From patchwork Fri Sep 25 09:36:07 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Price X-Patchwork-Id: 1371116 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=arm.com Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 4ByRgF6ZcGz9s0b for ; Fri, 25 Sep 2020 19:38:33 +1000 (AEST) Received: from localhost ([::1]:36084 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kLkBT-0000QO-LO for incoming@patchwork.ozlabs.org; Fri, 25 Sep 2020 05:38:31 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:33278) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kLk9U-0000PG-16 for qemu-devel@nongnu.org; Fri, 25 Sep 2020 05:36:28 -0400 Received: from foss.arm.com ([217.140.110.172]:32908) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kLk9R-0002R0-V8 for qemu-devel@nongnu.org; Fri, 25 Sep 2020 05:36:27 -0400 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 2FED61045; Fri, 25 Sep 2020 02:36:25 -0700 (PDT) Received: from e112269-lin.arm.com (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id C4B1C3F718; Fri, 25 Sep 2020 02:36:22 -0700 (PDT) From: Steven Price To: Catalin Marinas , Marc Zyngier , Will Deacon Subject: [PATCH v3 2/2] arm64: kvm: Introduce MTE VCPU feature Date: Fri, 25 Sep 2020 10:36:07 +0100 Message-Id: <20200925093607.3051-3-steven.price@arm.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200925093607.3051-1-steven.price@arm.com> References: <20200925093607.3051-1-steven.price@arm.com> MIME-Version: 1.0 Received-SPF: pass client-ip=217.140.110.172; envelope-from=steven.price@arm.com; helo=foss.arm.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/09/25 05:36:20 X-ACL-Warn: Detected OS = Linux 3.11 and newer [fuzzy] X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Peter Maydell , "Dr. David Alan Gilbert" , Haibo Xu , Suzuki K Poulose , qemu-devel@nongnu.org, Dave Martin , Juan Quintela , Richard Henderson , linux-kernel@vger.kernel.org, Steven Price , James Morse , Julien Thierry , Thomas Gleixner , kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" Add a new VM feature 'KVM_ARM_CAP_MTE' which enables memory tagging for a VM. This exposes the feature to the guest and automatically tags memory pages touched by the VM as PG_mte_tagged (and clears the tags storage) to ensure that the guest cannot see stale tags, and so that the tags are correctly saved/restored across swap. Signed-off-by: Steven Price Reviewed-by: Andrew Jones --- arch/arm64/include/asm/kvm_emulate.h | 3 +++ arch/arm64/include/asm/kvm_host.h | 3 +++ arch/arm64/kvm/arm.c | 9 +++++++++ arch/arm64/kvm/mmu.c | 15 +++++++++++++++ arch/arm64/kvm/sys_regs.c | 6 +++++- include/uapi/linux/kvm.h | 1 + 6 files changed, 36 insertions(+), 1 deletion(-) diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h index 49a55be2b9a2..4923a566ae6e 100644 --- a/arch/arm64/include/asm/kvm_emulate.h +++ b/arch/arm64/include/asm/kvm_emulate.h @@ -79,6 +79,9 @@ static inline void vcpu_reset_hcr(struct kvm_vcpu *vcpu) if (cpus_have_const_cap(ARM64_MISMATCHED_CACHE_TYPE) || vcpu_el1_is_32bit(vcpu)) vcpu->arch.hcr_el2 |= HCR_TID2; + + if (vcpu->kvm->arch.mte_enabled) + vcpu->arch.hcr_el2 |= HCR_ATA; } static inline unsigned long *vcpu_hcr(struct kvm_vcpu *vcpu) diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 4f4360dd149e..1379300c1487 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -110,6 +110,9 @@ struct kvm_arch { * supported. */ bool return_nisv_io_abort_to_user; + + /* Memory Tagging Extension enabled for the guest */ + bool mte_enabled; }; struct kvm_vcpu_fault_info { diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 46dc3d75cf13..624edca0a1fa 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -87,6 +87,12 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm, r = 0; kvm->arch.return_nisv_io_abort_to_user = true; break; + case KVM_CAP_ARM_MTE: + if (!system_supports_mte() || kvm->created_vcpus) + return -EINVAL; + r = 0; + kvm->arch.mte_enabled = true; + break; default: r = -EINVAL; break; @@ -206,6 +212,9 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) */ r = 1; break; + case KVM_CAP_ARM_MTE: + r = system_supports_mte(); + break; default: r = kvm_arch_vm_ioctl_check_extension(kvm, ext); break; diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index ba00bcc0c884..befb9e1f0aa6 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -1949,6 +1949,21 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, if (vma_pagesize == PAGE_SIZE && !force_pte) vma_pagesize = transparent_hugepage_adjust(memslot, hva, &pfn, &fault_ipa); + if (system_supports_mte() && kvm->arch.mte_enabled && pfn_valid(pfn)) { + /* + * VM will be able to see the page's tags, so we must ensure + * they have been initialised. + */ + struct page *page = pfn_to_page(pfn); + long i, nr_pages = compound_nr(page); + + /* if PG_mte_tagged is set, tags have already been initialised */ + for (i = 0; i < nr_pages; i++, page++) { + if (!test_and_set_bit(PG_mte_tagged, &page->flags)) + mte_clear_page_tags(page_address(page)); + } + } + if (writable) kvm_set_pfn_dirty(pfn); diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index a655f172b5ad..5010a47152b4 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -1132,7 +1132,8 @@ static u64 read_id_reg(const struct kvm_vcpu *vcpu, val &= ~(0xfUL << ID_AA64PFR0_SVE_SHIFT); val &= ~(0xfUL << ID_AA64PFR0_AMU_SHIFT); } else if (id == SYS_ID_AA64PFR1_EL1) { - val &= ~(0xfUL << ID_AA64PFR1_MTE_SHIFT); + if (!vcpu->kvm->arch.mte_enabled) + val &= ~(0xfUL << ID_AA64PFR1_MTE_SHIFT); } else if (id == SYS_ID_AA64ISAR1_EL1 && !vcpu_has_ptrauth(vcpu)) { val &= ~((0xfUL << ID_AA64ISAR1_APA_SHIFT) | (0xfUL << ID_AA64ISAR1_API_SHIFT) | @@ -1394,6 +1395,9 @@ static bool access_mte_regs(struct kvm_vcpu *vcpu, struct sys_reg_params *p, static unsigned int mte_visibility(const struct kvm_vcpu *vcpu, const struct sys_reg_desc *rd) { + if (vcpu->kvm->arch.mte_enabled) + return 0; + return REG_HIDDEN_USER | REG_HIDDEN_GUEST; } diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index f6d86033c4fa..87678ed82ab4 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -1035,6 +1035,7 @@ struct kvm_ppc_resize_hpt { #define KVM_CAP_LAST_CPU 184 #define KVM_CAP_SMALLER_MAXPHYADDR 185 #define KVM_CAP_S390_DIAG318 186 +#define KVM_CAP_ARM_MTE 188 #ifdef KVM_CAP_IRQ_ROUTING