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SubjectRe: [PATCH v7 06/11] pvqspinlock, x86: Allow unfair queue spinlock in a KVM guest
Il 19/03/2014 21:14, Waiman Long ha scritto:
> This patch adds a KVM init function to activate the unfair queue
> spinlock in a KVM guest when the PARAVIRT_UNFAIR_LOCKS kernel config
> option is selected.
>
> Signed-off-by: Waiman Long <Waiman.Long@hp.com>
> ---
> arch/x86/kernel/kvm.c | 17 +++++++++++++++++
> 1 files changed, 17 insertions(+), 0 deletions(-)
>
> diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
> index 713f1b3..a489140 100644
> --- a/arch/x86/kernel/kvm.c
> +++ b/arch/x86/kernel/kvm.c
> @@ -826,3 +826,20 @@ static __init int kvm_spinlock_init_jump(void)
> early_initcall(kvm_spinlock_init_jump);
>
> #endif /* CONFIG_PARAVIRT_SPINLOCKS */
> +
> +#ifdef CONFIG_PARAVIRT_UNFAIR_LOCKS
> +/*
> + * Enable unfair lock if running in a real para-virtualized environment
> + */
> +static __init int kvm_unfair_locks_init_jump(void)
> +{
> + if (!kvm_para_available())
> + return 0;
> +
> + static_key_slow_inc(&paravirt_unfairlocks_enabled);
> + printk(KERN_INFO "KVM setup unfair spinlock\n");
> +
> + return 0;
> +}
> +early_initcall(kvm_unfair_locks_init_jump);
> +#endif
>

No! Please do what I asked you to do. You are not handling Hyper-V or
VMWare. Just use X86_FEATURE_HYPERVISOR and it will cover all
hypervisors that actually follow Intel's guidelines.

Paolo


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