From mboxrd@z Thu Jan 1 00:00:00 1970 From: Will Deacon Subject: Re: [PATCH v3 2/4] arm64: KVM: add accessors to track guest/host only counters Date: Mon, 3 Dec 2018 14:31:14 +0000 Message-ID: <20181203143114.GA26831@arm.com> References: <1542885950-23816-3-git-send-email-andrew.murray@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id E91B74A2BB for ; Mon, 3 Dec 2018 09:30:56 -0500 (EST) 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 ajRTECAgLhw4 for ; Mon, 3 Dec 2018 09:30:55 -0500 (EST) Received: from foss.arm.com (usa-sjc-mx-foss1.foss.arm.com [217.140.101.70]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 9DF814A214 for ; Mon, 3 Dec 2018 09:30:55 -0500 (EST) Content-Disposition: inline In-Reply-To: <1542885950-23816-3-git-send-email-andrew.murray@arm.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu To: Andrew Murray Cc: Marc Zyngier , Catalin Marinas , kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org List-Id: kvmarm@lists.cs.columbia.edu On Thu, Nov 22, 2018 at 11:25:48AM +0000, Andrew Murray wrote: > In order to effeciently enable/disable guest/host only perf counters > at guest entry/exit we add bitfields to kvm_cpu_context for guest and > host only events as well as accessors for updating them. > > Signed-off-by: Andrew Murray > --- > arch/arm64/include/asm/kvm_host.h | 20 ++++++++++++++++++++ > 1 file changed, 20 insertions(+) > > diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h > index 1550192..4a828eb 100644 > --- a/arch/arm64/include/asm/kvm_host.h > +++ b/arch/arm64/include/asm/kvm_host.h > @@ -203,6 +203,8 @@ struct kvm_cpu_context { > }; > > struct kvm_vcpu *__hyp_running_vcpu; > + u32 events_host_only; > + u32 events_guest_only; > }; > > typedef struct kvm_cpu_context kvm_cpu_context_t; > @@ -472,6 +474,24 @@ static inline int kvm_arch_vcpu_run_pid_change(struct kvm_vcpu *vcpu) > { > return kvm_arch_vcpu_run_map_fp(vcpu); > } > +static inline void kvm_clr_set_host_pmu_events(u32 clr, u32 set) > +{ > + kvm_cpu_context_t *ctx = this_cpu_ptr(&kvm_host_cpu_state); > + > + ctx->events_host_only &= ~clr; > + ctx->events_host_only |= set; > +} Do you actually need this clr/set function, or can you just use the facilities provided by bitfield.h at the callsites? Will