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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 98234E6896B for ; Thu, 31 Oct 2024 09:50:23 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 13E676B008A; Thu, 31 Oct 2024 05:50:23 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 0EEE16B008C; Thu, 31 Oct 2024 05:50:23 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id EA9F76B0092; Thu, 31 Oct 2024 05:50:22 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id CE0EF6B008A for ; Thu, 31 Oct 2024 05:50:22 -0400 (EDT) Received: from smtpin28.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 84930C1397 for ; Thu, 31 Oct 2024 09:50:22 +0000 (UTC) X-FDA: 82733426832.28.335260C Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by imf08.hostedemail.com (Postfix) with ESMTP id 51B9516001A for ; Thu, 31 Oct 2024 09:50:02 +0000 (UTC) Authentication-Results: imf08.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=Y77Iweku; dmarc=pass (policy=none) header.from=redhat.com; spf=pass (imf08.hostedemail.com: domain of david@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=david@redhat.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1730368164; a=rsa-sha256; cv=none; b=llx3K/N5B9nRNltwGNhmff+Z8NbnkceGWBcf9v3F+vWPyRA9+5uXccrOcLTmoRfKWZcXgT zv1R/Mx45CaK9dBu7AWXifqaf/qfQsPt9/s17NSvFJPu7RhJV29beveyLs7FHvSNYfIMQe YnkJq+UfCvrWVFJ3/5fDGUaZMGQwnws= ARC-Authentication-Results: i=1; imf08.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=Y77Iweku; dmarc=pass (policy=none) header.from=redhat.com; spf=pass (imf08.hostedemail.com: domain of david@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=david@redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1730368164; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=8dIcxwobV6BNAuIuaE7aLzJugH838eIdiZ2hVMt1ILQ=; b=P4eTGh4BykBhi89Yegce1YdLUNvXJfBizCGcay1e5o9DKsusF9tuvli394bm2071Ea3lUM J2vBZbVM/MhUCXiON6RuVu1oNJVOU+PKxAYYMIFoHpea4CkoWC2GKNigSuO0lK30huVuh1 TcytKhJ98NAngIiBe875CrBjdPAS9oQ= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1730368219; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=8dIcxwobV6BNAuIuaE7aLzJugH838eIdiZ2hVMt1ILQ=; b=Y77IwekubosuHnlyBYhV8pIE+nkrQSYf7GLTtGHGaPdxTf6HWE4vWGr3EBr+JKjg+l+BFJ FlUTwV69p2I0qqEdByCvv8QGz6aYp7/o8Ualfbz+pCY30XSqHI1hI+BHfgcBS9d5j6+Jh9 HCycZPf2YlzaIEerJJvvIVycLIk/vaA= Received: from mail-wr1-f72.google.com (mail-wr1-f72.google.com [209.85.221.72]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-611-kdSYxa-AM5aj5ZaTA9X-Vg-1; Thu, 31 Oct 2024 05:50:16 -0400 X-MC-Unique: kdSYxa-AM5aj5ZaTA9X-Vg-1 Received: by mail-wr1-f72.google.com with SMTP id ffacd0b85a97d-37d67fe93c6so417968f8f.0 for ; Thu, 31 Oct 2024 02:50:16 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1730368215; x=1730973015; h=content-transfer-encoding:in-reply-to:organization:autocrypt :content-language:from:references:cc:to:subject:user-agent :mime-version:date:message-id:x-gm-message-state:from:to:cc:subject :date:message-id:reply-to; bh=8dIcxwobV6BNAuIuaE7aLzJugH838eIdiZ2hVMt1ILQ=; b=P8cYJ+vnTUesX8SeuYIdQBulhq3zokYqHg8vcb1B3n6FrTqBqRI+A15c2LfhGvbtzD Z0zGhZWu4+u3s5SSY2TCQfgFPR2tJWdE1TaQQopnR7AHcdylScdA3Du9iobgYiPCLVZN 6lbNIQ+C6NvJl4Tw7On3977V4Pg+0g0ZUfgTm0fFS9V5ksss0mVUqw3yfOOUmSOjsg+0 AV3QQLFb5e9nzxlKKzwRYmB/dnw5a8U78zqbxby++YrVV1YdNYw2BTmkR4t45+9kEI5x dY182EP4VRU1eyMnZpbCtPH/uMWEIwuWl6qw3bq5+VpBye7tUrhe2KV0fUzScp3Vb4Cz iyKw== X-Forwarded-Encrypted: i=1; AJvYcCV1qLh68E5Ggy7HAjhRbb1yILyVVpysfPjHE12Ugweq71Z6IjNaGxnkfxk11szFYG0KnfFJjP9WJQ==@kvack.org X-Gm-Message-State: AOJu0YwIodY4yUlnnVRSj4jUWr2FdPa2d3rdRE32AV/bQsZAepuwbRXj N93/uv4N84/y2a9evYMrB0VNNnelNI5mXMBKJ9FE4IvQcTvbgTeEiBQCSmi9FqsLS9uZLCUmHSf eZHVmLC0NBZyjrDuyHJTDlkx0BcdJtnmy5cusgcIZ7ezFw2pX X-Received: by 2002:a05:6000:1866:b0:37d:33a3:de14 with SMTP id ffacd0b85a97d-381be7adfdemr2447461f8f.7.1730368214917; Thu, 31 Oct 2024 02:50:14 -0700 (PDT) X-Google-Smtp-Source: AGHT+IFeVaRdVGCqBIKY+7Vfj4lrlXB4BTEaQ/Q5YZsm5NFKJxn9YuGzq2b6/rrf6LYaZ8QcgqCaug== X-Received: by 2002:a05:6000:1866:b0:37d:33a3:de14 with SMTP id ffacd0b85a97d-381be7adfdemr2447426f8f.7.1730368214468; Thu, 31 Oct 2024 02:50:14 -0700 (PDT) Received: from ?IPV6:2003:cb:c70a:ed00:7ddf:1ea9:4f7a:91fe? (p200300cbc70aed007ddf1ea94f7a91fe.dip0.t-ipconnect.de. [2003:cb:c70a:ed00:7ddf:1ea9:4f7a:91fe]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-381c10d49d4sm1605679f8f.34.2024.10.31.02.50.11 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 31 Oct 2024 02:50:13 -0700 (PDT) Message-ID: <4aa0ccf4-ebbe-4244-bc85-8bc8dcd14e74@redhat.com> Date: Thu, 31 Oct 2024 10:50:10 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH v3 0/6] Direct Map Removal for guest_memfd To: Patrick Roy , tabba@google.com, quic_eberman@quicinc.com, seanjc@google.com, pbonzini@redhat.com, jthoughton@google.com, ackerleytng@google.com, vannapurve@google.com, rppt@kernel.org Cc: graf@amazon.com, jgowans@amazon.com, derekmn@amazon.com, kalyazin@amazon.com, xmarcalx@amazon.com, linux-mm@kvack.org, corbet@lwn.net, catalin.marinas@arm.com, will@kernel.org, chenhuacai@kernel.org, kernel@xen0n.name, paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, hca@linux.ibm.com, gor@linux.ibm.com, agordeev@linux.ibm.com, borntraeger@linux.ibm.com, svens@linux.ibm.com, gerald.schaefer@linux.ibm.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, luto@kernel.org, peterz@infradead.org, rostedt@goodmis.org, mhiramat@kernel.org, mathieu.desnoyers@efficios.com, shuah@kernel.org, kvm@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, loongarch@lists.linux.dev, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org References: <20241030134912.515725-1-roypat@amazon.co.uk> From: David Hildenbrand Autocrypt: addr=david@redhat.com; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZgEEwEIAEICGwMGCwkIBwMCBhUIAgkKCwQW AgMBAh4BAheAAhkBFiEEG9nKrXNcTDpGDfzKTd4Q9wD/g1oFAl8Ox4kFCRKpKXgACgkQTd4Q 9wD/g1oHcA//a6Tj7SBNjFNM1iNhWUo1lxAja0lpSodSnB2g4FCZ4R61SBR4l/psBL73xktp rDHrx4aSpwkRP6Epu6mLvhlfjmkRG4OynJ5HG1gfv7RJJfnUdUM1z5kdS8JBrOhMJS2c/gPf wv1TGRq2XdMPnfY2o0CxRqpcLkx4vBODvJGl2mQyJF/gPepdDfcT8/PY9BJ7FL6Hrq1gnAo4 3Iv9qV0JiT2wmZciNyYQhmA1V6dyTRiQ4YAc31zOo2IM+xisPzeSHgw3ONY/XhYvfZ9r7W1l pNQdc2G+o4Di9NPFHQQhDw3YTRR1opJaTlRDzxYxzU6ZnUUBghxt9cwUWTpfCktkMZiPSDGd KgQBjnweV2jw9UOTxjb4LXqDjmSNkjDdQUOU69jGMUXgihvo4zhYcMX8F5gWdRtMR7DzW/YE BgVcyxNkMIXoY1aYj6npHYiNQesQlqjU6azjbH70/SXKM5tNRplgW8TNprMDuntdvV9wNkFs 9TyM02V5aWxFfI42+aivc4KEw69SE9KXwC7FSf5wXzuTot97N9Phj/Z3+jx443jo2NR34XgF 89cct7wJMjOF7bBefo0fPPZQuIma0Zym71cP61OP/i11ahNye6HGKfxGCOcs5wW9kRQEk8P9 M/k2wt3mt/fCQnuP/mWutNPt95w9wSsUyATLmtNrwccz63XOwU0EVcufkQEQAOfX3n0g0fZz Bgm/S2zF/kxQKCEKP8ID+Vz8sy2GpDvveBq4H2Y34XWsT1zLJdvqPI4af4ZSMxuerWjXbVWb T6d4odQIG0fKx4F8NccDqbgHeZRNajXeeJ3R7gAzvWvQNLz4piHrO/B4tf8svmRBL0ZB5P5A 2uhdwLU3NZuK22zpNn4is87BPWF8HhY0L5fafgDMOqnf4guJVJPYNPhUFzXUbPqOKOkL8ojk CXxkOFHAbjstSK5Ca3fKquY3rdX3DNo+EL7FvAiw1mUtS+5GeYE+RMnDCsVFm/C7kY8c2d0G NWkB9pJM5+mnIoFNxy7YBcldYATVeOHoY4LyaUWNnAvFYWp08dHWfZo9WCiJMuTfgtH9tc75 7QanMVdPt6fDK8UUXIBLQ2TWr/sQKE9xtFuEmoQGlE1l6bGaDnnMLcYu+Asp3kDT0w4zYGsx 5r6XQVRH4+5N6eHZiaeYtFOujp5n+pjBaQK7wUUjDilPQ5QMzIuCL4YjVoylWiBNknvQWBXS lQCWmavOT9sttGQXdPCC5ynI+1ymZC1ORZKANLnRAb0NH/UCzcsstw2TAkFnMEbo9Zu9w7Kv AxBQXWeXhJI9XQssfrf4Gusdqx8nPEpfOqCtbbwJMATbHyqLt7/oz/5deGuwxgb65pWIzufa N7eop7uh+6bezi+rugUI+w6DABEBAAHCwXwEGAEIACYCGwwWIQQb2cqtc1xMOkYN/MpN3hD3 AP+DWgUCXw7HsgUJEqkpoQAKCRBN3hD3AP+DWrrpD/4qS3dyVRxDcDHIlmguXjC1Q5tZTwNB boaBTPHSy/Nksu0eY7x6HfQJ3xajVH32Ms6t1trDQmPx2iP5+7iDsb7OKAb5eOS8h+BEBDeq 3ecsQDv0fFJOA9ag5O3LLNk+3x3q7e0uo06XMaY7UHS341ozXUUI7wC7iKfoUTv03iO9El5f XpNMx/YrIMduZ2+nd9Di7o5+KIwlb2mAB9sTNHdMrXesX8eBL6T9b+MZJk+mZuPxKNVfEQMQ a5SxUEADIPQTPNvBewdeI80yeOCrN+Zzwy/Mrx9EPeu59Y5vSJOx/z6OUImD/GhX7Xvkt3kq Er5KTrJz3++B6SH9pum9PuoE/k+nntJkNMmQpR4MCBaV/J9gIOPGodDKnjdng+mXliF3Ptu6 3oxc2RCyGzTlxyMwuc2U5Q7KtUNTdDe8T0uE+9b8BLMVQDDfJjqY0VVqSUwImzTDLX9S4g/8 kC4HRcclk8hpyhY2jKGluZO0awwTIMgVEzmTyBphDg/Gx7dZU1Xf8HFuE+UZ5UDHDTnwgv7E th6RC9+WrhDNspZ9fJjKWRbveQgUFCpe1sa77LAw+XFrKmBHXp9ZVIe90RMe2tRL06BGiRZr jPrnvUsUUsjRoRNJjKKA/REq+sAnhkNPPZ/NNMjaZ5b8Tovi8C0tmxiCHaQYqj7G2rgnT0kt WNyWQQ== Organization: Red Hat In-Reply-To: <20241030134912.515725-1-roypat@amazon.co.uk> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Queue-Id: 51B9516001A X-Rspamd-Server: rspam11 X-Stat-Signature: 38du54d5k8ahc7fk1m1suhkz6cn3n6r1 X-HE-Tag: 1730368202-634677 X-HE-Meta: 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 dYF6bYwf MK8QMn6MGH+ch1JgettSOMJX4EZ1dNEPfIIOskdn5iQHjTDUSs6G8ylfPuVjOq6bfaIB3PnkFJnMSD153r/iudzV45QwepewqUXZck1K8c7aHGyMOcn6m0gHHMdtokvlk8kyYDIb80BEOAL70igJMZBhj1v828BjTHPGRZnHf6LhzG38JJyqbsZZp4IN293wSO0J4myUV8yp4AfZuPBdcdqnZ+ub+fOFAiVuQikS4P7MaxPj5de5aptjxKG0ylnlGAz/etiJa5VeH3aaAmBsyi/MJQI9P5bwuqWrvPWQUVSdMi44AUVmMLhssYZqdgQZ1KSQIYeniftd3HtE6k6x43oVIefdlfZD9zaZSpZNpygI3b8nE57YxN3eE+cxSEYBWZuS64256cDcsFOiHtXogmJS8f94DA0reeYe5eamQ7b1M68EB4c+s11qEOyQDp+7ywaWt X-Bogosity: Ham, tests=bogofilter, spamicity=0.009788, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 30.10.24 14:49, Patrick Roy wrote: > Unmapping virtual machine guest memory from the host kernel's direct map > is a successful mitigation against Spectre-style transient execution > issues: If the kernel page tables do not contain entries pointing to > guest memory, then any attempted speculative read through the direct map > will necessarily be blocked by the MMU before any observable > microarchitectural side-effects happen. This means that Spectre-gadgets > and similar cannot be used to target virtual machine memory. Roughly 60% > of speculative execution issues fall into this category [1, Table 1]. > > This patch series extends guest_memfd with the ability to remove its > memory from the host kernel's direct map, to be able to attain the above > protection for KVM guests running inside guest_memfd. > > === Changes to v2 === > > - Handle direct map removal for physically contiguous pages in arch code > (Mike R.) > - Track the direct map state in guest_memfd itself instead of at the > folio level, to prepare for huge pages support (Sean C.) > - Allow configuring direct map state of not-yet faulted in memory > (Vishal A.) > - Pay attention to alignment in ftrace structs (Steven R.) > > Most significantly, I've reduced the patch series to focus only on > direct map removal for guest_memfd for now, leaving the whole "how to do > non-CoCo VMs in guest_memfd" for later. If this separation is > acceptable, then I think I can drop the RFC tag in the next revision > (I've mainly kept it here because I'm not entirely sure what to do with > patches 3 and 4). Hi, keeping upcoming "shared and private memory in guest_memfd" in mind, I assume the focus would be to only remove the direct map for private memory? So in the current upstream state, you would only be removing the direct map for private memory, currently translating to "encrypted"/"protected" memory that is inaccessible either way already. Correct? -- Cheers, David / dhildenb