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>

1 files changed, 20 insertions, 6 deletions

diff --git a/softmmu/physmem.c b/softmmu/physmem.c
index 5232696571..e1da81ed2f 100644
--- a/softmmu/physmem.c
+++ b/softmmu/physmem.c
@@ -1694,6 +1694,11 @@ ram_addr_t qemu_ram_get_used_length(RAMBlock *rb)
     return rb->used_length;
 }
 
+ram_addr_t qemu_ram_get_max_length(RAMBlock *rb)
+{
+    return rb->max_length;
+}
+
 bool qemu_ram_is_shared(RAMBlock *rb)
 {
     return rb->flags & RAM_SHARED;
@@ -1793,8 +1798,9 @@ static int memory_try_enable_merging(void *addr, size_t len)
     return qemu_madvise(addr, len, QEMU_MADV_MERGEABLE);
 }
 
-/* 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.
  *
  * As memory core doesn't know how is memory accessed, it is up to
  * resize callback to update device state and/or add assertions to detect
@@ -1802,6 +1808,7 @@ static int memory_try_enable_merging(void *addr, size_t len)
  */
 int qemu_ram_resize(RAMBlock *block, ram_addr_t newsize, Error **errp)
 {
+    const ram_addr_t oldsize = block->used_length;
     const ram_addr_t unaligned_size = newsize;
 
     assert(block);
@@ -1838,6 +1845,11 @@ int qemu_ram_resize(RAMBlock *block, ram_addr_t newsize, Error **errp)
         return -EINVAL;
     }
 
+    /* Notify before modifying the ram block and touching the bitmaps. */
+    if (block->host) {
+        ram_block_notify_resize(block->host, oldsize, newsize);
+    }
+
     cpu_physical_memory_clear_dirty_range(block->offset, block->used_length);
     block->used_length = newsize;
     cpu_physical_memory_set_dirty_range(block->offset, block->used_length,
@@ -2005,7 +2017,8 @@ static void ram_block_add(RAMBlock *new_block, Error **errp, bool shared)
             qemu_madvise(new_block->host, new_block->max_length,
                          QEMU_MADV_DONTFORK);
         }
-        ram_block_notify_add(new_block->host, new_block->max_length);
+        ram_block_notify_add(new_block->host, new_block->used_length,
+                             new_block->max_length);
     }
 }
 
@@ -2184,7 +2197,8 @@ void qemu_ram_free(RAMBlock *block)
     }
 
     if (block->host) {
-        ram_block_notify_remove(block->host, block->max_length);
+        ram_block_notify_remove(block->host, block->used_length,
+                                block->max_length);
     }
 
     qemu_mutex_lock_ramlist();
@@ -3486,7 +3500,7 @@ int ram_block_discard_range(RAMBlock *rb, uint64_t start, size_t length)
         goto err;
     }
 
-    if ((start + length) <= rb->used_length) {
+    if ((start + length) <= rb->max_length) {
         bool need_madvise, need_fallocate;
         if (!QEMU_IS_ALIGNED(length, rb->page_size)) {
             error_report("ram_block_discard_range: Unaligned length: %zx",
@@ -3553,7 +3567,7 @@ int ram_block_discard_range(RAMBlock *rb, uint64_t start, size_t length)
     } else {
         error_report("ram_block_discard_range: Overrun block '%s' (%" PRIu64
                      "/%zx/" RAM_ADDR_FMT")",
-                     rb->idstr, start, length, rb->used_length);
+                     rb->idstr, start, length, rb->max_length);
     }
 
 err: