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SubjectRe: [PATCH] x86/kvmclock: Stop kvmclocks for hibernate restore
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On 3/26/21 9:01 AM, Vitaly Kuznetsov wrote:
> Vitaly Kuznetsov <vkuznets@redhat.com> writes:
>
> ..
>
>> (this is with your v2 included). There's nothing about CPU0 for
>> e.g. async PF + timestamps are really interesting. Seems we have issues
>> to fix) I'm playing with it right now.
>
> What if we do the following (instead of your patch):
>
> diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
> index 78bb0fae3982..c32392d6329d 100644
> --- a/arch/x86/kernel/kvm.c
> +++ b/arch/x86/kernel/kvm.c
> @@ -26,6 +26,7 @@
> #include <linux/kprobes.h>
> #include <linux/nmi.h>
> #include <linux/swait.h>
> +#include <linux/syscore_ops.h>
> #include <asm/timer.h>
> #include <asm/cpu.h>
> #include <asm/traps.h>
> @@ -598,17 +599,21 @@ static void kvm_guest_cpu_offline(void)
>
> static int kvm_cpu_online(unsigned int cpu)
> {
> - local_irq_disable();
> + unsigned long flags;
> +
> + local_irq_save(flags);
> kvm_guest_cpu_init();
> - local_irq_enable();
> + local_irq_restore(flags);
> return 0;
> }
>
> static int kvm_cpu_down_prepare(unsigned int cpu)
> {
> - local_irq_disable();
> + unsigned long flags;
> +
> + local_irq_save(flags);
> kvm_guest_cpu_offline();
> - local_irq_enable();
> + local_irq_restore(flags);
> return 0;
> }
> #endif
> @@ -639,6 +644,23 @@ static void kvm_flush_tlb_others(const struct cpumask *cpumask,
> native_flush_tlb_others(flushmask, info);
> }
>
> +static int kvm_suspend(void)
> +{
> + kvm_guest_cpu_offline();
> +
> + return 0;
> +}
> +
> +static void kvm_resume(void)
> +{
> + kvm_cpu_online(raw_smp_processor_id());
> +}
> +
> +static struct syscore_ops kvm_syscore_ops = {
> + .suspend = kvm_suspend,
> + .resume = kvm_resume,
> +};
> +
> static void __init kvm_guest_init(void)
> {
> int i;
> @@ -681,6 +703,8 @@ static void __init kvm_guest_init(void)
> kvm_guest_cpu_init();
> #endif
>
> + register_syscore_ops(&kvm_syscore_ops);
> +
> /*
> * Hard lockup detection is enabled by default. Disable it, as guests
> * can get false positives too easily, for example if the host is
>

Yes, I do like using register_syscore_ops for this. I will base my V3 on this. -Lenny.

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