@@ -104,6 +104,9 @@ static MemoryRegion io_mem_unassigned;
* (Set during postcopy)
*/
#define RAM_UF_ZEROPAGE (1 << 3)
+
+/* RAM can be migrated */
+#define RAM_MIGRATABLE (1 << 4)
#endif
#ifdef TARGET_PAGE_BITS_VARY
@@ -1807,6 +1810,11 @@ void qemu_ram_set_uf_zeroable(RAMBlock *rb)
rb->flags |= RAM_UF_ZEROPAGE;
}
+bool qemu_ram_is_migratable(RAMBlock *rb)
+{
+ return rb->flags & RAM_MIGRATABLE;
+}
+
/* Called with iothread lock held. */
void qemu_ram_set_idstr(RAMBlock *new_block, const char *name, DeviceState *dev)
{
@@ -1823,6 +1831,7 @@ void qemu_ram_set_idstr(RAMBlock *new_block, const char *name, DeviceState *dev)
}
}
pstrcat(new_block->idstr, sizeof(new_block->idstr), name);
+ new_block->flags |= RAM_MIGRATABLE;
rcu_read_lock();
RAMBLOCK_FOREACH(block) {
@@ -1845,6 +1854,7 @@ void qemu_ram_unset_idstr(RAMBlock *block)
*/
if (block) {
memset(block->idstr, 0, sizeof(block->idstr));
+ block->flags &= ~RAM_MIGRATABLE;
}
}
@@ -75,6 +75,7 @@ const char *qemu_ram_get_idstr(RAMBlock *rb);
bool qemu_ram_is_shared(RAMBlock *rb);
bool qemu_ram_is_uf_zeroable(RAMBlock *rb);
void qemu_ram_set_uf_zeroable(RAMBlock *rb);
+bool qemu_ram_is_migratable(RAMBlock *rb);
size_t qemu_ram_pagesize(RAMBlock *block);
size_t qemu_ram_pagesize_largest(void);
@@ -187,6 +187,11 @@ void ramblock_recv_bitmap_set_range(RAMBlock *rb, void *host_addr,
nr);
}
+/* Should be holding either ram_list.mutex, or the RCU lock. */
+#define RAMBLOCK_FOREACH_MIGRATABLE(block) \
+ RAMBLOCK_FOREACH(block) \
+ if (!qemu_ram_is_migratable(block)) {} else
+
/*
* An outstanding page request, on the source, having been received
* and queued
@@ -780,6 +785,10 @@ unsigned long migration_bitmap_find_dirty(RAMState *rs, RAMBlock *rb,
unsigned long *bitmap = rb->bmap;
unsigned long next;
+ if (!qemu_ram_is_migratable(rb)) {
+ return size;
+ }
+
if (rs->ram_bulk_stage && start > 0) {
next = start + 1;
} else {
@@ -825,7 +834,7 @@ uint64_t ram_pagesize_summary(void)
RAMBlock *block;
uint64_t summary = 0;
- RAMBLOCK_FOREACH(block) {
+ RAMBLOCK_FOREACH_MIGRATABLE(block) {
summary |= block->page_size;
}
@@ -849,7 +858,7 @@ static void migration_bitmap_sync(RAMState *rs)
qemu_mutex_lock(&rs->bitmap_mutex);
rcu_read_lock();
- RAMBLOCK_FOREACH(block) {
+ RAMBLOCK_FOREACH_MIGRATABLE(block) {
migration_bitmap_sync_range(rs, block, 0, block->used_length);
}
rcu_read_unlock();
@@ -1499,6 +1508,10 @@ static int ram_save_host_page(RAMState *rs, PageSearchStatus *pss,
size_t pagesize_bits =
qemu_ram_pagesize(pss->block) >> TARGET_PAGE_BITS;
+ if (!qemu_ram_is_migratable(pss->block)) {
+ return 0;
+ }
+
do {
tmppages = ram_save_target_page(rs, pss, last_stage);
if (tmppages < 0) {
@@ -1587,7 +1600,7 @@ uint64_t ram_bytes_total(void)
uint64_t total = 0;
rcu_read_lock();
- RAMBLOCK_FOREACH(block) {
+ RAMBLOCK_FOREACH_MIGRATABLE(block) {
total += block->used_length;
}
rcu_read_unlock();
@@ -1642,7 +1655,7 @@ static void ram_save_cleanup(void *opaque)
*/
memory_global_dirty_log_stop();
- QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
+ RAMBLOCK_FOREACH_MIGRATABLE(block) {
g_free(block->bmap);
block->bmap = NULL;
g_free(block->unsentmap);
@@ -1705,7 +1718,7 @@ void ram_postcopy_migrated_memory_release(MigrationState *ms)
{
struct RAMBlock *block;
- RAMBLOCK_FOREACH(block) {
+ RAMBLOCK_FOREACH_MIGRATABLE(block) {
unsigned long *bitmap = block->bmap;
unsigned long range = block->used_length >> TARGET_PAGE_BITS;
unsigned long run_start = find_next_zero_bit(bitmap, range, 0);
@@ -1783,7 +1796,7 @@ static int postcopy_each_ram_send_discard(MigrationState *ms)
struct RAMBlock *block;
int ret;
- RAMBLOCK_FOREACH(block) {
+ RAMBLOCK_FOREACH_MIGRATABLE(block) {
PostcopyDiscardState *pds =
postcopy_discard_send_init(ms, block->idstr);
@@ -1991,7 +2004,7 @@ int ram_postcopy_send_discard_bitmap(MigrationState *ms)
rs->last_sent_block = NULL;
rs->last_page = 0;
- QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
+ RAMBLOCK_FOREACH_MIGRATABLE(block) {
unsigned long pages = block->used_length >> TARGET_PAGE_BITS;
unsigned long *bitmap = block->bmap;
unsigned long *unsentmap = block->unsentmap;
@@ -2150,7 +2163,7 @@ static void ram_list_init_bitmaps(void)
/* Skip setting bitmap if there is no RAM */
if (ram_bytes_total()) {
- QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
+ RAMBLOCK_FOREACH_MIGRATABLE(block) {
pages = block->max_length >> TARGET_PAGE_BITS;
block->bmap = bitmap_new(pages);
bitmap_set(block->bmap, 0, pages);
@@ -2226,7 +2239,7 @@ static int ram_save_setup(QEMUFile *f, void *opaque)
qemu_put_be64(f, ram_bytes_total() | RAM_SAVE_FLAG_MEM_SIZE);
- RAMBLOCK_FOREACH(block) {
+ RAMBLOCK_FOREACH_MIGRATABLE(block) {
qemu_put_byte(f, strlen(block->idstr));
qemu_put_buffer(f, (uint8_t *)block->idstr, strlen(block->idstr));
qemu_put_be64(f, block->used_length);
@@ -2471,6 +2484,11 @@ static inline RAMBlock *ram_block_from_stream(QEMUFile *f, int flags)
return NULL;
}
+ if (!qemu_ram_is_migratable(block)) {
+ error_report("block %s should not be migrated !", id);
+ return NULL;
+ }
+
return block;
}
@@ -2921,7 +2939,11 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id)
length = qemu_get_be64(f);
block = qemu_ram_block_by_name(id);
- if (block) {
+ if (block && !qemu_ram_is_migratable(block)) {
+ error_report("block %s should not be migrated !", id);
+ ret = -EINVAL;
+
+ } else if (block) {
if (length != block->used_length) {
Error *local_err = NULL;
On the POWER9 processor, the XIVE interrupt controller can control interrupt sources using MMIO to trigger events, to EOI or to turn off the sources. Priority management and interrupt acknowledgment is also controlled by MMIO in the presenter sub-engine. These MMIO regions are exposed to guests in QEMU with a set of 'ram device' memory mappings, similarly to VFIO, and the VMAs are populated dynamically with the appropriate pages using a fault handler. But, these regions are an issue for migration. We need to discard the associated RAMBlocks from the RAM state on the source VM and let the destination VM rebuild the memory mappings on the new host in the post_load() operation just before resuming the system. To achieve this goal, the following introduces a new RAMBlock flag RAM_MIGRATABLE which is updated in the vmstate_register_ram() and vmstate_unregister_ram() routines. This flag is then used by the migration to identify RAMBlocks to discard on the source. Some checks are also performed on the destination to make sure nothing invalid was sent. Signed-off-by: Cédric Le Goater <clg@kaod.org> --- exec.c | 10 ++++++++++ include/exec/cpu-common.h | 1 + migration/ram.c | 42 ++++++++++++++++++++++++++++++++---------- 3 files changed, 43 insertions(+), 10 deletions(-)