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=-10.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 98AB3C433E1 for ; Mon, 17 Aug 2020 07:39:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 71F7020758 for ; Mon, 17 Aug 2020 07:39:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597649958; bh=5f7u17TvsjTrzreApIZ4x0jr/04LEQs1hIO1IBZJBVg=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=cEu479Wpq3i8RwZhWe/ata/DVGqSoR0KhRU8U7N23qAkYQ3G3cLf6l8fNprj8jlV0 D6XHYeyGyaUDlG9/zFW461w2qv4CnjPInP7Y4jQDQE0oYJQexY96YJovnmGDo5hX9V dxVX6Zbu7SwhYHs+7ITK9yxxlV9HuOBV1A80vp30= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726648AbgHQHjQ (ORCPT ); Mon, 17 Aug 2020 03:39:16 -0400 Received: from mail.kernel.org ([198.145.29.99]:40500 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726089AbgHQHjP (ORCPT ); Mon, 17 Aug 2020 03:39:15 -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 14CC420758; Mon, 17 Aug 2020 07:39:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597649954; bh=5f7u17TvsjTrzreApIZ4x0jr/04LEQs1hIO1IBZJBVg=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=MZk/ZzO0Xwj51vzBkOh6djd6cauo+roP/pRXxR0PLsTP9CxwmDwEQWJzTOZ+efS5N QUUrA+K/1xW95pGQ2wvCVRVUyJzPQ17UZXIXt1cfl5+9y6EMMgKTNeEDjcoRzAfaIj XlILTLZZUpgl+E35JmvL+d76aYnLmH9VvHC3F0nA= 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 1k7Zjc-003T4X-BL; Mon, 17 Aug 2020 08:39:12 +0100 MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Mon, 17 Aug 2020 08:39:12 +0100 From: Marc Zyngier To: Keqian Zhu Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, Catalin Marinas , Will Deacon , James Morse , Suzuki K Poulose , Steven Price , wanghaibin.wang@huawei.com Subject: Re: [PATCH 2/3] KVM: uapi: Remove KVM_DEV_TYPE_ARM_PV_TIME in kvm_device_type In-Reply-To: <20200817033729.10848-3-zhukeqian1@huawei.com> References: <20200817033729.10848-1-zhukeqian1@huawei.com> <20200817033729.10848-3-zhukeqian1@huawei.com> User-Agent: Roundcube Webmail/1.4.7 Message-ID: X-Sender: maz@kernel.org X-SA-Exim-Connect-IP: 51.254.78.96 X-SA-Exim-Rcpt-To: zhukeqian1@huawei.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, catalin.marinas@arm.com, will@kernel.org, james.morse@arm.com, suzuki.poulose@arm.com, steven.price@arm.com, wanghaibin.wang@huawei.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2020-08-17 04:37, Keqian Zhu wrote: > ARM64 PV-time ST is configured by userspace through vCPU attribute, > and KVM_DEV_TYPE_ARM_PV_TIME is unused. > > Signed-off-by: Keqian Zhu > --- > include/uapi/linux/kvm.h | 2 -- > tools/include/uapi/linux/kvm.h | 2 -- > 2 files changed, 4 deletions(-) > > diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h > index 4fdf303..9a6b97e 100644 > --- a/include/uapi/linux/kvm.h > +++ b/include/uapi/linux/kvm.h > @@ -1258,8 +1258,6 @@ enum kvm_device_type { > #define KVM_DEV_TYPE_ARM_VGIC_ITS KVM_DEV_TYPE_ARM_VGIC_ITS > KVM_DEV_TYPE_XIVE, > #define KVM_DEV_TYPE_XIVE KVM_DEV_TYPE_XIVE > - KVM_DEV_TYPE_ARM_PV_TIME, > -#define KVM_DEV_TYPE_ARM_PV_TIME KVM_DEV_TYPE_ARM_PV_TIME > KVM_DEV_TYPE_MAX, > }; > > diff --git a/tools/include/uapi/linux/kvm.h > b/tools/include/uapi/linux/kvm.h > index 4fdf303..9a6b97e 100644 > --- a/tools/include/uapi/linux/kvm.h > +++ b/tools/include/uapi/linux/kvm.h > @@ -1258,8 +1258,6 @@ enum kvm_device_type { > #define KVM_DEV_TYPE_ARM_VGIC_ITS KVM_DEV_TYPE_ARM_VGIC_ITS > KVM_DEV_TYPE_XIVE, > #define KVM_DEV_TYPE_XIVE KVM_DEV_TYPE_XIVE > - KVM_DEV_TYPE_ARM_PV_TIME, > -#define KVM_DEV_TYPE_ARM_PV_TIME KVM_DEV_TYPE_ARM_PV_TIME > KVM_DEV_TYPE_MAX, > }; No. You can't drop anything from UAPI, used or not. Doing so will break the compilation of any userspace that, for any reason, references this value. We cannot reuse this value in the future either, as it would create a we wouldn't know which device to create. It is pretty unfortunate that PV time has turned into such a train wreck, but that's what we have now, and it has to stay. M. -- Jazz is not dead. It just smells funny...