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 6F548C79F89 for ; Mon, 7 Sep 2026 10:11:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type:MIME-Version: References:In-Reply-To:Subject:Cc:To:From:Message-ID:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Q7sejMU0l9gfX0j72uKaQiah2rzxVb9QaSNefrHXSfE=; b=Z/8HZLTU3vYcQP2k3M8tCH+96F AGGb3jFFdKO5nqcgmxISqFxj17qlu6/AHFB6oYXVTInq21WJqHzrQ3gYdVveYGDX5LTqChpaCWWzQ lgFnzJEun9uwarnmVPXKKJfopBTmR+wEDxOrWaA++GKeCPmmhqXQfy/PgH4EYmhzePaFw7/iKnKKx fyZwa6hRraZgrDckUGdDUbZuKoM3KSDmUQhRtLqBxHIRP1ozc0h97O92WrptYiFaBQfwDnOCzqeUY Lw51C+J22PhXJ6TgNUKryI9X1ToQVX+G0LelhnIwGDXbeQMvDmgZ7lDXcphshLMhnM62f6w3Ug7C3 01WhBmbQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1x3WJT-00000006SQT-36Se; Mon, 07 Sep 2026 10:10:55 +0000 Received: from sea.source.kernel.org ([172.234.252.31]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1x3WJQ-00000006SPm-3rmY for linux-arm-kernel@lists.infradead.org; Mon, 07 Sep 2026 10:10:52 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id A905340E01; Mon, 7 Sep 2026 10:10:52 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 88B581F00A3A; Mon, 7 Sep 2026 10:10:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788775852; bh=Q7sejMU0l9gfX0j72uKaQiah2rzxVb9QaSNefrHXSfE=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=nV2+X68E39cQ9E4OknOTWhNQTE1ZzYAPtm/Pg7/HQ/r4ivpB6KuxoVLOKcC1y9Z+S lFRqADegtw6QnImfC/yzTH7+s4q/5Kdmehhyrqvwv5Lsj5R+tpy8I8sJTIf2SPxmE2 67Pu4Wloo8ZD/mx2GaKsfXkbEN4vBmI8cF9oq7XA3okkcFOJbPcaTsfMFU0iwQNbCb ys9bBlOktzqpyMDbcHPTGHh4GrgRFZT8uUudYKHr0jZK6e3JoAwniwTUzGo7DdF0o7 NvJ61iwHuFuT0Ml/aRpCbuymDg3/rwH3qb59dVZJJrNHU8TZZxsWMnkpQnu8M5HF54 YgRQpAw3mK3Hg== Received: from sofa.misterjones.org ([185.219.108.64] helo=goblin-girl.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.98.2) (envelope-from ) id 1x3WJO-00000005hHQ-1NLm; Mon, 07 Sep 2026 10:10:50 +0000 Date: Mon, 07 Sep 2026 11:10:49 +0100 Message-ID: <86fqzl4biu.wl-maz@kernel.org> From: Marc Zyngier To: Kohei Enju Cc: Steven Price , kvm@vger.kernel.org, kvmarm@lists.linux.dev, Catalin Marinas , Will Deacon , James Morse , Oliver Upton , Suzuki K Poulose , Zenghui Yu , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Joey Gouly , Alexandru Elisei , Christoffer Dall , Fuad Tabba , linux-coco@lists.linux.dev, Ganapatrao Kulkarni , Gavin Shan , Shanker Donthineni , Alper Gun , "Aneesh Kumar K . V" , Emi Kisanuki , Vishal Annapurve , WeiLin.Chang@arm.com, Lorenzo Pieralisi Subject: Re: [PATCH v16 22/45] KVM: arm64: CCA: Handle RMI_EXIT_RIPAS_CHANGE In-Reply-To: References: <20260803134403.80630-1-steven.price@arm.com> <20260803134403.80630-23-steven.price@arm.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/30.1 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: enju.kohei@fujitsu.com, steven.price@arm.com, kvm@vger.kernel.org, kvmarm@lists.linux.dev, catalin.marinas@arm.com, will@kernel.org, james.morse@arm.com, oliver.upton@linux.dev, suzuki.poulose@arm.com, yuzenghui@huawei.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, joey.gouly@arm.com, alexandru.elisei@arm.com, christoffer.dall@arm.com, tabba@google.com, linux-coco@lists.linux.dev, gankulkarni@os.amperecomputing.com, gshan@redhat.com, sdonthineni@nvidia.com, alpergun@google.com, aneesh.kumar@kernel.org, fj0570is@fujitsu.com, vannapurve@google.com, WeiLin.Chang@arm.com, lpieralisi@kernel.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, 07 Sep 2026 06:05:29 +0100, Kohei Enju wrote: [...] > Although the root cause is an RMM bug, should we also guard RIPAS_SET > against this no-progress case? No. We really should *prevent* the kernel from using a known broken RMM. Which brings me to one of my long standing request: how to we enforce the minimum version of RMM that KVM is willing to work with? We absolutely need to have a hard deprecation mechanism in place before day-1. M. -- Without deviation from the norm, progress is not possible.