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=-10.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,INCLUDES_CR_TRAILER,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 EFD03C433FE for ; Thu, 10 Dec 2020 13:55:36 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 96EF223119 for ; Thu, 10 Dec 2020 13:55:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 96EF223119 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=hyVvp8p2Bz7i1f2s639Lw2Yq/jDrzTpsXn8/kljzuls=; b=pROm8mDrrB/teHsFAy+pyP/7u TKm6Hhy1KAdqanPSmkx7poAupXNZgNLl8c8O32veR5SdOVIXhNbJ3RIKCqDpAEC7e+o7tBoJmFZYk cNHZEF/lyeYIVtQEfTbWkeI3dW/LBJZEypCX+/UzZzudhkNDKKI3Dk04OirC0YK9//PBJeZzJNqOO OnnSQVcftS3aShDO7iHVsSsYUvv2CmF70lIHnXL3IehfJ/aClVRMywFm6IxW7CF7N9krQJHGijk+h cvalMmkZ7E5M4zYOFjqI8xSGLvnYJ/s76fHPKrhFdlv2NFzfF15KyAwNqQbYQkWpLomcTmd5n5EXt ZkpZywy+g==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1knMOY-000682-0Y; Thu, 10 Dec 2020 13:54:10 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1knMOC-0005zC-JH for linux-arm-kernel@lists.infradead.org; Thu, 10 Dec 2020 13:54:05 +0000 Date: Thu, 10 Dec 2020 13:53:41 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1607608427; bh=NjrQ4FJF5266Z90UJ72u1Wg6hCMf64J2BYn3ruDlCmM=; h=From:To:Cc:Subject:References:In-Reply-To:From; b=OEPHAVOhWkIGpVAHib6eInZKs+4RcuFzg6tl2dG3haMd7QNgF9yOHoMF7ye0hqlQ9 omcJKaLkBYMJASEvcgVM0BV6YOzfh7esaPQiE6sILqzQSK/g44y8XrjQHwpfCXYrmH EuEU34T3U6N4Ww+DQ4Se5XmyU+DcdKaLZT9ebxOdI+oc+YAX6h5NXLfeR12zrU+roq qdVBWzVj9hyBfCa4ChpHMVk/R6OnHepOX5D3r9iGoySk/z4RpRwRxAefIrJMMCT3fc /6EnxEqfvpMpArhXZg6MGSo/acLDk5cDdE6kMPyW9rhg5cN7lhMxV+XIQLS5ZjlqCo iOKArx0T+z5JQ== From: Will Deacon To: Marc Zyngier Subject: Re: [PATCH v2 0/2] KVM: arm64: Expose CSV3 to guests on running on Meltdown-safe HW Message-ID: <20201210135341.GA10255@willie-the-truck> References: <20201204183709.784533-1-maz@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20201204183709.784533-1-maz@kernel.org> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201210_085348_773909_CC4E4610 X-CRM114-Status: GOOD ( 12.52 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kvm@vger.kernel.org, Suzuki K Poulose , David Brazdil , James Morse , linux-arm-kernel@lists.infradead.org, kernel-team@android.com, kvmarm@lists.cs.columbia.edu, Julien Thierry 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 Fri, Dec 04, 2020 at 06:37:07PM +0000, Marc Zyngier wrote: > Will recently pointed out that when running on big-little systems that > are known not to be vulnerable to Metldown, guests are not presented > with the CSV3 property if the physical HW include a core that doesn't > have CSV3, despite being known to be safe (it is on the kpti_safe_list). > > Since this is valuable information that can be cheaply given to the > guest, let's just do that. The scheme is the same as what we do for > CSV2, allowing userspace to change the default setting if this doesn't > advertise a safer setting than what the kernel thinks it is. > > * From v1: > - Fix the clearing of ID_AA64PFR0_EL1.CSV3 on update from userspace > - Actually store the userspace value > > Marc Zyngier (2): > arm64: Make the Meltdown mitigation state available > KVM: arm64: Advertise ID_AA64PFR0_EL1.CSV3=1 if the CPUs are > Meltdown-safe Acked-by: Will Deacon Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel