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=-14.0 required=3.0 tests=BAYES_00,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 F0938C433E9 for ; Mon, 8 Mar 2021 14:43:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C316C65202 for ; Mon, 8 Mar 2021 14:43:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231335AbhCHOmb (ORCPT ); Mon, 8 Mar 2021 09:42:31 -0500 Received: from mail.kernel.org ([198.145.29.99]:46962 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231301AbhCHOmE (ORCPT ); Mon, 8 Mar 2021 09:42:04 -0500 Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7E3FF61574; Mon, 8 Mar 2021 14:42:03 +0000 (UTC) Received: from 78.163-31-62.static.virginmediabusiness.co.uk ([62.31.163.78] helo=why.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94) (envelope-from ) id 1lJH57-000M3p-DG; Mon, 08 Mar 2021 14:42:01 +0000 Date: Mon, 08 Mar 2021 14:42:00 +0000 Message-ID: <8735x5zozr.wl-maz@kernel.org> From: Marc Zyngier To: Anshuman Khandual Cc: linux-arm-kernel@lists.infradead.org, James Morse , Catalin Marinas , Will Deacon , Suzuki K Poulose , Ard Biesheuvel , Mark Rutland , kvmarm@lists.cs.columbia.edu, linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] arm64/mm: Fix __enable_mmu() for new TGRAN range values In-Reply-To: <1614954969-14338-1-git-send-email-anshuman.khandual@arm.com> References: <1614954969-14338-1-git-send-email-anshuman.khandual@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/27.1 (x86_64-pc-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: 62.31.163.78 X-SA-Exim-Rcpt-To: anshuman.khandual@arm.com, linux-arm-kernel@lists.infradead.org, james.morse@arm.com, catalin.marinas@arm.com, will@kernel.org, suzuki.poulose@arm.com, ardb@kernel.org, mark.rutland@arm.com, kvmarm@lists.cs.columbia.edu, linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org 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: linux-kernel@vger.kernel.org On Fri, 05 Mar 2021 14:36:09 +0000, Anshuman Khandual wrote: > > From: James Morse > > As per ARM ARM DDI 0487G.a, when FEAT_LPA2 is implemented, ID_AA64MMFR0_EL1 > might contain a range of values to describe supported translation granules > (4K and 16K pages sizes in particular) instead of just enabled or disabled > values. This changes __enable_mmu() function to handle complete acceptable > range of values (depending on whether the field is signed or unsigned) now > represented with ID_AA64MMFR0_TGRAN_SUPPORTED_[MIN..MAX] pair. While here, > also fix similar situations in EFI stub and KVM as well. > > Cc: Catalin Marinas > Cc: Will Deacon > Cc: Marc Zyngier > Cc: James Morse > Cc: Suzuki K Poulose > Cc: Ard Biesheuvel > Cc: Mark Rutland > Cc: linux-arm-kernel@lists.infradead.org > Cc: kvmarm@lists.cs.columbia.edu > Cc: linux-efi@vger.kernel.org > Cc: linux-kernel@vger.kernel.org > Signed-off-by: James Morse > Signed-off-by: Anshuman Khandual > --- > arch/arm64/include/asm/sysreg.h | 20 ++++++++++++++------ > arch/arm64/kernel/head.S | 6 ++++-- > arch/arm64/kvm/reset.c | 23 ++++++++++++----------- > drivers/firmware/efi/libstub/arm64-stub.c | 2 +- > 4 files changed, 31 insertions(+), 20 deletions(-) > > diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h > index dfd4edb..d4a5fca9 100644 > --- a/arch/arm64/include/asm/sysreg.h > +++ b/arch/arm64/include/asm/sysreg.h > @@ -796,6 +796,11 @@ > #define ID_AA64MMFR0_PARANGE_48 0x5 > #define ID_AA64MMFR0_PARANGE_52 0x6 > > +#define ID_AA64MMFR0_TGRAN_2_SUPPORTED_DEFAULT 0x0 > +#define ID_AA64MMFR0_TGRAN_2_SUPPORTED_NONE 0x1 > +#define ID_AA64MMFR0_TGRAN_2_SUPPORTED_MIN 0x2 > +#define ID_AA64MMFR0_TGRAN_2_SUPPORTED_MAX 0x7 It really feels like we're inventing stuff that the ARM ARM couldn't be bothered to describe. Oh well. > - switch (cpuid_feature_extract_unsigned_field(mmfr0, tgran_2)) { > - default: > - case 1: > + tgran_2 = cpuid_feature_extract_unsigned_field(mmfr0, tgran_2_shift); > + if (tgran_2 == ID_AA64MMFR0_TGRAN_2_SUPPORTED_NONE) { > kvm_err("PAGE_SIZE not supported at Stage-2, giving up\n"); > return -EINVAL; > - case 0: > + } else if (tgran_2 == ID_AA64MMFR0_TGRAN_2_SUPPORTED_DEFAULT) { > kvm_debug("PAGE_SIZE supported at Stage-2 (default)\n"); > - break; > - case 2: > + } else if (tgran_2 >= ID_AA64MMFR0_TGRAN_2_SUPPORTED_MIN && > + tgran_2 <= ID_AA64MMFR0_TGRAN_2_SUPPORTED_MAX) { > kvm_debug("PAGE_SIZE supported at Stage-2 (advertised)\n"); > - break; > + } else { > + kvm_err("Unsupported value, giving up\n"); > + return -EINVAL; nit: this doesn't say *what* value is unsupported, and I really preferred the switch-case version, such as this: diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c index 1f22b36a0eff..d267e4b1aec6 100644 --- a/arch/arm64/kvm/reset.c +++ b/arch/arm64/kvm/reset.c @@ -312,15 +312,18 @@ int kvm_set_ipa_limit(void) switch (cpuid_feature_extract_unsigned_field(mmfr0, tgran_2)) { default: - case 1: + case ID_AA64MMFR0_TGRAN_2_SUPPORTED_NONE: kvm_err("PAGE_SIZE not supported at Stage-2, giving up\n"); return -EINVAL; - case 0: + case ID_AA64MMFR0_TGRAN_2_SUPPORTED_DEFAULT: kvm_debug("PAGE_SIZE supported at Stage-2 (default)\n"); break; - case 2: + case ID_AA64MMFR0_TGRAN_2_SUPPORTED_MIN ... ID_AA64MMFR0_TGRAN_2_SUPPORTED_MAX: kvm_debug("PAGE_SIZE supported at Stage-2 (advertised)\n"); break; + default: + kvm_err("Unsupported value for TGRAN_2, giving up\n"); + return -EINVAL; } kvm_ipa_limit = id_aa64mmfr0_parange_to_phys_shift(parange); Otherwise: Acked-by: Marc Zyngier M. -- Without deviation from the norm, progress is not possible.