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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, 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 B1D24C433E1 for ; Tue, 26 May 2020 16:28:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 91D162073B for ; Tue, 26 May 2020 16:28:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729401AbgEZQ26 (ORCPT ); Tue, 26 May 2020 12:28:58 -0400 Received: from foss.arm.com ([217.140.110.172]:53204 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726282AbgEZQ26 (ORCPT ); Tue, 26 May 2020 12:28:58 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id C079730E; Tue, 26 May 2020 09:28:57 -0700 (PDT) Received: from [192.168.0.14] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id BE2CF3F52E; Tue, 26 May 2020 09:28:55 -0700 (PDT) From: James Morse Subject: Re: [PATCH 10/26] KVM: arm64: Refactor vcpu_{read,write}_sys_reg To: Marc Zyngier Cc: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, Andre Przywara , Christoffer Dall , Dave Martin , Jintack Lim , Alexandru Elisei , George Cherian , "Zengtao (B)" , Will Deacon , Catalin Marinas , Mark Rutland , Julien Thierry , Suzuki K Poulose References: <20200422120050.3693593-1-maz@kernel.org> <20200422120050.3693593-11-maz@kernel.org> Message-ID: <09da829c-1640-40fe-313f-df021759fb34@arm.com> Date: Tue, 26 May 2020 17:28:54 +0100 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <20200422120050.3693593-11-maz@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Hi Marc, On 22/04/2020 13:00, Marc Zyngier wrote: > Extract the direct HW accessors for later reuse. > diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c > index 51db934702b64..46f218982df8c 100644 > --- a/arch/arm64/kvm/sys_regs.c > +++ b/arch/arm64/kvm/sys_regs.c > +u64 vcpu_read_sys_reg(const struct kvm_vcpu *vcpu, int reg) > +{ > + u64 val = 0x8badf00d8badf00d; > + > + if (!vcpu->arch.sysregs_loaded_on_cpu) { > + goto memory_read; > } > > -immediate_write: > + if (__vcpu_read_sys_reg_from_cpu(reg, &val)) > + return val; > + > +memory_read: > + return __vcpu_sys_reg(vcpu, reg); > +} The goto here is a bit odd, is it just an artefact of how we got here? Is this easier on the eye?: | u64 vcpu_read_sys_reg(const struct kvm_vcpu *vcpu, int reg) | { | u64 val = 0x8badf00d8badf00d; | | if (vcpu->arch.sysregs_loaded_on_cpu && | __vcpu_read_sys_reg_from_cpu(reg, &val)) | return val; | | return __vcpu_sys_reg(vcpu, reg); | } > +void vcpu_write_sys_reg(struct kvm_vcpu *vcpu, u64 val, int reg) > +{ > + if (!vcpu->arch.sysregs_loaded_on_cpu) > + goto memory_write; > + > + if (__vcpu_write_sys_reg_to_cpu(val, reg)) > + return; > + > +memory_write: > __vcpu_sys_reg(vcpu, reg) = val; > } Again I think its clearer without the goto.... Regardless: Reviewed-by: James Morse Thanks, James