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=-9.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 1571BC433DF for ; Wed, 27 May 2020 10:04:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DF881208FE for ; Wed, 27 May 2020 10:04:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590573853; bh=zSIdbYQzBzwhjrQI1hWwupDBNv6wpaxUIuCkjXojSUs=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=aq4kluMw0f5OQS7BsVY6NOI8Yailo74iR9oIBokVgZ511T25U2ELY2nWeTenI+lZt yQHC6z7xNXUKX9PLdTZ8nX9THEvCDyfnZZNY15dsTQN1IMdjEeURz4seXcJsaUaUzs IH6ICl6KwvK6TLJ3upyAGPP5Sno+QwcY4fAQkLt0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728185AbgE0KEM (ORCPT ); Wed, 27 May 2020 06:04:12 -0400 Received: from mail.kernel.org ([198.145.29.99]:53760 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725775AbgE0KEK (ORCPT ); Wed, 27 May 2020 06:04:10 -0400 Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 6EBCA2084C; Wed, 27 May 2020 10:04:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590573850; bh=zSIdbYQzBzwhjrQI1hWwupDBNv6wpaxUIuCkjXojSUs=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=mdxZIF05SH6elzOSo9ZapHNOQTVJUmqp6M8R2ruYxkwZfsnML55SowgexSg4vGSjR 9BrMXLjFGrYP0ZeSZ8q1G2q8UjOZL+OwezjpS3XZ4MXV1NuaCWhNoG73aOTLSrtsLc wS9UJZ2vgVazwPa9OxZQ4zUZbrOv7fmLZg4hCw9E= Received: from disco-boy.misterjones.org ([51.254.78.96] helo=www.loen.fr) by disco-boy.misterjones.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.92) (envelope-from ) id 1jdsuu-00Ff8O-Pj; Wed, 27 May 2020 11:04:08 +0100 MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Wed, 27 May 2020 11:04:08 +0100 From: Marc Zyngier To: James Morse 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 Subject: Re: [PATCH 10/26] KVM: arm64: Refactor vcpu_{read,write}_sys_reg In-Reply-To: <09da829c-1640-40fe-313f-df021759fb34@arm.com> References: <20200422120050.3693593-1-maz@kernel.org> <20200422120050.3693593-11-maz@kernel.org> <09da829c-1640-40fe-313f-df021759fb34@arm.com> User-Agent: Roundcube Webmail/1.4.4 Message-ID: <1612302e289ba15fb0ffbfba5ea18e3b@kernel.org> X-Sender: maz@kernel.org X-SA-Exim-Connect-IP: 51.254.78.96 X-SA-Exim-Rcpt-To: james.morse@arm.com, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, andre.przywara@arm.com, christoffer.dall@arm.com, Dave.Martin@arm.com, jintack@cs.columbia.edu, alexandru.elisei@arm.com, gcherian@marvell.com, prime.zeng@hisilicon.com, will@kernel.org, catalin.marinas@arm.com, mark.rutland@arm.com, julien.thierry.kdev@gmail.com, suzuki.poulose@arm.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 2020-05-26 17:28, James Morse wrote: > 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? That's because a lot of this changes when NV gets added to the mix, see [1]. > 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); > | } Definitely. I don't mind reworking the NV branch so that the label gets introduced there. >> +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, M. [1] https://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git/commit/?h=kvm-arm64/nv-5.7-rc1-WIP&id=11f3217d39a602cbfac7d08064c8b31afb57348e -- Jazz is not dead. It just smells funny...