diff options
| -rw-r--r-- | accel/kvm/kvm-all.c | 44 |
1 files changed, 29 insertions, 15 deletions
diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c index ca00daa..7b9f92d 100644 --- a/accel/kvm/kvm-all.c +++ b/accel/kvm/kvm-all.c @@ -518,6 +518,27 @@ static int kvm_get_dirty_pages_log_range(MemoryRegionSection *section, #define ALIGN(x, y) (((x)+(y)-1) & ~((y)-1)) +/* Allocate the dirty bitmap for a slot */ +static void kvm_memslot_init_dirty_bitmap(KVMSlot *mem) +{ + /* + * XXX bad kernel interface alert + * For dirty bitmap, kernel allocates array of size aligned to + * bits-per-long. But for case when the kernel is 64bits and + * the userspace is 32bits, userspace can't align to the same + * bits-per-long, since sizeof(long) is different between kernel + * and user space. This way, userspace will provide buffer which + * may be 4 bytes less than the kernel will use, resulting in + * userspace memory corruption (which is not detectable by valgrind + * too, in most cases). + * So for now, let's align to 64 instead of HOST_LONG_BITS here, in + * a hope that sizeof(long) won't become >8 any time soon. + */ + hwaddr bitmap_size = ALIGN(((mem->memory_size) >> TARGET_PAGE_BITS), + /*HOST_LONG_BITS*/ 64) / 8; + mem->dirty_bmap = g_malloc0(bitmap_size); +} + /** * kvm_physical_sync_dirty_bitmap - Sync dirty bitmap from kernel space * @@ -550,23 +571,9 @@ static int kvm_physical_sync_dirty_bitmap(KVMMemoryListener *kml, goto out; } - /* XXX bad kernel interface alert - * For dirty bitmap, kernel allocates array of size aligned to - * bits-per-long. But for case when the kernel is 64bits and - * the userspace is 32bits, userspace can't align to the same - * bits-per-long, since sizeof(long) is different between kernel - * and user space. This way, userspace will provide buffer which - * may be 4 bytes less than the kernel will use, resulting in - * userspace memory corruption (which is not detectable by valgrind - * too, in most cases). - * So for now, let's align to 64 instead of HOST_LONG_BITS here, in - * a hope that sizeof(long) won't become >8 any time soon. - */ if (!mem->dirty_bmap) { - hwaddr bitmap_size = ALIGN(((mem->memory_size) >> TARGET_PAGE_BITS), - /*HOST_LONG_BITS*/ 64) / 8; /* Allocate on the first log_sync, once and for all */ - mem->dirty_bmap = g_malloc0(bitmap_size); + kvm_memslot_init_dirty_bitmap(mem); } d.dirty_bitmap = mem->dirty_bmap; @@ -1067,6 +1074,13 @@ static void kvm_set_phys_mem(KVMMemoryListener *kml, mem->ram = ram; mem->flags = kvm_mem_flags(mr); + if (mem->flags & KVM_MEM_LOG_DIRTY_PAGES) { + /* + * Reallocate the bmap; it means it doesn't disappear in + * middle of a migrate. + */ + kvm_memslot_init_dirty_bitmap(mem); + } err = kvm_set_user_memory_region(kml, mem, true); if (err) { fprintf(stderr, "%s: error registering slot: %s\n", __func__, |