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 84D6EC433F5 for ; Thu, 24 Mar 2022 14:20:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350870AbiCXOVh (ORCPT ); Thu, 24 Mar 2022 10:21:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34398 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242072AbiCXOVf (ORCPT ); Thu, 24 Mar 2022 10:21:35 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id DD09758381 for ; Thu, 24 Mar 2022 07:20:02 -0700 (PDT) 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 3FB7E1515; Thu, 24 Mar 2022 07:20:02 -0700 (PDT) Received: from [10.1.39.159] (e121487-lin.cambridge.arm.com [10.1.39.159]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id B465A3F73D; Thu, 24 Mar 2022 07:20:00 -0700 (PDT) Message-ID: Date: Thu, 24 Mar 2022 14:19:58 +0000 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.7.0 Subject: Re: [kvmtool PATCH v2 2/2] aarch64: Add support for MTE Content-Language: en-US To: Alexandru Elisei , will@kernel.org, julien.thierry.kdev@gmail.com, kvm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, catalin.marinas@arm.com, steven.price@arm.com References: <20220324113942.24217-1-alexandru.elisei@arm.com> <20220324113942.24217-3-alexandru.elisei@arm.com> From: Vladimir Murzin In-Reply-To: <20220324113942.24217-3-alexandru.elisei@arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Hi Alexandru, On 3/24/22 11:39 AM, Alexandru Elisei wrote: > MTE has been supported in Linux since commit 673638f434ee ("KVM: arm64: > Expose KVM_ARM_CAP_MTE"), add support for it in kvmtool. MTE is enabled by > default. > > Enabling the MTE capability incurs a cost, both in time (for each > translation fault the tags need to be cleared), and in space (the tags need > to be saved when a physical page is swapped out). This overhead is expected > to be negligible for most users, but for those cases where they matter > (like performance benchmarks), a --disable-mte option has been added. > > Signed-off-by: Alexandru Elisei > --- > arm/aarch32/include/kvm/kvm-arch.h | 3 +++ > arm/aarch64/include/kvm/kvm-arch.h | 1 + > arm/aarch64/include/kvm/kvm-config-arch.h | 2 ++ > arm/aarch64/kvm.c | 23 +++++++++++++++++++++++ > arm/include/arm-common/kvm-config-arch.h | 1 + > arm/kvm.c | 2 ++ > 6 files changed, 32 insertions(+) > > diff --git a/arm/aarch32/include/kvm/kvm-arch.h b/arm/aarch32/include/kvm/kvm-arch.h > index bee2fc255a82..5616b27e257e 100644 > --- a/arm/aarch32/include/kvm/kvm-arch.h > +++ b/arm/aarch32/include/kvm/kvm-arch.h > @@ -5,6 +5,9 @@ > > #define kvm__arch_get_kern_offset(...) 0x8000 > > +struct kvm; > +static inline void kvm__arch_enable_mte(struct kvm *kvm) {} > + > #define ARM_MAX_MEMORY(...) ARM_LOMAP_MAX_MEMORY > > #define MAX_PAGE_SIZE SZ_4K > diff --git a/arm/aarch64/include/kvm/kvm-arch.h b/arm/aarch64/include/kvm/kvm-arch.h > index 5e5ee41211ed..9124f6919d0f 100644 > --- a/arm/aarch64/include/kvm/kvm-arch.h > +++ b/arm/aarch64/include/kvm/kvm-arch.h > @@ -6,6 +6,7 @@ > struct kvm; > unsigned long long kvm__arch_get_kern_offset(struct kvm *kvm, int fd); > int kvm__arch_get_ipa_limit(struct kvm *kvm); > +void kvm__arch_enable_mte(struct kvm *kvm); > > #define ARM_MAX_MEMORY(kvm) ({ \ > u64 max_ram; \ > diff --git a/arm/aarch64/include/kvm/kvm-config-arch.h b/arm/aarch64/include/kvm/kvm-config-arch.h > index 04be43dfa9b2..df4a15ff00a7 100644 > --- a/arm/aarch64/include/kvm/kvm-config-arch.h > +++ b/arm/aarch64/include/kvm/kvm-config-arch.h > @@ -6,6 +6,8 @@ > "Run AArch32 guest"), \ > OPT_BOOLEAN('\0', "pmu", &(cfg)->has_pmuv3, \ > "Create PMUv3 device"), \ > + OPT_BOOLEAN('\0', "disable-mte", &(cfg)->mte_disabled, \ > + "Disable Memory Tagging Extension capability"), \ > OPT_U64('\0', "kaslr-seed", &(cfg)->kaslr_seed, \ > "Specify random seed for Kernel Address Space " \ > "Layout Randomization (KASLR)"), > diff --git a/arm/aarch64/kvm.c b/arm/aarch64/kvm.c > index 56a0aedc263d..1035171a00f0 100644 > --- a/arm/aarch64/kvm.c > +++ b/arm/aarch64/kvm.c > @@ -81,3 +81,26 @@ int kvm__get_vm_type(struct kvm *kvm) > > return KVM_VM_TYPE_ARM_IPA_SIZE(ipa_bits); > } > + > +void kvm__arch_enable_mte(struct kvm *kvm) > +{ > + struct kvm_enable_cap cap = { > + .cap = KVM_CAP_ARM_MTE, > + }; > + > + if (kvm->cfg.arch.mte_disabled) { > + pr_debug("MTE capability disabled by user"); > + return; > + } Nitpick: I'd move that bellow capability check, so it'd appear only in setups which support MTE > + > + if (!kvm__supports_extension(kvm, KVM_CAP_ARM_MTE)) { > + kvm->cfg.arch.mte_disabled = true; > + pr_debug("MTE capability not present"); > + return; > + } > + > + if (ioctl(kvm->vm_fd, KVM_ENABLE_CAP, &cap)) > + die_perror("KVM_ENABLE_CAP(KVM_CAP_ARM_MTE)"); > + > + pr_debug("MTE capability enabled"); > +} > diff --git a/arm/include/arm-common/kvm-config-arch.h b/arm/include/arm-common/kvm-config-arch.h > index 5734c46ab9e6..f2049994d859 100644 > --- a/arm/include/arm-common/kvm-config-arch.h > +++ b/arm/include/arm-common/kvm-config-arch.h > @@ -9,6 +9,7 @@ struct kvm_config_arch { > bool virtio_trans_pci; > bool aarch32_guest; > bool has_pmuv3; > + bool mte_disabled; > u64 kaslr_seed; > enum irqchip_type irqchip; > u64 fw_addr; > diff --git a/arm/kvm.c b/arm/kvm.c > index 80d233f13d0b..c5913000e1ed 100644 > --- a/arm/kvm.c > +++ b/arm/kvm.c > @@ -86,6 +86,8 @@ void kvm__arch_init(struct kvm *kvm, const char *hugetlbfs_path, u64 ram_size) > /* Create the virtual GIC. */ > if (gic__create(kvm, kvm->cfg.arch.irqchip)) > die("Failed to create virtual GIC"); > + > + kvm__arch_enable_mte(kvm); > } > > #define FDT_ALIGN SZ_2M FWIW: Reviewed-by: Vladimir Murzin Tested-by: Vladimir Murzin Thanks! Vladimir