[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH 03/10] cpu: init vmstate for ticks and clock off
From: |
Juan Quintela |
Subject: |
Re: [Qemu-devel] [PATCH 03/10] cpu: init vmstate for ticks and clock offset |
Date: |
Tue, 09 Sep 2014 15:25:10 +0200 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) |
Paolo Bonzini <address@hidden> wrote:
> From: Pavel Dovgalyuk <address@hidden>
>
> Ticks and clock offset used by CPU timers have to be saved in vmstate.
> But vmstate for these fields registered only in icount mode.
> Missing registration leads to breaking the continuity when vmstate is loaded.
> This patch introduces new initialization function which fixes this.
>
> Signed-off-by: Pavel Dovgalyuk <address@hidden>
> Signed-off-by: Paolo Bonzini <address@hidden>
Nack.
This break migration when using with older machine types.
Several questions before I propose an alternative:
- are we this fields always needed (then why migration has worked until
now)
- after reding cpus.c the question is .... why it ever worked?
After reading cpus.c, it appears that we only really need this
functionality for
qemu_clock_get_ns()
when called with QEMU_CLOCK_VIRTUAL with icount disabled, right?
further grep shows that it is used for acpi_pm_tmr_get_clock, whatever
that is. When is this used, thanks?
Later, Juan.
> ---
> cpus.c | 8 ++++++--
> include/qemu-common.h | 2 ++
> vl.c | 1 +
> 3 files changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/cpus.c b/cpus.c
> index 0f7d0ea..2a0e133 100644
> --- a/cpus.c
> +++ b/cpus.c
> @@ -493,13 +493,17 @@ static const VMStateDescription vmstate_timers = {
> }
> };
>
> +void cpu_ticks_init(void)
> +{
> + seqlock_init(&timers_state.vm_clock_seqlock, NULL);
> + vmstate_register(NULL, 0, &vmstate_timers, &timers_state);
> +}
> +
> void configure_icount(QemuOpts *opts, Error **errp)
> {
> const char *option;
> char *rem_str = NULL;
>
> - seqlock_init(&timers_state.vm_clock_seqlock, NULL);
> - vmstate_register(NULL, 0, &vmstate_timers, &timers_state);
> option = qemu_opt_get(opts, "shift");
> if (!option) {
> if (qemu_opt_get(opts, "align") != NULL) {
> diff --git a/include/qemu-common.h b/include/qemu-common.h
> index bcf7a6a..dcb57ab 100644
> --- a/include/qemu-common.h
> +++ b/include/qemu-common.h
> @@ -105,6 +105,8 @@ static inline char *realpath(const char *path, char
> *resolved_path)
> }
> #endif
>
> +void cpu_ticks_init(void);
> +
> /* icount */
> void configure_icount(QemuOpts *opts, Error **errp);
> extern int use_icount;
> diff --git a/vl.c b/vl.c
> index 15aea95..5db0d08 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -4334,6 +4334,7 @@ int main(int argc, char **argv, char **envp)
> qemu_spice_init();
> #endif
>
> + cpu_ticks_init();
> if (icount_opts) {
> if (kvm_enabled() || xen_enabled()) {
> fprintf(stderr, "-icount is not allowed with kvm or xen\n");
- [Qemu-devel] [PATCH 00/10] x86: migrate more data, Paolo Bonzini, 2014/09/09
- [Qemu-devel] [PATCH 02/10] apic_common: vapic_paddr synchronization fix, Paolo Bonzini, 2014/09/09
- [Qemu-devel] [PATCH 03/10] cpu: init vmstate for ticks and clock offset, Paolo Bonzini, 2014/09/09
- Re: [Qemu-devel] [PATCH 03/10] cpu: init vmstate for ticks and clock offset,
Juan Quintela <=
- [Qemu-devel] [PATCH 01/10] vl: use QLIST_FOREACH_SAFE to visit change state handlers, Paolo Bonzini, 2014/09/09
- [Qemu-devel] [PATCH 04/10] pcspk: adding vmstate for save/restore, Paolo Bonzini, 2014/09/09
- Re: [Qemu-devel] [PATCH 04/10] pcspk: adding vmstate for save/restore, Juan Quintela, 2014/09/09
- Re: [Qemu-devel] [PATCH 04/10] pcspk: adding vmstate for save/restore, Paolo Bonzini, 2014/09/09
- Re: [Qemu-devel] [PATCH 04/10] pcspk: adding vmstate for save/restore, Michael S. Tsirkin, 2014/09/10
- Re: [Qemu-devel] [PATCH 04/10] pcspk: adding vmstate for save/restore, Paolo Bonzini, 2014/09/10
- Re: [Qemu-devel] [PATCH 04/10] pcspk: adding vmstate for save/restore, Michael S. Tsirkin, 2014/09/10
- Re: [Qemu-devel] [PATCH 04/10] pcspk: adding vmstate for save/restore, Paolo Bonzini, 2014/09/10