From mboxrd@z Thu Jan  1 00:00:00 1970
From: Radim =?utf-8?B?S3LEjW3DocWZ?= <rkrcmar@redhat.com>
Subject: Re: [PATCH 0/8] KVM: minor APIC fixes and cleanups
Date: Fri, 30 Jan 2015 16:20:31 +0100
Message-ID: <20150130152031.GC28519@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 10:22+0100, Paolo Bonzini:
> On 29/01/2015 22:48, Radim Kr=C4=8Dm=C3=A1=C5=99 wrote:
> > This patch series is made our of three logical parts,
> >=20
> > [1-3/8] are just a cleanup and could be omitted
> > [4-6/8] improve broadcast detection and unoptimized delivery
> > [7-8/8] handle mixed mode (by falling back to improvements from [5-=
6/9])
>=20
> I applied patches 1-4 and commented on patch 5.
>=20
> I'm afraid that patches 7-8 could lead to missed optimizations in som=
e cases.

True, I'll do more research on complexity of its assembly.

> Regarding patch 6, perhaps there's a way to avoid this:
>=20
> +	/* XXX: A superset of x2APIC broadcasts is fine in practice as long=
 as
> +	 * we don't support APIC ID > 0xfeffffff.
> +	 */
>=20
> It's ugly. :)

Yeah, there is: don't deliver x2APIC broadcasts to xAPIC.
(I'm not even sure if it is correct ...)

Without that delivery, we could do something like
  if (irq->dest_id =3D=3D (x2apic_ipi ? X2APIC_BROADCAST : APIC_BROADCA=
ST))