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=-15.6 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,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 3C82EC43460 for ; Thu, 20 May 2021 10:54:35 +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 B89EA61028 for ; Thu, 20 May 2021 10:54:34 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B89EA61028 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:In-Reply-To:MIME-Version:Date:Message-ID:From: References:Cc:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=O668rzWxE1q+a9jCWwytpOPSLGH84Qu8yg607BwITLU=; b=DZnqwv+GNalNtEKyGL5H1z/0KP X8qdkoQlV5szPXUQP0RzC+8hqsHoFmdEIj5gvzBvl2TsaZobyyuAuVcSZ8Rmg/YcP2Ujg82zKh1Ws XUoac2v7FGTmbmUD/keN6oEtct40ulzw8nXmvXBNzWbZrwJ6tn3o9FlJnDa44r6mruaZk1+Dpu7zV s9bQwPU9mQ8gt9cZBbi9qyhrrWIJW2f325JgyRlzxwBoH4bUmyY+jqlx2t5VS1HkCO1g1jCOaGVoI dWBTdeEEnlGgnIYA4Mmoxmt3xqu/M3U0quGUM9hXG0h13Yp7NukA+RGNNkB7DPCNefGpuasDPBw4O 38vqUW0Q==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1ljgHC-000GDg-HC; Thu, 20 May 2021 10:51:41 +0000 Received: from bombadil.infradead.org ([2607:7c80:54:e::133]) by desiato.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1ljgH8-000GCL-MF for linux-arm-kernel@desiato.infradead.org; Thu, 20 May 2021 10:51:34 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Content-Transfer-Encoding: Content-Type:In-Reply-To:MIME-Version:Date:Message-ID:From:References:Cc:To: Subject:Sender:Reply-To:Content-ID:Content-Description; bh=9eIKZ1tENglVrK2vnSmFRdpWWALWrpvuID1yjMAW+IM=; b=UnrQUhPytHPdilfT5H+sBHFnlg uOjiRGOtwHMaxmsrai3r/YeB0bjeP4m+t3YGgGDJdMMn4C2R9R92pLQUq6EJE7lT3Gd0++PKnm/J0 /jtIAc/WvKSOYQT5VG3jGRCHzuefYxNSS1etdNe7BPIv/w5SFwUehm+laxm1PrCSYnVpZjhGAnSkR cI1YC9znQngNn4YA2YTSNPnnmkrXimK0ONSTeCTWsNV4mcXk1cDnfLUE0s7GpDPqgaymWNMEtgDAx +ozjHEr9DqPkmT2nNmzJrCcyQg3vk/5MSVLXNtF+3RLO6Zg0P8bAn3yDFFkQW/S1OdEjR8y3L905n bY6RjBUg==; Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1ljgH5-00GCQR-Ko for linux-arm-kernel@lists.infradead.org; Thu, 20 May 2021 10:51:33 +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 F182B14FF; Thu, 20 May 2021 03:51:28 -0700 (PDT) Received: from [192.168.1.179] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 4372F3F719; Thu, 20 May 2021 03:51:26 -0700 (PDT) Subject: Re: [PATCH v12 6/8] arm64: kvm: Expose KVM_ARM_CAP_MTE To: Marc Zyngier Cc: Catalin Marinas , Will Deacon , 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 References: <20210517123239.8025-1-steven.price@arm.com> <20210517123239.8025-7-steven.price@arm.com> <87tun1tg1l.wl-maz@kernel.org> <4e1fc7b7-ea8c-a87c-9177-d9e03ff96cb8@arm.com> <8735uhvhqz.wl-maz@kernel.org> From: Steven Price Message-ID: <2dff0e85-abfd-4261-a670-6008ff9195ff@arm.com> Date: Thu, 20 May 2021 11:51:21 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.1 MIME-Version: 1.0 In-Reply-To: <8735uhvhqz.wl-maz@kernel.org> Content-Language: en-GB X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210520_035131_808223_FCD3490D X-CRM114-Status: GOOD ( 23.59 ) 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 On 20/05/2021 11:09, Marc Zyngier wrote: > On Wed, 19 May 2021 14:26:31 +0100, > Steven Price wrote: >> >> On 17/05/2021 18:40, Marc Zyngier wrote: >>> On Mon, 17 May 2021 13:32:37 +0100, >>> Steven Price wrote: >>>> >>>> It's now safe for the VMM to enable MTE in a guest, so expose the >>>> capability to user space. >>>> >>>> Signed-off-by: Steven Price >>>> --- >>>> arch/arm64/kvm/arm.c | 9 +++++++++ >>>> arch/arm64/kvm/sys_regs.c | 3 +++ >>>> 2 files changed, 12 insertions(+) >>>> >>>> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c >>>> index 1cb39c0803a4..e89a5e275e25 100644 >>>> --- a/arch/arm64/kvm/arm.c >>>> +++ b/arch/arm64/kvm/arm.c >>>> @@ -93,6 +93,12 @@ 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; >>> >>> As far as I can tell from the architecture, this isn't valid for a >>> 32bit guest. >> >> Indeed, however the MTE flag is a property of the VM not of the vCPU. >> And, unless I'm mistaken, it's technically possible to create a VM where >> some CPUs are 32 bit and some 64 bit. Not that I can see much use of a >> configuration like that. > > It looks that this is indeed a bug, and I'm on my way to squash it. > Can't believe we allowed that for so long... Ah, well if you're going to kill off mixed 32bit/64bit VMs then... > But the architecture clearly states: > > > These features are supported in AArch64 state only. > > > So I'd expect something like: > > diff --git a/arch/arm64/kvm/reset.c b/arch/arm64/kvm/reset.c > index 956cdc240148..50635eacfa43 100644 > --- a/arch/arm64/kvm/reset.c > +++ b/arch/arm64/kvm/reset.c > @@ -220,7 +220,8 @@ int kvm_reset_vcpu(struct kvm_vcpu *vcpu) > switch (vcpu->arch.target) { > default: > if (test_bit(KVM_ARM_VCPU_EL1_32BIT, vcpu->arch.features)) { > - if (!cpus_have_const_cap(ARM64_HAS_32BIT_EL1)) { > + if (!cpus_have_const_cap(ARM64_HAS_32BIT_EL1) || > + vcpu->kvm->arch.mte_enabled) { > ret = -EINVAL; > goto out; > } > > that makes it completely impossible to create 32bit CPUs within a > MTE-enabled guest. ... that makes complete sense, and I'll include this hunk in my next posting. Thanks, Steve _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel