From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755512AbbAHBsX (ORCPT ); Wed, 7 Jan 2015 20:48:23 -0500 Received: from gate.crashing.org ([63.228.1.57]:40612 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751044AbbAHBsV (ORCPT ); Wed, 7 Jan 2015 20:48:21 -0500 Date: Wed, 7 Jan 2015 18:49:08 -0600 From: Segher Boessenkool To: Benjamin Herrenschmidt Cc: Purcareata Bogdan , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: [RFC] PPC: MPIC: necessary readback after EOI? Message-ID: <20150108004908.GA11770@gate.crashing.org> References: <54AA9C4D.3000001@freescale.com> <1420641610.5830.29.camel@kernel.crashing.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1420641610.5830.29.camel@kernel.crashing.org> User-Agent: Mutt/1.4.2.3i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 07, 2015 at 03:40:10PM +0100, Benjamin Herrenschmidt wrote: > One way to work around the performance loss for you would be to add some > DT property to indicate to the guest that the read isn't necessary. Or KVM could use a virtual interrupt controller better suited to its needs. Segher