From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751963AbdJPJoK (ORCPT ); Mon, 16 Oct 2017 05:44:10 -0400 Received: from mx1.redhat.com ([209.132.183.28]:44850 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750914AbdJPJoJ (ORCPT ); Mon, 16 Oct 2017 05:44:09 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 011D4356F2 Authentication-Results: ext-mx06.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx06.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=eric.auger@redhat.com Subject: Re: [PATCH 7/9] KVM: arm/arm64: vgic-its: free caches when GITS_BASER Valid bit is cleared To: Christoffer Dall References: <1506346478-1631-1-git-send-email-eric.auger@redhat.com> <1506346478-1631-8-git-send-email-eric.auger@redhat.com> <20171016092624.GA1845@lvm> Cc: eric.auger.pro@gmail.com, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, marc.zyngier@arm.com, peter.maydell@linaro.org, andre.przywara@arm.com, wanghaibin.wang@huawei.com, wu.wubin@huawei.com From: Auger Eric Message-ID: <96697f44-9f1d-347c-82dd-bb5b1c6cbdc2@redhat.com> Date: Mon, 16 Oct 2017 11:44:05 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: <20171016092624.GA1845@lvm> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Mon, 16 Oct 2017 09:44:09 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Christoffer, On 16/10/2017 11:26, Christoffer Dall wrote: > Hi Eric, > > On Mon, Sep 25, 2017 at 03:34:36PM +0200, Eric Auger wrote: >> When the GITS_BASER.Valid gets cleared, the data structures in >> guest RAM are not provisionned anymore. The device, collection >> and LPI lists stored in the in-kernel ITS represent the same >> information in some form of cache. So let's void the cache. > > Just a thought. What about the opposite case, if the BASERs were > previously not valid, and then become valid, is the ITS expected restore > the state from memory? > > Thanks, > -Christoffer > No the spec does not mandate that as far as I understand. Also the spec does not mandate clearing the cache when BASER moves to invalid (which this patch does), although this would have madee sense to me. So maybe we should drop that patch and only clean the cache when the IOCTL is used. Thanks Eric