Merge remote-tracking branch 'remotes/dgilbert/tags/pull-migration-20210513a' into staging

Migration pull 2021-05-13

Fix of the 2021-05-11 version, with a fix to build on the armhf
cross.

The largest change in this set is David's changes for ram block size
changing; then there's a pile of other cleanups and fixes.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

# gpg: Signature made Thu 13 May 2021 18:36:06 BST
# gpg:                using RSA key 45F5C71B4A0CB7FB977A9FA90516331EBC5BFDE7
# gpg: Good signature from "Dr. David Alan Gilbert (RH2) <dgilbert@redhat.com>" [full]
# Primary key fingerprint: 45F5 C71B 4A0C B7FB 977A  9FA9 0516 331E BC5B FDE7

* remotes/dgilbert/tags/pull-migration-20210513a:
  tests/migration: introduce multifd into guestperf
  tests/qtest/migration-test: Use g_autofree to avoid leaks on error paths
  tests/migration-test: Fix "true" vs true
  migration/ram: Use offset_in_ramblock() in range checks
  migration/multifd: Print used_length of memory block
  migration/ram: Handle RAM block resizes during postcopy
  migration/ram: Simplify host page handling in ram_load_postcopy()
  migration/ram: Discard RAM when growing RAM blocks after ram_postcopy_incoming_init()
  exec: Relax range check in ram_block_discard_range()
  migration/ram: Handle RAM block resizes during precopy
  numa: Make all callbacks of ram block notifiers optional
  numa: Teach ram block notifiers about resizeable ram blocks
  util: vfio-helpers: Factor out and fix processing of existing ram blocks
  migration: Drop redundant query-migrate result @blocked
  migration/ram: Optimize ram_save_host_page()
  migration/ram: Reduce unnecessary rate limiting
  migrate/ram: remove "ram_bulk_stage" and "fpo_enabled"

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

5 files changed, 26 insertions, 9 deletions

diff --git a/include/exec/cpu-common.h b/include/exec/cpu-common.h
index 5a0a2d9..ccabed4 100644
--- a/include/exec/cpu-common.h
+++ b/include/exec/cpu-common.h
@@ -57,6 +57,7 @@ const char *qemu_ram_get_idstr(RAMBlock *rb);
 void *qemu_ram_get_host_addr(RAMBlock *rb);
 ram_addr_t qemu_ram_get_offset(RAMBlock *rb);
 ram_addr_t qemu_ram_get_used_length(RAMBlock *rb);
+ram_addr_t qemu_ram_get_max_length(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);
diff --git a/include/exec/memory.h b/include/exec/memory.h
index 5728a68..c8b9088 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -131,7 +131,7 @@ typedef struct IOMMUTLBEvent {
 #define RAM_SHARED     (1 << 1)
 
 /* Only a portion of RAM (used_length) is actually used, and migrated.
- * This used_length size can change across reboots.
+ * Resizing RAM while migrating can result in the migration being canceled.
  */
 #define RAM_RESIZEABLE (1 << 2)
 
@@ -955,7 +955,9 @@ void memory_region_init_ram_shared_nomigrate(MemoryRegion *mr,
  *                                     RAM.  Accesses into the region will
  *                                     modify memory directly.  Only an initial
  *                                     portion of this RAM is actually used.
- *                                     The used size can change across reboots.
+ *                                     Changing the size while migrating
+ *                                     can result in the migration being
+ *                                     canceled.
  *
  * @mr: the #MemoryRegion to be initialized.
  * @owner: the object that tracks the region's reference count
@@ -1586,8 +1588,8 @@ void *memory_region_get_ram_ptr(MemoryRegion *mr);
 
 /* memory_region_ram_resize: Resize a RAM region.
  *
- * Only legal before guest might have detected the memory size: e.g. on
- * incoming migration, or right after reset.
+ * Resizing RAM while migrating can result in the migration being canceled.
+ * Care has to be taken if the guest might have already detected the memory.
  *
  * @mr: a memory region created with @memory_region_init_resizeable_ram.
  * @newsize: the new size the region
diff --git a/include/exec/ramblock.h b/include/exec/ramblock.h
index 07d5086..664701b 100644
--- a/include/exec/ramblock.h
+++ b/include/exec/ramblock.h
@@ -59,6 +59,16 @@ struct RAMBlock {
      */
     unsigned long *clear_bmap;
     uint8_t clear_bmap_shift;
+
+    /*
+     * RAM block length that corresponds to the used_length on the migration
+     * source (after RAM block sizes were synchronized). Especially, after
+     * starting to run the guest, used_length and postcopy_length can differ.
+     * Used to register/unregister uffd handlers and as the size of the received
+     * bitmap. Receiving any page beyond this length will bail out, as it
+     * could not have been valid on the source.
+     */
+    ram_addr_t postcopy_length;
 };
 #endif
 #endif
diff --git a/include/exec/ramlist.h b/include/exec/ramlist.h
index 26704aa..ece6497 100644
--- a/include/exec/ramlist.h
+++ b/include/exec/ramlist.h
@@ -65,15 +65,20 @@ void qemu_mutex_lock_ramlist(void);
 void qemu_mutex_unlock_ramlist(void);
 
 struct RAMBlockNotifier {
-    void (*ram_block_added)(RAMBlockNotifier *n, void *host, size_t size);
-    void (*ram_block_removed)(RAMBlockNotifier *n, void *host, size_t size);
+    void (*ram_block_added)(RAMBlockNotifier *n, void *host, size_t size,
+                            size_t max_size);
+    void (*ram_block_removed)(RAMBlockNotifier *n, void *host, size_t size,
+                              size_t max_size);
+    void (*ram_block_resized)(RAMBlockNotifier *n, void *host, size_t old_size,
+                              size_t new_size);
     QLIST_ENTRY(RAMBlockNotifier) next;
 };
 
 void ram_block_notifier_add(RAMBlockNotifier *n);
 void ram_block_notifier_remove(RAMBlockNotifier *n);
-void ram_block_notify_add(void *host, size_t size);
-void ram_block_notify_remove(void *host, size_t size);
+void ram_block_notify_add(void *host, size_t size, size_t max_size);
+void ram_block_notify_remove(void *host, size_t size, size_t max_size);
+void ram_block_notify_resize(void *host, size_t old_size, size_t new_size);
 
 void ram_block_dump(Monitor *mon);
 
diff --git a/include/migration/misc.h b/include/migration/misc.h
index 738675e..4659067 100644
--- a/include/migration/misc.h
+++ b/include/migration/misc.h
@@ -37,7 +37,6 @@ void precopy_infrastructure_init(void);
 void precopy_add_notifier(NotifierWithReturn *n);
 void precopy_remove_notifier(NotifierWithReturn *n);
 int precopy_notify(PrecopyNotifyReason reason, Error **errp);
-void precopy_enable_free_page_optimization(void);
 
 void ram_mig_init(void);
 void qemu_guest_free_page_hint(void *addr, size_t len);