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 DE598C3DA78 for ; Fri, 13 Jan 2023 17:39:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230148AbjAMRjS (ORCPT ); Fri, 13 Jan 2023 12:39:18 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52826 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229953AbjAMRiv (ORCPT ); Fri, 13 Jan 2023 12:38:51 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E8FCCB7875 for ; Fri, 13 Jan 2023 09:26:32 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id E2607B820D3 for ; Fri, 13 Jan 2023 17:25:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 67273C433EF; Fri, 13 Jan 2023 17:25:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1673630732; bh=uBwzoDfIi5zx3t1cQvei6z7fqeSGlX0Xvp4YKJJlYBU=; h=From:To:Cc:Subject:Date:From; b=O2Q8UIRTe5brWI6BtTOkh3lNN1olC74z6oG8FjKm/81W9JYh6N+S66X9VU0Ux+yD8 VOEY2HJlTa/eJxQT9ZxwXsCjvDlakJjgDkxPDcMVZI0qdpxJE5DpUEwSh2pGIStAnA rfK8cNyfi5v5F9n09fA723l/FJ2pf/teYcqqOhpJSzb+0ejEeSkzmmYijBJXxpuKcs slthuzJRwRWItsmqRXaG2cETVBu7ncaYrVL9kITJ+z+OnnPUb9gadhgyiNywb0mVag ID2AresCQ72ExLpw3ni2pLPvjn+TTomfRZ0cHaSkJ2u+JQtrzoQ796bK7o64vtTm07 2fUmLw+R5h1kw== Received: from sofa.misterjones.org ([185.219.108.64] helo=valley-girl.lan) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1pGNo2-001bBu-3p; Fri, 13 Jan 2023 17:25:30 +0000 From: Marc Zyngier To: kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org Cc: Will Deacon , Catalin Marinas , Mark Rutland , James Morse , Suzuki K Poulose , Oliver Upton , Zenghui Yu Subject: [PATCH 0/2] KVM: arm64: Drop support for VPIPT i-cache policy Date: Fri, 13 Jan 2023 17:25:21 +0000 Message-Id: <20230113172523.2063867-1-maz@kernel.org> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org, will@kernel.org, catalin.marinas@arm.com, mark.rutland@arm.com, james.morse@arm.com, suzuki.poulose@arm.com, oliver.upton@linux.dev, yuzenghui@huawei.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org ARMv8.2 introduced support for VPIPT i-caches, the V standing for VMID-tagged. Although this looks like a reasonable idea, no implementation has ever made it into the wild. Linux has supported this for almost 6 years (amusingly, just as the architecture was dropping support for AVIVT i-caches), but we have no way to even test it, and it is likely that this code is just bit-rotting. This isn't great. Since this only impacts KVM, let's drop the support from the hypervisor. The kernel itself can still work as a guest on such a system, assuming that there is HW and a hypervisor that supports this architecture variation. On the other hand, if you are aware of such an implementation and can actively test KVM on this setup, please shout! M. Marc Zyngier (2): KVM: arm64: Disable KVM on systems with a VPIPT i-cache KVM: arm64: Remove VPIPT I-cache handling arch/arm64/include/asm/kvm_mmu.h | 3 +-- arch/arm64/kvm/arm.c | 5 +++++ arch/arm64/kvm/hyp/nvhe/tlb.c | 35 -------------------------------- arch/arm64/kvm/hyp/vhe/tlb.c | 13 ------------ 4 files changed, 6 insertions(+), 50 deletions(-) -- 2.34.1