Merge tag 'migration-20230213-pull-request' of https://gitlab.com/juan.quintela/qemu into staging

Migration Pull request (take3)

Hi

In this PULL request:
- Added to leonardo fixes:
Fixes: b5eea99ec2 ("migration: Add yank feature")
Reported-by: Li Xiaohui <xiaohli@redhat.com>

Please apply.

[take 2]
- rebase to latest upstream
- fix compilation of linux-user (if have_system was missing) (me)
- cleanup multifd_load_cleanup(leonardo)
- Document RAM flags (me)

Please apply.

[take 1]
This are all the reviewed patches for migration:
- AVX512 support for xbzrle (Ling Xu)
- /dev/userfaultd support (Peter Xu)
- Improve ordering of channels (Peter Xu)
- multifd cleanups (Li Zhang)
- Remove spurious files from last merge (me)
  Rebase makes that to you
- Fix mixup between state_pending_{exact,estimate} (me)
- Cache RAM size during migration (me)
- cleanup several functions (me)

Please apply.

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# gpg: Signature made Mon 13 Feb 2023 02:51:02 GMT
# gpg:                using RSA key 1899FF8EDEBF58CCEE034B82F487EF185872D723
# gpg: Good signature from "Juan Quintela <quintela@redhat.com>" [full]
# gpg:                 aka "Juan Quintela <quintela@trasno.org>" [full]
# Primary key fingerprint: 1899 FF8E DEBF 58CC EE03  4B82 F487 EF18 5872 D723

* tag 'migration-20230213-pull-request' of https://gitlab.com/juan.quintela/qemu: (22 commits)
  ram: Document migration ram flags
  migration/multifd: Move load_cleanup inside incoming_state_destroy
  migration/multifd: Join all multifd threads in order to avoid leaks
  migration/multifd: Remove unnecessary assignment on multifd_load_cleanup()
  migration/multifd: Change multifd_load_cleanup() signature and usage
  migration: Postpone postcopy preempt channel to be after main
  migration: Add a semaphore to count PONGs
  migration: Cleanup postcopy_preempt_setup()
  migration: Rework multi-channel checks on URI
  Update bench-code for addressing CI problem
  AVX512 support for xbzrle_encode_buffer
  migration: I messed state_pending_exact/estimate
  migration: Make ram_save_target_page() a pointer
  migration: Calculate ram size once
  migration: Split ram_bytes_total_common() in two functions
  migration: Make find_dirty_block() return a single parameter
  migration: Simplify ram_find_and_save_block()
  util/userfaultfd: Support /dev/userfaultfd
  linux-headers: Update to v6.1
  multifd: Remove some redundant code
  ...

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

1 files changed, 13 insertions, 9 deletions

diff --git a/migration/savevm.c b/migration/savevm.c
index e9cf4999ad..b5e6962bb6 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -1552,7 +1552,7 @@ void qemu_savevm_state_pending_estimate(uint64_t *res_precopy_only,
     *res_postcopy_only = 0;
 
     QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
-        if (!se->ops || !se->ops->state_pending_exact) {
+        if (!se->ops || !se->ops->state_pending_estimate) {
             continue;
         }
         if (se->ops->is_active) {
@@ -1560,9 +1560,9 @@ void qemu_savevm_state_pending_estimate(uint64_t *res_precopy_only,
                 continue;
             }
         }
-        se->ops->state_pending_exact(se->opaque,
-                                     res_precopy_only, res_compatible,
-                                     res_postcopy_only);
+        se->ops->state_pending_estimate(se->opaque,
+                                        res_precopy_only, res_compatible,
+                                        res_postcopy_only);
     }
 }
 
@@ -1577,7 +1577,7 @@ void qemu_savevm_state_pending_exact(uint64_t *res_precopy_only,
     *res_postcopy_only = 0;
 
     QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
-        if (!se->ops || !se->ops->state_pending_estimate) {
+        if (!se->ops || !se->ops->state_pending_exact) {
             continue;
         }
         if (se->ops->is_active) {
@@ -1585,9 +1585,9 @@ void qemu_savevm_state_pending_exact(uint64_t *res_precopy_only,
                 continue;
             }
         }
-        se->ops->state_pending_estimate(se->opaque,
-                                        res_precopy_only, res_compatible,
-                                        res_postcopy_only);
+        se->ops->state_pending_exact(se->opaque,
+                                     res_precopy_only, res_compatible,
+                                     res_postcopy_only);
     }
 }
 
@@ -2200,7 +2200,11 @@ static int loadvm_postcopy_handle_resume(MigrationIncomingState *mis)
     qemu_sem_post(&mis->postcopy_pause_sem_fault);
 
     if (migrate_postcopy_preempt()) {
-        /* The channel should already be setup again; make sure of it */
+        /*
+         * The preempt channel will be created in async manner, now let's
+         * wait for it and make sure it's created.
+         */
+        qemu_sem_wait(&mis->postcopy_qemufile_dst_done);
         assert(mis->postcopy_qemufile_dst);
         /* Kick the fast ram load thread too */
         qemu_sem_post(&mis->postcopy_pause_sem_fast_load);