On Wed, Jul 06, 2016 at 02:29:18PM +0530, Bharata B Rao wrote:
> Add CPUState::migration_id and use that as instance_id in
> vmstate_register() call.
>
> Introduce use-migration-id property that allows target machines to
> optionally switch to using migration_id instead of cpu_index.
> This will help allow successful migration in cases where holes are
> introduced in cpu_index range after CPU hot removals.
>
> The default implementation of CPUClass:get_migration_id() continues
> to return cpu_index.
>
> Suggested-by: Igor Mammedov <imamm...@redhat.com>
> Signed-off-by: Bharata B Rao <bhar...@linux.vnet.ibm.com>
> ---
> exec.c | 5 +++--
> include/qom/cpu.h | 6 ++++++
> qom/cpu.c | 21 +++++++++++++++++++++
> 3 files changed, 30 insertions(+), 2 deletions(-)
>
> diff --git a/exec.c b/exec.c
> index fb73910..a8afeda 100644
> --- a/exec.c
> +++ b/exec.c
> @@ -619,12 +619,13 @@ static void cpu_release_index(CPUState *cpu)
> void cpu_vmstate_register(CPUState *cpu)
> {
> CPUClass *cc = CPU_GET_CLASS(cpu);
> + int instance_id = cc->get_migration_id(cpu);
>
> if (qdev_get_vmsd(DEVICE(cpu)) == NULL) {
> - vmstate_register(NULL, cpu->cpu_index, &vmstate_cpu_common, cpu);
> + vmstate_register(NULL, instance_id, &vmstate_cpu_common, cpu);
> }
> if (cc->vmsd != NULL) {
> - vmstate_register(NULL, cpu->cpu_index, cc->vmsd, cpu);
> + vmstate_register(NULL, instance_id, cc->vmsd, cpu);
> }
> }
>
> diff --git a/include/qom/cpu.h b/include/qom/cpu.h
> index 29ccf5c..6d00143 100644
> --- a/include/qom/cpu.h
> +++ b/include/qom/cpu.h
> @@ -187,6 +187,7 @@ typedef struct CPUClass {
> bool (*cpu_exec_interrupt)(CPUState *cpu, int interrupt_request);
>
> void (*disas_set_info)(CPUState *cpu, disassemble_info *info);
> + int (*get_migration_id)(CPUState *cpu);
> } CPUClass;
>
> #ifdef HOST_WORDS_BIGENDIAN
> @@ -273,6 +274,9 @@ struct qemu_work_item {
> * @kvm_fd: vCPU file descriptor for KVM.
> * @work_mutex: Lock to prevent multiple access to queued_work_*.
> * @queued_work_first: First asynchronous work pending.
> + * @migration_id: Use as instance_id argument in cpu vmstate_register calls
> + * @use_migration_id: Set to enforce the use of CPUClass.get_migration_id()
> + * over cpu_index during vmstate registration.
I don't really understand the purpose of the use-migration-id bool.
Can't you just leave the migration-id as cpu_index by default if you
don't want a different migration id. AFAICT this flag is never
tested.
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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