From patchwork Fri Jun 18 13:28:25 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Price X-Patchwork-Id: 12331425 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=-16.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT 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 3215BC48BE8 for ; Fri, 18 Jun 2021 13:33:02 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 05DDF61042 for ; Fri, 18 Jun 2021 13:33:02 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 05DDF61042 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=0Q6bTeQ1Qg1INKpUn5yC9ovg0/WeurTeq2iKz6MhFEs=; b=TgjIHl2MK9FYks ATac2I6R0NxbQKHhH/1XdXTfG/0CbMyfhwJ4sdOOCjtQSeSCrEfbXYa2442Bmd4C4jiCjZFpNCRyU xLxcERoi9Kng8QsS6x2iMt10gJlh/wWTvPnBeVvEXm9DH4pcwfiyVOtXbMMzHEkX4MDbnWWZIsIf6 SrmxRmKexdQhDs2sDy1ncaPZxsVC3QK9f+A8lUzlPUZoncMof2/JZdaDz3/f3GgvW7XwI/xtKMdAd 7Yc5GOrJVslN4cj2iYEoXJfU6lxaX9CTvA9xqm/SrFjAza73XGifvQ2CdvRn+POeNa9Wcd1H4IP+Y x7WbOpToxeokPjoPH5QA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1luEai-00EFow-2b; Fri, 18 Jun 2021 13:31:24 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1luEYJ-00EEt8-Ld for linux-arm-kernel@lists.infradead.org; Fri, 18 Jun 2021 13:28:57 +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 37C6E1478; Fri, 18 Jun 2021 06:28:55 -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 8D5C93F719; Fri, 18 Jun 2021 06:28:52 -0700 (PDT) From: Steven Price To: Catalin Marinas , Marc Zyngier , Will Deacon Cc: Steven Price , James Morse , Julien Thierry , Suzuki K Poulose , kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Dave Martin , Mark Rutland , Thomas Gleixner , qemu-devel@nongnu.org, Juan Quintela , "Dr. David Alan Gilbert" , Richard Henderson , Peter Maydell , Andrew Jones Subject: [PATCH v16 6/7] KVM: arm64: ioctl to fetch/store tags in a guest Date: Fri, 18 Jun 2021 14:28:25 +0100 Message-Id: <20210618132826.54670-7-steven.price@arm.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210618132826.54670-1-steven.price@arm.com> References: <20210618132826.54670-1-steven.price@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210618_062855_849533_DCF6B270 X-CRM114-Status: GOOD ( 21.50 ) 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org The VMM may not wish to have it's own mapping of guest memory mapped with PROT_MTE because this causes problems if the VMM has tag checking enabled (the guest controls the tags in physical RAM and it's unlikely the tags are correct for the VMM). Instead add a new ioctl which allows the VMM to easily read/write the tags from guest memory, allowing the VMM's mapping to be non-PROT_MTE while the VMM can still read/write the tags for the purpose of migration. Reviewed-by: Catalin Marinas Signed-off-by: Steven Price --- arch/arm64/include/asm/kvm_host.h | 3 ++ arch/arm64/include/asm/mte-def.h | 1 + arch/arm64/include/uapi/asm/kvm.h | 11 +++++ arch/arm64/kvm/arm.c | 7 +++ arch/arm64/kvm/guest.c | 82 +++++++++++++++++++++++++++++++ include/uapi/linux/kvm.h | 1 + 6 files changed, 105 insertions(+) diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index 309e36cc1b42..6a2ac4636d42 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -729,6 +729,9 @@ int kvm_arm_vcpu_arch_get_attr(struct kvm_vcpu *vcpu, int kvm_arm_vcpu_arch_has_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr); +long kvm_vm_ioctl_mte_copy_tags(struct kvm *kvm, + struct kvm_arm_copy_mte_tags *copy_tags); + /* Guest/host FPSIMD coordination helpers */ int kvm_arch_vcpu_run_map_fp(struct kvm_vcpu *vcpu); void kvm_arch_vcpu_load_fp(struct kvm_vcpu *vcpu); diff --git a/arch/arm64/include/asm/mte-def.h b/arch/arm64/include/asm/mte-def.h index cf241b0f0a42..626d359b396e 100644 --- a/arch/arm64/include/asm/mte-def.h +++ b/arch/arm64/include/asm/mte-def.h @@ -7,6 +7,7 @@ #define MTE_GRANULE_SIZE UL(16) #define MTE_GRANULE_MASK (~(MTE_GRANULE_SIZE - 1)) +#define MTE_GRANULES_PER_PAGE (PAGE_SIZE / MTE_GRANULE_SIZE) #define MTE_TAG_SHIFT 56 #define MTE_TAG_SIZE 4 #define MTE_TAG_MASK GENMASK((MTE_TAG_SHIFT + (MTE_TAG_SIZE - 1)), MTE_TAG_SHIFT) diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h index 24223adae150..b3edde68bc3e 100644 --- a/arch/arm64/include/uapi/asm/kvm.h +++ b/arch/arm64/include/uapi/asm/kvm.h @@ -184,6 +184,17 @@ struct kvm_vcpu_events { __u32 reserved[12]; }; +struct kvm_arm_copy_mte_tags { + __u64 guest_ipa; + __u64 length; + void __user *addr; + __u64 flags; + __u64 reserved[2]; +}; + +#define KVM_ARM_TAGS_TO_GUEST 0 +#define KVM_ARM_TAGS_FROM_GUEST 1 + /* If you need to interpret the index values, here is the key: */ #define KVM_REG_ARM_COPROC_MASK 0x000000000FFF0000 #define KVM_REG_ARM_COPROC_SHIFT 16 diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index e89a5e275e25..baa33359e477 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -1345,6 +1345,13 @@ long kvm_arch_vm_ioctl(struct file *filp, return 0; } + case KVM_ARM_MTE_COPY_TAGS: { + struct kvm_arm_copy_mte_tags copy_tags; + + if (copy_from_user(©_tags, argp, sizeof(copy_tags))) + return -EFAULT; + return kvm_vm_ioctl_mte_copy_tags(kvm, ©_tags); + } default: return -EINVAL; } diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c index 5cb4a1cd5603..4ddb20017b2f 100644 --- a/arch/arm64/kvm/guest.c +++ b/arch/arm64/kvm/guest.c @@ -995,3 +995,85 @@ int kvm_arm_vcpu_arch_has_attr(struct kvm_vcpu *vcpu, return ret; } + +long kvm_vm_ioctl_mte_copy_tags(struct kvm *kvm, + struct kvm_arm_copy_mte_tags *copy_tags) +{ + gpa_t guest_ipa = copy_tags->guest_ipa; + size_t length = copy_tags->length; + void __user *tags = copy_tags->addr; + gpa_t gfn; + bool write = !(copy_tags->flags & KVM_ARM_TAGS_FROM_GUEST); + int ret = 0; + + if (!kvm_has_mte(kvm)) + return -EINVAL; + + if (copy_tags->reserved[0] || copy_tags->reserved[1]) + return -EINVAL; + + if (copy_tags->flags & ~KVM_ARM_TAGS_FROM_GUEST) + return -EINVAL; + + if (length & ~PAGE_MASK || guest_ipa & ~PAGE_MASK) + return -EINVAL; + + gfn = gpa_to_gfn(guest_ipa); + + mutex_lock(&kvm->slots_lock); + + while (length > 0) { + kvm_pfn_t pfn = gfn_to_pfn_prot(kvm, gfn, write, NULL); + void *maddr; + unsigned long num_tags; + struct page *page; + + if (is_error_noslot_pfn(pfn)) { + ret = -EFAULT; + goto out; + } + + page = pfn_to_online_page(pfn); + if (!page) { + /* Reject ZONE_DEVICE memory */ + ret = -EFAULT; + goto out; + } + maddr = page_address(page); + + if (!write) { + if (test_bit(PG_mte_tagged, &page->flags)) + num_tags = mte_copy_tags_to_user(tags, maddr, + MTE_GRANULES_PER_PAGE); + else + /* No tags in memory, so write zeros */ + num_tags = MTE_GRANULES_PER_PAGE - + clear_user(tags, MTE_GRANULES_PER_PAGE); + kvm_release_pfn_clean(pfn); + } else { + num_tags = mte_copy_tags_from_user(maddr, tags, + MTE_GRANULES_PER_PAGE); + kvm_release_pfn_dirty(pfn); + } + + if (num_tags != MTE_GRANULES_PER_PAGE) { + ret = -EFAULT; + goto out; + } + + /* Set the flag after checking the write completed fully */ + if (write) + set_bit(PG_mte_tagged, &page->flags); + + gfn++; + tags += num_tags; + length -= PAGE_SIZE; + } + +out: + mutex_unlock(&kvm->slots_lock); + /* If some data has been copied report the number of bytes copied */ + if (length != copy_tags->length) + return copy_tags->length - length; + return ret; +} diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 8c95ba0fadda..4c011c60d468 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -1428,6 +1428,7 @@ struct kvm_s390_ucas_mapping { /* Available with KVM_CAP_PMU_EVENT_FILTER */ #define KVM_SET_PMU_EVENT_FILTER _IOW(KVMIO, 0xb2, struct kvm_pmu_event_filter) #define KVM_PPC_SVM_OFF _IO(KVMIO, 0xb3) +#define KVM_ARM_MTE_COPY_TAGS _IOR(KVMIO, 0xb4, struct kvm_arm_copy_mte_tags) /* ioctl for vm fd */ #define KVM_CREATE_DEVICE _IOWR(KVMIO, 0xe0, struct kvm_create_device)