From mboxrd@z Thu Jan  1 00:00:00 1970
From: Radim =?utf-8?B?S3LEjW3DocWZ?= <rkrcmar@redhat.com>
Subject: Re: [PATCH 5/8] KVM: x86: use MDA for interrupt matching
Date: Fri, 30 Jan 2015 14:09:41 +0100
Message-ID: <20150130130941.GB28519@potion.redhat.com>
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Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
	Nadav Amit <namit@cs.technion.ac.il>,
	Gleb Natapov <gleb@kernel.org>
To: Paolo Bonzini <pbonzini@redhat.com>
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2015-01-30 10:03+0100, Paolo Bonzini:
> On 29/01/2015 22:48, Radim Kr=C4=8Dm=C3=A1=C5=99 wrote:
> > +/* KVM APIC implementation has two quirks
> > + *  - dest always begins at 0 while xAPIC MDA has offset 24,
> > + *  - IOxAPIC messages have to be delivered (directly) to x2APIC.
> > + */
> > +static u32
> > +kvm_apic_mda(unsigned int dest, struct kvm_lapic *ipi, bool x2apic=
_dest)
>=20
> Please pass two struct kvm_lapic, so that you can write
>=20
> 	bool ipi =3D source !=3D NULL;
> 	bool x2apic_mda =3D apic_x2apic_mode(ipi ? source : dest);
>=20
> Looks a little nicer to me at least.

Definitely.

> > +{
> > +	bool x2apic_mda =3D ipi ? apic_x2apic_mode(ipi) : x2apic_dest;
> > +
> > +	if (!ipi && dest =3D=3D APIC_BROADCAST)
> > +		dest =3D X2APIC_BROADCAST;
>=20
> This works, but it is not super-clear that you are shifting left by 2=
4
> here, and right in kvm_apic_broadcast().  What if you just make it
>=20
> 	if (!ipi && dest =3D=3D APIC_BROADCAST && x2apic_mda)
> 		return X2APIC_BROADCAST.

It's better, it will be that way in v2 of [5-8/8], thanks.

(I was using it twice in earlier iterations and didn't think again.)