[V5,00/12] fix migration of suspended runstate

Message

Steven Sistare Nov. 13, 2023, 6:33 p.m. UTC

Migration of a guest in the suspended runstate is broken.  The incoming
migration code automatically tries to wake the guest, which is wrong;
the guest should end migration in the same runstate it started.  Further,
for a restored snapshot, the automatic wakeup fails.  The runstate is
RUNNING, but the guest is not.  See the commit messages for the details.

Changes in V2:
  * simplify "start on wakeup request"
  * fix postcopy, snapshot, and background migration
  * refactor fixes for each type of migration
  * explicitly handled suspended events and runstate in tests
  * add test for postcopy and background migration

Changes in V3:
  * rebase to tip
  * fix hang in new function migrate_wait_for_dirty_mem

Changes in V4:
  * rebase to tip
  * add patch for vm_prepare_start (thanks Peter)
  * add patch to preserve cpu ticks

Changes in V5:
  * rebase to tip
  * added patches to completely stop vm in suspended state:
      cpus: refactor vm_stop
      cpus: stop vm in suspended state
  * added patch to partially resume vm in suspended state:
      cpus: start vm in suspended state
  * modified "preserve suspended ..." patches to use the above.
  * deleted patch "preserve cpu ticks if suspended".  stop ticks in
    vm_stop_force_state instead.
  * deleted patch "add runstate function".  defined new helper function
    migrate_new_runstate in "preserve suspended runstate"
  * Added some RB's, but removed other RB's because the patches changed.

Steve Sistare (12):
  cpus: refactor vm_stop
  cpus: stop vm in suspended state
  cpus: pass runstate to vm_prepare_start
  cpus: start vm in suspended state
  migration: preserve suspended runstate
  migration: preserve suspended for snapshot
  migration: preserve suspended for bg_migration
  tests/qtest: migration events
  tests/qtest: option to suspend during migration
  tests/qtest: precopy migration with suspend
  tests/qtest: postcopy migration with suspend
  tests/qtest: background migration with suspend

 backends/tpm/tpm_emulator.c          |   2 +-
 gdbstub/system.c                     |   2 +-
 hw/usb/hcd-ehci.c                    |   2 +-
 hw/usb/redirect.c                    |   2 +-
 hw/xen/xen-hvm-common.c              |   2 +-
 include/migration/snapshot.h         |   7 ++
 include/sysemu/runstate.h            |  12 ++-
 migration/migration-hmp-cmds.c       |  12 ++-
 migration/migration.c                |  40 ++++---
 migration/migration.h                |   1 +
 migration/savevm.c                   |  41 +++----
 system/cpus.c                        |  71 ++++++------
 system/runstate.c                    |  13 +++
 system/vl.c                          |   2 +
 tests/migration/i386/Makefile        |   5 +-
 tests/migration/i386/a-b-bootblock.S |  50 ++++++++-
 tests/migration/i386/a-b-bootblock.h |  26 +++--
 tests/qtest/migration-helpers.c      |  27 ++---
 tests/qtest/migration-helpers.h      |  11 +-
 tests/qtest/migration-test.c         | 202 ++++++++++++++++++++++++++---------
 20 files changed, 362 insertions(+), 168 deletions(-)