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 ABAC9C87FCF for ; Thu, 7 Aug 2025 14:14:03 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1uk1Mu-0004WX-88; Thu, 07 Aug 2025 10:13:22 -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 1uk1Mn-0004US-HE for qemu-devel@nongnu.org; Thu, 07 Aug 2025 10:13:13 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1uk1Mi-0004Qy-TK for qemu-devel@nongnu.org; Thu, 07 Aug 2025 10:13:12 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1754575986; 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=TZeGEn5xHM1k/EW+W75gI6JAh/2Pw8L54gV9Jh0EXnc=; b=FWMMNZaWigSnCSpP6UIEcsXGr41rhqS/+IhA0NiHBQslchs5w713zBQ+bekIWM+iGHan1l EjPhFA1lsuRrhATvAWRu3xAEopMxdlZ+RRN2pGJ9XCsfK9XUP/aYXKMTm9VWrZmIoo9xKj IWIj8YsbqGZv2YY1biT+NiGDHPUQ56o= Received: from mail-wr1-f71.google.com (mail-wr1-f71.google.com [209.85.221.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-14-j6-w7s0MOsWBhlzoHOJ_IA-1; Thu, 07 Aug 2025 10:13:04 -0400 X-MC-Unique: j6-w7s0MOsWBhlzoHOJ_IA-1 X-Mimecast-MFC-AGG-ID: j6-w7s0MOsWBhlzoHOJ_IA_1754575984 Received: by mail-wr1-f71.google.com with SMTP id ffacd0b85a97d-3b7931d3d76so672230f8f.1 for ; Thu, 07 Aug 2025 07:13:04 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1754575984; x=1755180784; h=content-transfer-encoding:in-reply-to: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=TZeGEn5xHM1k/EW+W75gI6JAh/2Pw8L54gV9Jh0EXnc=; b=vUAM1JnEXSmuwa1ypXR2u2sZJtvoVZgnqynQuzK0eVOINYGG+chiyCm2dukAWWfpkU P2Hem60W31oa9iNdQXbbN0Tp0gj82j9Zv/nrab4oapwtQwcvMrSkW/6wKhoZ9PCFvz9p 1DJoual43KFh9tnZdA6Y6w449tG4Yh2EEI/D2/ckOL8X9reZSu36dZ+RfCMM6Kx0DZR+ Ft/eutwPpmBc60JB2SzQ//tUNHzeRSCu7KHx1UY5BfXxt786kpEZVbsrXhEK26nDtckr YO7ElG1kOg63s1DxnyTQiTRJ+FmIpXFkWsSRfyXcwT0XD6X5yba+P5/37MGeVXMSwGcE xA9g== X-Gm-Message-State: AOJu0YwvH2mmHWDV6kOVvA4c30uxgG5Lrg3pGnZpODKddHWXC2ybh+UO zXZ32T1tQ2M9E7uxh/KBQcj3/79/EOXqvDdvoLmiSaEA9TAtRiysIyET1XBXZZT/z3vjE+v/yOv E/S3QBEj/5z7LsK0fkObH6zbY6drrSPuADtMby+6RnxiFPAW9W6Xb/1iR X-Gm-Gg: ASbGncs3Und3EjJCrwjPcgTCm5bS0mB5Ib6soE9BNLqBFHex+X98nW6hYdeLO8+gtiN co7mF3vPKWdZIjsV6ZEzTCd43cWJOlvL/D1tMFhXLvh38l2lcdi9lqVn7IAUI+u6/0XNkqeHivh 3FQzqM2F4K++Gzq6YTeEP4dQEMmNQ27uGdJ74wxMbAcLEzOzmx/H5dN7VTwpTcM1kSqURvSLbP0 nZROxoEaPS/F9JW4IA58FiZ5Wpfaty0q4uzCVbfGm4HZ0nte3z3LgV5EiTqZYqrQ0FNXiVgm0Ah 6ZUreUROQacir5Kzr837YhKDP+IjmLwL3Mu3+TKkONmW X-Received: by 2002:a05:6000:2204:b0:3b4:9721:2b2d with SMTP id ffacd0b85a97d-3b8f48de380mr5424927f8f.9.1754575983525; Thu, 07 Aug 2025 07:13:03 -0700 (PDT) X-Google-Smtp-Source: AGHT+IFIFCzEYBHd1ZGXQnwZIzcOzskL80owLj2MB3R97Q0u/w3GvlERiNbET4dj3HB6HsX4gjOD5w== X-Received: by 2002:a05:6000:2204:b0:3b4:9721:2b2d with SMTP id ffacd0b85a97d-3b8f48de380mr5424890f8f.9.1754575983050; Thu, 07 Aug 2025 07:13:03 -0700 (PDT) Received: from [192.168.10.48] ([151.49.253.173]) by smtp.googlemail.com with ESMTPSA id 5b1f17b1804b1-459dbba5210sm165256865e9.2.2025.08.07.07.13.01 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 07 Aug 2025 07:13:02 -0700 (PDT) Message-ID: Date: Thu, 7 Aug 2025 16:13:00 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC 00/26] rust/memory: Integrate the vm-memory API from rust-vmm To: Zhao Liu , Peter Xu , David Hildenbrand , =?UTF-8?Q?Philippe_Mathieu-Daud=C3=A9?= , Manos Pitsidianakis , =?UTF-8?Q?Alex_Benn=C3=A9e?= , Thomas Huth , Junjie Mao , Hanna Reitz Cc: qemu-devel@nongnu.org, qemu-rust@nongnu.org, Dapeng Mi , Chuanxiao Dong References: <20250807123027.2910950-1-zhao1.liu@intel.com> From: Paolo Bonzini Content-Language: en-US Autocrypt: addr=pbonzini@redhat.com; keydata= xsEhBFRCcBIBDqDGsz4K0zZun3jh+U6Z9wNGLKQ0kSFyjN38gMqU1SfP+TUNQepFHb/Gc0E2 CxXPkIBTvYY+ZPkoTh5xF9oS1jqI8iRLzouzF8yXs3QjQIZ2SfuCxSVwlV65jotcjD2FTN04 hVopm9llFijNZpVIOGUTqzM4U55sdsCcZUluWM6x4HSOdw5F5Utxfp1wOjD/v92Lrax0hjiX DResHSt48q+8FrZzY+AUbkUS+Jm34qjswdrgsC5uxeVcLkBgWLmov2kMaMROT0YmFY6A3m1S P/kXmHDXxhe23gKb3dgwxUTpENDBGcfEzrzilWueOeUWiOcWuFOed/C3SyijBx3Av/lbCsHU Vx6pMycNTdzU1BuAroB+Y3mNEuW56Yd44jlInzG2UOwt9XjjdKkJZ1g0P9dwptwLEgTEd3Fo UdhAQyRXGYO8oROiuh+RZ1lXp6AQ4ZjoyH8WLfTLf5g1EKCTc4C1sy1vQSdzIRu3rBIjAvnC tGZADei1IExLqB3uzXKzZ1BZ+Z8hnt2og9hb7H0y8diYfEk2w3R7wEr+Ehk5NQsT2MPI2QBd wEv1/Aj1DgUHZAHzG1QN9S8wNWQ6K9DqHZTBnI1hUlkp22zCSHK/6FwUCuYp1zcAEQEAAc0j UGFvbG8gQm9uemluaSA8cGJvbnppbmlAcmVkaGF0LmNvbT7CwU0EEwECACMFAlRCcBICGwMH CwkIBwMCAQYVCAIJCgsEFgIDAQIeAQIXgAAKCRB+FRAMzTZpsbceDp9IIN6BIA0Ol7MoB15E 11kRz/ewzryFY54tQlMnd4xxfH8MTQ/mm9I482YoSwPMdcWFAKnUX6Yo30tbLiNB8hzaHeRj jx12K+ptqYbg+cevgOtbLAlL9kNgLLcsGqC2829jBCUTVeMSZDrzS97ole/YEez2qFpPnTV0 VrRWClWVfYh+JfzpXmgyhbkuwUxNFk421s4Ajp3d8nPPFUGgBG5HOxzkAm7xb1cjAuJ+oi/K CHfkuN+fLZl/u3E/fw7vvOESApLU5o0icVXeakfSz0LsygEnekDbxPnE5af/9FEkXJD5EoYG SEahaEtgNrR4qsyxyAGYgZlS70vkSSYJ+iT2rrwEiDlo31MzRo6Ba2FfHBSJ7lcYdPT7bbk9 AO3hlNMhNdUhoQv7M5HsnqZ6unvSHOKmReNaS9egAGdRN0/GPDWr9wroyJ65ZNQsHl9nXBqE AukZNr5oJO5vxrYiAuuTSd6UI/xFkjtkzltG3mw5ao2bBpk/V/YuePrJsnPFHG7NhizrxttB nTuOSCMo45pfHQ+XYd5K1+Cv/NzZFNWscm5htJ0HznY+oOsZvHTyGz3v91pn51dkRYN0otqr bQ4tlFFuVjArBZcapSIe6NV8C4cEiSTOwE0EVEJx7gEIAMeHcVzuv2bp9HlWDp6+RkZe+vtl KwAHplb/WH59j2wyG8V6i33+6MlSSJMOFnYUCCL77bucx9uImI5nX24PIlqT+zasVEEVGSRF m8dgkcJDB7Tps0IkNrUi4yof3B3shR+vMY3i3Ip0e41zKx0CvlAhMOo6otaHmcxr35sWq1Jk tLkbn3wG+fPQCVudJJECvVQ//UAthSSEklA50QtD2sBkmQ14ZryEyTHQ+E42K3j2IUmOLriF dNr9NvE1QGmGyIcbw2NIVEBOK/GWxkS5+dmxM2iD4Jdaf2nSn3jlHjEXoPwpMs0KZsgdU0pP JQzMUMwmB1wM8JxovFlPYrhNT9MAEQEAAcLBMwQYAQIACQUCVEJx7gIbDAAKCRB+FRAMzTZp sadRDqCctLmYICZu4GSnie4lKXl+HqlLanpVMOoFNnWs9oRP47MbE2wv8OaYh5pNR9VVgyhD OG0AU7oidG36OeUlrFDTfnPYYSF/mPCxHttosyt8O5kabxnIPv2URuAxDByz+iVbL+RjKaGM GDph56ZTswlx75nZVtIukqzLAQ5fa8OALSGum0cFi4ptZUOhDNz1onz61klD6z3MODi0sBZN Aj6guB2L/+2ZwElZEeRBERRd/uommlYuToAXfNRdUwrwl9gRMiA0WSyTb190zneRRDfpSK5d usXnM/O+kr3Dm+Ui+UioPf6wgbn3T0o6I5BhVhs4h4hWmIW7iNhPjX1iybXfmb1gAFfjtHfL xRUr64svXpyfJMScIQtBAm0ihWPltXkyITA92ngCmPdHa6M1hMh4RDX+Jf1fiWubzp1voAg0 JBrdmNZSQDz0iKmSrx8xkoXYfA3bgtFN8WJH2xgFL28XnqY4M6dLhJwV3z08tPSRqYFm4NMP dRsn0/7oymhneL8RthIvjDDQ5ktUjMe8LtHr70OZE/TT88qvEdhiIVUogHdo4qBrk41+gGQh b906Dudw5YhTJFU3nC6bbF2nrLlB4C/XSiH76ZvqzV0Z/cAMBo5NF/w= In-Reply-To: <20250807123027.2910950-1-zhao1.liu@intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=170.10.133.124; envelope-from=pbonzini@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, 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_PASS=-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 [Adding Hanna who's been working on vm-memory] On 8/7/25 14:30, Zhao Liu wrote: > Hi, > > This RFC series explores integrating the vm-memory API into QEMU's > rust/memory bindings. > > Thanks to Paolo and Manos's many suggestions and feedback, I have > resolved many issues over the past few months, but there are still > some open issues that I would like to discuss. > > This series finally provides the following safe interfaces in Rust: > * AddressSpace::write in Rust <=> address_space_write in C > - **but only** supports MEMTXATTRS_UNSPECIFIED > > * AddressSpace::read in Rust <=> address_space_read_full in C > - **but only** supports MEMTXATTRS_UNSPECIFIED. > > * AddressSpace::store in Rust <=> address_space_st{size} in C > - **but only** supports MEMTXATTRS_UNSPECIFIED and native endian. > > * AddressSpace::load in Rust <=> address_space_ld{size} in C > - **but only** supports MEMTXATTRS_UNSPECIFIED and native endian. Endianness can be handled by BeNN and LeNN. For MemTxAttrs we can use Bytes<(GuestAddress, MemTxAttrs)> (a variant on something you mention below). Thinking out loud: maybe if we do our implementation in Bytes<(GuestAddress, MemTxAttrs)>, and Bytes::try_access wraps Bytes<(GuestAddress, MemTxAttrs)>, your downstream-only changes are not needed anymore? > And this series involves changes mainly to these three parts: > * NEW QEMU memory APIs wrapper at C side. > * Extra changes for vm-memory (downstream for now). > * NEW QEMU memory bindings/APIs based on vm-memory at Rust side. > > Although the number of line changes appears to be significant, more > than half of them are documentation and comments. Yep, thanks for writing them. This is a good RFC, it's complete enough to show the challenges and the things that are missing stand up easily. I'll look into what vm-memory is missing so that we can simplify QEMU's code further, but the basic traits match which is nice. And the final outcome, which is essentially: let (addr, value) = (GuestAddress(self.fsb >> 32), Le32(self.fsb as u32)); ADDRESS_SPACE_MEMORY.memory().store(addr, value); is as clean as it can be, if anything a bit wordy due to the GuestAddress "newtype" wrapper. (If we decide it's too bad, the convenience methods in AddressSpace can automatically do the GuestAddress conversion...) Paolo