From patchwork Wed Aug 17 21:47:26 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Axel Rasmussen X-Patchwork-Id: 12946505 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 13A59C32772 for ; Wed, 17 Aug 2022 21:47:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242365AbiHQVrz (ORCPT ); Wed, 17 Aug 2022 17:47:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49062 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241794AbiHQVrw (ORCPT ); Wed, 17 Aug 2022 17:47:52 -0400 Received: from mail-yw1-x1149.google.com (mail-yw1-x1149.google.com [IPv6:2607:f8b0:4864:20::1149]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8B6D0AB1BD for ; Wed, 17 Aug 2022 14:47:40 -0700 (PDT) Received: by mail-yw1-x1149.google.com with SMTP id 00721157ae682-334f49979a0so52211007b3.10 for ; Wed, 17 Aug 2022 14:47:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:references:mime-version:message-id:in-reply-to :date:from:to:cc; bh=yddoa+559b8nrUIn5RkzA6LuoLnD/Z+9mfZhmJLmujQ=; b=m9tiA0nPg/s7VYVOjcdjDNni4budWfetLx4rz82pZbVDwEPrPwRNE+d0za8Ah41wVX fAZ9qV7UwzKqhXTuh15M/FMYRAjV5W8R9lY//jQ5RJ+qm9Pu+o+KpTelgenH5TAnKE4X cvQWA++nmAxmU3CLPfqnSRY+N+KY8PPFoBLYeOwn7NxThxdLKXwGQkhEwwKZ4utGheye gRVg8rFECj25MeBphygKyPxeUprIcAXTnCEkY8F1Sz9BHEmIldeeg5VjXBGC2pnmhIOp 48WWLZ9QbUGdbla+SIs+rDOPKuT+EF2+7NZ004G3S1o0JwvkQ3HqTFd0RUz1R9bkouNS zmCQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:references:mime-version:message-id:in-reply-to :date:x-gm-message-state:from:to:cc; bh=yddoa+559b8nrUIn5RkzA6LuoLnD/Z+9mfZhmJLmujQ=; b=pVuN0JDMSf/FjLiBONhw76j+omyPTKnNI5XHX4eR+wDCWlyi8bc22OdmzEVMt7Oljx EhPKCwtxfHuG8fb/eHCa59o2fXBk8NgHLxDcX2FyewRPgJKemBJTkcxhxrEGO8A184uN V1wL/EP3mClCKHJAnt1eu7be55iJy5m9/m3APulTvL7PARDpfk+Phi4m+2WW4sSfwYSF UpWT68KSA/ojAw2yBABULR4vbKS1Zf4DMlTsnG3GvYC67cbW40AZ3ax9sEI58VBmP07T SDsCAMZ3RkFllRl7xhfqiQbpBBLcY/CP5zHQS1vTVVsQh7wSCybkJgQaB9F7Qm9w//sS nBcg== X-Gm-Message-State: ACgBeo00ZUbc5qiwzyYZm4nxf6AeiTFckPHeUvJ+8vsZAVKSl37kbSMf NcISTXo8+ArUTOt94PlGrCifTkktXaNpeviW0CUb X-Google-Smtp-Source: AA6agR5uiGSbWNSyAVwfvEjoliYuIG/CANePnm5YVailnBUiHaTKY38N4XKiRjGKv1XOqkLFxT5GeSaoN05kueWOJ71k X-Received: from ajr0.svl.corp.google.com ([2620:15c:2d4:203:2f41:f176:4bac:b729]) (user=axelrasmussen job=sendgmr) by 2002:a5b:a0d:0:b0:689:9eee:348f with SMTP id k13-20020a5b0a0d000000b006899eee348fmr219249ybq.111.1660772859837; Wed, 17 Aug 2022 14:47:39 -0700 (PDT) Date: Wed, 17 Aug 2022 14:47:26 -0700 In-Reply-To: <20220817214728.489904-1-axelrasmussen@google.com> Message-Id: <20220817214728.489904-4-axelrasmussen@google.com> Mime-Version: 1.0 References: <20220817214728.489904-1-axelrasmussen@google.com> X-Mailer: git-send-email 2.37.1.595.g718a3a8f04-goog Subject: [PATCH v6 3/5] userfaultfd: selftests: modify selftest to use /dev/userfaultfd From: Axel Rasmussen To: Alexander Viro , Andrew Morton , Dave Hansen , "Dmitry V . Levin" , Gleb Fotengauer-Malinovskiy , Hugh Dickins , Jan Kara , Jonathan Corbet , Mel Gorman , Mike Kravetz , Mike Rapoport , Nadav Amit , Peter Xu , Shuah Khan , Suren Baghdasaryan , Vlastimil Babka , zhangyi Cc: Axel Rasmussen , linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org, linux-security-module@vger.kernel.org, Mike Rapoport Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org We clearly want to ensure both userfaultfd(2) and /dev/userfaultfd keep working into the future, so just run the test twice, using each interface. Instead of always testing both userfaultfd(2) and /dev/userfaultfd, let the user choose which to test. As with other test features, change the behavior based on a new command line flag. Introduce the idea of "test mods", which are generic (not specific to a test type) modifications to the behavior of the test. This is sort of borrowed from this RFC patch series [1], but simplified a bit. The benefit is, in "typical" configurations this test is somewhat slow (say, 30sec or something). Testing both clearly doubles it, so it may not always be desirable, as users are likely to use one or the other, but never both, in the "real world". [1]: https://patchwork.kernel.org/project/linux-mm/patch/20201129004548.1619714-14-namit@vmware.com/ Acked-by: Mike Rapoport Acked-by: Peter Xu Signed-off-by: Axel Rasmussen --- tools/testing/selftests/vm/userfaultfd.c | 76 ++++++++++++++++++++---- 1 file changed, 66 insertions(+), 10 deletions(-) diff --git a/tools/testing/selftests/vm/userfaultfd.c b/tools/testing/selftests/vm/userfaultfd.c index 7c3f1b0ab468..7be709d9eed0 100644 --- a/tools/testing/selftests/vm/userfaultfd.c +++ b/tools/testing/selftests/vm/userfaultfd.c @@ -77,6 +77,11 @@ static int bounces; #define TEST_SHMEM 3 static int test_type; +#define UFFD_FLAGS (O_CLOEXEC | O_NONBLOCK | UFFD_USER_MODE_ONLY) + +/* test using /dev/userfaultfd, instead of userfaultfd(2) */ +static bool test_dev_userfaultfd; + /* exercise the test_uffdio_*_eexist every ALARM_INTERVAL_SECS */ #define ALARM_INTERVAL_SECS 10 static volatile bool test_uffdio_copy_eexist = true; @@ -125,6 +130,8 @@ struct uffd_stats { const char *examples = "# Run anonymous memory test on 100MiB region with 99999 bounces:\n" "./userfaultfd anon 100 99999\n\n" + "# Run the same anonymous memory test, but using /dev/userfaultfd:\n" + "./userfaultfd anon:dev 100 99999\n\n" "# Run share memory test on 1GiB region with 99 bounces:\n" "./userfaultfd shmem 1000 99\n\n" "# Run hugetlb memory test on 256MiB region with 50 bounces:\n" @@ -141,6 +148,14 @@ static void usage(void) "[hugetlbfs_file]\n\n"); fprintf(stderr, "Supported : anon, hugetlb, " "hugetlb_shared, shmem\n\n"); + fprintf(stderr, "'Test mods' can be joined to the test type string with a ':'. " + "Supported mods:\n"); + fprintf(stderr, "\tsyscall - Use userfaultfd(2) (default)\n"); + fprintf(stderr, "\tdev - Use /dev/userfaultfd instead of userfaultfd(2)\n"); + fprintf(stderr, "\nExample test mod usage:\n"); + fprintf(stderr, "# Run anonymous memory test with /dev/userfaultfd:\n"); + fprintf(stderr, "./userfaultfd anon:dev 100 99999\n\n"); + fprintf(stderr, "Examples:\n\n"); fprintf(stderr, "%s", examples); exit(1); @@ -154,12 +169,14 @@ static void usage(void) ret, __LINE__); \ } while (0) -#define err(fmt, ...) \ +#define errexit(exitcode, fmt, ...) \ do { \ _err(fmt, ##__VA_ARGS__); \ - exit(1); \ + exit(exitcode); \ } while (0) +#define err(fmt, ...) errexit(1, fmt, ##__VA_ARGS__) + static void uffd_stats_reset(struct uffd_stats *uffd_stats, unsigned long n_cpus) { @@ -383,13 +400,34 @@ static void assert_expected_ioctls_present(uint64_t mode, uint64_t ioctls) } } +static int __userfaultfd_open_dev(void) +{ + int fd, _uffd; + + fd = open("/dev/userfaultfd", O_RDWR | O_CLOEXEC); + if (fd < 0) + errexit(KSFT_SKIP, "opening /dev/userfaultfd failed"); + + _uffd = ioctl(fd, USERFAULTFD_IOC_NEW, UFFD_FLAGS); + if (_uffd < 0) + errexit(errno == ENOTTY ? KSFT_SKIP : 1, + "creating userfaultfd failed"); + close(fd); + return _uffd; +} + static void userfaultfd_open(uint64_t *features) { struct uffdio_api uffdio_api; - uffd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK | UFFD_USER_MODE_ONLY); - if (uffd < 0) - err("userfaultfd syscall not available in this kernel"); + if (test_dev_userfaultfd) + uffd = __userfaultfd_open_dev(); + else { + uffd = syscall(__NR_userfaultfd, UFFD_FLAGS); + if (uffd < 0) + errexit(errno == ENOSYS ? KSFT_SKIP : 1, + "creating userfaultfd failed"); + } uffd_flags = fcntl(uffd, F_GETFD, NULL); uffdio_api.api = UFFD_API; @@ -1584,8 +1622,6 @@ unsigned long default_huge_page_size(void) static void set_test_type(const char *type) { - uint64_t features = UFFD_API_FEATURES; - if (!strcmp(type, "anon")) { test_type = TEST_ANON; uffd_test_ops = &anon_uffd_test_ops; @@ -1603,9 +1639,29 @@ static void set_test_type(const char *type) test_type = TEST_SHMEM; uffd_test_ops = &shmem_uffd_test_ops; test_uffdio_minor = true; - } else { - err("Unknown test type: %s", type); } +} + +static void parse_test_type_arg(const char *raw_type) +{ + char *buf = strdup(raw_type); + uint64_t features = UFFD_API_FEATURES; + + while (buf) { + const char *token = strsep(&buf, ":"); + + if (!test_type) + set_test_type(token); + else if (!strcmp(token, "dev")) + test_dev_userfaultfd = true; + else if (!strcmp(token, "syscall")) + test_dev_userfaultfd = false; + else + err("unrecognized test mod '%s'", token); + } + + if (!test_type) + err("failed to parse test type argument: '%s'", raw_type); if (test_type == TEST_HUGETLB) page_size = default_huge_page_size(); @@ -1653,7 +1709,7 @@ int main(int argc, char **argv) err("failed to arm SIGALRM"); alarm(ALARM_INTERVAL_SECS); - set_test_type(argv[1]); + parse_test_type_arg(argv[1]); nr_cpus = sysconf(_SC_NPROCESSORS_ONLN); nr_pages_per_cpu = atol(argv[2]) * 1024*1024 / page_size /