From patchwork Wed Nov 20 18:12:06 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Elliot Berman X-Patchwork-Id: 844547 Received: from mx0b-0031df01.pphosted.com (mx0b-0031df01.pphosted.com [205.220.180.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 425F31E515; Wed, 20 Nov 2024 18:12:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=205.220.180.131 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732126364; cv=none; b=rBntKq8+JdrBC7LnLyuTbVOTVTiJsAi53RB/K7gQDS72NSVcbPn/x2Q1e/I/DzE+E4WDtVlBwAPovsNsziCKZxT9w9ERqawMwo5vG9L4ca+SaUCq0DEMcYhBuCfmSP9Kj4lGN45VwFjNUErz+TGo+p4RSc9cQC9mU7xyY+3toe4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732126364; c=relaxed/simple; bh=+GIAMTVbJ1ixJStHsEbMHlliDpePtNm2e3H3BFBrBvg=; h=From:Subject:Date:Message-ID:MIME-Version:Content-Type:To:CC; b=BuBSytoEYYHrYO3fRfb8D8YZal6q9fIDOzf+LHY+2I6ewvAGseGfUokJwkQYI1bggVPPgpo0AvJbktfdp4QspT+VgFMDo7HK3oTYWrHuEfZq3eFvtZtmKADey0MHOig36lOK3BB3JH4qqV5x878+0YymFLDlUw/LQyxhdYGiWDU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=quicinc.com; spf=pass smtp.mailfrom=quicinc.com; dkim=pass (2048-bit key) header.d=quicinc.com header.i=@quicinc.com header.b=lFiAVJA/; arc=none smtp.client-ip=205.220.180.131 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=quicinc.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=quicinc.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=quicinc.com header.i=@quicinc.com header.b="lFiAVJA/" Received: from pps.filterd (m0279871.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 4AK9GWxj025929; Wed, 20 Nov 2024 18:12:15 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; h= cc:content-transfer-encoding:content-type:date:from:message-id :mime-version:subject:to; s=qcppdkim1; bh=EhNaM1mzvIH9f+QEUvvyQ1 l0k56DBuV7rXs6Bl8yZT4=; b=lFiAVJA/Rqalps64p2UfO3u40nM1FzbsFDrJ1D THUltmdgjEBUEcKlBvuxBT2L8RhqW72MgoEeiz98N0J6C8mPYg8cR6IJf0+f5a1E tn5mRsV5pKw/Bh3OUJMieLY5YCiKa/a5ncxVEE55gFxUjhDWgXayN3LR4jWourMR NOrvqJV5nOCv8tx1a1G1Hyz7dVFc1p2B6uHYR0W+dcbkNKEaN+lXs278Ps71Leps 93blNZDTZU8rDEECrj3D+MQXgIZYzyG1UKLcCs4FCuIWrWKFtk2uEvj88dHGcWNs vy9XkecfWSUdp49K2mX+KB1yhH6RzQ6rXArt9iwmDgJk8Q6Q== Received: from nasanppmta03.qualcomm.com (i-global254.qualcomm.com [199.106.103.254]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 431byjhkpj-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 20 Nov 2024 18:12:15 +0000 (GMT) Received: from nasanex01b.na.qualcomm.com (nasanex01b.na.qualcomm.com [10.46.141.250]) by NASANPPMTA03.qualcomm.com (8.18.1.2/8.18.1.2) with ESMTPS id 4AKICEkM001246 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 20 Nov 2024 18:12:14 GMT Received: from hu-eberman-lv.qualcomm.com (10.49.16.6) by nasanex01b.na.qualcomm.com (10.46.141.250) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.9; Wed, 20 Nov 2024 10:12:13 -0800 From: Elliot Berman Subject: [PATCH v4 0/2] mm: Refactor KVM guest_memfd to introduce guestmem library Date: Wed, 20 Nov 2024 10:12:06 -0800 Message-ID: <20241120-guestmem-library-v4-0-0c597f733909@quicinc.com> Precedence: bulk X-Mailing-List: linux-arm-msm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-B4-Tracking: v=1; b=H4sIAHcmPmcC/2WNwQ6CMBAFf4Xs2RraYqme/A/DgZYFNrGALTQSw r9bSTx5nEnevA0CesIAt2wDj5ECjUOC4pSB7euhQ0ZNYhC5KDjngnULhtmhY08yvvYrU1oqaY2 4cq0gzSaPLb2P5KNK3FOYR78eD1F+7S8m/2NRspyVvG0Q9UWVytxfC1ka7NmODqp93z+32UyVs gAAAA== X-Change-ID: 20241112-guestmem-library-68363cb29186 To: Paolo Bonzini , Andrew Morton , Sean Christopherson , "Fuad Tabba" , Ackerley Tng , "Mike Rapoport" , David Hildenbrand , "H. Peter Anvin" , "Matthew Wilcox (Oracle)" , Jonathan Corbet , Trond Myklebust , "Anna Schumaker" , Mike Marshall , "Martin Brandenburg" , Alexander Viro , Christian Brauner , Jan Kara CC: James Gowans , Mike Day , , , , , , , , , , , "Elliot Berman" X-Mailer: b4 0.14.2 X-ClientProxiedBy: nalasex01a.na.qualcomm.com (10.47.209.196) To nasanex01b.na.qualcomm.com (10.46.141.250) X-QCInternal: smtphost X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=5800 signatures=585085 X-Proofpoint-GUID: nd43uozb7EZ_SXIRUmbmgsxDVz64o2Pc X-Proofpoint-ORIG-GUID: nd43uozb7EZ_SXIRUmbmgsxDVz64o2Pc X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1039,Hydra:6.0.680,FMLib:17.12.60.29 definitions=2024-09-06_09,2024-09-06_01,2024-09-02_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 clxscore=1011 suspectscore=0 phishscore=0 lowpriorityscore=0 impostorscore=0 malwarescore=0 priorityscore=1501 bulkscore=0 adultscore=0 mlxlogscore=954 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2409260000 definitions=main-2411200125 In preparation for adding more features to KVM's guest_memfd, refactor and introduce a library which abtracts some of the core-mm decisions about managing folios associated with guest memory. The goal of the refactor serves two purposes: 1. Provide an easier way to reason about memory in guest_memfd. KVM needs to support multiple confidentiality models (TDX, SEV, pKVM, Arm CCA). These models support different semantics for when the host can(not) access guest memory. An abstraction for the allocator and managing the state of pages will make it eaiser to reason about the state of folios within the guest_memfd. 2. Provide a common implementation for other users such as Gunyah [1] and guestmemfs [2]. In this initial series, I'm seeking comments for the line I'm drawing between library and user (KVM). I've not introduced new functionality in this series; the first new feature will probably be Fuad's mappability patches [3]. I've decided to only bring out the address_space from guest_memfd as it seemed the simplest approach. In the current iteration, KVM "attaches" the guestmem to the inode. I expect we'll want to provide some helpers for inode, file, and vm operations when it's relevant to mappability/accessiblity/faultability. I'd appreciate any feedback, especially on how much we should pull into the guestmem library. [1]: https://lore.kernel.org/lkml/20240222-gunyah-v17-0-1e9da6763d38@quicinc.com/ [2]: https://lore.kernel.org/all/20240805093245.889357-1-jgowans@amazon.com/ [3]: https://lore.kernel.org/all/20241010085930.1546800-3-tabba@google.com/ Changes in v4: - Update folio_free() to add address_space mapping instead of invalidate_folio/free_folio path. - Link to v3: https://lore.kernel.org/r/20241113-guestmem-library-v3-0-71fdee85676b@quicinc.com Changes in v3: - Refactor/extract only the address_space - Link to v2: https://lore.kernel.org/all/20240829-guest-memfd-lib-v2-0-b9afc1ff3656@quicinc.com/ Changes in v2: - Significantly reworked to introduce "accessible" and "safe" reference counters - Link to v1: https://lore.kernel.org/r/20240805-guest-memfd-lib-v1-0-e5a29a4ff5d7@quicinc.com Signed-off-by: Elliot Berman --- Elliot Berman (2): filemap: Pass address_space mapping to ->free_folio() mm: guestmem: Convert address_space operations to guestmem library Documentation/filesystems/locking.rst | 2 +- MAINTAINERS | 2 + fs/nfs/dir.c | 11 +- fs/orangefs/inode.c | 3 +- include/linux/fs.h | 2 +- include/linux/guestmem.h | 33 ++++++ mm/Kconfig | 3 + mm/Makefile | 1 + mm/filemap.c | 9 +- mm/guestmem.c | 196 ++++++++++++++++++++++++++++++++++ mm/secretmem.c | 3 +- mm/vmscan.c | 4 +- virt/kvm/Kconfig | 1 + virt/kvm/guest_memfd.c | 97 +++++------------ 14 files changed, 283 insertions(+), 84 deletions(-) --- base-commit: 5cb1659f412041e4780f2e8ee49b2e03728a2ba6 change-id: 20241112-guestmem-library-68363cb29186 Best regards,