From patchwork Tue Jan 18 13:21:12 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chao Peng X-Patchwork-Id: 12716357 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 B4DE7C433FE for ; Tue, 18 Jan 2022 13:22:23 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 33EE86B0075; Tue, 18 Jan 2022 08:22:23 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 2EF0B6B0078; Tue, 18 Jan 2022 08:22:23 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 18F696B007B; Tue, 18 Jan 2022 08:22:23 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0067.hostedemail.com [216.40.44.67]) by kanga.kvack.org (Postfix) with ESMTP id 09E456B0075 for ; Tue, 18 Jan 2022 08:22:23 -0500 (EST) Received: from smtpin03.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id C03CD18179025 for ; Tue, 18 Jan 2022 13:22:22 +0000 (UTC) X-FDA: 79043471724.03.9F28FB8 Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by imf26.hostedemail.com (Postfix) with ESMTP id DC7A7140006 for ; Tue, 18 Jan 2022 13:22:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1642512142; x=1674048142; h=from:to:cc:subject:date:message-id:in-reply-to: references; bh=2dspJZW+Fb695a/O+SFc/x1OjrhtU2wFDKh4IAY6Z+0=; b=nLak1m0rAb75sysHEwpqBEsd72E0yR1FI/YIxCUBfVTkoaDZfDjcZoBU Zp5x6yQx6QMdZiXJOE42g95FT+cAKn4az6cbc0sJSf9ToI5E0Ql2lO4JU laNG8LpDG3iNUYy9TxWSG+8GviZd/JvhGjIWG6HTw7KLViypGyaAgdgWM 7RQFmyZWx+uR/0WrcSp+PWahkVPHTGc8H54cjU2aG7KNgk/L7VG/A6YRE FjD37zcOOnxFGGul6BSf5At8SS1WoEWrjcJAFn2A3ZZ8ETZab+ThvyS+y KkTf8189FzLbYubtahSUS3WhMocWfIl8Eq7/Oli6jNovjxOUYUMipVFAL Q==; X-IronPort-AV: E=McAfee;i="6200,9189,10230"; a="244771041" X-IronPort-AV: E=Sophos;i="5.88,297,1635231600"; d="scan'208";a="244771041" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Jan 2022 05:22:20 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.88,297,1635231600"; d="scan'208";a="531791700" Received: from chaop.bj.intel.com ([10.240.192.101]) by orsmga008.jf.intel.com with ESMTP; 18 Jan 2022 05:22:13 -0800 From: Chao Peng To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, qemu-devel@nongnu.org Cc: Paolo Bonzini , Jonathan Corbet , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H . Peter Anvin" , Hugh Dickins , Jeff Layton , "J . Bruce Fields" , Andrew Morton , Yu Zhang , Chao Peng , "Kirill A . Shutemov" , luto@kernel.org, jun.nakajima@intel.com, dave.hansen@intel.com, ak@linux.intel.com, david@redhat.com Subject: [PATCH v4 03/12] mm: Introduce memfile_notifier Date: Tue, 18 Jan 2022 21:21:12 +0800 Message-Id: <20220118132121.31388-4-chao.p.peng@linux.intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20220118132121.31388-1-chao.p.peng@linux.intel.com> References: <20220118132121.31388-1-chao.p.peng@linux.intel.com> X-Rspamd-Queue-Id: DC7A7140006 X-Stat-Signature: izcez4oqfb94anpyfs9xhsusyo385141 Authentication-Results: imf26.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=nLak1m0r; dmarc=pass (policy=none) header.from=intel.com; spf=none (imf26.hostedemail.com: domain of chao.p.peng@linux.intel.com has no SPF policy when checking 134.134.136.65) smtp.mailfrom=chao.p.peng@linux.intel.com X-Rspamd-Server: rspam02 X-HE-Tag: 1642512141-104627 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: This patch introduces memfile_notifier facility so existing memory file subsystems (e.g. tmpfs/hugetlbfs) can provide memory pages to allow a third kernel component to make use of memory bookmarked in the memory file and gets notified when the pages in the memory file become allocated/invalidated. It will be used for KVM to use a file descriptor as the guest memory backing store and KVM will use this memfile_notifier interface to interact with memory file subsystems. In the future there might be other consumers (e.g. VFIO with encrypted device memory). It consists two sets of callbacks: - memfile_notifier_ops: callbacks for memory backing store to notify KVM when memory gets allocated/invalidated. - memfile_pfn_ops: callbacks for KVM to call into memory backing store to request memory pages for guest private memory. Userspace is in charge of guest memory lifecycle: it first allocates pages in memory backing store and then passes the fd to KVM and lets KVM register each memory slot to memory backing store via memfile_register_notifier. The supported memory backing store should maintain a memfile_notifier list and provide routine for memfile_notifier to get the list head address and memfile_pfn_ops callbacks for memfile_register_notifier. It also should call memfile_notifier_fallocate/memfile_notifier_invalidate when the bookmarked memory gets allocated/invalidated. Signed-off-by: Kirill A. Shutemov Signed-off-by: Chao Peng --- include/linux/memfile_notifier.h | 53 +++++++++++++++++++ mm/Kconfig | 4 ++ mm/Makefile | 1 + mm/memfile_notifier.c | 89 ++++++++++++++++++++++++++++++++ 4 files changed, 147 insertions(+) create mode 100644 include/linux/memfile_notifier.h create mode 100644 mm/memfile_notifier.c diff --git a/include/linux/memfile_notifier.h b/include/linux/memfile_notifier.h new file mode 100644 index 000000000000..a03bebdd1322 --- /dev/null +++ b/include/linux/memfile_notifier.h @@ -0,0 +1,53 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _LINUX_MEMFILE_NOTIFIER_H +#define _LINUX_MEMFILE_NOTIFIER_H + +#include +#include +#include +#include + +struct memfile_notifier; + +struct memfile_notifier_ops { + void (*invalidate)(struct memfile_notifier *notifier, + pgoff_t start, pgoff_t end); + void (*fallocate)(struct memfile_notifier *notifier, + pgoff_t start, pgoff_t end); +}; + +struct memfile_pfn_ops { + long (*get_lock_pfn)(struct inode *inode, pgoff_t offset, int *order); + void (*put_unlock_pfn)(unsigned long pfn); +}; + +struct memfile_notifier { + struct list_head list; + struct memfile_notifier_ops *ops; +}; + +struct memfile_notifier_list { + struct list_head head; + spinlock_t lock; +}; + +#ifdef CONFIG_MEMFILE_NOTIFIER +static inline void memfile_notifier_list_init(struct memfile_notifier_list *list) +{ + INIT_LIST_HEAD(&list->head); + spin_lock_init(&list->lock); +} + +extern void memfile_notifier_invalidate(struct memfile_notifier_list *list, + pgoff_t start, pgoff_t end); +extern void memfile_notifier_fallocate(struct memfile_notifier_list *list, + pgoff_t start, pgoff_t end); +extern int memfile_register_notifier(struct inode *inode, + struct memfile_notifier *notifier, + struct memfile_pfn_ops **pfn_ops); +extern void memfile_unregister_notifier(struct inode *inode, + struct memfile_notifier *notifier); + +#endif /* CONFIG_MEMFILE_NOTIFIER */ + +#endif /* _LINUX_MEMFILE_NOTIFIER_H */ diff --git a/mm/Kconfig b/mm/Kconfig index 28edafc820ad..fa31eda3c895 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -900,6 +900,10 @@ config IO_MAPPING config SECRETMEM def_bool ARCH_HAS_SET_DIRECT_MAP && !EMBEDDED +config MEMFILE_NOTIFIER + bool + select SRCU + source "mm/damon/Kconfig" endmenu diff --git a/mm/Makefile b/mm/Makefile index d6c0042e3aa0..80588f7c3bc2 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -130,3 +130,4 @@ obj-$(CONFIG_PAGE_REPORTING) += page_reporting.o obj-$(CONFIG_IO_MAPPING) += io-mapping.o obj-$(CONFIG_HAVE_BOOTMEM_INFO_NODE) += bootmem_info.o obj-$(CONFIG_GENERIC_IOREMAP) += ioremap.o +obj-$(CONFIG_MEMFILE_NOTIFIER) += memfile_notifier.o diff --git a/mm/memfile_notifier.c b/mm/memfile_notifier.c new file mode 100644 index 000000000000..8171d4601a04 --- /dev/null +++ b/mm/memfile_notifier.c @@ -0,0 +1,89 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * linux/mm/memfile_notifier.c + * + * Copyright (C) 2022 Intel Corporation. + * Chao Peng + */ + +#include +#include + +DEFINE_STATIC_SRCU(srcu); + +void memfile_notifier_invalidate(struct memfile_notifier_list *list, + pgoff_t start, pgoff_t end) +{ + struct memfile_notifier *notifier; + int id; + + id = srcu_read_lock(&srcu); + list_for_each_entry_srcu(notifier, &list->head, list, + srcu_read_lock_held(&srcu)) { + if (notifier->ops && notifier->ops->invalidate) + notifier->ops->invalidate(notifier, start, end); + } + srcu_read_unlock(&srcu, id); +} + +void memfile_notifier_fallocate(struct memfile_notifier_list *list, + pgoff_t start, pgoff_t end) +{ + struct memfile_notifier *notifier; + int id; + + id = srcu_read_lock(&srcu); + list_for_each_entry_srcu(notifier, &list->head, list, + srcu_read_lock_held(&srcu)) { + if (notifier->ops && notifier->ops->fallocate) + notifier->ops->fallocate(notifier, start, end); + } + srcu_read_unlock(&srcu, id); +} + +static int memfile_get_notifier_info(struct inode *inode, + struct memfile_notifier_list **list, + struct memfile_pfn_ops **ops) +{ + return -EOPNOTSUPP; +} + +int memfile_register_notifier(struct inode *inode, + struct memfile_notifier *notifier, + struct memfile_pfn_ops **pfn_ops) +{ + struct memfile_notifier_list *list; + int ret; + + if (!inode || !notifier | !pfn_ops) + return -EINVAL; + + ret = memfile_get_notifier_info(inode, &list, pfn_ops); + if (ret) + return ret; + + spin_lock(&list->lock); + list_add_rcu(¬ifier->list, &list->head); + spin_unlock(&list->lock); + + return 0; +} +EXPORT_SYMBOL_GPL(memfile_register_notifier); + +void memfile_unregister_notifier(struct inode *inode, + struct memfile_notifier *notifier) +{ + struct memfile_notifier_list *list; + + if (!inode || !notifier) + return; + + BUG_ON(memfile_get_notifier_info(inode, &list, NULL)); + + spin_lock(&list->lock); + list_del_rcu(¬ifier->list); + spin_unlock(&list->lock); + + synchronize_srcu(&srcu); +} +EXPORT_SYMBOL_GPL(memfile_unregister_notifier);