linux-kernel - Re: [PATCH v5 03/12] Add async PF initialization to PV guest.

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Date:	Mon, 23 Aug 2010 18:26:58 +0300
From:	Avi Kivity <avi@...hat.com>
To:	Gleb Natapov <gleb@...hat.com>
CC:	kvm@...r.kernel.org, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org, mingo@...e.hu,
	a.p.zijlstra@...llo.nl, tglx@...utronix.de, hpa@...or.com,
	riel@...hat.com, cl@...ux-foundation.org, mtosatti@...hat.com
Subject: Re: [PATCH v5 03/12] Add async PF initialization to PV guest.

  On 07/19/2010 06:30 PM, Gleb Natapov wrote:
> Enable async PF in a guest if async PF capability is discovered.
>
> Signed-off-by: Gleb Natapov<gleb@...hat.com>
> ---
>   arch/x86/include/asm/kvm_para.h |    5 +++
>   arch/x86/kernel/kvm.c           |   68 +++++++++++++++++++++++++++++++++++++++
>   2 files changed, 73 insertions(+), 0 deletions(-)
>
> diff --git a/arch/x86/include/asm/kvm_para.h b/arch/x86/include/asm/kvm_para.h
> index 5b05e9f..f1662d7 100644
> --- a/arch/x86/include/asm/kvm_para.h
> +++ b/arch/x86/include/asm/kvm_para.h
> @@ -65,6 +65,11 @@ struct kvm_mmu_op_release_pt {
>   	__u64 pt_phys;
>   };
>
> +struct kvm_vcpu_pv_apf_data {
> +	__u32 reason;
> +	__u32 enabled;
> +};
> +

The guest will have to align this on a 64 byte boundary, should this be 
marked __aligned(64) here?

> @@ -231,12 +235,72 @@ static void __init paravirt_ops_setup(void)
>   #endif
>   }
>
> +void __cpuinit kvm_guest_cpu_init(void)
> +{
> +	if (!kvm_para_available())
> +		return;
> +
> +	if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF)) {
> +		u64 pa = __pa(&__get_cpu_var(apf_reason));
> +
> +		if (native_write_msr_safe(MSR_KVM_ASYNC_PF_EN,
> +					  pa | KVM_ASYNC_PF_ENABLED, pa>>  32))
> +			return;
> +		__get_cpu_var(apf_reason).enabled = 1;
> +		printk(KERN_INFO"KVM setup async PF for cpu %d\n",
> +		       smp_processor_id());
> +	}
> +}

Need a way to disable apf from the guest kernel command line.

> +
> +static int __cpuinit kvm_cpu_notify(struct notifier_block *self,
> +				    unsigned long action, void *hcpu)
> +{
> +	switch (action) {
> +	case CPU_ONLINE:
> +	case CPU_ONLINE_FROZEN:
> +		kvm_guest_cpu_init();
> +		break;
> +	default:
> +		break;

Should we disable apf if the cpu is dying here?

> +	}
> +	return NOTIFY_OK;
> +}
> +

-- 
error compiling committee.c: too many arguments to function

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