Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752993AbdIFKhM (ORCPT ); Wed, 6 Sep 2017 06:37:12 -0400 Received: from szxga05-in.huawei.com ([45.249.212.191]:5563 "EHLO szxga05-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752508AbdIFKhI (ORCPT ); Wed, 6 Sep 2017 06:37:08 -0400 Subject: Re: [PATCH] arm64: KVM: VHE: save and restore some PSTATE bits To: Vladimir Murzin , Marc Zyngier , "christoffer.dall@linaro.org" , "pbonzini@redhat.com" , "rkrcmar@redhat.com" , "linux-arm-kernel@lists.infradead.org" , "kvmarm@lists.cs.columbia.edu" , "kvm@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "suzuki.poulose@arm.com" , , References: <0184EA26B2509940AA629AE1405DD7F2015DF717@DGGEMA503-MBX.china.huawei.com> <2a5d4299-2523-aef5-7db1-f351ca66b562@arm.com> <981d7334-8841-d3e3-0833-1aa061bf97a2@arm.com> CC: James Morse , , Huangshaoyu From: gengdongjiu Message-ID: <62860a85-c29c-87bb-24b7-c6e5ac6065f9@huawei.com> Date: Wed, 6 Sep 2017 18:35:52 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.7.1 MIME-Version: 1.0 In-Reply-To: <981d7334-8841-d3e3-0833-1aa061bf97a2@arm.com> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.142.68.147] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020203.59AFCFA8.01AA,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2014-11-16 11:51:01, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: 570afe614323726a0ec56b533c2c6037 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 497 Lines: 8 Vladimir, On 2017/9/6 17:41, Vladimir Murzin wrote: > Can you please elaborate on cases where PAN is not enabled? I mean the informal private usage, For example, he disabled the PAN dynamically to let kernel space to access the user space. After he dynamic disabled the PAN, then switched to guest OS. after return to host. he found the PAN stage is modified. Of cause this is not a formal usage, in our host kernel, it is always enabled, no dynamic change, but I means it may exist such cases.