From patchwork Fri Jul 7 21:55:40 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Axel Rasmussen X-Patchwork-Id: 13305369 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 7C019EB64D9 for ; Fri, 7 Jul 2023 21:56:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232910AbjGGV4g (ORCPT ); Fri, 7 Jul 2023 17:56:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44372 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232698AbjGGV4Y (ORCPT ); Fri, 7 Jul 2023 17:56:24 -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 9D6B926BD for ; Fri, 7 Jul 2023 14:55:59 -0700 (PDT) Received: by mail-yw1-x1149.google.com with SMTP id 00721157ae682-579dd7e77f5so26870827b3.0 for ; Fri, 07 Jul 2023 14:55:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1688766958; x=1691358958; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=vNyM+7c0est1wcVkLGeYyWS2zFzaKr32nANrKlDiGpI=; b=OMdpoDHVwHWGjrcqQJPsCz18MHB25H0LJo2nJDpMTFaEBMMVUhi44V1ldpofEQheC0 m4JfYqAGr/gmOByQh659ri0DTCXPUN3wq0q9Y61OTOaapOrMdiNoHQh6afOT6Th9pdol 6+Ht5/zRVaIIhULOylK6yhUyyPHER4k+z45bkpq2bwwXlhD5GQG21YfPfmVH3RloLN6w wtstq9y90K39zITeLzb/scB5M7A5pCo8nSgwdCQYNkCCv8K/hLgyaE+soykDU5ln1WLL 7xsIGId5npFZRXxs0JphIddyCoDPMBn40haDcCt74ON/WBh0oWvk/3GCiN3vTTt9Y71N aqMQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1688766958; x=1691358958; 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=vNyM+7c0est1wcVkLGeYyWS2zFzaKr32nANrKlDiGpI=; b=ji7e6VQG7sd4nmgd+RTrPTXg5bNuN6xjJkccw4+/7MSPaJyD/wZ5IX/Ek2/r4yrhqu KnEKogZOgGVpCDdsJIEhde98Y05+2nUXqEPhAx94t5u2omUtqxr7aMNSr1INXxfbirDC A/Jm7qEx/2pXLd0UE7VgtwoXJvu0bpwt9542vDMjvwRR2MrdR9f38N72OTNKkbeMCRfv kCyJbQvJmaq5OvKaktDyIPQ0xfocGvJHG3ywxcxRh5i54peUSb1tEUa4OHehGgdgbpxu FQp1le/nMZU9GyXx6tvpYOmzs4rKD3IvOu1FkFLPimrHCZ68gq9dafqb0eIQLOIRdi2x CxKQ== X-Gm-Message-State: ABy/qLZ79bTJ9LHdZ+/RatjUrv5gQnexT6jEbTq98koekhMoY0Wdew5e 8SQ1B/7IG5/OCGDXuummgvcE+abe/2wdYonJQ9I0 X-Google-Smtp-Source: APBJJlEkVp64R6YyNIYgkWWJLixkffDfIZz5S4mpdabnKl15q3RW7laRRo2Y50RlxbwI2hpdw7ztg2lX8JH5LcyqTH+L X-Received: from axel.svl.corp.google.com ([2620:15c:2a3:200:c201:5125:39d1:ef3f]) (user=axelrasmussen job=sendgmr) by 2002:a81:b3c3:0:b0:569:e04a:239d with SMTP id r186-20020a81b3c3000000b00569e04a239dmr45939ywh.0.1688766958488; Fri, 07 Jul 2023 14:55:58 -0700 (PDT) Date: Fri, 7 Jul 2023 14:55:40 -0700 In-Reply-To: <20230707215540.2324998-1-axelrasmussen@google.com> Mime-Version: 1.0 References: <20230707215540.2324998-1-axelrasmussen@google.com> X-Mailer: git-send-email 2.41.0.255.g8b1d071c50-goog Message-ID: <20230707215540.2324998-9-axelrasmussen@google.com> Subject: [PATCH v4 8/8] selftests/mm: add uffd unit test for UFFDIO_POISON From: Axel Rasmussen To: Alexander Viro , Andrew Morton , Brian Geffon , Christian Brauner , David Hildenbrand , Gaosheng Cui , Huang Ying , Hugh Dickins , James Houghton , "Jan Alexander Steffens (heftig)" , Jiaqi Yan , Jonathan Corbet , Kefeng Wang , "Liam R. Howlett" , Miaohe Lin , Mike Kravetz , "Mike Rapoport (IBM)" , Muchun Song , Nadav Amit , Naoya Horiguchi , Peter Xu , Ryan Roberts , Shuah Khan , Suleiman Souhlal , Suren Baghdasaryan , "T.J. Alumbaugh" , Yu Zhao , ZhangPeng Cc: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, Axel Rasmussen Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org The test is pretty basic, and exercises UFFDIO_POISON straightforwardly. We register a region with userfaultfd, in missing fault mode. For each fault, we either UFFDIO_COPY a zeroed page (odd pages) or UFFDIO_POISON (even pages). We do this mix to test "something like a real use case", where guest memory would be some mix of poisoned and non-poisoned pages. We read each page in the region, and assert that the odd pages are zeroed as expected, and the even pages yield a SIGBUS as expected. Why UFFDIO_COPY instead of UFFDIO_ZEROPAGE? Because hugetlb doesn't support UFFDIO_ZEROPAGE, and we don't want to have special case code. Acked-by: Peter Xu Signed-off-by: Axel Rasmussen --- tools/testing/selftests/mm/uffd-unit-tests.c | 117 +++++++++++++++++++ 1 file changed, 117 insertions(+) diff --git a/tools/testing/selftests/mm/uffd-unit-tests.c b/tools/testing/selftests/mm/uffd-unit-tests.c index 04d91f144d1c..2709a34a39c5 100644 --- a/tools/testing/selftests/mm/uffd-unit-tests.c +++ b/tools/testing/selftests/mm/uffd-unit-tests.c @@ -951,6 +951,117 @@ static void uffd_zeropage_test(uffd_test_args_t *args) uffd_test_pass(); } +static void uffd_register_poison(int uffd, void *addr, uint64_t len) +{ + uint64_t ioctls = 0; + uint64_t expected = (1 << _UFFDIO_COPY) | (1 << _UFFDIO_POISON); + + if (uffd_register_with_ioctls(uffd, addr, len, true, + false, false, &ioctls)) + err("poison register fail"); + + if ((ioctls & expected) != expected) + err("registered area doesn't support COPY and POISON ioctls"); +} + +static void do_uffdio_poison(int uffd, unsigned long offset) +{ + struct uffdio_poison uffdio_poison = { 0 }; + int ret; + __s64 res; + + uffdio_poison.range.start = (unsigned long) area_dst + offset; + uffdio_poison.range.len = page_size; + uffdio_poison.mode = 0; + ret = ioctl(uffd, UFFDIO_POISON, &uffdio_poison); + res = uffdio_poison.updated; + + if (ret) + err("UFFDIO_POISON error: %"PRId64, (int64_t)res); + else if (res != page_size) + err("UFFDIO_POISON unexpected size: %"PRId64, (int64_t)res); +} + +static void uffd_poison_handle_fault( + struct uffd_msg *msg, struct uffd_args *args) +{ + unsigned long offset; + + if (msg->event != UFFD_EVENT_PAGEFAULT) + err("unexpected msg event %u", msg->event); + + if (msg->arg.pagefault.flags & + (UFFD_PAGEFAULT_FLAG_WP | UFFD_PAGEFAULT_FLAG_MINOR)) + err("unexpected fault type %llu", msg->arg.pagefault.flags); + + offset = (char *)(unsigned long)msg->arg.pagefault.address - area_dst; + offset &= ~(page_size-1); + + /* Odd pages -> copy zeroed page; even pages -> poison. */ + if (offset & page_size) + copy_page(uffd, offset, false); + else + do_uffdio_poison(uffd, offset); +} + +static void uffd_poison_test(uffd_test_args_t *targs) +{ + pthread_t uffd_mon; + char c; + struct uffd_args args = { 0 }; + struct sigaction act = { 0 }; + unsigned long nr_sigbus = 0; + unsigned long nr; + + fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK); + + uffd_register_poison(uffd, area_dst, nr_pages * page_size); + memset(area_src, 0, nr_pages * page_size); + + args.handle_fault = uffd_poison_handle_fault; + if (pthread_create(&uffd_mon, NULL, uffd_poll_thread, &args)) + err("uffd_poll_thread create"); + + sigbuf = &jbuf; + act.sa_sigaction = sighndl; + act.sa_flags = SA_SIGINFO; + if (sigaction(SIGBUS, &act, 0)) + err("sigaction"); + + for (nr = 0; nr < nr_pages; ++nr) { + unsigned long offset = nr * page_size; + const char *bytes = (const char *) area_dst + offset; + const char *i; + + if (sigsetjmp(*sigbuf, 1)) { + /* + * Access below triggered a SIGBUS, which was caught by + * sighndl, which then jumped here. Count this SIGBUS, + * and move on to next page. + */ + ++nr_sigbus; + continue; + } + + for (i = bytes; i < bytes + page_size; ++i) { + if (*i) + err("nonzero byte in area_dst (%p) at %p: %u", + area_dst, i, *i); + } + } + + if (write(pipefd[1], &c, sizeof(c)) != sizeof(c)) + err("pipe write"); + if (pthread_join(uffd_mon, NULL)) + err("pthread_join()"); + + if (nr_sigbus != nr_pages / 2) + err("expected to receive %lu SIGBUS, actually received %lu", + nr_pages / 2, nr_sigbus); + + uffd_test_pass(); +} + /* * Test the returned uffdio_register.ioctls with different register modes. * Note that _UFFDIO_ZEROPAGE is tested separately in the zeropage test. @@ -1126,6 +1237,12 @@ uffd_test_case_t uffd_tests[] = { UFFD_FEATURE_PAGEFAULT_FLAG_WP | UFFD_FEATURE_WP_HUGETLBFS_SHMEM, }, + { + .name = "poison", + .uffd_fn = uffd_poison_test, + .mem_targets = MEM_ALL, + .uffd_feature_required = UFFD_FEATURE_POISON, + }, }; static void usage(const char *prog)