From patchwork Thu Jun 29 20:50:39 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Axel Rasmussen X-Patchwork-Id: 13297321 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 C0F69C001DD for ; Thu, 29 Jun 2023 20:51:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232277AbjF2Uvv (ORCPT ); Thu, 29 Jun 2023 16:51:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46008 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230401AbjF2Uu6 (ORCPT ); Thu, 29 Jun 2023 16:50:58 -0400 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 786D73591 for ; Thu, 29 Jun 2023 13:50:56 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id 3f1490d57ef6-bfe702f99b8so945666276.1 for ; Thu, 29 Jun 2023 13:50:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1688071855; x=1690663855; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=FDMn97NE4k9ts/MbSvQk7TIpBtwkvtlY8wmg3pzMxc0=; b=b9ic7m0uviwwst/a/b6ej/KmTI1fbXLL05tIs7ZZktU/1u1vjioSSlgudRjzPPssiy tp8Df963g7Gw9okHBP74jobr3AMGXd284bnbTndsz/MzbhN8YGVA8qDN4fDKB/ndeZVg QJI4l1QU+fC4jjOAj9fa1B2eKR2xgGeEAW2jObEdLCiYk4pjpamRXhIA/AvCrm3AxS1A S57uq/giJWwpOzsio0l1XJxDbLPkIQcot63aSrBC/XjE/hIXayLN7QhrNIf6De7X0ojG MHaKy6jVInPl550XNyYzoiSALiiydqGt38OXbmQvLutW7JTQFw252iMVADLjBUBo1bab iXag== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1688071855; x=1690663855; 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=FDMn97NE4k9ts/MbSvQk7TIpBtwkvtlY8wmg3pzMxc0=; b=T47fnMBeRrzNIlEEHLIvfrjYWUl3zo2ZN4NHdTzh66YwOxhTO3d8wnrYy3E7gjfaW2 apI81rzkg5JjJGcGTGLNhi68RzEh8GD5UIW1B0vAi2jPj3ny8tiN37hwP3s2fwDSEGGe pLHp3108MkYckfYiAYrjjK5P3BY9uSEZa4XEyG61HvSDboL4wYxc1gKhTRdq6sJz2aM0 /okku7L1NhavFbiHNUIzlcaJ6scjpZnwr0Kt8uIeoiPbJyvKvddZa5SLJQWfTm5KYhWW x1A8ehfhvG1AyDFqVK/bTgyCVATSKUWfN2cIgbu3dsqp8uh5lZOxyyQ6SI5UpREbbno7 AbwQ== X-Gm-Message-State: ABy/qLa9hq9chABm8TmaeQ9msn60GDR7XIMBJO4QsXByYroNjmx2trMQ f6Oel0FyOcX0mPTZASSndxSOdE7MzzOkGaiFNQug X-Google-Smtp-Source: APBJJlFEeXNU5wkKYldS4vdZYkexQZAWshF/qAuKQS3UJdZOiHvOTMlytCrLVWGNw78bI6vNEGHYZeLbYDtkVMX51oUg X-Received: from axel.svl.corp.google.com ([2620:15c:2a3:200:e20f:5917:3efa:d4bb]) (user=axelrasmussen job=sendgmr) by 2002:a25:d243:0:b0:c38:b4b5:13d5 with SMTP id j64-20020a25d243000000b00c38b4b513d5mr6655ybg.3.1688071855661; Thu, 29 Jun 2023 13:50:55 -0700 (PDT) Date: Thu, 29 Jun 2023 13:50:39 -0700 In-Reply-To: <20230629205040.665834-1-axelrasmussen@google.com> Mime-Version: 1.0 References: <20230629205040.665834-1-axelrasmussen@google.com> X-Mailer: git-send-email 2.41.0.255.g8b1d071c50-goog Message-ID: <20230629205040.665834-5-axelrasmussen@google.com> Subject: [PATCH v2 5/6] selftests/mm: add uffd unit test for UFFDIO_POISON From: Axel Rasmussen To: Alexander Viro , Andrew Morton , Christian Brauner , David Hildenbrand , Huang Ying , Hugh Dickins , James Houghton , Jiaqi Yan , Jonathan Corbet , "Liam R. Howlett" , Miaohe Lin , Mike Kravetz , "Mike Rapoport (IBM)" , Muchun Song , Nadav Amit , Naoya Horiguchi , Peter Xu , Shuah Khan , 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-fsdevel@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. Signed-off-by: Axel Rasmussen Acked-by: Peter Xu --- 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)