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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id EAD43C433FE for ; Tue, 23 Nov 2021 00:56:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230057AbhKWBAB (ORCPT ); Mon, 22 Nov 2021 20:00:01 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48336 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229628AbhKWA76 (ORCPT ); Mon, 22 Nov 2021 19:59:58 -0500 Received: from mail-pj1-x102e.google.com (mail-pj1-x102e.google.com [IPv6:2607:f8b0:4864:20::102e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1DCECC061574 for ; Mon, 22 Nov 2021 16:56:51 -0800 (PST) Received: by mail-pj1-x102e.google.com with SMTP id n15-20020a17090a160f00b001a75089daa3so694079pja.1 for ; Mon, 22 Nov 2021 16:56:51 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=ZXvoEcLrIGAYAoxovKlZgNb0DwtzZO0ytuqE+a5WWL0=; b=ogIpIsg3sg06ztfxFAMnN7UHnHDsDlSDO6ts+2BlChHtSHaNZKXPTxxu5vXTx0LnCn YSdAsYxJTSvXNwhD/09DLEwIJVkcoh6fdk5gOmtzdVVLDo2QlPlaiIHrr5rmO0hdtEP+ VOp0wmzqH8Av2MYELfhNJRzPloGL2gBz8KzAh8eupjuXi/XU7roRauyh5XYKxtglMPRg IivlxRLUJC/HgKxKQnBti03sV6oF37yQky4ofR3y+NZSU2wHRIxVE4KxhBpeXrH4mMUt wGhSOVhAvLvl4HM1LQS8ud/nG0b4Poir5J+WitnyeLN4urGhIUw9vwjzPFyn7p5IC/di vxRg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=ZXvoEcLrIGAYAoxovKlZgNb0DwtzZO0ytuqE+a5WWL0=; b=AIxJr70pmtI31hFDQp3OS9kekwYH8RUuZpxkaksS/SW+AM9HfQmXem349vnQCTeuyi xcP5QoTxoApbNoU7Us8DQX/6WnLB5fidvxbK32eRUz54X1svrDLzTJoRHzAkMsORDc0o s7GTtbh/ktI69YvpPhzljpqm1QAZ3K0C4pWpLo9yCYGvj287nqMuFfcEV8HBvoKBodeI 8bpuGe+sGwUzN2CWmeRd5k+WTyupKz2E3YRzzPVMCDsZdZMNFS3/vzLZS05gNzteRoux CpRRBFQRJl+HB+6ENjC7wzxaNwLLKeguoeTiInc4tU25Cw2rjwg2mSneIvAg3yFoWOM4 yX5w== X-Gm-Message-State: AOAM533i4SMNNJ2W8PCUdSvh2QHm6xof+cnTT9r0HPIzZwqMKXvszyFw CPhAmEhqfT1fHNywtQJRORW05pgtdHZPFMq1TKpjSA== X-Google-Smtp-Source: ABdhPJxiNkaElnGL+/0qOxDZz3IwVrLy5Ntwdx8UmLE6q9RCwWPsBv7dFYR/iNcZsdp8VxNtYX3ZSl2LbBW7cQX7klU= X-Received: by 2002:a17:90b:380d:: with SMTP id mq13mr1521017pjb.110.1637629010508; Mon, 22 Nov 2021 16:56:50 -0800 (PST) MIME-Version: 1.0 References: <20211117064359.2362060-1-reijiw@google.com> <20211117064359.2362060-4-reijiw@google.com> <87ilwlsn0e.wl-maz@kernel.org> In-Reply-To: <87ilwlsn0e.wl-maz@kernel.org> From: Reiji Watanabe Date: Mon, 22 Nov 2021 16:56:34 -0800 Message-ID: Subject: Re: [RFC PATCH v3 03/29] KVM: arm64: Introduce struct id_reg_info To: Marc Zyngier Cc: Eric Auger , kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, Will Deacon , Peter Shier , Paolo Bonzini , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Sun, Nov 21, 2021 at 4:37 AM Marc Zyngier wrote: > > On Fri, 19 Nov 2021 04:47:53 +0000, > Reiji Watanabe wrote: > > > > I am going to add the following comment. Does it look clear enough for you ? > > > > /* > > * This is an optional ID register specific validation function. > > * When userspace tries to set the ID register, arm64_check_features() > > * will check if the requested value indicates any features that cannot > > * be supported by KVM on the host. But, some ID register fields need > > * a special checking and this function can be used for such fields. > > * e.g. KVM_CREATE_DEVICE must be used to configure GICv3 for a guest. > > * ID_AA64PFR0_EL1.GIC shouldn't be set to 1 unless GICv3 is configured. > > There is no such requirement. GICv3 has a compatibility interface, and > although KVM doesn't make use of it, there is no reason not to expose > that GICv3 exists on the CPU even if not using it. Even more, this has > been the case forever, and making this change now would probably break > migration. Shockingly, I somehow misunderstood what read_id_reg() did for GICv3... I will use a different example for it. Thanks, Reiji