From patchwork Sat Sep 23 01:31:46 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Suren Baghdasaryan X-Patchwork-Id: 725960 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 432B9CE7A81 for ; Sat, 23 Sep 2023 01:32:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231202AbjIWBcM (ORCPT ); Fri, 22 Sep 2023 21:32:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35302 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231171AbjIWBcK (ORCPT ); Fri, 22 Sep 2023 21:32:10 -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 C7EA81AB for ; Fri, 22 Sep 2023 18:32:00 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id 3f1490d57ef6-d81503de9c9so3978795276.3 for ; Fri, 22 Sep 2023 18:32:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1695432720; x=1696037520; darn=vger.kernel.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=6sBdVMfMRjf51/A4FAmBdDBudgEJD7XIV0S+Rn1ebf8=; b=DHDysvaQOkX+1QeT/kRjvxWEKSghwM022OG9aVVfIA1HUHjcImsI4IF+/RT6YSchjW fQDyr2N2FylsXYPtG1o+DoTbmH36dC2J/hpq09BjZJ/vyAH7BfCAkWaBq66Bi+zo/x/W xkXiqymmKqvkBlPMxJ6FLjQm/JAfDhpUgJUrxucLVjn5skb/7lCJ6qydVcoEMakQTvay rYb+IURzuvPwyTg7c7JJoI+x1HmEbcdIvBldc1G5e773ILAkauXmf0RjlXBmtoHPVEOo wQlBuequYCqx/SI8LLggkRYDcUIGFt/kDu8uZmcO18tRvQ1eU1uUgXjmLcsz0ZSZ6H8Q VT2w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1695432720; x=1696037520; 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=6sBdVMfMRjf51/A4FAmBdDBudgEJD7XIV0S+Rn1ebf8=; b=G+QeZGeIfzZXTNSzhujJC4vZkclP40L2bFMClTenSNMawNvfRJNvONMKc7l0Af+sPY IRrvTE5THAWl3AxGOqBmLiqqmafsJM+2IWEf/cPWmmWx2sxn/3k6xylhv5NM9K1cO5gf eAoQks0xTlKvGRgJ8lGRFo/M4CS1W9cHj2v7ev7+pN27M1zT1gcovVbVoDajde/eQ8nJ lk2wNtGFrm4moxxjUbZTKTBbUD08gyI7JQ94S1Ibt6McjljLN70mRTrOatlKUbvTf0mk D8it1Eg4OqjvKFMjBF4PHHKDppDv0MNgqDHe0LZ36aDHftDlH4dUlqIyIaT+vEYb2qDk kRJg== X-Gm-Message-State: AOJu0YxnaTEKCPd0D2ulX+pMzbBY9gXB1HJ27/ULUtNy2NdUo6JkjwQ8 LJYPsGubU+/7/+CEl72K16W7MyOJdWw= X-Google-Smtp-Source: AGHT+IE2yWzcwua2aqDzlLl0Y+Ymi3r6rJDilflyRWbYZnXXI88FhB4QNhRbeG/BF6XKbV1cknxCSUOXvog= X-Received: from surenb-desktop.mtv.corp.google.com ([2620:15c:211:201:3398:6644:ed7f:bec9]) (user=surenb job=sendgmr) by 2002:a25:d09:0:b0:d7b:9185:e23d with SMTP id 9-20020a250d09000000b00d7b9185e23dmr9469ybn.6.1695432719939; Fri, 22 Sep 2023 18:31:59 -0700 (PDT) Date: Fri, 22 Sep 2023 18:31:46 -0700 In-Reply-To: <20230923013148.1390521-1-surenb@google.com> Mime-Version: 1.0 References: <20230923013148.1390521-1-surenb@google.com> X-Mailer: git-send-email 2.42.0.515.g380fc7ccd1-goog Message-ID: <20230923013148.1390521-4-surenb@google.com> Subject: [PATCH v2 3/3] selftests/mm: add UFFDIO_REMAP ioctl test From: Suren Baghdasaryan To: akpm@linux-foundation.org Cc: viro@zeniv.linux.org.uk, brauner@kernel.org, shuah@kernel.org, aarcange@redhat.com, lokeshgidra@google.com, peterx@redhat.com, david@redhat.com, hughd@google.com, mhocko@suse.com, axelrasmussen@google.com, rppt@kernel.org, willy@infradead.org, Liam.Howlett@oracle.com, jannh@google.com, zhangpeng362@huawei.com, bgeffon@google.com, kaleshsingh@google.com, ngeoffray@google.com, jdduke@google.com, surenb@google.com, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, kernel-team@android.com Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org Add a test for new UFFDIO_REMAP ioctl which uses uffd to remaps source into destination buffer while checking the contents of both after remapping. After the operation the content of the destination buffer should match the original source buffer's content while the source buffer should be zeroed. Signed-off-by: Suren Baghdasaryan --- tools/testing/selftests/mm/uffd-common.c | 41 ++++++++++++- tools/testing/selftests/mm/uffd-common.h | 1 + tools/testing/selftests/mm/uffd-unit-tests.c | 62 ++++++++++++++++++++ 3 files changed, 102 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/mm/uffd-common.c b/tools/testing/selftests/mm/uffd-common.c index 02b89860e193..2a3ffd0ce96e 100644 --- a/tools/testing/selftests/mm/uffd-common.c +++ b/tools/testing/selftests/mm/uffd-common.c @@ -52,6 +52,13 @@ static int anon_allocate_area(void **alloc_area, bool is_src) *alloc_area = NULL; return -errno; } + + /* Prevent source pages from collapsing into THPs */ + if (madvise(*alloc_area, nr_pages * page_size, MADV_NOHUGEPAGE)) { + *alloc_area = NULL; + return -errno; + } + return 0; } @@ -484,8 +491,14 @@ void uffd_handle_page_fault(struct uffd_msg *msg, struct uffd_args *args) offset = (char *)(unsigned long)msg->arg.pagefault.address - area_dst; offset &= ~(page_size-1); - if (copy_page(uffd, offset, args->apply_wp)) - args->missing_faults++; + /* UFFD_REMAP is supported for anon non-shared mappings. */ + if (uffd_test_ops == &anon_uffd_test_ops && !map_shared) { + if (remap_page(uffd, offset)) + args->missing_faults++; + } else { + if (copy_page(uffd, offset, args->apply_wp)) + args->missing_faults++; + } } } @@ -620,6 +633,30 @@ int copy_page(int ufd, unsigned long offset, bool wp) return __copy_page(ufd, offset, false, wp); } +int remap_page(int ufd, unsigned long offset) +{ + struct uffdio_remap uffdio_remap; + + if (offset >= nr_pages * page_size) + err("unexpected offset %lu\n", offset); + uffdio_remap.dst = (unsigned long) area_dst + offset; + uffdio_remap.src = (unsigned long) area_src + offset; + uffdio_remap.len = page_size; + uffdio_remap.mode = UFFDIO_REMAP_MODE_ALLOW_SRC_HOLES; + uffdio_remap.remap = 0; + if (ioctl(ufd, UFFDIO_REMAP, &uffdio_remap)) { + /* real retval in uffdio_remap.remap */ + if (uffdio_remap.remap != -EEXIST) + err("UFFDIO_REMAP error: %"PRId64, + (int64_t)uffdio_remap.remap); + wake_range(ufd, uffdio_remap.dst, page_size); + } else if (uffdio_remap.remap != page_size) { + err("UFFDIO_REMAP error: %"PRId64, (int64_t)uffdio_remap.remap); + } else + return 1; + return 0; +} + int uffd_open_dev(unsigned int flags) { int fd, uffd; diff --git a/tools/testing/selftests/mm/uffd-common.h b/tools/testing/selftests/mm/uffd-common.h index 7c4fa964c3b0..2bbb15d1920c 100644 --- a/tools/testing/selftests/mm/uffd-common.h +++ b/tools/testing/selftests/mm/uffd-common.h @@ -111,6 +111,7 @@ void wp_range(int ufd, __u64 start, __u64 len, bool wp); void uffd_handle_page_fault(struct uffd_msg *msg, struct uffd_args *args); int __copy_page(int ufd, unsigned long offset, bool retry, bool wp); int copy_page(int ufd, unsigned long offset, bool wp); +int remap_page(int ufd, unsigned long offset); void *uffd_poll_thread(void *arg); int uffd_open_dev(unsigned int flags); diff --git a/tools/testing/selftests/mm/uffd-unit-tests.c b/tools/testing/selftests/mm/uffd-unit-tests.c index 2709a34a39c5..a33819639187 100644 --- a/tools/testing/selftests/mm/uffd-unit-tests.c +++ b/tools/testing/selftests/mm/uffd-unit-tests.c @@ -824,6 +824,10 @@ static void uffd_events_test_common(bool wp) char c; struct uffd_args args = { 0 }; + /* Prevent source pages from being mapped more than once */ + if (madvise(area_src, nr_pages * page_size, MADV_DONTFORK)) + err("madvise(MADV_DONTFORK) failed"); + fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK); if (uffd_register(uffd, area_dst, nr_pages * page_size, true, wp, false)) @@ -1062,6 +1066,58 @@ static void uffd_poison_test(uffd_test_args_t *targs) uffd_test_pass(); } +static void uffd_remap_test(uffd_test_args_t *targs) +{ + unsigned long nr; + pthread_t uffd_mon; + char c; + unsigned long long count; + struct uffd_args args = { 0 }; + + if (uffd_register(uffd, area_dst, nr_pages * page_size, + true, false, false)) + err("register failure"); + + if (pthread_create(&uffd_mon, NULL, uffd_poll_thread, &args)) + err("uffd_poll_thread create"); + + /* + * Read each of the pages back using the UFFD-registered mapping. We + * expect that the first time we touch a page, it will result in a missing + * fault. uffd_poll_thread will resolve the fault by remapping source + * page to destination. + */ + for (nr = 0; nr < nr_pages; nr++) { + /* Check area_src content */ + count = *area_count(area_src, nr); + if (count != count_verify[nr]) + err("nr %lu source memory invalid %llu %llu\n", + nr, count, count_verify[nr]); + + /* Faulting into area_dst should remap the page */ + count = *area_count(area_dst, nr); + if (count != count_verify[nr]) + err("nr %lu memory corruption %llu %llu\n", + nr, count, count_verify[nr]); + + /* Re-check area_src content which should be empty */ + count = *area_count(area_src, nr); + if (count != 0) + err("nr %lu remap failed %llu %llu\n", + nr, count, count_verify[nr]); + } + + if (write(pipefd[1], &c, sizeof(c)) != sizeof(c)) + err("pipe write"); + if (pthread_join(uffd_mon, NULL)) + err("join() failed"); + + if (args.missing_faults != nr_pages || args.minor_faults != 0) + uffd_test_fail("stats check error"); + else + uffd_test_pass(); +} + /* * Test the returned uffdio_register.ioctls with different register modes. * Note that _UFFDIO_ZEROPAGE is tested separately in the zeropage test. @@ -1139,6 +1195,12 @@ uffd_test_case_t uffd_tests[] = { .mem_targets = MEM_ALL, .uffd_feature_required = 0, }, + { + .name = "remap", + .uffd_fn = uffd_remap_test, + .mem_targets = MEM_ANON, + .uffd_feature_required = 0, + }, { .name = "wp-fork", .uffd_fn = uffd_wp_fork_test,