diff options
author | Jan Kiszka <jan.kiszka@siemens.com> | 2010-03-01 18:17:21 +0100 |
---|---|---|
committer | Marcelo Tosatti <mtosatti@redhat.com> | 2010-03-01 14:30:12 -0300 |
commit | 4e13bf68753a25581e4604538b3eaa27e24dcdfa (patch) | |
tree | 8861cd5bd88ea944020c92adf28b03e963646a2d /savevm.c | |
parent | a4f9b864e44c179fb1af7d9d486089ca5b0562b5 (diff) |
qemu-kvm: Rework VCPU state writeback API
This grand cleanup drops all reset and vmsave/load related
synchronization points in favor of four(!) generic hooks:
- cpu_synchronize_all_states in qemu_savevm_state_complete
(initial sync from kernel before vmsave)
- cpu_synchronize_all_post_init in qemu_loadvm_state
(writeback after vmload)
- cpu_synchronize_all_post_init in main after machine init
- cpu_synchronize_all_post_reset in qemu_system_reset
(writeback after system reset)
These writeback points + the existing one of VCPU exec after
cpu_synchronize_state map on three levels of writeback:
- KVM_PUT_RUNTIME_STATE (during runtime, other VCPUs continue to run)
- KVM_PUT_RESET_STATE (on synchronous system reset, all VCPUs stopped)
- KVM_PUT_FULL_STATE (on init or vmload, all VCPUs stopped as well)
This level is passed to the arch-specific VCPU state writing function
that will decide which concrete substates need to be written. That way,
no writer of load, save or reset functions that interact with in-kernel
KVM states will ever have to worry about synchronization again. That
also means that a lot of reasons for races, segfaults and deadlocks are
eliminated.
cpu_synchronize_state remains untouched, just as Anthony suggested. We
continue to need it before reading or writing of VCPU states that are
also tracked by in-kernel KVM subsystems.
Consequently, this patch removes many cpu_synchronize_state calls that
are now redundant, just like remaining explicit register syncs. It does
not touch qemu-kvm's special hooks for mpstate, vcpu_events, or tsc
loading. They will be cleaned up by individual patches.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Diffstat (limited to 'savevm.c')
-rw-r--r-- | savevm.c | 4 |
1 files changed, 4 insertions, 0 deletions
@@ -1368,6 +1368,8 @@ int qemu_savevm_state_complete(Monitor *mon, QEMUFile *f) { SaveStateEntry *se; + cpu_synchronize_all_states(); + QTAILQ_FOREACH(se, &savevm_handlers, entry) { if (se->save_live_state == NULL) continue; @@ -1568,6 +1570,8 @@ int qemu_loadvm_state(QEMUFile *f) } } + cpu_synchronize_all_post_init(); + ret = 0; out: |