Let's add a simple test for MADV_POPULATE_READ and MADV_POPULATE_WRITE, verifying some error handling, that population works, and that softdirty tracking works as expected. For now, limit the test to private anonymous memory.

Cc: Andrew Morton akpm@linux-foundation.org Cc: Arnd Bergmann arnd@arndb.de Cc: Michal Hocko mhocko@suse.com Cc: Oscar Salvador osalvador@suse.de Cc: Matthew Wilcox (Oracle) willy@infradead.org Cc: Andrea Arcangeli aarcange@redhat.com Cc: Minchan Kim minchan@kernel.org Cc: Jann Horn jannh@google.com Cc: Jason Gunthorpe jgg@ziepe.ca Cc: Dave Hansen dave.hansen@intel.com Cc: Hugh Dickins hughd@google.com Cc: Rik van Riel riel@surriel.com Cc: Michael S. Tsirkin mst@redhat.com Cc: Kirill A. Shutemov kirill.shutemov@linux.intel.com Cc: Vlastimil Babka vbabka@suse.cz Cc: Richard Henderson rth@twiddle.net Cc: Ivan Kokshaysky ink@jurassic.park.msu.ru Cc: Matt Turner mattst88@gmail.com Cc: Thomas Bogendoerfer tsbogend@alpha.franken.de Cc: "James E.J. Bottomley" James.Bottomley@HansenPartnership.com Cc: Helge Deller deller@gmx.de Cc: Chris Zankel chris@zankel.net Cc: Max Filippov jcmvbkbc@gmail.com Cc: Mike Kravetz mike.kravetz@oracle.com Cc: Peter Xu peterx@redhat.com Cc: Rolf Eike Beer eike-kernel@sf-tec.de Cc: Shuah Khan shuah@kernel.org Cc: linux-alpha@vger.kernel.org Cc: linux-mips@vger.kernel.org Cc: linux-parisc@vger.kernel.org Cc: linux-xtensa@linux-xtensa.org Cc: linux-arch@vger.kernel.org Cc: linux-kselftest@vger.kernel.org Cc: Linux API linux-api@vger.kernel.org Signed-off-by: David Hildenbrand david@redhat.com --- tools/testing/selftests/vm/.gitignore | 1 + tools/testing/selftests/vm/Makefile | 1 + tools/testing/selftests/vm/madv_populate.c | 342 +++++++++++++++++++++ tools/testing/selftests/vm/run_vmtests.sh | 16 + 4 files changed, 360 insertions(+) create mode 100644 tools/testing/selftests/vm/madv_populate.c

diff --git a/tools/testing/selftests/vm/.gitignore b/tools/testing/selftests/vm/.gitignore index b4fc0148360e..c9a5dd1adf7d 100644 --- a/tools/testing/selftests/vm/.gitignore +++ b/tools/testing/selftests/vm/.gitignore @@ -24,3 +24,4 @@ hmm-tests local_config.* protection_keys_32 protection_keys_64 +madv_populate diff --git a/tools/testing/selftests/vm/Makefile b/tools/testing/selftests/vm/Makefile index 8b0cd421ebd3..04b6650c1924 100644 --- a/tools/testing/selftests/vm/Makefile +++ b/tools/testing/selftests/vm/Makefile @@ -42,6 +42,7 @@ TEST_GEN_FILES += on-fault-limit TEST_GEN_FILES += thuge-gen TEST_GEN_FILES += transhuge-stress TEST_GEN_FILES += userfaultfd +TEST_GEN_FILES += madv_populate

ifeq ($(MACHINE),x86_64) CAN_BUILD_I386 := $(shell ./../x86/check_cc.sh $(CC) ../x86/trivial_32bit_program.c -m32) diff --git a/tools/testing/selftests/vm/madv_populate.c b/tools/testing/selftests/vm/madv_populate.c new file mode 100644 index 000000000000..b959e4ebdad4 --- /dev/null +++ b/tools/testing/selftests/vm/madv_populate.c @@ -0,0 +1,342 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * MADV_POPULATE_READ and MADV_POPULATE_WRITE tests + * + * Copyright 2021, Red Hat, Inc. + * + * Author(s): David Hildenbrand david@redhat.com + */ +#define _GNU_SOURCE +#include <stdlib.h> +#include <string.h> +#include <stdbool.h> +#include <stdint.h> +#include <unistd.h> +#include <errno.h> +#include <fcntl.h> +#include <sys/mman.h> + +#include "../kselftest.h" + +#if defined(MADV_POPULATE_READ) && defined(MADV_POPULATE_WRITE) + +/* + * For now, we're using 2 MiB of private anonymous memory for all tests. + */ +#define SIZE (2 * 1024 * 1024) + +static size_t pagesize; + +static uint64_t pagemap_get_entry(int fd, char *start) +{ + const unsigned long pfn = (unsigned long)start / pagesize; + uint64_t entry; + int ret; + + ret = pread(fd, &entry, sizeof(entry), pfn * sizeof(entry)); + if (ret != sizeof(entry)) + ksft_exit_fail_msg("reading pagemap failed\n"); + return entry; +} + +static bool pagemap_is_populated(int fd, char *start) +{ + uint64_t entry = pagemap_get_entry(fd, start); + + /* Present or swapped. */ + return entry & 0xc000000000000000ull; +} + +static bool pagemap_is_softdirty(int fd, char *start) +{ + uint64_t entry = pagemap_get_entry(fd, start); + + return entry & 0x0080000000000000ull; +} + +static void sense_support(void) +{ + char *addr; + int ret; + + addr = mmap(0, pagesize, PROT_READ | PROT_WRITE, + MAP_ANONYMOUS | MAP_PRIVATE, 0, 0); + if (!addr) + ksft_exit_fail_msg("mmap failed\n"); + + ret = madvise(addr, pagesize, MADV_POPULATE_READ); + if (ret) + ksft_exit_skip("MADV_POPULATE_READ is not available\n"); + + ret = madvise(addr, pagesize, MADV_POPULATE_WRITE); + if (ret) + ksft_exit_skip("MADV_POPULATE_WRITE is not available\n"); + + munmap(addr, pagesize); +} + +static void test_prot_read(void) +{ + char *addr; + int ret; + + ksft_print_msg("[RUN] %s\n", __func__); + + addr = mmap(0, SIZE, PROT_READ, MAP_ANONYMOUS | MAP_PRIVATE, 0, 0); + if (addr == MAP_FAILED) + ksft_exit_fail_msg("mmap failed\n"); + + ret = madvise(addr, SIZE, MADV_POPULATE_READ); + ksft_test_result(!ret, "MADV_POPULATE_READ with PROT_READ\n"); + + ret = madvise(addr, SIZE, MADV_POPULATE_WRITE); + ksft_test_result(ret == -1 && errno == EINVAL, + "MADV_POPULATE_WRITE with PROT_READ\n"); + + munmap(addr, SIZE); +} + +static void test_prot_write(void) +{ + char *addr; + int ret; + + ksft_print_msg("[RUN] %s\n", __func__); + + addr = mmap(0, SIZE, PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, 0, 0); + if (addr == MAP_FAILED) + ksft_exit_fail_msg("mmap failed\n"); + + ret = madvise(addr, SIZE, MADV_POPULATE_READ); + ksft_test_result(ret == -1 && errno == EINVAL, + "MADV_POPULATE_READ with PROT_WRITE\n"); + + ret = madvise(addr, SIZE, MADV_POPULATE_WRITE); + ksft_test_result(!ret, "MADV_POPULATE_WRITE with PROT_WRITE\n"); + + munmap(addr, SIZE); +} + +static void test_holes(void) +{ + char *addr; + int ret; + + ksft_print_msg("[RUN] %s\n", __func__); + + addr = mmap(0, SIZE, PROT_READ | PROT_WRITE, + MAP_ANONYMOUS | MAP_PRIVATE, 0, 0); + if (addr == MAP_FAILED) + ksft_exit_fail_msg("mmap failed\n"); + ret = munmap(addr + pagesize, pagesize); + if (ret) + ksft_exit_fail_msg("munmap failed\n"); + + /* Hole in the middle */ + ret = madvise(addr, SIZE, MADV_POPULATE_READ); + ksft_test_result(ret == -1 && errno == ENOMEM, + "MADV_POPULATE_READ with holes in the middle\n"); + ret = madvise(addr, SIZE, MADV_POPULATE_WRITE); + ksft_test_result(ret == -1 && errno == ENOMEM, + "MADV_POPULATE_WRITE with holes in the middle\n"); + + /* Hole at end */ + ret = madvise(addr, 2 * pagesize, MADV_POPULATE_READ); + ksft_test_result(ret == -1 && errno == ENOMEM, + "MADV_POPULATE_READ with holes at the end\n"); + ret = madvise(addr, 2 * pagesize, MADV_POPULATE_WRITE); + ksft_test_result(ret == -1 && errno == ENOMEM, + "MADV_POPULATE_WRITE with holes at the end\n"); + + /* Hole at beginning */ + ret = madvise(addr + pagesize, pagesize, MADV_POPULATE_READ); + ksft_test_result(ret == -1 && errno == ENOMEM, + "MADV_POPULATE_READ with holes at the beginning\n"); + ret = madvise(addr + pagesize, pagesize, MADV_POPULATE_WRITE); + ksft_test_result(ret == -1 && errno == ENOMEM, + "MADV_POPULATE_WRITE with holes at the beginning\n"); + + munmap(addr, SIZE); +} + +static bool range_is_populated(char *start, ssize_t size) +{ + int fd = open("/proc/self/pagemap", O_RDONLY); + bool ret = true; + + if (fd < 0) + ksft_exit_fail_msg("opening pagemap failed\n"); + for (; size > 0 && ret; size -= pagesize, start += pagesize) + if (!pagemap_is_populated(fd, start)) + ret = false; + close(fd); + return ret; +} + +static bool range_is_not_populated(char *start, ssize_t size) +{ + int fd = open("/proc/self/pagemap", O_RDONLY); + bool ret = true; + + if (fd < 0) + ksft_exit_fail_msg("opening pagemap failed\n"); + for (; size > 0 && ret; size -= pagesize, start += pagesize) + if (pagemap_is_populated(fd, start)) + ret = false; + close(fd); + return ret; +} + +static void test_populate_read(void) +{ + char *addr; + int ret; + + ksft_print_msg("[RUN] %s\n", __func__); + + addr = mmap(0, SIZE, PROT_READ | PROT_WRITE, + MAP_ANONYMOUS | MAP_PRIVATE, 0, 0); + if (addr == MAP_FAILED) + ksft_exit_fail_msg("mmap failed\n"); + ksft_test_result(range_is_not_populated(addr, SIZE), + "range initially not populated\n"); + + ret = madvise(addr, SIZE, MADV_POPULATE_READ); + ksft_test_result(!ret, "MADV_POPULATE_READ\n"); + ksft_test_result(range_is_populated(addr, SIZE), + "range is populated\n"); + + munmap(addr, SIZE); +} + +static void test_populate_write(void) +{ + char *addr; + int ret; + + ksft_print_msg("[RUN] %s\n", __func__); + + addr = mmap(0, SIZE, PROT_READ | PROT_WRITE, + MAP_ANONYMOUS | MAP_PRIVATE, 0, 0); + if (addr == MAP_FAILED) + ksft_exit_fail_msg("mmap failed\n"); + ksft_test_result(range_is_not_populated(addr, SIZE), + "range initially not populated\n"); + + ret = madvise(addr, SIZE, MADV_POPULATE_WRITE); + ksft_test_result(!ret, "MADV_POPULATE_WRITE\n"); + ksft_test_result(range_is_populated(addr, SIZE), + "range is populated\n"); + + munmap(addr, SIZE); +} + +static bool range_is_softdirty(char *start, ssize_t size) +{ + int fd = open("/proc/self/pagemap", O_RDONLY); + bool ret = true; + + if (fd < 0) + ksft_exit_fail_msg("opening pagemap failed\n"); + for (; size > 0 && ret; size -= pagesize, start += pagesize) + if (!pagemap_is_softdirty(fd, start)) + ret = false; + close(fd); + return ret; +} + +static bool range_is_not_softdirty(char *start, ssize_t size) +{ + int fd = open("/proc/self/pagemap", O_RDONLY); + bool ret = true; + + if (fd < 0) + ksft_exit_fail_msg("opening pagemap failed\n"); + for (; size > 0 && ret; size -= pagesize, start += pagesize) + if (pagemap_is_softdirty(fd, start)) + ret = false; + close(fd); + return ret; +} + +static void clear_softdirty(void) +{ + int fd = open("/proc/self/clear_refs", O_WRONLY); + const char *ctrl = "4"; + int ret; + + if (fd < 0) + ksft_exit_fail_msg("opening clear_refs failed\n"); + ret = write(fd, ctrl, strlen(ctrl)); + if (ret != strlen(ctrl)) + ksft_exit_fail_msg("writing clear_refs failed\n"); + close(fd); +} + +static void test_softdirty(void) +{ + char *addr; + int ret; + + ksft_print_msg("[RUN] %s\n", __func__); + + addr = mmap(0, SIZE, PROT_READ | PROT_WRITE, + MAP_ANONYMOUS | MAP_PRIVATE, 0, 0); + if (addr == MAP_FAILED) + ksft_exit_fail_msg("mmap failed\n"); + + /* Clear any softdirty bits. */ + clear_softdirty(); + ksft_test_result(range_is_not_softdirty(addr, SIZE), + "range is not softdirty\n"); + + /* Populating READ should set softdirty. */ + ret = madvise(addr, SIZE, MADV_POPULATE_READ); + ksft_test_result(!ret, "MADV_POPULATE_READ\n"); + ksft_test_result(range_is_not_softdirty(addr, SIZE), + "range is not softdirty\n"); + + /* Populating WRITE should set softdirty. */ + ret = madvise(addr, SIZE, MADV_POPULATE_WRITE); + ksft_test_result(!ret, "MADV_POPULATE_WRITE\n"); + ksft_test_result(range_is_softdirty(addr, SIZE), + "range is softdirty\n"); + + munmap(addr, SIZE); +} + +int main(int argc, char **argv) +{ + int err; + + pagesize = getpagesize(); + + ksft_print_header(); + ksft_set_plan(21); + + sense_support(); + test_prot_read(); + test_prot_write(); + test_holes(); + test_populate_read(); + test_populate_write(); + test_softdirty(); + + err = ksft_get_fail_cnt(); + if (err) + ksft_exit_fail_msg("%d out of %d tests failed\n", + err, ksft_test_num()); + return ksft_exit_pass(); +} + +#else /* defined(MADV_POPULATE_READ) && defined(MADV_POPULATE_WRITE) */ + +#warning "missing MADV_POPULATE_READ or MADV_POPULATE_WRITE definition" + +int main(int argc, char **argv) +{ + ksft_print_header(); + ksft_exit_skip("MADV_POPULATE_READ or MADV_POPULATE_WRITE not defined\n"); +} + +#endif /* defined(MADV_POPULATE_READ) && defined(MADV_POPULATE_WRITE) */ diff --git a/tools/testing/selftests/vm/run_vmtests.sh b/tools/testing/selftests/vm/run_vmtests.sh index e953f3cd9664..955782d138ab 100755 --- a/tools/testing/selftests/vm/run_vmtests.sh +++ b/tools/testing/selftests/vm/run_vmtests.sh @@ -346,4 +346,20 @@ else exitcode=1 fi

+echo "--------------------------------------------------------" +echo "running MADV_POPULATE_READ and MADV_POPULATE_WRITE tests" +echo "--------------------------------------------------------" +./madv_populate +ret_val=$? + +if [ $ret_val -eq 0 ]; then + echo "[PASS]" +elif [ $ret_val -eq $ksft_skip ]; then + echo "[SKIP]" + exitcode=$ksft_skip +else + echo "[FAIL]" + exitcode=1 +fi + exit $exitcode