linux-kernel - Re: [PATCH repost] kvm: drop parameter validation

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Message-ID: <20120813143053.GC11194@redhat.com>
Date:	Mon, 13 Aug 2012 17:30:53 +0300
From:	Gleb Natapov <gleb@...hat.com>
To:	"Michael S. Tsirkin" <mst@...hat.com>
Cc:	Avi Kivity <avi@...hat.com>, Marcelo Tosatti <mtosatti@...hat.com>,
	kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH repost] kvm: drop parameter validation

On Mon, Aug 13, 2012 at 01:43:58PM +0300, Michael S. Tsirkin wrote:
> We validate irq pin number when routing is setup, so
> code handling illegal irq # in pic and ioapic on each injection
> is never called.
> Drop it.
> 
I would leave BUG_ON there for a while.

> Signed-off-by: Michael S. Tsirkin <mst@...hat.com>
> ---
> 
> Reposting, applies without changes to kvm/next.
> 
>  arch/x86/kvm/i8259.c | 16 +++++++---------
>  virt/kvm/ioapic.c    | 35 +++++++++++++++++------------------
>  2 files changed, 24 insertions(+), 27 deletions(-)
> 
> diff --git a/arch/x86/kvm/i8259.c b/arch/x86/kvm/i8259.c
> index 1df8fb9..277ec0d 100644
> --- a/arch/x86/kvm/i8259.c
> +++ b/arch/x86/kvm/i8259.c
> @@ -190,17 +190,15 @@ void kvm_pic_update_irq(struct kvm_pic *s)
>  
>  int kvm_pic_set_irq(struct kvm_pic *s, int irq, int irq_source_id, int level)
>  {
> -	int ret = -1;
> +	int ret, irq_level;
>  
>  	pic_lock(s);
> -	if (irq >= 0 && irq < PIC_NUM_PINS) {
> -		int irq_level = __kvm_irq_line_state(&s->irq_states[irq],
> -						     irq_source_id, level);
> -		ret = pic_set_irq1(&s->pics[irq >> 3], irq & 7, irq_level);
> -		pic_update_irq(s);
> -		trace_kvm_pic_set_irq(irq >> 3, irq & 7, s->pics[irq >> 3].elcr,
> -				      s->pics[irq >> 3].imr, ret == 0);
> -	}
> +	irq_level = __kvm_irq_line_state(&s->irq_states[irq],
> +					 irq_source_id, level);
> +	ret = pic_set_irq1(&s->pics[irq >> 3], irq & 7, irq_level);
> +	pic_update_irq(s);
> +	trace_kvm_pic_set_irq(irq >> 3, irq & 7, s->pics[irq >> 3].elcr,
> +			      s->pics[irq >> 3].imr, ret == 0);
>  	pic_unlock(s);
>  
>  	return ret;
> diff --git a/virt/kvm/ioapic.c b/virt/kvm/ioapic.c
> index ef61d52..4d824c7 100644
> --- a/virt/kvm/ioapic.c
> +++ b/virt/kvm/ioapic.c
> @@ -197,28 +197,27 @@ int kvm_ioapic_set_irq(struct kvm_ioapic *ioapic, int irq, int irq_source_id,
>  	u32 old_irr;
>  	u32 mask = 1 << irq;
>  	union kvm_ioapic_redirect_entry entry;
> -	int ret = 1;
> +	int ret, irq_level;
>  
>  	spin_lock(&ioapic->lock);
>  	old_irr = ioapic->irr;
> -	if (irq >= 0 && irq < IOAPIC_NUM_PINS) {
> -		int irq_level = __kvm_irq_line_state(&ioapic->irq_states[irq],
> -						     irq_source_id, level);
> -		entry = ioapic->redirtbl[irq];
> -		irq_level ^= entry.fields.polarity;
> -		if (!irq_level)
> -			ioapic->irr &= ~mask;
> -		else {
> -			int edge = (entry.fields.trig_mode == IOAPIC_EDGE_TRIG);
> -			ioapic->irr |= mask;
> -			if ((edge && old_irr != ioapic->irr) ||
> -			    (!edge && !entry.fields.remote_irr))
> -				ret = ioapic_service(ioapic, irq);
> -			else
> -				ret = 0; /* report coalesced interrupt */
> -		}
> -		trace_kvm_ioapic_set_irq(entry.bits, irq, ret == 0);
> +	irq_level = __kvm_irq_line_state(&ioapic->irq_states[irq],
> +					 irq_source_id, level);
> +	entry = ioapic->redirtbl[irq];
> +	irq_level ^= entry.fields.polarity;
> +	if (!irq_level) {
> +		ioapic->irr &= ~mask;
> +		ret = 1;
> +	} else {
> +		int edge = (entry.fields.trig_mode == IOAPIC_EDGE_TRIG);
> +		ioapic->irr |= mask;
> +		if ((edge && old_irr != ioapic->irr) ||
> +		    (!edge && !entry.fields.remote_irr))
> +			ret = ioapic_service(ioapic, irq);
> +		else
> +			ret = 0; /* report coalesced interrupt */
>  	}
> +	trace_kvm_ioapic_set_irq(entry.bits, irq, ret == 0);
>  	spin_unlock(&ioapic->lock);
>  
>  	return ret;
> -- 
> MST

--
			Gleb.
--
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