From patchwork Fri Nov 22 17:29:37 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Elliot Berman X-Patchwork-Id: 13883464 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 3FD7DE69183 for ; Fri, 22 Nov 2024 17:32:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:CC:To: Content-Transfer-Encoding:Content-Type:MIME-Version:Message-ID:Date:Subject: From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=XQD1PU6ptvKeI0fuFGCRRHzhvac3i1byGnmnm5ZKMNQ=; b=LAefEsQ48+9bkK CEErrOd0OLpZqPCvDWAn0UtEdcMEdOWn34r0Hk5n83dLPhpd8i//SRQDQ1fq1D2ZwuYPi9eJ9TTfH uWJwGCrw0ddMDMm9unA0PbxL9ffmkMzMHJW3LVvtFqyNk20Wy9lc1NKOW+FwEMqCMWcRmHPJwjnK6 oXvqp99mlphgZ5LPaP1zMrq4yAHEuSz1uJ80AXAqIuflecfLwNbVRHW5jtTswQjUckUC53GW+Nde4 YCAOr0H8hDgd/p5M909UekzoKYwqoLEnJps+GgSrRUzhtCTi6hcuRzHZCKglT4MJjenNSgqLcHfjV lYb9pmhChMfSGjB9FclQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tEXVf-00000002zDy-1ycN; Fri, 22 Nov 2024 17:31:59 +0000 Received: from mx0b-0031df01.pphosted.com ([205.220.180.131]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1tEXTm-00000002yfU-3Gwr for linux-arm-kernel@lists.infradead.org; Fri, 22 Nov 2024 17:30:04 +0000 Received: from pps.filterd (m0279873.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 4AMAMOeZ020697; Fri, 22 Nov 2024 17:29:43 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=XQD1PU6ptvKeI0fuFGCRRH zhvac3i1byGnmnm5ZKMNQ=; b=J6u/19z19r8pbkyVFouVXseewIRW9lf/XXr5OY xMtAMdYaR3wbGrkPjNxVCsc/cdxs5Esu1wm8TydJwBef+M0BvxaSF9jfDpYnYmlX +NYxvkagKjvymiPGHp3V36XefLFtIiHUGHY/Ys1DKRbfZxyNxOWRWrkkGjOmYut3 5juU7WFtSNtEhTnw2VmGVr6wOmeH4/e9RpCHAfnaZm6yKReEWAjAZdBKokIgW70C g0OKLCxgXEDYM5RhHvopGMf1BeBSEU3vCTaL6UwIS4NzDhtoXiTichlvFIgPmhfo vzmP+fYvX1Dvf3M28vvcC3EXX+mxASbVbFC4QPokrTRSClSw== Received: from nasanppmta04.qualcomm.com (i-global254.qualcomm.com [199.106.103.254]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 431sv2nwj4-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 22 Nov 2024 17:29:43 +0000 (GMT) Received: from nasanex01b.na.qualcomm.com (nasanex01b.na.qualcomm.com [10.46.141.250]) by NASANPPMTA04.qualcomm.com (8.18.1.2/8.18.1.2) with ESMTPS id 4AMHTgut021006 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 22 Nov 2024 17:29:42 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; Fri, 22 Nov 2024 09:29:41 -0800 From: Elliot Berman Subject: [PATCH v5 0/2] mm: Refactor KVM guest_memfd to introduce guestmem library Date: Fri, 22 Nov 2024 09:29:37 -0800 Message-ID: <20241122-guestmem-library-v5-0-450e92951a15@quicinc.com> MIME-Version: 1.0 X-B4-Tracking: v=1; b=H4sIAIG/QGcC/23NTQ6CMBCG4auQrq3pD7TUlfcwLqAMMImAttBIC He3kJhodPl+yTyzEA8OwZNTshAHAT0OfYzskBDbFn0DFKvYRDCRcs4FbSbwYwcdvWHpCjdTlUs lbSkMzxWJZ3cHNT538nKN3aIfBzfvH4Lc1jcmf7EgKaOa1xVAnimtyvNjQou9PdqhIxsX0g9Cs D9EGglmM6NrLaVh5ptY1/UFy5Xc0vUAAAA= 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-Originating-IP: [10.49.16.6] X-ClientProxiedBy: nalasex01b.na.qualcomm.com (10.47.209.197) 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: F6Lm3BVFcc9UAbluTuBt_BvMDPNh2TaM X-Proofpoint-ORIG-GUID: F6Lm3BVFcc9UAbluTuBt_BvMDPNh2TaM 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 impostorscore=0 lowpriorityscore=0 clxscore=1015 bulkscore=0 adultscore=0 suspectscore=0 spamscore=0 malwarescore=0 mlxscore=0 mlxlogscore=984 phishscore=0 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2409260000 definitions=main-2411220147 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241122_093002_958439_FA037299 X-CRM114-Status: GOOD ( 16.72 ) 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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 v5: - Free all folios when the owner removes detaches the guestmem - Link to v4: https://lore.kernel.org/r/20241120-guestmem-library-v4-0-0c597f733909@quicinc.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 Tested-by: Mike Day --- 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 | 34 ++++++ mm/Kconfig | 3 + mm/Makefile | 1 + mm/filemap.c | 9 +- mm/guestmem.c | 201 ++++++++++++++++++++++++++++++++++ mm/secretmem.c | 3 +- mm/vmscan.c | 4 +- virt/kvm/Kconfig | 1 + virt/kvm/guest_memfd.c | 98 +++++------------ 14 files changed, 290 insertions(+), 84 deletions(-) --- base-commit: 5cb1659f412041e4780f2e8ee49b2e03728a2ba6 change-id: 20241112-guestmem-library-68363cb29186 Best regards,