From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 911E9C18E5B for ; Mon, 16 Mar 2020 10:50:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6DD022051A for ; Mon, 16 Mar 2020 10:50:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730733AbgCPKuH (ORCPT ); Mon, 16 Mar 2020 06:50:07 -0400 Received: from szxga04-in.huawei.com ([45.249.212.190]:11650 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1730478AbgCPKuG (ORCPT ); Mon, 16 Mar 2020 06:50:06 -0400 Received: from DGGEMS403-HUB.china.huawei.com (unknown [172.30.72.59]) by Forcepoint Email with ESMTP id 1798D6017481BD96D1A2; Mon, 16 Mar 2020 18:50:02 +0800 (CST) Received: from [127.0.0.1] (10.173.222.27) by DGGEMS403-HUB.china.huawei.com (10.3.19.203) with Microsoft SMTP Server id 14.3.487.0; Mon, 16 Mar 2020 18:49:53 +0800 Subject: Re: [PATCH] KVM: arm64: Use the correct timer for accessing CNT To: KarimAllah Ahmed , CC: Marc Zyngier , , References: <1584351546-5018-1-git-send-email-karahmed@amazon.de> From: Zenghui Yu Message-ID: <7ed91b9b-e968-770c-28f9-0ca479359657@huawei.com> Date: Mon, 16 Mar 2020 18:49:51 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.2.0 MIME-Version: 1.0 In-Reply-To: <1584351546-5018-1-git-send-email-karahmed@amazon.de> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.173.222.27] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On 2020/3/16 17:39, KarimAllah Ahmed wrote: > Use the physical timer object when reading the physical timer counter > instead of using the virtual timer object. This is only visible when > reading it from user-space as kvm_arm_timer_get_reg() is only executed on > the get register patch from user-space. s/patch/path/ I think the physical counter hasn't yet been accessed by the current userspace, wrong? > > Cc: Marc Zyngier > Cc: James Morse > Cc: Julien Thierry > Cc: Suzuki K Poulose > Cc: linux-arm-kernel@lists.infradead.org > Cc: kvmarm@lists.cs.columbia.edu > Cc: linux-kernel@vger.kernel.org > Signed-off-by: KarimAllah Ahmed Reviewed-by: Zenghui Yu And this might also deserve: Fixes: 84135d3d18da ("KVM: arm/arm64: consolidate arch timer trap handlers") Thanks. > --- > virt/kvm/arm/arch_timer.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c > index 0d9438e..93bd59b 100644 > --- a/virt/kvm/arm/arch_timer.c > +++ b/virt/kvm/arm/arch_timer.c > @@ -788,7 +788,7 @@ u64 kvm_arm_timer_get_reg(struct kvm_vcpu *vcpu, u64 regid) > vcpu_ptimer(vcpu), TIMER_REG_CTL); > case KVM_REG_ARM_PTIMER_CNT: > return kvm_arm_timer_read(vcpu, > - vcpu_vtimer(vcpu), TIMER_REG_CNT); > + vcpu_ptimer(vcpu), TIMER_REG_CNT); > case KVM_REG_ARM_PTIMER_CVAL: > return kvm_arm_timer_read(vcpu, > vcpu_ptimer(vcpu), TIMER_REG_CVAL); >