
struct kvm_dirty_log *log)
{
int r;
- int n;
+ unsigned long n;
struct kvm_memory_slot *memslot;
int is_dirty = 0;
@@ -1850,7 +1851,7 @@
if (is_dirty) {
kvm_flush_remote_tlbs(kvm);
memslot = &kvm->memslots->memslots[log->slot];
- n = ALIGN(memslot->npages, BITS_PER_LONG) / 8;
+ n = kvm_dirty_bitmap_bytes(memslot);
memset(memslot->dirty_bitmap, 0, n);
}
r = 0;
diff --git a/arch/powerpc/kvm/book3s.c b/arch/powerpc/kvm/book3s.c
index 25da07f..604af29 100644
--- a/arch/powerpc/kvm/book3s.c
+++ b/arch/powerpc/kvm/book3s.c
@@ -1004,7 +1004,8 @@
struct kvm_vcpu *vcpu;
ulong ga, ga_end;
int is_dirty = 0;
- int r, n;
+ int r;
+ unsigned long n;
mutex_lock(&kvm->slots_lock);
@@ -1022,7 +1023,7 @@
kvm_for_each_vcpu(n, vcpu, kvm)
kvmppc_mmu_pte_pflush(vcpu, ga, ga_end);
- n = ALIGN(memslot->npages, BITS_PER_LONG) / 8;
+ n = kvm_dirty_bitmap_bytes(memslot);
memset(memslot->dirty_bitmap, 0, n);
}
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 9ad3d06..45aa90f 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2612,8 +2612,9 @@
int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
struct kvm_dirty_log *log)
{
- int r, n, i;
+ int r, i;
struct kvm_memory_slot *memslot;
+ unsigned long n;
unsigned long is_dirty = 0;
unsigned long *dirty_bitmap = NULL;
@@ -2628,7 +2629,7 @@
if (!memslot->dirty_bitmap)
goto out;
- n = ALIGN(memslot->npages, BITS_PER_LONG) / 8;
+ n = kvm_dirty_bitmap_bytes(memslot);
r = -ENOMEM;
dirty_bitmap = vmalloc(n);