From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: [PATCH 5/8] arm64: KVM: Disable virtual timer even if the guest is not using it Date: Thu, 17 Sep 2015 17:31:02 +0200 Message-ID: <55FADCB6.8010100@redhat.com> References: <1442501171-24484-1-git-send-email-marc.zyngier@arm.com> <1442501171-24484-6-git-send-email-marc.zyngier@arm.com> <55FAD607.9040305@redhat.com> <55FADC1E.50909@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Cc: Christoffer Dall , Will Deacon , Peter Maydell , =?UTF-8?Q?Alex_Benn=c3=a9e?= , Marek Majtyka , Pavel Fedin , Ming Lei , kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org To: Marc Zyngier , Gleb Natapov Return-path: Received: from mx1.redhat.com ([209.132.183.28]:33866 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751963AbbIQPbJ (ORCPT ); Thu, 17 Sep 2015 11:31:09 -0400 In-Reply-To: <55FADC1E.50909@arm.com> Sender: kvm-owner@vger.kernel.org List-ID: On 17/09/2015 17:28, Marc Zyngier wrote: > > diff --git a/arch/arm/kvm/interrupts_head.S b/arch/arm/kvm/interrupts_head.S > > index 702740d37465..93e322b4d242 100644 > > --- a/arch/arm/kvm/interrupts_head.S > > +++ b/arch/arm/kvm/interrupts_head.S > > @@ -514,6 +514,7 @@ ARM_BE8(rev r6, r6 ) > > beq 1f > > > > mrc p15, 0, r2, c14, c3, 1 @ CNTV_CTL > > + and r2, r2, #3 > > I don't think we need this. Exposing the ISTATUS bit to the kernel (or > even userspace) is not really a problem (that's actually an interesting > piece of information), and restoring it is not possible since it is > read-only. > > We should drop the equivalent 'and' from the arm64 version. Ok. I'll resend the thing as a proper patch. Paolo