diff --git a/hw/ide/core.c b/hw/ide/core.c
index a29ae9f..d145b19 100644
--- a/hw/ide/core.c
+++ b/hw/ide/core.c
@@ -1789,9 +1789,13 @@
     s->unit = unit;
     s->drive_serial = drive_serial++;
     /* we need at least 2k alignment for accessing CDROMs using O_DIRECT */
-    s->io_buffer = qemu_memalign(2048, IDE_DMA_BUF_SECTORS*512 + 4);
     s->io_buffer_total_len = IDE_DMA_BUF_SECTORS*512 + 4;
+    s->io_buffer = qemu_memalign(2048, s->io_buffer_total_len);
+    memset(s->io_buffer, 0, s->io_buffer_total_len);
+
     s->smart_selftest_data = qemu_blockalign(s->bs, 512);
+    memset(s->smart_selftest_data, 0, 512);
+
     s->sector_write_timer = qemu_new_timer_ns(vm_clock,
                                            ide_sector_write_timer_cb, s);
 }