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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 2D7A8C433F5 for ; Tue, 23 Nov 2021 00:58:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:Cc:To:Subject:Message-ID:Date:From: In-Reply-To:References:MIME-Version:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=PlyxPCGu6ha98aCJslc7n01JravOoTjW10AC3skLARE=; b=u59DdoUlb+UIoZ M8qxcBpkbXC4a/qUapD64BBTQfAIZ8oFVvjyhUT4M0ZZ2arwlrIZG+2Kmb3o5sCBT1QvoE0bb7GMB lUhJ/F0TsXY67LRzy7tj/u5gZyq7zttZmaDtobtzupvJ98hiuAnvq/E1fCAX7iWkgKL+dSmpdKpST iiPmB76/EnRY6VvuCJd5/kvDyyDjQkmoKCHEIcROc6KZ6/1p5+c8nUpzC8oJB3b5IiKzqbpYd2T75 T/RVHajbMFuGooFyZHA4Aa5/HSxZFGusFGMwGRdnENIOLDfJQ5bqDWLE1AAPag6hiyuQ1n94wEPZQ qxrvWkBnp/BBb+d8Oi5Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mpK7D-000Z0k-SZ; Tue, 23 Nov 2021 00:56:56 +0000 Received: from mail-pj1-x1035.google.com ([2607:f8b0:4864:20::1035]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1mpK79-000Z0J-OW for linux-arm-kernel@lists.infradead.org; Tue, 23 Nov 2021 00:56:53 +0000 Received: by mail-pj1-x1035.google.com with SMTP id np6-20020a17090b4c4600b001a90b011e06so1381924pjb.5 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=pdsGPj7on8Ut8jhgKE517+J0XhmkWk2nJQCystRpnu2T1w4oiNTMhsqQgu3IcTDCMl z0SFJSO2I+aFhWRqQA/OhtO8zYjaE0fgBCFJx9IEmCZfpFqq17rLubgCQvTo+eLWJ6J3 uaYZobUZStCAm4KjC20Lzm4QMUP2EyFECqRaP/7EIQfxZB1MStvbF807itqcV88FiIIF 87ZkYVyMpWwK8vFX3LYv09/Gbj/lxOLzcfEqJwBGrfcPGnc2+2BSYmeYvMsv7xAr2cwH 2G2/JzmoXGZfcs3sT8vgjQb29R5SEZwMx0TnePTIyHIzsAs8sajmD/+zU55hVrN6wzA0 umDw== X-Gm-Message-State: AOAM531C4JdNZvAktaSTa8DBdgkWY+rfizorcuU7UQU3eJVdsdjS4Eus ThA/EUxm5XW4gBFbmaoOCSHmcxq80KX3e5TuJxnMpw== 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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211122_165651_825977_047F68DE X-CRM114-Status: GOOD ( 19.44 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.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 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel