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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 1BB10C369C2 for ; Fri, 25 Apr 2025 12:49:51 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1u8IUe-0007qT-G9; Fri, 25 Apr 2025 08:49:24 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1u8IUc-0007q2-B7 for qemu-devel@nongnu.org; Fri, 25 Apr 2025 08:49:22 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1u8IUa-0006vS-K3 for qemu-devel@nongnu.org; Fri, 25 Apr 2025 08:49:22 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1745585357; 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=QYGRSk9EMOc+ohdOFgvOsQqhOO83k3hgQYJev3Y0mt8=; b=J/02qZSjrKvI2kNBOmnwc+TP+jLxOXQwrlCIhwrf19j3D1BK12HJifr5nWJa0WhazOmBtc Xjg1YC9NoiVSwNGE/CtKxOV3tBi32zFlD+Ucynd2UlWkyD/BdEO/Ea7NgPy7nrWl87ZzcH +z3QisrCWNvtSW5mZSBGQPiwN1IvcKM= 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-637-gx3lvUN_ORaHcTVjSygQ8w-1; Fri, 25 Apr 2025 08:49:16 -0400 X-MC-Unique: gx3lvUN_ORaHcTVjSygQ8w-1 X-Mimecast-MFC-AGG-ID: gx3lvUN_ORaHcTVjSygQ8w_1745585355 Received: by mail-wr1-f72.google.com with SMTP id ffacd0b85a97d-3912d5f6689so1132951f8f.1 for ; Fri, 25 Apr 2025 05:49:15 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1745585355; x=1746190155; 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=QYGRSk9EMOc+ohdOFgvOsQqhOO83k3hgQYJev3Y0mt8=; b=v5+mD5IgFfZRWKVI9HUolvHGtxA3ht2YIDzL7dj/kXCSFa73ObyLkTXdjZ6h/rxevD /vqF0MSRqUvNlh8dspm9occ7r3f1a95S40IWz+6xbm753Y8HoRtAw5DZ2Cg4HXk0VK1Z 11acuCa8ou+2UYclf/C2+d1Cx3/sky/7ka1DpcwYm7hmJvJwiAS6+xpv+UIjwhtodPKw VdeN2/9ofhfBokMALU8wq8hm8KI8nQaetecl+ojcjH+gxx8T/JVABtpOTDq3Td8ulyPI vmBxKGecDI1hcQMhG9RqObM40grjCQZEKj1+QjYHJdA8FR6zAumj2rdIzScJdy8YoArd 5MRQ== X-Gm-Message-State: AOJu0Ywvms+AmaQYAOCPgJ5wSd6rRjuv5m+TpBrdBkaHH9ga/xUNOc8d 5wTqoqoe2tn28tBy+leIQD3G2m3FyxtfqP8EmqiTdDXBAHqDk1uMzIuYiFxhUXwLxVVXpj5QLKj MdHDeDEteUEYTK3HDPctOAPQ7sg+32aaaebhwoqEQKE8DhmbjFf2d X-Gm-Gg: ASbGnctGWLr3zgAq1R4XjDI3oomEl5m3pXZiCdrOl7m4+QMFFvSDv/CmxWBL2sPyy7Q ywpPjRSMkw57Uy4KKgUDAdjhFWOv659piJ9IL6ddXQAEnncBKQK3C/9nuid/eLFTG2xgUFfm23l FK09sLhQfyqgZ9EaAMwpFTgdmf+RcF4K2dG9Yqf0foO601Ejj4O38qSyoPbdjt69L4w2WNn89jm QxcY4CACCZCa/qbr7M1uQpY1m0J58yu/44AyAYbqZGdfxC7mbB9pXuFejy7chUA6X6d01Yhy2n3 T4W+DZYRdxUxbmuHcsrikPzAuR05RabirYK7bEAJJXJQ+2MOK7ZUIMvxpv0OdndKZq2tuAIPPk3 64uPi8dgDXiCZOa2TIcXKm88SgI5fD3LS+42B X-Received: by 2002:a5d:6d82:0:b0:391:4559:876a with SMTP id ffacd0b85a97d-3a074f2ecbemr1829656f8f.46.1745585354879; Fri, 25 Apr 2025 05:49:14 -0700 (PDT) X-Google-Smtp-Source: AGHT+IHtw87bkAqffObS5495XqBM3FBiJn3HJ1+ERi3N86EKTpOViCMyMKry06K00JbDrQNOGIhGbg== X-Received: by 2002:a5d:6d82:0:b0:391:4559:876a with SMTP id ffacd0b85a97d-3a074f2ecbemr1829635f8f.46.1745585354480; Fri, 25 Apr 2025 05:49:14 -0700 (PDT) Received: from ?IPV6:2003:cb:c70f:6900:6c56:80f8:c14:6d2a? (p200300cbc70f69006c5680f80c146d2a.dip0.t-ipconnect.de. [2003:cb:c70f:6900:6c56:80f8:c14:6d2a]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3a073e5d4b0sm2239853f8f.89.2025.04.25.05.49.11 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 25 Apr 2025 05:49:12 -0700 (PDT) Message-ID: Date: Fri, 25 Apr 2025 14:49:11 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 04/13] memory: Introduce generic state change parent class for RamDiscardManager To: Alexey Kardashevskiy , Chenyi Qiang , Peter Xu , Gupta Pankaj , Paolo Bonzini , =?UTF-8?Q?Philippe_Mathieu-Daud=C3=A9?= , Michael Roth Cc: qemu-devel@nongnu.org, kvm@vger.kernel.org, Williams Dan J , Peng Chao P , Gao Chao , Xu Yilun , Li Xiaoyao References: <20250407074939.18657-1-chenyi.qiang@intel.com> <20250407074939.18657-5-chenyi.qiang@intel.com> <402e0db2-b1af-4629-a651-79d71feffeec@amd.com> From: David Hildenbrand Content-Language: en-US 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: <402e0db2-b1af-4629-a651-79d71feffeec@amd.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=170.10.129.124; envelope-from=david@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -23 X-Spam_score: -2.4 X-Spam_bar: -- X-Spam_report: (-2.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.314, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, 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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On 09.04.25 11:56, Alexey Kardashevskiy wrote: > > > On 7/4/25 17:49, Chenyi Qiang wrote: >> RamDiscardManager is an interface used by virtio-mem to adjust VFIO >> mappings in relation to VM page assignment. It manages the state of >> populated and discard for the RAM. To accommodate future scnarios for >> managing RAM states, such as private and shared states in confidential >> VMs, the existing RamDiscardManager interface needs to be generalized. >> >> Introduce a parent class, GenericStateManager, to manage a pair of > > "GenericState" is the same as "State" really. Call it RamStateManager. > > > >> opposite states with RamDiscardManager as its child. The changes include >> - Define a new abstract class GenericStateChange. >> - Extract six callbacks into GenericStateChangeClass and allow the child >> classes to inherit them. >> - Modify RamDiscardManager-related helpers to use GenericStateManager >> ones. >> - Define a generic StatChangeListener to extract fields from > > "e" missing in StateChangeListener. > >> RamDiscardManager listener which allows future listeners to embed it >> and avoid duplication. >> - Change the users of RamDiscardManager (virtio-mem, migration, etc.) to >> switch to use GenericStateChange helpers. >> >> It can provide a more flexible and resuable framework for RAM state >> management, facilitating future enhancements and use cases. > > I fail to see how new interface helps with this. RamDiscardManager > manipulates populated/discarded. It would make sense may be if the new > class had more bits per page, say private/shared/discarded but it does > not. And PrivateSharedManager cannot coexist with RamDiscard. imho this > is going in a wrong direction. Agreed. In the future, we will have virtio-mem co-exist with guest_memfd. Both are information sources, and likely we'd have some instance on top, that merges these sources to identify if anybody needs to be notified. Until we figure out how that would look like, I would suggest to keep it as is. Maybe, in the future we would have a single RamDiscardManager and multiple RamDiscardSources per RAMBlock. The sources notify the manager, and the manager can ask other sources to merge the information. -- Cheers, David / dhildenb