linux-kernel - Re: [PATCH v5 12/12] Send async PF when guest is not in userspace too.

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Date:	Tue, 24 Aug 2010 12:36:10 +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 12/12] Send async PF when guest is not in userspace
 too.

  On 07/19/2010 06:31 PM, Gleb Natapov wrote:
> If guest indicates that it can handle async pf in kernel mode too send
> it, but only if interrupt are enabled.
>
> Reviewed-by: Rik van Riel<riel@...hat.com>
> Signed-off-by: Gleb Natapov<gleb@...hat.com>
> ---
>   arch/x86/kvm/mmu.c |    8 +++++++-
>   1 files changed, 7 insertions(+), 1 deletions(-)
>
> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> index 12d1a7b..ed87b1c 100644
> --- a/arch/x86/kvm/mmu.c
> +++ b/arch/x86/kvm/mmu.c
> @@ -2361,7 +2361,13 @@ static bool can_do_async_pf(struct kvm_vcpu *vcpu)
>   	if (!vcpu->arch.apf_data || kvm_event_needs_reinjection(vcpu))
>   		return false;
>
> -	return !!kvm_x86_ops->get_cpl(vcpu);
> +	if (vcpu->arch.apf_send_user_only)
> +		return !!kvm_x86_ops->get_cpl(vcpu);

cpl is not a bool.  Compare it with 0.

> +
> +	if (!kvm_x86_ops->interrupt_allowed(vcpu))
> +		return false;
> +
> +	return true;
>   }

Should have commented before, but get_cpl() is not accurate when doing 
nested virtualization.  When L1 intercepts page faults, being in L2 is 
equivalent to CPL 3.  But we need to get the apf information to L1 somehow.

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

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