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=-17.0 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 1103CC433DB for ; Fri, 12 Mar 2021 15:21:55 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (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 77B7864FEE for ; Fri, 12 Mar 2021 15:21:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 77B7864FEE 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=desiato.20200630; 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=Eqh5H5LSdoihYauNWQOYOcQzW9WUjY5myPv1s3exukQ=; b=mjFLHHyIukXx9t0xQzxPVBuL3 h2/CnOt90S+ctlIF5DBflELXIdMlPn5hPKUPpiFcN0HUToRkytSjFG8K+ApGl9EaKUuBOXGEXWucS ItLxXPOlZU41qW/MMOmEQg74NrjZuF+SEiDqeqTUs8nnzyJy7dp6KAvgJ6WjxRoflfPCcGQt5IL51 JHcJIPye9z0wpcpS8rgrliVlqd8aWZw+mG6MopL2jUb1OoKOaixNnDewMJnPrJteQctgKAw/0GoVe sBPfh6dfJTBA1vvU0z91S/b9htUv6hmxnID4/2K/ioRsi5LuuSYVKsoQaVJzP288UkJDfXzyGmmx/ Vz8IRsSUQ==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lKjaS-00Bleu-Ii; Fri, 12 Mar 2021 15:20:24 +0000 Received: from foss.arm.com ([217.140.110.172]) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lKjZc-00BlNs-7s for linux-arm-kernel@lists.infradead.org; Fri, 12 Mar 2021 15:19:34 +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 2C1531FB; Fri, 12 Mar 2021 07:19:30 -0800 (PST) Received: from e112269-lin.arm.com (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 56CCE3F7D7; Fri, 12 Mar 2021 07:19:27 -0800 (PST) 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 , Haibo Xu , Andrew Jones Subject: [PATCH v10 6/6] KVM: arm64: Document MTE capability and ioctl Date: Fri, 12 Mar 2021 15:19:02 +0000 Message-Id: <20210312151902.17853-7-steven.price@arm.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210312151902.17853-1-steven.price@arm.com> References: <20210312151902.17853-1-steven.price@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210312_151932_854187_832FE319 X-CRM114-Status: GOOD ( 12.29 ) 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 A new capability (KVM_CAP_ARM_MTE) identifies that the kernel supports granting a guest access to the tags, and provides a mechanism for the VMM to enable it. A new ioctl (KVM_ARM_MTE_COPY_TAGS) provides a simple way for a VMM to access the tags of a guest without having to maintain a PROT_MTE mapping in userspace. The above capability gates access to the ioctl. Signed-off-by: Steven Price --- Documentation/virt/kvm/api.rst | 53 ++++++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index 1a2b5210cdbf..ccc84f21ba5e 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -4938,6 +4938,40 @@ see KVM_XEN_VCPU_SET_ATTR above. The KVM_XEN_VCPU_ATTR_TYPE_RUNSTATE_ADJUST type may not be used with the KVM_XEN_VCPU_GET_ATTR ioctl. +4.131 KVM_ARM_MTE_COPY_TAGS +--------------------------- + +:Capability: KVM_CAP_ARM_MTE +:Architectures: arm64 +:Type: vm ioctl +:Parameters: struct kvm_arm_copy_mte_tags +:Returns: 0 on success, < 0 on error + +:: + + struct kvm_arm_copy_mte_tags { + __u64 guest_ipa; + __u64 length; + union { + void __user *addr; + __u64 padding; + }; + __u64 flags; + __u64 reserved[2]; + }; + +Copies Memory Tagging Extension (MTE) tags to/from guest tag memory. The +``guest_ipa`` and ``length`` fields must be ``PAGE_SIZE`` aligned. The ``addr`` +fieldmust point to a buffer which the tags will be copied to or from. + +``flags`` specifies the direction of copy, either ``KVM_ARM_TAGS_TO_GUEST`` or +``KVM_ARM_TAGS_FROM_GUEST``. + +The size of the buffer to store the tags is ``(length / MTE_GRANULE_SIZE)`` +bytes (i.e. 1/16th of the corresponding size). Each byte contains a single tag +value. This matches the format of ``PTRACE_PEEKMTETAGS`` and +``PTRACE_POKEMTETAGS``. + 5. The kvm_run structure ======================== @@ -6227,6 +6261,25 @@ KVM_RUN_BUS_LOCK flag is used to distinguish between them. This capability can be used to check / enable 2nd DAWR feature provided by POWER10 processor. +7.23 KVM_CAP_ARM_MTE +-------------------- + +:Architectures: arm64 +:Parameters: none + +This capability indicates that KVM (and the hardware) supports exposing the +Memory Tagging Extensions (MTE) to the guest. It must also be enabled by the +VMM before the guest will be granted access. + +When enabled the guest is able to access tags associated with any memory given +to the guest. KVM will ensure that the pages are flagged ``PG_mte_tagged`` so +that the tags are maintained during swap or hibernation of the host; however +the VMM needs to manually save/restore the tags as appropriate if the VM is +migrated. + +When enabled the VMM may make use of the ``KVM_ARM_MTE_COPY_TAGS`` ioctl to +perform a bulk copy of tags to/from the guest. + 8. Other capabilities. ====================== -- 2.20.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel