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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id A1216E77182 for ; Fri, 13 Dec 2024 16:48:21 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 2B6CC6B0098; Fri, 13 Dec 2024 11:48:21 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 267716B009B; Fri, 13 Dec 2024 11:48:21 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0DF876B009E; Fri, 13 Dec 2024 11:48:21 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id E0C636B0098 for ; Fri, 13 Dec 2024 11:48:20 -0500 (EST) Received: from smtpin23.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 9EF92160F70 for ; Fri, 13 Dec 2024 16:48:20 +0000 (UTC) X-FDA: 82890517962.23.FDE03F6 Received: from mail-wm1-f73.google.com (mail-wm1-f73.google.com [209.85.128.73]) by imf25.hostedemail.com (Postfix) with ESMTP id 48CD8A0014 for ; Fri, 13 Dec 2024 16:48:00 +0000 (UTC) Authentication-Results: imf25.hostedemail.com; dkim=pass header.d=google.com header.s=20230601 header.b=odDBaH5E; spf=pass (imf25.hostedemail.com: domain of 3UWVcZwUKCM4Duvvu08805y.w86527EH-664Fuw4.8B0@flex--tabba.bounces.google.com designates 209.85.128.73 as permitted sender) smtp.mailfrom=3UWVcZwUKCM4Duvvu08805y.w86527EH-664Fuw4.8B0@flex--tabba.bounces.google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1734108487; h=from:from:sender: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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=8sbfS8W1wicHM5vsGa5IMowjJ2CAstrX6T9HihvAEa4=; b=XRVOs8oM822zxn9iSXMHLQvcYALupImKzGdByFfIYjOwBE7IwJi7cBH9X7hFvIQ7togvkz 0MMX4GOmIkikMvV1lxPe20Pr1RjMLFI8LaN5Viw5NVTCkEWPuombI7fRRrNjyFmpMNDJ+D z8QMx3vDlMEum6asnBAUErucBUVCeJQ= ARC-Authentication-Results: i=1; imf25.hostedemail.com; dkim=pass header.d=google.com header.s=20230601 header.b=odDBaH5E; spf=pass (imf25.hostedemail.com: domain of 3UWVcZwUKCM4Duvvu08805y.w86527EH-664Fuw4.8B0@flex--tabba.bounces.google.com designates 209.85.128.73 as permitted sender) smtp.mailfrom=3UWVcZwUKCM4Duvvu08805y.w86527EH-664Fuw4.8B0@flex--tabba.bounces.google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1734108487; a=rsa-sha256; cv=none; b=SiChK+PwxQfr/Dkm51bWrKC94IHa/zjLdj11voUGWQ7y0d/BfJZwHukhixypN97iFPW+V1 g/urdestOAcV8MQmi57eCQoKwy7luS5EyEtNmI0Nellg1E7m2vY89UyMZoeMqVkgq9ezWB KjJIT7QG+pimDHX0ae+kCWiNAf1kzJ0= Received: by mail-wm1-f73.google.com with SMTP id 5b1f17b1804b1-4361efc9d23so18649625e9.3 for ; Fri, 13 Dec 2024 08:48:18 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1734108497; x=1734713297; darn=kvack.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=8sbfS8W1wicHM5vsGa5IMowjJ2CAstrX6T9HihvAEa4=; b=odDBaH5E3FRHnnh4/D5oMPez8bem0r70gNtliSp6xj2HfUiPy5Uk4tEFmHBm5z6iUl uf5qaOGp4ir42va0woZMfJXcRoi9Qv22B0E9STDA5y+LTUEwLuO5+HRMjZPyjZt9zN2p aMtiMnU9XqeBRXViC4plV9+9HT9n0pUmaoPY+EW28Y9BFDeHD4/jDVFx0BU8HuKtNFhZ PjOk69Ss7nLuU2/HsAc5gBVumThz544kXoIuTmVtdnVi8X/wDT+AhhaHRSEBRZjjdmeS Bf8mYRQy38CWoN/IRvF/2VWEtUpzyEm+me0w/e1ge2wFAemWnMt1sP5AC3ae/RjuMjWV M3OQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1734108497; x=1734713297; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=8sbfS8W1wicHM5vsGa5IMowjJ2CAstrX6T9HihvAEa4=; b=gCfoJKKeVaqez0EuGHET7GhrY6Hb3n6iRL+nRqOFTm7oKJ5EPcfMKGq+uu72BIqjDG 5RnFF6xMabFHhWOS2x0t+bxacAVfffNX77w2q//gSF/qULCcmy56A83UAj2gEiCLuwK1 ST5oVHT4XfTtmefJqWkFerKpOQzd+SY6DESfemuyQqZUMU4fUf+nqvgxZzjzcKuXFMnB 9Rn2ePnCNkDbBlOW4MEJkHZvvT7jnR8l5/tuG+vuHrrgKvaPFSF5OB0VXg/+VnppTIV/ 9ClO6XzZmwXZ8s+fUD7Vota88k0mkKnuEyF/YNE/SkBh63cQ7YCxJ/UOZz2iKnjiX0Ub Cv4g== X-Forwarded-Encrypted: i=1; AJvYcCW4igGUTzGQHtoKvj5h7k6s3jcmdtjOO0bXYBjYD208YhRdFpZpzOPMTHcSAaekQamKKTMzWxuF1g==@kvack.org X-Gm-Message-State: AOJu0YxT4Zsj814MuAUU7VJRkmdb4bLUofWmyN4Ocj7hhFxcwZtg1w/W KO7iB+DunQ7vNhUqK/GgWtY09YbKscW7haiCny3HOu8yiowfx+RJR1FAID8+OvvYTLRMHKscWg= = X-Google-Smtp-Source: AGHT+IEPhjbYVrPG4OvpW3X6Nrv45wDkaxf1Je2UWVRf/3W/68PxH4JbNqktpfTiAT0Xl8J+JFcRBc200g== X-Received: from wmnb22.prod.google.com ([2002:a05:600c:6d6:b0:434:a4bc:534f]) (user=tabba job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:1da4:b0:434:f753:6012 with SMTP id 5b1f17b1804b1-4362aa509abmr35207575e9.17.1734108497542; Fri, 13 Dec 2024 08:48:17 -0800 (PST) Date: Fri, 13 Dec 2024 16:47:58 +0000 In-Reply-To: <20241213164811.2006197-1-tabba@google.com> Mime-Version: 1.0 References: <20241213164811.2006197-1-tabba@google.com> X-Mailer: git-send-email 2.47.1.613.gc27f4b7a9f-goog Message-ID: <20241213164811.2006197-3-tabba@google.com> Subject: [RFC PATCH v4 02/14] KVM: guest_memfd: Make guest mem use guest mem inodes instead of anonymous inodes From: Fuad Tabba To: kvm@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-mm@kvack.org Cc: pbonzini@redhat.com, chenhuacai@kernel.org, mpe@ellerman.id.au, anup@brainfault.org, paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, seanjc@google.com, viro@zeniv.linux.org.uk, brauner@kernel.org, willy@infradead.org, akpm@linux-foundation.org, xiaoyao.li@intel.com, yilun.xu@intel.com, chao.p.peng@linux.intel.com, jarkko@kernel.org, amoorthy@google.com, dmatlack@google.com, yu.c.zhang@linux.intel.com, isaku.yamahata@intel.com, mic@digikod.net, vbabka@suse.cz, vannapurve@google.com, ackerleytng@google.com, mail@maciej.szmigiero.name, david@redhat.com, michael.roth@amd.com, wei.w.wang@intel.com, liam.merwick@oracle.com, isaku.yamahata@gmail.com, kirill.shutemov@linux.intel.com, suzuki.poulose@arm.com, steven.price@arm.com, quic_eberman@quicinc.com, quic_mnalajal@quicinc.com, quic_tsoni@quicinc.com, quic_svaddagi@quicinc.com, quic_cvanscha@quicinc.com, quic_pderrin@quicinc.com, quic_pheragu@quicinc.com, catalin.marinas@arm.com, james.morse@arm.com, yuzenghui@huawei.com, oliver.upton@linux.dev, maz@kernel.org, will@kernel.org, qperret@google.com, keirf@google.com, roypat@amazon.co.uk, shuah@kernel.org, hch@infradead.org, jgg@nvidia.com, rientjes@google.com, jhubbard@nvidia.com, fvdl@google.com, hughd@google.com, jthoughton@google.com, tabba@google.com Content-Type: text/plain; charset="UTF-8" X-Rspamd-Queue-Id: 48CD8A0014 X-Stat-Signature: 73p71bjrpxipmp5foqb4b3w8x39utfhs X-Rspam-User: X-Rspamd-Server: rspam11 X-HE-Tag: 1734108480-796182 X-HE-Meta: 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 NsSbpyqQ XkromywsFVHWc2VpFCTdke9YNy1T07wLxcEr/iQHpQUoguZqCcvEk8uWCuC5BQAxyNViPGPGoqO2yWWLXomWXqmPNB6TwlspcI0ywyMGmsCkuD7fJkxDuTCvGMY+xfMh5/iiahurN/9cM3BN3W+LSGPCLll0PwIZzI2WDrNKFBKU40qwT9drlzVOsXT1E9llZedYQ2w/y1eQeLN4vG+OM/LmduP6FbZaA/xzpfedd30mJJw2C2Scn9IKn8CP3qifJyggAXYiSQryYNO3ugeZ37z+3XRrlz1qjsqt2V++7umOcAxfcToGhrze04fEGoS9jecBcqIrNTQ3/2+FEjdCbXY0OppqOq7R8YhQKE6CykADYPDYIm14vadcDS5mbWC+OTEDceXJG+CcdbVTCV1u7BJ+mvUkJddRaRcN4jjqB8HIKI1wEI+5yofEvsAx+PYGhkrzy1VAuubCU3i9n3N2b/SP9nGDJMLmOSjLDoWfJMpJqHAr9PALf/x5wt1BH7ZzCQ2cGtF9B+RU8hRXnfflTKQNBLWB7qzfbK0/PEmMIyONbOU9tD9R7aJevYDWldmzxGpsGStJtFTICBsU1PSWmg9iKp9MbMaLHG1KuVjStAf8nuItWQLfLB6SzAFN1WbNxKeBYrGiqb8GcTwzCpugVQkx/6Q== 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: List-Subscribe: List-Unsubscribe: From: Ackerley Tng Using guest mem inodes allows us to store metadata for the backing memory on the inode. Metadata will be added in a later patch to support HugeTLB pages. Metadata about backing memory should not be stored on the file, since the file represents a guest_memfd's binding with a struct kvm, and metadata about backing memory is not unique to a specific binding and struct kvm. Signed-off-by: Ackerley Tng Signed-off-by: Fuad Tabba --- include/uapi/linux/magic.h | 1 + virt/kvm/guest_memfd.c | 119 ++++++++++++++++++++++++++++++------- 2 files changed, 100 insertions(+), 20 deletions(-) diff --git a/include/uapi/linux/magic.h b/include/uapi/linux/magic.h index bb575f3ab45e..169dba2a6920 100644 --- a/include/uapi/linux/magic.h +++ b/include/uapi/linux/magic.h @@ -103,5 +103,6 @@ #define DEVMEM_MAGIC 0x454d444d /* "DMEM" */ #define SECRETMEM_MAGIC 0x5345434d /* "SECM" */ #define PID_FS_MAGIC 0x50494446 /* "PIDF" */ +#define GUEST_MEMORY_MAGIC 0x474d454d /* "GMEM" */ #endif /* __LINUX_MAGIC_H__ */ diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c index 47a9f68f7b24..198554b1f0b5 100644 --- a/virt/kvm/guest_memfd.c +++ b/virt/kvm/guest_memfd.c @@ -1,12 +1,17 @@ // SPDX-License-Identifier: GPL-2.0 +#include +#include #include #include #include +#include #include #include #include "kvm_mm.h" +static struct vfsmount *kvm_gmem_mnt; + struct kvm_gmem { struct kvm *kvm; struct xarray bindings; @@ -307,6 +312,38 @@ static pgoff_t kvm_gmem_get_index(struct kvm_memory_slot *slot, gfn_t gfn) return gfn - slot->base_gfn + slot->gmem.pgoff; } +static const struct super_operations kvm_gmem_super_operations = { + .statfs = simple_statfs, +}; + +static int kvm_gmem_init_fs_context(struct fs_context *fc) +{ + struct pseudo_fs_context *ctx; + + if (!init_pseudo(fc, GUEST_MEMORY_MAGIC)) + return -ENOMEM; + + ctx = fc->fs_private; + ctx->ops = &kvm_gmem_super_operations; + + return 0; +} + +static struct file_system_type kvm_gmem_fs = { + .name = "kvm_guest_memory", + .init_fs_context = kvm_gmem_init_fs_context, + .kill_sb = kill_anon_super, +}; + +static void kvm_gmem_init_mount(void) +{ + kvm_gmem_mnt = kern_mount(&kvm_gmem_fs); + BUG_ON(IS_ERR(kvm_gmem_mnt)); + + /* For giggles. Userspace can never map this anyways. */ + kvm_gmem_mnt->mnt_flags |= MNT_NOEXEC; +} + static struct file_operations kvm_gmem_fops = { .open = generic_file_open, .release = kvm_gmem_release, @@ -316,6 +353,8 @@ static struct file_operations kvm_gmem_fops = { void kvm_gmem_init(struct module *module) { kvm_gmem_fops.owner = module; + + kvm_gmem_init_mount(); } static int kvm_gmem_migrate_folio(struct address_space *mapping, @@ -397,11 +436,67 @@ static const struct inode_operations kvm_gmem_iops = { .setattr = kvm_gmem_setattr, }; +static struct inode *kvm_gmem_inode_make_secure_inode(const char *name, + loff_t size, u64 flags) +{ + const struct qstr qname = QSTR_INIT(name, strlen(name)); + struct inode *inode; + int err; + + inode = alloc_anon_inode(kvm_gmem_mnt->mnt_sb); + if (IS_ERR(inode)) + return inode; + + err = security_inode_init_security_anon(inode, &qname, NULL); + if (err) { + iput(inode); + return ERR_PTR(err); + } + + inode->i_private = (void *)(unsigned long)flags; + inode->i_op = &kvm_gmem_iops; + inode->i_mapping->a_ops = &kvm_gmem_aops; + inode->i_mode |= S_IFREG; + inode->i_size = size; + mapping_set_gfp_mask(inode->i_mapping, GFP_HIGHUSER); + mapping_set_inaccessible(inode->i_mapping); + /* Unmovable mappings are supposed to be marked unevictable as well. */ + WARN_ON_ONCE(!mapping_unevictable(inode->i_mapping)); + + return inode; +} + +static struct file *kvm_gmem_inode_create_getfile(void *priv, loff_t size, + u64 flags) +{ + static const char *name = "[kvm-gmem]"; + struct inode *inode; + struct file *file; + + if (kvm_gmem_fops.owner && !try_module_get(kvm_gmem_fops.owner)) + return ERR_PTR(-ENOENT); + + inode = kvm_gmem_inode_make_secure_inode(name, size, flags); + if (IS_ERR(inode)) + return ERR_CAST(inode); + + file = alloc_file_pseudo(inode, kvm_gmem_mnt, name, O_RDWR, + &kvm_gmem_fops); + if (IS_ERR(file)) { + iput(inode); + return file; + } + + file->f_mapping = inode->i_mapping; + file->f_flags |= O_LARGEFILE; + file->private_data = priv; + + return file; +} + static int __kvm_gmem_create(struct kvm *kvm, loff_t size, u64 flags) { - const char *anon_name = "[kvm-gmem]"; struct kvm_gmem *gmem; - struct inode *inode; struct file *file; int fd, err; @@ -415,32 +510,16 @@ static int __kvm_gmem_create(struct kvm *kvm, loff_t size, u64 flags) goto err_fd; } - file = anon_inode_create_getfile(anon_name, &kvm_gmem_fops, gmem, - O_RDWR, NULL); + file = kvm_gmem_inode_create_getfile(gmem, size, flags); if (IS_ERR(file)) { err = PTR_ERR(file); goto err_gmem; } - file->f_flags |= O_LARGEFILE; - - inode = file->f_inode; - WARN_ON(file->f_mapping != inode->i_mapping); - - inode->i_private = (void *)(unsigned long)flags; - inode->i_op = &kvm_gmem_iops; - inode->i_mapping->a_ops = &kvm_gmem_aops; - inode->i_mode |= S_IFREG; - inode->i_size = size; - mapping_set_gfp_mask(inode->i_mapping, GFP_HIGHUSER); - mapping_set_inaccessible(inode->i_mapping); - /* Unmovable mappings are supposed to be marked unevictable as well. */ - WARN_ON_ONCE(!mapping_unevictable(inode->i_mapping)); - kvm_get_kvm(kvm); gmem->kvm = kvm; xa_init(&gmem->bindings); - list_add(&gmem->entry, &inode->i_mapping->i_private_list); + list_add(&gmem->entry, &file_inode(file)->i_mapping->i_private_list); fd_install(fd, file); return fd; -- 2.47.1.613.gc27f4b7a9f-goog