From patchwork Fri Jan 17 19:11:06 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kashyap Chamarthy X-Patchwork-Id: 13943916 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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (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 E7F3DC02183 for ; Fri, 17 Jan 2025 19:12:11 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1tYrkc-0005Yn-Ux; Fri, 17 Jan 2025 14:11:26 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1tYrkb-0005Tp-Jq for qemu-devel@nongnu.org; Fri, 17 Jan 2025 14:11:25 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1tYrkZ-0006gP-Qk for qemu-devel@nongnu.org; Fri, 17 Jan 2025 14:11:25 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1737141082; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Vocor7ji6a0ZalKT0F5SpYX94+ZVs7kkvUFkosAMxTA=; b=ezcQxH2vaKmoI6epdkEqV3JDB6Ad9d/X3UFGuYemKfBO6ZXCcx5Yf/5576CrwtchNVM9Mp 8NcWtC5Ka6CDBQdYzllwrbrVW89b7E9O9Ja0Mr1jS0r+z+Yvf44tow9D/mZM9R/iE7aoQ3 xQbjExGBmTBBHdvnh82wgQ95Rpb9tks= Received: from mx-prod-mc-02.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-435-eVwqRoYXOYGGHCHlAz-6gA-1; Fri, 17 Jan 2025 14:11:18 -0500 X-MC-Unique: eVwqRoYXOYGGHCHlAz-6gA-1 X-Mimecast-MFC-AGG-ID: eVwqRoYXOYGGHCHlAz-6gA Received: from mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.40]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id C806F1955DCF; Fri, 17 Jan 2025 19:11:16 +0000 (UTC) Received: from gezellig.redhat.com (unknown [10.39.192.203]) by mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 8590519560BF; Fri, 17 Jan 2025 19:11:14 +0000 (UTC) From: Kashyap Chamarthy To: qemu-devel@nongnu.org Cc: qemu-arm@nongnu.org, maz@kernel.org, sebott@redhat.com, Peter Maydell , Kashyap Chamarthy Subject: [PATCH 2/2] docs/cpu-features: Update "PAuth" (Pointer Authentication) details Date: Fri, 17 Jan 2025 20:11:06 +0100 Message-ID: <20250117191106.322363-3-kchamart@redhat.com> In-Reply-To: <20250117191106.322363-1-kchamart@redhat.com> References: <20250117191106.322363-1-kchamart@redhat.com> MIME-Version: 1.0 Content-type: text/plain X-Scanned-By: MIMEDefang 3.0 on 10.30.177.40 Received-SPF: pass client-ip=170.10.129.124; envelope-from=kchamart@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.132, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org PAuth (Pointer Authentication), a security feature in software, is relevant for both KVM and QEMU. Relect this fact into the docs: - For KVM, `pauth` is a binary, "on" vs "off" option. The host CPU will choose the cryptographic algorithm. - For TCG, however, along with `pauth`, a couple of properties can be controlled -- they're are related to cryptographic algorithm choice. Thanks to Peter Maydell and Marc Zyngier for explaining more about PAuth on IRC (#qemu, OFTC). Signed-off-by: Kashyap Chamarthy --- docs/system/arm/cpu-features.rst | 23 +++++++++++++++++++---- 1 file changed, 19 insertions(+), 4 deletions(-) diff --git a/docs/system/arm/cpu-features.rst b/docs/system/arm/cpu-features.rst index 78f18c87a81..7f99f7614b4 100644 --- a/docs/system/arm/cpu-features.rst +++ b/docs/system/arm/cpu-features.rst @@ -204,11 +204,26 @@ the list of KVM vCPU features and their descriptions. the guest scheduler behavior and/or be exposed to the guest userspace. -TCG vCPU Features -================= +"PAuth" (Pointer Authentication) +================================ + +PAuth (Pointer Authentication) is a security feature in software that +was introduced in Armv8.3-A and Armv9.0-A. It aims to protect against +ROP (return-oriented programming) attacks. + +KVM +--- + +``pauth`` + + Enable or disable ``FEAT_Pauth``. The host silicon will choose the + cryptographic algorithm. No other properties can be controlled. + +TCG +--- -TCG vCPU features are CPU features that are specific to TCG. -Below is the list of TCG vCPU features and their descriptions. +For TCG, along with ``pauth``, it is possible to control a few other +properties of PAuth: ``pauth`` Enable or disable ``FEAT_Pauth`` entirely.