From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id DED7C1A0EC7 for ; Thu, 8 Jan 2015 11:49:37 +1100 (AEDT) Date: Wed, 7 Jan 2015 18:49:08 -0600 From: Segher Boessenkool To: Benjamin Herrenschmidt 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 In-Reply-To: <1420641610.5830.29.camel@kernel.crashing.org> Cc: linuxppc-dev@lists.ozlabs.org, Purcareata Bogdan , linux-kernel@vger.kernel.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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