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=-7.0 required=3.0 tests=INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 390AFC2D0C0 for ; Sun, 22 Dec 2019 10:44:08 +0000 (UTC) Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by mail.kernel.org (Postfix) with ESMTP id AE7F920733 for ; Sun, 22 Dec 2019 10:44:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AE7F920733 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvmarm-bounces@lists.cs.columbia.edu Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 695374AF09; Sun, 22 Dec 2019 05:44:06 -0500 (EST) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id cGDbVZGJJ8TR; Sun, 22 Dec 2019 05:44:05 -0500 (EST) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 449A14AF0B; Sun, 22 Dec 2019 05:44:05 -0500 (EST) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id ED07A4AEEF for ; Sun, 22 Dec 2019 05:44:03 -0500 (EST) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id rGWoMeaWFR4Z for ; Sun, 22 Dec 2019 05:43:59 -0500 (EST) Received: from inca-roads.misterjones.org (inca-roads.misterjones.org [213.251.177.50]) by mm01.cs.columbia.edu (Postfix) with ESMTPS id B26124AEEE for ; Sun, 22 Dec 2019 05:43:59 -0500 (EST) Received: from 78.163-31-62.static.virginmediabusiness.co.uk ([62.31.163.78] helo=big-swifty.misterjones.org) by cheepnis.misterjones.org with esmtpsa (TLSv1.2:AES256-GCM-SHA384:256) (Exim 4.80) (envelope-from ) id 1iiygN-0005Y6-Rv; Sun, 22 Dec 2019 11:43:56 +0100 Date: Sun, 22 Dec 2019 10:42:05 +0000 Message-ID: <86bls0iqv6.wl-maz@kernel.org> From: Marc Zyngier To: Andrew Murray Subject: Re: [PATCH v2 11/18] KVM: arm64: don't trap Statistical Profiling controls to EL2 In-Reply-To: <20191220143025.33853-12-andrew.murray@arm.com> References: <20191220143025.33853-1-andrew.murray@arm.com> <20191220143025.33853-12-andrew.murray@arm.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL/10.8 EasyPG/1.0.0 Emacs/26 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") X-SA-Exim-Connect-IP: 62.31.163.78 X-SA-Exim-Rcpt-To: andrew.murray@arm.com, marc.zyngier@arm.com, catalin.marinas@arm.com, will.deacon@arm.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, sudeep.holla@arm.com, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on cheepnis.misterjones.org); SAEximRunCond expanded to false Cc: kvm@vger.kernel.org, Marc Zyngier , Catalin Marinas , Will Deacon , linux-kernel@vger.kernel.org, Sudeep Holla , kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list List-Id: Where KVM/ARM decisions are made List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu On Fri, 20 Dec 2019 14:30:18 +0000, Andrew Murray wrote: > > As we now save/restore the profiler state there is no need to trap > accesses to the statistical profiling controls. Let's unset the > _TPMS bit. > > Signed-off-by: Andrew Murray > --- > arch/arm64/kvm/debug.c | 2 -- > 1 file changed, 2 deletions(-) > > diff --git a/arch/arm64/kvm/debug.c b/arch/arm64/kvm/debug.c > index 43487f035385..07ca783e7d9e 100644 > --- a/arch/arm64/kvm/debug.c > +++ b/arch/arm64/kvm/debug.c > @@ -88,7 +88,6 @@ void kvm_arm_reset_debug_ptr(struct kvm_vcpu *vcpu) > * - Performance monitors (MDCR_EL2_TPM/MDCR_EL2_TPMCR) > * - Debug ROM Address (MDCR_EL2_TDRA) > * - OS related registers (MDCR_EL2_TDOSA) > - * - Statistical profiler (MDCR_EL2_TPMS/MDCR_EL2_E2PB) > * > * Additionally, KVM only traps guest accesses to the debug registers if > * the guest is not actively using them (see the KVM_ARM64_DEBUG_DIRTY > @@ -111,7 +110,6 @@ void kvm_arm_setup_debug(struct kvm_vcpu *vcpu) > */ > vcpu->arch.mdcr_el2 = __this_cpu_read(mdcr_el2) & MDCR_EL2_HPMN_MASK; > vcpu->arch.mdcr_el2 |= (MDCR_EL2_TPM | > - MDCR_EL2_TPMS | No. This is an *optional* feature (the guest could not be presented with the SPE feature, or the the support simply not be compiled in). If the guest is not allowed to see the feature, for whichever reason, the traps *must* be enabled and handled. M. -- Jazz is not dead, it just smells funny. _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm