Re: [PATCH v7 2/4] KVM: X86: Add Paravirt TLB Shootdown

Radim Krčmář
2017-11-30T15:17:22Z

2017-11-29 22:01-0800, Wanpeng Li:
> From: Wanpeng Li <wanpeng.li@hotmail.com>
> ---
> diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
> @@ -498,6 +498,34 @@ static void __init kvm_apf_trap_init(void)
> update_intr_gate(X86_TRAP_PF, async_page_fault);
> }
>
> +static DEFINE_PER_CPU(cpumask_var_t, __pv_tlb_mask);
> +
> +static void kvm_flush_tlb_others(const struct cpumask *cpumask,
> + const struct flush_tlb_info *info)
> +{
> + u8 state;
> + int cpu;
> + struct kvm_steal_time *src;
> + struct cpumask *flushmask = this_cpu_cpumask_var_ptr(__pv_tlb_mask);
> +
> + cpumask_copy(flushmask, cpumask);

Is it impossible to call this function before the allocation?

I was guessing that early_initcall might allow us to avoid a (static)
condition as there is no point in calling when there are no others, but
expected the worst ...

thanks.