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

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Message-ID: <20120813205932.GA15395@amt.cnet>
Date:	Mon, 13 Aug 2012 17:59:32 -0300
From:	Marcelo Tosatti <mtosatti@...hat.com>
To:	Gleb Natapov <gleb@...hat.com>
Cc:	"Michael S. Tsirkin" <mst@...hat.com>, Avi Kivity <avi@...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 05:30:53PM +0300, Gleb Natapov wrote:
> 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.

Which BUG_ON?

> 
> > 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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