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 4259EC4167B for ; Mon, 4 Dec 2023 14:45:35 +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:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc: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=hfzQLXD/x3N/TZwIdMGdAeV3zIf5cS1NHNZ6k40fK7w=; b=pIqt5a/BawXPgY T6+7VmlbckxxVLKPU1gnxlKb9lEmWkuwU0zLYV66lJSgE2OIizLuHkW3aPXzUwBiV4BZAwdXCTbwM QjX4cKSrAN8qzGCUgu7bmlxKodiJ4laUgckhqTjXTqJynD2B1Q1dVMcq6PrL6YGs0CMfX61EU0VKm JX/QBfjgX6f4j4QzMnPl45+w2prdjHCZsaymc2aiU2VZAHmuiVqjQ3qwUqxF2/Rnu03HbVaWLeAcE 7pM4oJcjf0m5YQrs91GShJFdnnINEwqD5wKO8NuF9VLggKuu4Cg73fm6Cthk7kBsEEcqokT7b1Id3 otcNOJd3Y4HayK3wkhFg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1rAAC1-004pdf-1J; Mon, 04 Dec 2023 14:45:05 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1rAABy-004pad-1k for linux-arm-kernel@lists.infradead.org; Mon, 04 Dec 2023 14:45:03 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 35010152B; Mon, 4 Dec 2023 06:45:48 -0800 (PST) Received: from FVFF77S0Q05N (unknown [10.57.44.129]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 00DFF3F5A1; Mon, 4 Dec 2023 06:44:58 -0800 (PST) Date: Mon, 4 Dec 2023 14:44:56 +0000 From: Mark Rutland To: Marc Zyngier Cc: kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org, Will Deacon , Catalin Marinas , Ard Biesheuvel , Anshuman Khandual , James Morse , Suzuki K Poulose , Oliver Upton , Zenghui Yu Subject: Re: [PATCH v3 0/3] arm64: Drop support for VPIPT i-cache policy Message-ID: References: <20231204143606.1806432-1-maz@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20231204143606.1806432-1-maz@kernel.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20231204_064502_683322_E67F9EF9 X-CRM114-Status: GOOD ( 21.72 ) 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 Mon, Dec 04, 2023 at 02:36:03PM +0000, Marc Zyngier wrote: > ARMv8.2 introduced support for VPIPT i-caches, the V standing for > VMID-tagged. Although this looked like a reasonable idea, no > implementation has ever made it into the wild. > > Linux has supported this for over 6 years (amusingly, just as the > architecture was dropping support for AIVIVT i-caches), but we had no > way to even test it, and it is likely that this code was just > bit-rotting. > > However, in a recent breakthrough (XML drop 2023-09, tagged as > d55f5af8e09052abe92a02adf820deea2eaed717), the architecture has > finally been purged of this option, making VIPT and PIPT the only two > valid options. > > This really means this code is just dead code. Nobody will ever come > up with such an implementation, and we can just get rid of it. > > Most of the impact is on KVM, where we drop a few large comment blocks > (and a bit of code), while the core arch code loses the detection code > itself. > > * From v2: > - Fix reserved naming for RESERVED_AIVIVT > - Collected RBs from Anshuman an Zenghui > > Marc Zyngier (3): > KVM: arm64: Remove VPIPT I-cache handling > arm64: Kill detection of VPIPT i-cache policy > arm64: Rename reserved values for CTR_EL0.L1Ip For the series: Acked-by: Mark Rutland Looking forward, we can/should probably replace __icache_flags with a single ICACHE_NOALIASING or ICACHE_PIPT cpucap, which'd get rid of a bunch of duplicated logic and make that more sound in the case of races around cpu onlining. Mark. > > arch/arm64/include/asm/cache.h | 6 ---- > arch/arm64/include/asm/kvm_mmu.h | 7 ---- > arch/arm64/kernel/cpuinfo.c | 5 --- > arch/arm64/kvm/hyp/nvhe/pkvm.c | 2 +- > arch/arm64/kvm/hyp/nvhe/tlb.c | 61 -------------------------------- > arch/arm64/kvm/hyp/vhe/tlb.c | 13 ------- > arch/arm64/tools/sysreg | 5 +-- > 7 files changed, 4 insertions(+), 95 deletions(-) > > -- > 2.39.2 > > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel