From patchwork Thu Feb 16 00:41:17 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ackerley Tng X-Patchwork-Id: 13142350 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 87BECC636D4 for ; Thu, 16 Feb 2023 00:41:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229633AbjBPAlz (ORCPT ); Wed, 15 Feb 2023 19:41:55 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39622 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229640AbjBPAlm (ORCPT ); Wed, 15 Feb 2023 19:41:42 -0500 Received: from mail-pg1-x54a.google.com (mail-pg1-x54a.google.com [IPv6:2607:f8b0:4864:20::54a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 91F9F457C1 for ; Wed, 15 Feb 2023 16:41:38 -0800 (PST) Received: by mail-pg1-x54a.google.com with SMTP id o19-20020a63fb13000000b004fb5e56e652so152473pgh.9 for ; Wed, 15 Feb 2023 16:41:38 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=RwSw3tYb5bXq9fGeFYVzZ4Uji8t9bzNp02Nu0wqGVr8=; b=a6/aZwZMKgM9Qwg+eZcRGVXefYnK2gekXci5+402C9kYjaRKvCntG9/9UB64dqHJj4 utKOg+syvAUy0EV4DBkBSn9lMSketoQ/IKXaOt1Z/yjVFG1HfWHMlNFXX4aNcRKANnmH eAPnL1XgdbYfIT8hZYQ8fObP+OEaQS1UkFxrNAsWasJb6HEbZXTNCOF/s33NcZRZ+OQk BqNQ/CyZLmfjBzr7r1oNqVmOkPA5/8tV65euXIZEud6Iazk/zMeKJDYccPllrwFkPAEO ukqjTuuwoXWvGYWEq+OSuWeuT3TY7Y2Z+KS2DU57mQtp8rwmzmbo5nddYHr9bU6Se8r/ J7Rw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; 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=RwSw3tYb5bXq9fGeFYVzZ4Uji8t9bzNp02Nu0wqGVr8=; b=AjJ8HcSxI0u1hWrv/z3hCJ6bWqlETNlb4PUjKsMBdThkwVuEBzAyFfAy1L373dKScF 4gHpZwoeHSMLdckuTcbJYID2DGoLXze7QpFw1CHP67BQXQdOQ2kG1/htwnoGzPmPHkxC 50cqAL7Q8BRtQ/H6I5wKIrtHNrqqPFsioNpz4Q9ezHB/2eLg36CcPZaYyZvpjZyIYdPK 5EAy+b5j0Jziei0PHWLTa9BZj0Kj2l3gCfQqk6b0W3ybQSRiqmWl+4Kg2QOCj5GVOCVq PCG2MxNCqSwT2X0r30EoPvzgLaja5CaDHTRLVr3gZoeYeFiKb4uCSFR8q6FofwmMPlVB EJ+A== X-Gm-Message-State: AO0yUKXUnZryCzx+gunBgFLdPLlWB6XLG+lv4FWV//wBZ6Z0E19/VZaX SnkWzLX+oe4u3RvrBemFU3ThniYLDj/q0SnNYdIuD1APP/GC8bElUxqUGqe14LOQnhp0xs5MY/o JBZZfY/kAXBNe2EVU4jlGHF5pr1dH5Hg2C2XaWlvzI+W7kAXTrPv1/OMXxDpML6AmTa91O68= X-Google-Smtp-Source: AK7set+Z1QsboPNl7B2dUCqzJnv4n3cQF2QXtmZ8FpQ59D9VPXhoYAFz0KibJoYgA3wgebXfV3oTbIw8kSpaDzjaOg== X-Received: from ackerleytng-cloudtop.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:1f5f]) (user=ackerleytng job=sendgmr) by 2002:a17:903:2594:b0:19a:b107:bd11 with SMTP id jb20-20020a170903259400b0019ab107bd11mr951631plb.29.1676508097502; Wed, 15 Feb 2023 16:41:37 -0800 (PST) Date: Thu, 16 Feb 2023 00:41:17 +0000 In-Reply-To: Mime-Version: 1.0 References: X-Mailer: git-send-email 2.39.1.637.g21b0678d19-goog Message-ID: <06098450437ba5ed2011090d95f6ccb817728710.1676507663.git.ackerleytng@google.com> Subject: [RFC PATCH 2/2] selftests: restrictedmem: Check hugepage-ness of shmem file backing restrictedmem fd From: Ackerley Tng To: kvm@vger.kernel.org, linux-api@vger.kernel.org, linux-arch@vger.kernel.org, linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, qemu-devel@nongnu.org Cc: chao.p.peng@linux.intel.com, aarcange@redhat.com, ak@linux.intel.com, akpm@linux-foundation.org, arnd@arndb.de, bfields@fieldses.org, bp@alien8.de, corbet@lwn.net, dave.hansen@intel.com, david@redhat.com, ddutile@redhat.com, dhildenb@redhat.com, hpa@zytor.com, hughd@google.com, jlayton@kernel.org, jmattson@google.com, joro@8bytes.org, jun.nakajima@intel.com, kirill.shutemov@linux.intel.com, linmiaohe@huawei.com, luto@kernel.org, mail@maciej.szmigiero.name, mhocko@suse.com, michael.roth@amd.com, mingo@redhat.com, naoya.horiguchi@nec.com, pbonzini@redhat.com, qperret@google.com, rppt@kernel.org, seanjc@google.com, shuah@kernel.org, steven.price@arm.com, tabba@google.com, tglx@linutronix.de, vannapurve@google.com, vbabka@suse.cz, vkuznets@redhat.com, wanpengli@tencent.com, wei.w.wang@intel.com, x86@kernel.org, yu.c.zhang@linux.intel.com, Ackerley Tng Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org For memfd_restricted() calls without a userspace mount, the backing file should be the shmem mount in the kernel, and the size of backing pages should be as defined by system-wide shmem configuration. If a userspace mount is provided, the size of backing pages should be as defined in the mount. Signed-off-by: Ackerley Tng --- tools/testing/selftests/Makefile | 1 + .../selftests/restrictedmem/.gitignore | 3 + .../testing/selftests/restrictedmem/Makefile | 14 + .../testing/selftests/restrictedmem/common.c | 9 + .../testing/selftests/restrictedmem/common.h | 8 + .../restrictedmem_hugepage_test.c | 344 ++++++++++++++++++ 6 files changed, 379 insertions(+) create mode 100644 tools/testing/selftests/restrictedmem/.gitignore create mode 100644 tools/testing/selftests/restrictedmem/Makefile create mode 100644 tools/testing/selftests/restrictedmem/common.c create mode 100644 tools/testing/selftests/restrictedmem/common.h create mode 100644 tools/testing/selftests/restrictedmem/restrictedmem_hugepage_test.c diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile index f07aef7c592c..44078eeefb79 100644 --- a/tools/testing/selftests/Makefile +++ b/tools/testing/selftests/Makefile @@ -60,6 +60,7 @@ TARGETS += pstore TARGETS += ptrace TARGETS += openat2 TARGETS += resctrl +TARGETS += restrictedmem TARGETS += rlimits TARGETS += rseq TARGETS += rtc diff --git a/tools/testing/selftests/restrictedmem/.gitignore b/tools/testing/selftests/restrictedmem/.gitignore new file mode 100644 index 000000000000..2581bcc8ff29 --- /dev/null +++ b/tools/testing/selftests/restrictedmem/.gitignore @@ -0,0 +1,3 @@ +# SPDX-License-Identifier: GPL-2.0-only + +restrictedmem_hugepage_test diff --git a/tools/testing/selftests/restrictedmem/Makefile b/tools/testing/selftests/restrictedmem/Makefile new file mode 100644 index 000000000000..da9665718c8a --- /dev/null +++ b/tools/testing/selftests/restrictedmem/Makefile @@ -0,0 +1,14 @@ +# SPDX-License-Identifier: GPL-2.0 + +CFLAGS = $(KHDR_INCLUDES) + +TEST_GEN_PROGS += restrictedmem_hugepage_test + +include ../lib.mk + +EXTRA_CLEAN = $(OUTPUT)/common.o + +$(OUTPUT)/common.o: common.c + $(CC) $(CFLAGS) $(CPPFLAGS) $(TARGET_ARCH) -c -ffreestanding $< -o $@ + +$(TEST_GEN_PROGS): $(OUTPUT)/common.o diff --git a/tools/testing/selftests/restrictedmem/common.c b/tools/testing/selftests/restrictedmem/common.c new file mode 100644 index 000000000000..79b2ac98cc89 --- /dev/null +++ b/tools/testing/selftests/restrictedmem/common.c @@ -0,0 +1,9 @@ +// SPDX-License-Identifier: GPL-2.0-only + +#include +#include + +int memfd_restricted(unsigned int flags, char *mount_path) +{ + return syscall(__NR_memfd_restricted, flags, mount_path); +} diff --git a/tools/testing/selftests/restrictedmem/common.h b/tools/testing/selftests/restrictedmem/common.h new file mode 100644 index 000000000000..5d59edc4f23f --- /dev/null +++ b/tools/testing/selftests/restrictedmem/common.h @@ -0,0 +1,8 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +#ifndef SELFTESTS_RESTRICTEDMEM_COMMON_H +#define SELFTESTS_RESTRICTEDMEM_COMMON_H + +int memfd_restricted(unsigned int flags, char *mount_path); + +#endif // SELFTESTS_RESTRICTEDMEM_COMMON_H diff --git a/tools/testing/selftests/restrictedmem/restrictedmem_hugepage_test.c b/tools/testing/selftests/restrictedmem/restrictedmem_hugepage_test.c new file mode 100644 index 000000000000..0d9cf2ced754 --- /dev/null +++ b/tools/testing/selftests/restrictedmem/restrictedmem_hugepage_test.c @@ -0,0 +1,344 @@ +// SPDX-License-Identifier: GPL-2.0-only + +#include "linux/limits.h" +#include +#include +#include +#include +#include +#include +#include + +#include "linux/restrictedmem.h" + +#include "common.h" +#include "../kselftest_harness.h" + +static int get_hpage_pmd_size(void) +{ + FILE *fp; + char buf[100]; + char *ret; + int size; + + fp = fopen("/sys/kernel/mm/transparent_hugepage/hpage_pmd_size", "r"); + if (!fp) + return -1; + + ret = fgets(buf, 100, fp); + if (ret != buf) { + size = -1; + goto out; + } + + if (sscanf(buf, "%d\n", &size) != 1) + size = -1; + +out: + fclose(fp); + + return size; +} + +static bool is_valid_shmem_thp_policy(char *policy) +{ + if (strcmp(policy, "always") == 0) + return true; + if (strcmp(policy, "within_size") == 0) + return true; + if (strcmp(policy, "advise") == 0) + return true; + if (strcmp(policy, "never") == 0) + return true; + if (strcmp(policy, "deny") == 0) + return true; + if (strcmp(policy, "force") == 0) + return true; + + return false; +} + +static int get_shmem_thp_policy(char *policy) +{ + FILE *fp; + char buf[100]; + char *left = NULL; + char *right = NULL; + int ret = -1; + + fp = fopen("/sys/kernel/mm/transparent_hugepage/shmem_enabled", "r"); + if (!fp) + return -1; + + if (fgets(buf, 100, fp) != buf) + goto out; + + /* + * Expect shmem_enabled to be of format like "always within_size advise + * [never] deny force" + */ + left = memchr(buf, '[', 100); + if (!left) + goto out; + + right = memchr(buf, ']', 100); + if (!right) + goto out; + + memcpy(policy, left + 1, right - left - 1); + + ret = !is_valid_shmem_thp_policy(policy); + +out: + fclose(fp); + return ret; +} + +static int set_shmem_thp_policy(char *policy) +{ + FILE *fp; + size_t len = strlen(policy); + int ret = -1; + + if (!is_valid_shmem_thp_policy(policy)) + return ret; + + fp = fopen("/sys/kernel/mm/transparent_hugepage/shmem_enabled", "w"); + if (!fp) + return ret; + + if (fwrite(policy, 1, len, fp) != len) + goto out; + + if (fwrite("\n", 1, 1, fp) != 1) + goto out; + + ret = 0; + +out: + fclose(fp); + return ret; +} + +FIXTURE(reset_shmem_enabled) +{ + /* + * Expect shmem_enabled to be one of always, within_size, advise, never, + * deny, force + */ + char shmem_enabled[12]; +}; + +FIXTURE_SETUP(reset_shmem_enabled) +{ + memset(self->shmem_enabled, 0, 12); + ASSERT_EQ(0, get_shmem_thp_policy(self->shmem_enabled)); +} + +FIXTURE_TEARDOWN(reset_shmem_enabled) +{ + ASSERT_EQ(0, set_shmem_thp_policy(self->shmem_enabled)); +} + +TEST_F(reset_shmem_enabled, restrictedmem_fstat_shmem_enabled_never) +{ + int mfd = -1; + struct stat stat; + char *orig_shmem_enabled; + + ASSERT_EQ(0, set_shmem_thp_policy("never")); + + mfd = memfd_restricted(0, NULL); + ASSERT_NE(-1, mfd); + + ASSERT_EQ(0, fstat(mfd, &stat)); + + /* + * st_blksize is set based on the superblock's s_blocksize_bits. For + * shmem, this is set to PAGE_SHIFT + */ + ASSERT_EQ(stat.st_blksize, getpagesize()); + + close(mfd); +} + +TEST_F(reset_shmem_enabled, restrictedmem_fstat_shmem_enabled_always) +{ + int mfd = -1; + struct stat stat; + char *orig_shmem_enabled; + + ASSERT_EQ(0, set_shmem_thp_policy("always")); + + mfd = memfd_restricted(0, NULL); + ASSERT_NE(-1, mfd); + + ASSERT_EQ(0, fstat(mfd, &stat)); + + ASSERT_EQ(stat.st_blksize, get_hpage_pmd_size()); + + close(mfd); +} + +TEST(restrictedmem_tmpfile_no_mount_path) +{ + int mfd = memfd_restricted(RMFD_TMPFILE, NULL); + + ASSERT_EQ(-1, mfd); + ASSERT_EQ(EINVAL, errno); +} + +TEST(restrictedmem_tmpfile_nonexistent_mount_path) +{ + int mfd = memfd_restricted(RMFD_TMPFILE, + "/nonexistent/nonexistent/nonexistent"); + + ASSERT_EQ(-1, mfd); + ASSERT_EQ(ENOENT, errno); +} + +TEST(restrictedmem_tmpfile_not_tmpfs_mount) +{ + int mfd = memfd_restricted(RMFD_TMPFILE, "/proc"); + + ASSERT_EQ(-1, mfd); + ASSERT_EQ(EINVAL, errno); +} + +static bool directory_exists(const char *path) +{ + struct stat sb; + + return stat(path, &sb) == 0 && S_ISDIR(sb.st_mode); +} + +FIXTURE(tmpfs_hugepage_mount_path) +{ + char *mount_path; +}; + +FIXTURE_SETUP(tmpfs_hugepage_mount_path) +{ + int ret = -1; + + /* /tmp is an FHS-mandated world-writable directory */ + self->mount_path = "/tmp/restrictedmem-selftest-mnt"; + + if (!directory_exists(self->mount_path)) { + ret = mkdir(self->mount_path, 0777); + ASSERT_EQ(0, ret); + } +} + +FIXTURE_TEARDOWN(tmpfs_hugepage_mount_path) +{ + int ret = -1; + + if (!directory_exists(self->mount_path)) + return; + + ret = umount2(self->mount_path, MNT_FORCE); + EXPECT_EQ(0, ret); + if (ret == -1 && errno == EINVAL) + fprintf(stderr, "%s was not mounted\n", self->mount_path); + + ret = rmdir(self->mount_path); + ASSERT_EQ(0, ret); +} + +TEST_F(tmpfs_hugepage_mount_path, restrictedmem_fstat_tmpfs_huge_always) +{ + int ret = -1; + int mfd = -1; + struct stat stat; + + ret = mount("name", self->mount_path, "tmpfs", 0, "huge=always"); + ASSERT_EQ(0, ret); + + mfd = memfd_restricted(RMFD_TMPFILE, self->mount_path); + ASSERT_NE(-1, mfd); + + ret = fstat(mfd, &stat); + ASSERT_EQ(0, ret); + ASSERT_EQ(stat.st_blksize, get_hpage_pmd_size()); + + close(mfd); +} + +TEST_F(tmpfs_hugepage_mount_path, restrictedmem_fstat_tmpfs_huge_never) +{ + int ret = -1; + int mfd = -1; + struct stat stat; + + ret = mount("name", self->mount_path, "tmpfs", 0, "huge=never"); + ASSERT_EQ(0, ret); + + mfd = memfd_restricted(RMFD_TMPFILE, self->mount_path); + ASSERT_NE(-1, mfd); + + ret = fstat(mfd, &stat); + ASSERT_EQ(0, ret); + ASSERT_EQ(stat.st_blksize, getpagesize()); + + close(mfd); +} + +TEST_F(tmpfs_hugepage_mount_path, restrictedmem_umount_rmdir_while_file_open) +{ + int ret = -1; + int mfd = -1; + + ret = mount("name", self->mount_path, "tmpfs", 0, "huge=always"); + ASSERT_EQ(0, ret); + + mfd = memfd_restricted(RMFD_TMPFILE, self->mount_path); + ASSERT_NE(-1, mfd); + + ret = umount2(self->mount_path, MNT_FORCE); + ASSERT_EQ(-1, ret); + ASSERT_EQ(EBUSY, errno); + + ret = rmdir(self->mount_path); + ASSERT_EQ(-1, ret); + ASSERT_EQ(EBUSY, errno); + + close(mfd); +} + +TEST_F(tmpfs_hugepage_mount_path, restrictedmem_provide_mount_subdir) +{ + int ret = -1; + int mfd = -1; + struct stat stat; + char subdir_path[PATH_MAX] = {0}; + + ret = mount("name", self->mount_path, "tmpfs", 0, "huge=always"); + ASSERT_EQ(0, ret); + + snprintf(subdir_path, PATH_MAX, "%s/%s", self->mount_path, "subdir"); + ret = mkdir(subdir_path, 0777); + ASSERT_EQ(0, ret); + + /* + * Any subdirectory of a tmpfs mount can be provided to memfd_restricted + * as a reference to a mount + */ + mfd = memfd_restricted(RMFD_TMPFILE, subdir_path); + ASSERT_NE(-1, mfd); + + ret = fstat(mfd, &stat); + ASSERT_EQ(0, ret); + ASSERT_EQ(stat.st_blksize, get_hpage_pmd_size()); + + /* + * shmem file is created at the mount, so the subdirectory can be + * removed without issues. + */ + ret = rmdir(subdir_path); + ASSERT_EQ(0, ret); + + close(mfd); +} + +TEST_HARNESS_MAIN