- Linux-kselftest-mirror - lists.linaro.org

[RFC v2 0/9] kunit: Add test attributes API

by Rae Moar

Hello everyone, This is an RFC patch series to propose the addition of a test attributes framework to KUnit. There has been interest in filtering out "slow" KUnit tests. Most notably, a new config, CONFIG_MEMCPY_SLOW_KUNIT_TEST, has been added to exclude a particularly slow memcpy test (https://lore.kernel.org/all/20230118200653.give.574-kees@kernel.org/). This proposed attributes framework would be used to save and access test associated data, including whether a test is slow. These attributes would be reportable (via KTAP and command line output) and some will be filterable. This framework is designed to allow for the addition of other attributes in the future. These attributes could include whether the test is flaky, associated test files, etc. This is the second version of the RFC I have added a few big changes: - Change method for inputting filters to allow for spaces in filtering values - Add option to skip filtered tests instead of not run or show them with the --filter_skip flag - Separate the new feature to list tests and their attributes into both --list_tests (lists just tests) and --list_tests_attr (lists all) - Add new attribute to store module name associated with test - Add Tests to executor_test.c - Add Documentation - A few small changes to code commented on previously I would love to hear about the new features. If the series seems overall good I will send out the next version as an official patch series. Thanks! Rae Rae Moar (9): kunit: Add test attributes API structure kunit: Add speed attribute kunit: Add module attribute kunit: Add ability to filter attributes kunit: tool: Add command line interface to filter and report attributes kunit: memcpy: Mark tests as slow using test attributes kunit: time: Mark test as slow using test attributes kunit: add tests for filtering attributes kunit: Add documentation of KUnit test attributes .../dev-tools/kunit/running_tips.rst | 163 +++++++ include/kunit/attributes.h | 50 +++ include/kunit/test.h | 68 ++- kernel/time/time_test.c | 2 +- lib/Kconfig.debug | 3 + lib/kunit/Makefile | 3 +- lib/kunit/attributes.c | 406 ++++++++++++++++++ lib/kunit/executor.c | 115 ++++- lib/kunit/executor_test.c | 119 ++++- lib/kunit/kunit-example-test.c | 9 + lib/kunit/test.c | 27 +- lib/memcpy_kunit.c | 8 +- tools/testing/kunit/kunit.py | 80 +++- tools/testing/kunit/kunit_kernel.py | 6 +- tools/testing/kunit/kunit_tool_test.py | 39 +- 15 files changed, 1022 insertions(+), 76 deletions(-) create mode 100644 include/kunit/attributes.h create mode 100644 lib/kunit/attributes.c base-commit: 2e66833579ed759d7b7da1a8f07eb727ec6e80db -- 2.41.0.255.g8b1d071c50-goog

1 year, 11 months

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[PATCH v3] selftests/input: add tests for the EVIOCSCLOCKID ioctl

by Dana Elfassy

From: Dana Elfassy <dangel101(a)gmail.com> This patch introduces tests for the EVIOCSCLOCKID ioctl, for full coverage of the different clkids Signed-off-by: Dana Elfassy <delfassy(a)redhat.com> Reviewed-by: Enric Balletbo Serra <eballetbo(a)gmail.com> Reviewed-by: Shuah Khan <skhan(a)linuxfoundation.org> --- Changes in v3: - Modified signed-off-by email - Added Reviewed-by tag Changes in v2: - Replaced clkids numerical values with their equivalent definition This patch depends on '[v3] selftests/input: Introduce basic tests for evdev ioctls' [1] sent to the ML. [1] https://patchwork.kernel.org/project/linux-input/patch/20230607153214.15933… tools/testing/selftests/input/evioc-test.c | 30 ++++++++++++++++++++++ 1 file changed, 30 insertions(+) diff --git a/tools/testing/selftests/input/evioc-test.c b/tools/testing/selftests/input/evioc-test.c index ad7b93fe39cf..83ce1a3c9b84 100644 --- a/tools/testing/selftests/input/evioc-test.c +++ b/tools/testing/selftests/input/evioc-test.c @@ -17,6 +17,7 @@ #include <sys/stat.h> #include <time.h> #include <unistd.h> +#include <linux/time.h> #include "../kselftest_harness.h" @@ -234,4 +235,33 @@ TEST(eviocsrep_set_repeat_settings) selftest_uinput_destroy(uidev); } +TEST(eviocsclockid_set_clockid) +{ + struct selftest_uinput *uidev; + int clkid = CLOCK_REALTIME; + int rc; + + rc = selftest_uinput_create_device(&uidev, -1); + ASSERT_EQ(0, rc); + ASSERT_NE(NULL, uidev); + + rc = ioctl(uidev->evdev_fd, EVIOCSCLOCKID, &clkid); + ASSERT_EQ(0, rc); + + clkid = CLOCK_MONOTONIC; + rc = ioctl(uidev->evdev_fd, EVIOCSCLOCKID, &clkid); + ASSERT_EQ(0, rc); + + clkid = CLOCK_BOOTTIME; + rc = ioctl(uidev->evdev_fd, EVIOCSCLOCKID, &clkid); + ASSERT_EQ(0, rc); + + // case default + clkid = -1; + rc = ioctl(uidev->evdev_fd, EVIOCSCLOCKID, &clkid); + ASSERT_EQ(-1, rc); + + selftest_uinput_destroy(uidev); +} + TEST_HARNESS_MAIN -- 2.41.0

1 year, 11 months

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[PATCH bpf-next 0/3] allow bpf_map_sum_elem_count for all program types

by Anton Protopopov

This short series is a follow up to the recent series [1] which added per-cpu insert/delete statistics for maps. The bpf_map_sum_elem_count kfunc presented in the original series was only available to tracing programs, so let's make it available to all. The first patch allows to treat CONST_PTR_TO_MAP as trusted pointers from kfunc's point of view. The second patch just adds const to the map argument of the bpf_map_sum_elem_count kfunc. The third patch registers the bpf_map_sum_elem_count for all programs, and patches selftests correspondingly. Anton Protopopov (3): bpf: consider CONST_PTR_TO_MAP as trusted pointer to struct bpf_map bpf: make an argument const in the bpf_map_sum_elem_count kfunc bpf: allow any program to use the bpf_map_sum_elem_count kfunc include/linux/btf_ids.h | 1 + kernel/bpf/map_iter.c | 7 +++---- kernel/bpf/verifier.c | 5 ++++- tools/testing/selftests/bpf/progs/map_ptr_kern.c | 5 +++++ 4 files changed, 13 insertions(+), 5 deletions(-) -- 2.34.1

1 year, 11 months

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[PATCH v4 0/6] KVM: selftests: Improve PMU event filter settings and add test cases

by Jinrong Liang

Hi, This patch series aims to improve the PMU event filter settings with a cleaner and more organized structure and adds several test cases related to PMU event filters. These changes help to ensure that KVM's PMU event filter functions as expected in all supported use cases. Any feedback or suggestions are greatly appreciated. Sincerely, Jinrong Liang Changes log: v4: - Rebased to 88bb466c9dec(tag: kvm-x86-next-2023.06.22); - Add a patch to add macros for fixed counters in processor.h; - Add a patch to drop the return of remove_event(); (Sean) - Reverse xmas tree; (Sean) - Optimize code style and comments; (Sean) Previous: https://lore.kernel.org/kvm/20230607123700.40229-1-cloudliang@tencent.com/T Jinrong Liang (6): KVM: selftests: Add macros for fixed counters in processor.h KVM: selftests: Drop the return of remove_event() KVM: selftests: Introduce __kvm_pmu_event_filter to improved event filter settings KVM: selftests: Add test cases for unsupported PMU event filter input values KVM: selftests: Test if event filter meets expectations on fixed counters KVM: selftests: Test gp event filters don't affect fixed event filters .../selftests/kvm/include/x86_64/processor.h | 2 + .../kvm/x86_64/pmu_event_filter_test.c | 314 ++++++++++++------ 2 files changed, 222 insertions(+), 94 deletions(-) base-commit: 88bb466c9dec4f70d682cf38c685324e7b1b3d60 -- 2.39.3

1 year, 11 months

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[PATCH v4] selftests/net: replace manual array size calc with ARRAYSIZE macro.

by Mahmoud Maatuq

fixes coccinelle WARNING: Use ARRAY_SIZE Signed-off-by: Mahmoud Maatuq <mahmoudmatook.mm(a)gmail.com> --- changelog since v3: - move changelog outside commit message. changelog since v2: - integrat a commit that contains actual replacement for ARRAY_SIZE. - use ARRAY_SIZE for net/psock_lib.h changelog since v1: - remove unnecessary extra new line changelog since v0: - update net/Makefile to include kselftest.h - remove redefinition of ARRAYSIZE. --- tools/testing/selftests/net/Makefile | 2 ++ tools/testing/selftests/net/csum.c | 6 ++++-- tools/testing/selftests/net/hwtstamp_config.c | 6 ++++-- tools/testing/selftests/net/psock_lib.h | 4 +++- 4 files changed, 13 insertions(+), 5 deletions(-) diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile index 7f3ab2a93ed6..a06cc25489f9 100644 --- a/tools/testing/selftests/net/Makefile +++ b/tools/testing/selftests/net/Makefile @@ -3,6 +3,8 @@ CFLAGS = -Wall -Wl,--no-as-needed -O2 -g CFLAGS += -I../../../../usr/include/ $(KHDR_INCLUDES) +# Additional include paths needed by kselftest.h +CFLAGS += -I../ TEST_PROGS := run_netsocktests run_afpackettests test_bpf.sh netdevice.sh \ rtnetlink.sh xfrm_policy.sh test_blackhole_dev.sh diff --git a/tools/testing/selftests/net/csum.c b/tools/testing/selftests/net/csum.c index 82a1c1839da6..90eb06fefa59 100644 --- a/tools/testing/selftests/net/csum.c +++ b/tools/testing/selftests/net/csum.c @@ -91,6 +91,8 @@ #include <sys/types.h> #include <unistd.h> +#include "kselftest.h" + static bool cfg_bad_csum; static int cfg_family = PF_INET6; static int cfg_num_pkt = 4; @@ -450,7 +452,7 @@ static void send_packet(int fd, const char *buf, int len) iov[2].iov_len = len; msg.msg_iov = iov; - msg.msg_iovlen = sizeof(iov) / sizeof(iov[0]); + msg.msg_iovlen = ARRAY_SIZE(iov); msg.msg_name = &addr; msg.msg_namelen = sizeof(addr); @@ -505,7 +507,7 @@ static void __recv_prepare_packet_filter(int fd, int off_nexthdr, int off_dport) struct sock_fprog prog = {}; prog.filter = filter; - prog.len = sizeof(filter) / sizeof(struct sock_filter); + prog.len = ARRAY_SIZE(filter); if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &prog, sizeof(prog))) error(1, errno, "setsockopt filter"); } diff --git a/tools/testing/selftests/net/hwtstamp_config.c b/tools/testing/selftests/net/hwtstamp_config.c index e1fdee841021..170728c96c46 100644 --- a/tools/testing/selftests/net/hwtstamp_config.c +++ b/tools/testing/selftests/net/hwtstamp_config.c @@ -16,6 +16,8 @@ #include <linux/net_tstamp.h> #include <linux/sockios.h> +#include "kselftest.h" + static int lookup_value(const char **names, int size, const char *name) { @@ -50,7 +52,7 @@ static const char *tx_types[] = { TX_TYPE(ONESTEP_SYNC) #undef TX_TYPE }; -#define N_TX_TYPES ((int)(sizeof(tx_types) / sizeof(tx_types[0]))) +#define N_TX_TYPES ((int)(ARRAY_SIZE(tx_types))) static const char *rx_filters[] = { #define RX_FILTER(name) [HWTSTAMP_FILTER_ ## name] = #name @@ -71,7 +73,7 @@ static const char *rx_filters[] = { RX_FILTER(PTP_V2_DELAY_REQ), #undef RX_FILTER }; -#define N_RX_FILTERS ((int)(sizeof(rx_filters) / sizeof(rx_filters[0]))) +#define N_RX_FILTERS ((int)(ARRAY_SIZE(rx_filters))) static void usage(void) { diff --git a/tools/testing/selftests/net/psock_lib.h b/tools/testing/selftests/net/psock_lib.h index faa884385c45..6e4fef560873 100644 --- a/tools/testing/selftests/net/psock_lib.h +++ b/tools/testing/selftests/net/psock_lib.h @@ -14,6 +14,8 @@ #include <arpa/inet.h> #include <unistd.h> +#include "kselftest.h" + #define DATA_LEN 100 #define DATA_CHAR 'a' #define DATA_CHAR_1 'b' @@ -63,7 +65,7 @@ static __maybe_unused void pair_udp_setfilter(int fd) struct sock_fprog bpf_prog; bpf_prog.filter = bpf_filter; - bpf_prog.len = sizeof(bpf_filter) / sizeof(struct sock_filter); + bpf_prog.len = ARRAY_SIZE(bpf_filter); if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &bpf_prog, sizeof(bpf_prog))) { -- 2.34.1

1 year, 11 months

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[PATCH net 0/3] selftests: tc: increase timeout and add missing kconfig

by Matthieu Baerts

When looking for something else in LKFT reports [1], I noticed that the TC selftest ended with a timeout error: not ok 1 selftests: tc-testing: tdc.sh # TIMEOUT 45 seconds I also noticed most of the tests were skipped because the "teardown stage" did not complete successfully. It was due to missing kconfig. These patches fix these two errors plus an extra one because this selftest reads info from "/proc/net/nf_conntrack". Thank you Pedro for having helped me fixing these issues [2]. Link: https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20230711/te… [1] Link: https://lore.kernel.org/netdev/0e061d4a-9a23-9f58-3b35-d8919de332d7@tessare… [2] Signed-off-by: Matthieu Baerts <matthieu.baerts(a)tessares.net> --- Matthieu Baerts (3): selftests: tc: set timeout to 15 minutes selftests: tc: add 'ct' action kconfig dep selftests: tc: add ConnTrack procfs kconfig tools/testing/selftests/tc-testing/config | 2 ++ tools/testing/selftests/tc-testing/settings | 1 + 2 files changed, 3 insertions(+) --- base-commit: 9d23aac8a85f69239e585c8656c6fdb21be65695 change-id: 20230713-tc-selftests-lkft-363e4590f105 Best regards, -- Matthieu Baerts <matthieu.baerts(a)tessares.net>

1 year, 11 months

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nolibc: KTAP output and test reports

by Thomas Weißschuh

Hi Willy, Zhangjin, after your recent discussions about the test output and report I wondered if it would make sense to switch nolibc-test to KTAP output format [0]. With this it would be possible to have a wrapper script run each architecture test as its own test subcomponent. A (K)TAP parser/runner could then directly recognize and report failing testcases, making it easier to validate. Also maybe we can hook it up into the regular kselftests setup and have the bots run it as part of that. The kernel even includes a header-only library to implement the format [1]. It also should be fairly easy to emit the format without a library. Thomas [0] Documentation/dev-tools/ktap.rst [1] Documentation/dev-tools/kselftest.rst (Test harness)

1 year, 11 months

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[PATCH v1 00/22] selftests/nolibc: add minimal kernel config support

by Zhangjin Wu

Willy, Thomas We just sent the 'selftests/nolibc: allow run with minimal kernel config' series [1], Here is the 'minimal' kernel config support, with both of them, it is possible to run nolibc-test for all architectures with oneline command and in less than ~30 minutes - 1 hour (not fullly measured yet): // run with tiny config + qemu-system // Note: rv32 and loongarch require to download the bios at first $ time make run-tiny-all QUIET_RUN=1 // run with default config + qemu-system $ time make run-default-all QUIET_RUN=1 // run with qemu-user $ time make run-user-all QUIET_RUN=1 Besides the 'tinyconfig' suggestion from Thomas, this patch also merge the generic part of my local powerpc porting (the extconfig to add additional console support). This is applied after the test report patchset [2] and the rv32 compile patchset [3], because all of them touched the same Makefile. Even without the 'selftests/nolibc: allow run with minimal kernel config' series [1], all of the tests can pass except the /proc/self/net related ones (We haven't enable CONFIG_NET in this patchset), the chmod_net one will be removed by Thomas from this patchset [4] for the wrong chmodable attribute issue of /proc/self/net, the link_cross one can be simply fixed up by using another /proc/self interface (like /proc/self/cmdline), which will be covered in our revision of the [1] series. Beside the core 'minimal' config support, some generic patch are added together to avoid patch conflicts. * selftests/nolibc: add test for -include /path/to/nolibc.h Add a test switch to allow run nolibc-test with nolibc.h * selftests/nolibc: print result to the screen too Let the run targets print results by default, allow disable by QUIET_RUN=1 * selftests/nolibc: allow use x86_64 toolchain for i386 Allow use x86_64 toolchains for i386 * selftests/nolibc: add menuconfig target for manual config a new 'menuconfig' target added for development and debugging * selftests/nolibc: add tinyconfig target a new 'tinyconfig' compare to 'defconfig', smaller and faster, but not enough for boot and print, require following 'extconfig' target * selftests/nolibc: allow customize extra kernel config options a new 'extconfig' allows to add extra config options for 'defconfig' and 'tinyconfig' * selftests/nolibc: add common extra config options selftests/nolibc: add power reset control support selftests/nolibc: add procfs, shmem and tmpfs Add common extra configs, the 3rd one (procfs, shmem and tmpfs) can be completely reverted after [1] series, but as discuss with Thomas, procfs may be still a hard requirement. * selftests/nolibc: add extra configs for i386 selftests/nolibc: add extra configs for x86_64 selftests/nolibc: add extra configs for arm64 selftests/nolibc: add extra configs for arm selftests/nolibc: add extra configs for mips selftests/nolibc: add extra configs for riscv32 selftests/nolibc: add extra configs for riscv64 selftests/nolibc: add extra configs for s390x selftests/nolibc: add extra configs for loongarch Add architecture specific extra configs to let kernel boot and nolibc-test print. The rv32 added here is only for test, it should not be merged before the missing 64bit syscalls are added (still wait for the merging of the __sysret and -ENOSYS patches). * selftests/nolibc: config default CROSS_COMPILE selftests/nolibc: add run-tiny and run-default both run-tiny and run-default are added to do config and run together, this easier test a log. * selftests/nolibc: allow run tests on all targets selftests/nolibc: detect bios existing to avoid hang Further allow do run-user, run-tiny and run-default for all architectures at once, the -all suffix is added to do so. Since some generic patches are still in review, before sending the left rv32 patches, I'm will send more generic patches later, the coming one is arch-xxx.h cleanup, and then, the 32bit powerpc porting support. For the compile speedup, the next step may be add architecture specific 'O' support, which may allow us rerun across architectures without mrproper, for a single architecture development, this 'minimal' config should be enough ;-) Thanks. Best regards, Zhangjin --- [1]: https://lore.kernel.org/lkml/cover.1687344643.git.falcon@tinylab.org/ [2]: https://lore.kernel.org/lkml/cover.1687156559.git.falcon@tinylab.org/ [3]: https://lore.kernel.org/linux-riscv/cover.1687176996.git.falcon@tinylab.org/ [4]: https://lore.kernel.org/lkml/20230624-proc-net-setattr-v1-0-73176812adee@we… Zhangjin Wu (22): selftests/nolibc: add test for -include /path/to/nolibc.h selftests/nolibc: print result to the screen too selftests/nolibc: allow use x86_64 toolchain for i386 selftests/nolibc: add menuconfig target for manual config selftests/nolibc: add tinyconfig target selftests/nolibc: allow customize extra kernel config options selftests/nolibc: add common extra config options selftests/nolibc: add power reset control support selftests/nolibc: add procfs, shmem and tmpfs selftests/nolibc: add extra configs for i386 selftests/nolibc: add extra configs for x86_64 selftests/nolibc: add extra configs for arm64 selftests/nolibc: add extra configs for arm selftests/nolibc: add extra configs for mips selftests/nolibc: add extra configs for riscv32 selftests/nolibc: add extra configs for riscv64 selftests/nolibc: add extra configs for s390x selftests/nolibc: add extra configs for loongarch selftests/nolibc: config default CROSS_COMPILE selftests/nolibc: add run-tiny and run-default selftests/nolibc: allow run tests on all targets selftests/nolibc: detect bios existing to avoid hang tools/testing/selftests/nolibc/Makefile | 125 ++++++++++++++++++++++-- 1 file changed, 119 insertions(+), 6 deletions(-) -- 2.25.1

1 year, 11 months

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[GIT PULL] Kselftest fixes update for Linux 6.5-rc3

by Shuah Khan

Hi Linus, Please pull the following Kselftest fixes update for Linux 6.5-rc3. This Kselftest fixes update for Linux 6.5-rc3 consists of fixes to bugs that are interfering with arm64 and riscv workflows. This update also includes two fixes to timer and mincore tests that are causing test failures. diff is attached. thanks, -- Shuah ---------------------------------------------------------------- The following changes since commit 06c2afb862f9da8dc5efa4b6076a0e48c3fbaaa5: Linux 6.5-rc1 (2023-07-09 13:53:13 -0700) are available in the Git repository at: git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest tags/linux-kselftest-fixes-6.5-rc3 for you to fetch changes up to 569f8b501b177f21121d483a96491716ab8905f4: selftests/arm64: fix build failure during the "emit_tests" step (2023-07-14 12:33:35 -0600) ---------------------------------------------------------------- linux-kselftest-fixes-6.5-rc3 This Kselftest fixes update for Linux 6.5-rc3 consists of fixes to bugs that are interfering with arm64 and riscv workflows. This update also includes two fixes to timer and mincore tests that are causing test failures. ---------------------------------------------------------------- John Hubbard (2): selftests/riscv: fix potential build failure during the "emit_tests" step selftests/arm64: fix build failure during the "emit_tests" step Minjie Du (1): tools: timers: fix freq average calculation Ricardo Cañuelo (1): selftests/mincore: fix skip condition for check_huge_pages test tools/testing/selftests/arm64/Makefile | 2 +- tools/testing/selftests/mincore/mincore_selftest.c | 4 ++-- tools/testing/selftests/riscv/Makefile | 2 +- tools/testing/selftests/timers/raw_skew.c | 3 +-- 4 files changed, 5 insertions(+), 6 deletions(-) ----------------------------------------------------------------

1 year, 11 months

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[PATCH v25 0/5] Implement IOCTL to get and optionally clear info about PTEs

by Muhammad Usama Anjum

*Changes in v25*: - Do proper filtering on hole as well (hole got missed earlier) *Changes in v24*: - Rebase on top of next-20230710 - Place WP markers in case of hole as well *Changes in v23*: - Set vec_buf_index in loop only when vec_buf_index is set - Return -EFAULT instead of -EINVAL if vec is NULL - Correctly return the walk ending address to the page granularity *Changes in v22*: - Interface change: - Replace [start start + len) with [start, end) - Return the ending address of the address walk in start *Changes in v21*: - Abort walk instead of returning error if WP is to be performed on partial hugetlb *Changes in v20* - Correct PAGE_IS_FILE and add PAGE_IS_PFNZERO *Changes in v19* - Minor changes and interface updates *Changes in v18* - Rebase on top of next-20230613 - Minor updates *Changes in v17* - Rebase on top of next-20230606 - Minor improvements in PAGEMAP_SCAN IOCTL patch *Changes in v16* - Fix a corner case - Add exclusive PM_SCAN_OP_WP back *Changes in v15* - Build fix (Add missed build fix in RESEND) *Changes in v14* - Fix build error caused by #ifdef added at last minute in some configs *Changes in v13* - Rebase on top of next-20230414 - Give-up on using uffd_wp_range() and write new helpers, flush tlb only once *Changes in v12* - Update and other memory types to UFFD_FEATURE_WP_ASYNC - Rebaase on top of next-20230406 - Review updates *Changes in v11* - Rebase on top of next-20230307 - Base patches on UFFD_FEATURE_WP_UNPOPULATED - Do a lot of cosmetic changes and review updates - Remove ENGAGE_WP + !GET operation as it can be performed with UFFDIO_WRITEPROTECT *Changes in v10* - Add specific condition to return error if hugetlb is used with wp async - Move changes in tools/include/uapi/linux/fs.h to separate patch - Add documentation *Changes in v9:* - Correct fault resolution for userfaultfd wp async - Fix build warnings and errors which were happening on some configs - Simplify pagemap ioctl's code *Changes in v8:* - Update uffd async wp implementation - Improve PAGEMAP_IOCTL implementation *Changes in v7:* - Add uffd wp async - Update the IOCTL to use uffd under the hood instead of soft-dirty flags *Motivation* The real motivation for adding PAGEMAP_SCAN IOCTL is to emulate Windows GetWriteWatch() syscall [1]. The GetWriteWatch{} retrieves the addresses of the pages that are written to in a region of virtual memory. This syscall is used in Windows applications and games etc. This syscall is being emulated in pretty slow manner in userspace. Our purpose is to enhance the kernel such that we translate it efficiently in a better way. Currently some out of tree hack patches are being used to efficiently emulate it in some kernels. We intend to replace those with these patches. So the whole gaming on Linux can effectively get benefit from this. It means there would be tons of users of this code. CRIU use case [2] was mentioned by Andrei and Danylo: > Use cases for migrating sparse VMAs are binaries sanitized with ASAN, > MSAN or TSAN [3]. All of these sanitizers produce sparse mappings of > shadow memory [4]. Being able to migrate such binaries allows to highly > reduce the amount of work needed to identify and fix post-migration > crashes, which happen constantly. Andrei's defines the following uses of this code: * it is more granular and allows us to track changed pages more effectively. The current interface can clear dirty bits for the entire process only. In addition, reading info about pages is a separate operation. It means we must freeze the process to read information about all its pages, reset dirty bits, only then we can start dumping pages. The information about pages becomes more and more outdated, while we are processing pages. The new interface solves both these downsides. First, it allows us to read pte bits and clear the soft-dirty bit atomically. It means that CRIU will not need to freeze processes to pre-dump their memory. Second, it clears soft-dirty bits for a specified region of memory. It means CRIU will have actual info about pages to the moment of dumping them. * The new interface has to be much faster because basic page filtering is happening in the kernel. With the old interface, we have to read pagemap for each page. *Implementation Evolution (Short Summary)* From the definition of GetWriteWatch(), we feel like kernel's soft-dirty feature can be used under the hood with some additions like: * reset soft-dirty flag for only a specific region of memory instead of clearing the flag for the entire process * get and clear soft-dirty flag for a specific region atomically So we decided to use ioctl on pagemap file to read or/and reset soft-dirty flag. But using soft-dirty flag, sometimes we get extra pages which weren't even written. They had become soft-dirty because of VMA merging and VM_SOFTDIRTY flag. This breaks the definition of GetWriteWatch(). We were able to by-pass this short coming by ignoring VM_SOFTDIRTY until David reported that mprotect etc messes up the soft-dirty flag while ignoring VM_SOFTDIRTY [5]. This wasn't happening until [6] got introduced. We discussed if we can revert these patches. But we could not reach to any conclusion. So at this point, I made couple of tries to solve this whole VM_SOFTDIRTY issue by correcting the soft-dirty implementation: * [7] Correct the bug fixed wrongly back in 2014. It had potential to cause regression. We left it behind. * [8] Keep a list of soft-dirty part of a VMA across splits and merges. I got the reply don't increase the size of the VMA by 8 bytes. At this point, we left soft-dirty considering it is too much delicate and userfaultfd [9] seemed like the only way forward. From there onward, we have been basing soft-dirty emulation on userfaultfd wp feature where kernel resolves the faults itself when WP_ASYNC feature is used. It was straight forward to add WP_ASYNC feature in userfautlfd. Now we get only those pages dirty or written-to which are really written in reality. (PS There is another WP_UNPOPULATED userfautfd feature is required which is needed to avoid pre-faulting memory before write-protecting [9].) All the different masks were added on the request of CRIU devs to create interface more generic and better. [1] https://learn.microsoft.com/en-us/windows/win32/api/memoryapi/nf-memoryapi-… [2] https://lore.kernel.org/all/20221014134802.1361436-1-mdanylo@google.com [3] https://github.com/google/sanitizers [4] https://github.com/google/sanitizers/wiki/AddressSanitizerAlgorithm#64-bit [5] https://lore.kernel.org/all/bfcae708-db21-04b4-0bbe-712badd03071@redhat.com [6] https://lore.kernel.org/all/20220725142048.30450-1-peterx@redhat.com/ [7] https://lore.kernel.org/all/20221122115007.2787017-1-usama.anjum@collabora.… [8] https://lore.kernel.org/all/20221220162606.1595355-1-usama.anjum@collabora.… [9] https://lore.kernel.org/all/20230306213925.617814-1-peterx@redhat.com [10] https://lore.kernel.org/all/20230125144529.1630917-1-mdanylo@google.com * Original Cover letter from v8* Hello, Note: Soft-dirty pages and pages which have been written-to are synonyms. As kernel already has soft-dirty feature inside which we have given up to use, we are using written-to terminology while using UFFD async WP under the hood. This IOCTL, PAGEMAP_SCAN on pagemap file can be used to get and/or clear the info about page table entries. The following operations are supported in this ioctl: - Get the information if the pages have been written-to (PAGE_IS_WRITTEN), file mapped (PAGE_IS_FILE), present (PAGE_IS_PRESENT) or swapped (PAGE_IS_SWAPPED). - Write-protect the pages (PAGEMAP_WP_ENGAGE) to start finding which pages have been written-to. - Find pages which have been written-to and write protect the pages (atomic PAGE_IS_WRITTEN + PAGEMAP_WP_ENGAGE) It is possible to find and clear soft-dirty pages entirely in userspace. But it isn't efficient: - The mprotect and SIGSEGV handler for bookkeeping - The userfaultfd wp (synchronous) with the handler for bookkeeping Some benchmarks can be seen here[1]. This series adds features that weren't present earlier: - There is no atomic get soft-dirty/Written-to status and clear present in the kernel. - The pages which have been written-to can not be found in accurate way. (Kernel's soft-dirty PTE bit + sof_dirty VMA bit shows more soft-dirty pages than there actually are.) Historically, soft-dirty PTE bit tracking has been used in the CRIU project. The procfs interface is enough for finding the soft-dirty bit status and clearing the soft-dirty bit of all the pages of a process. We have the use case where we need to track the soft-dirty PTE bit for only specific pages on-demand. We need this tracking and clear mechanism of a region of memory while the process is running to emulate the getWriteWatch() syscall of Windows. *(Moved to using UFFD instead of soft-dirtyi feature to find pages which have been written-to from v7 patch series)*: Stop using the soft-dirty flags for finding which pages have been written to. It is too delicate and wrong as it shows more soft-dirty pages than the actual soft-dirty pages. There is no interest in correcting it [2][3] as this is how the feature was written years ago. It shouldn't be updated to changed behaviour. Peter Xu has suggested using the async version of the UFFD WP [4] as it is based inherently on the PTEs. So in this patch series, I've added a new mode to the UFFD which is asynchronous version of the write protect. When this variant of the UFFD WP is used, the page faults are resolved automatically by the kernel. The pages which have been written-to can be found by reading pagemap file (!PM_UFFD_WP). This feature can be used successfully to find which pages have been written to from the time the pages were write protected. This works just like the soft-dirty flag without showing any extra pages which aren't soft-dirty in reality. The information related to pages if the page is file mapped, present and swapped is required for the CRIU project [5][6]. The addition of the required mask, any mask, excluded mask and return masks are also required for the CRIU project [5]. The IOCTL returns the addresses of the pages which match the specific masks. The page addresses are returned in struct page_region in a compact form. The max_pages is needed to support a use case where user only wants to get a specific number of pages. So there is no need to find all the pages of interest in the range when max_pages is specified. The IOCTL returns when the maximum number of the pages are found. The max_pages is optional. If max_pages is specified, it must be equal or greater than the vec_size. This restriction is needed to handle worse case when one page_region only contains info of one page and it cannot be compacted. This is needed to emulate the Windows getWriteWatch() syscall. The patch series include the detailed selftest which can be used as an example for the uffd async wp test and PAGEMAP_IOCTL. It shows the interface usages as well. [1] https://lore.kernel.org/lkml/54d4c322-cd6e-eefd-b161-2af2b56aae24@collabora… [2] https://lore.kernel.org/all/20221220162606.1595355-1-usama.anjum@collabora.… [3] https://lore.kernel.org/all/20221122115007.2787017-1-usama.anjum@collabora.… [4] https://lore.kernel.org/all/Y6Hc2d+7eTKs7AiH@x1n [5] https://lore.kernel.org/all/YyiDg79flhWoMDZB@gmail.com/ [6] https://lore.kernel.org/all/20221014134802.1361436-1-mdanylo@google.com/ Regards, Muhammad Usama Anjum Muhammad Usama Anjum (4): fs/proc/task_mmu: Implement IOCTL to get and optionally clear info about PTEs tools headers UAPI: Update linux/fs.h with the kernel sources mm/pagemap: add documentation of PAGEMAP_SCAN IOCTL selftests: mm: add pagemap ioctl tests Peter Xu (1): userfaultfd: UFFD_FEATURE_WP_ASYNC Documentation/admin-guide/mm/pagemap.rst | 58 + Documentation/admin-guide/mm/userfaultfd.rst | 35 + fs/proc/task_mmu.c | 591 +++++++ fs/userfaultfd.c | 26 +- include/linux/hugetlb.h | 1 + include/linux/userfaultfd_k.h | 21 +- include/uapi/linux/fs.h | 55 + include/uapi/linux/userfaultfd.h | 9 +- mm/hugetlb.c | 34 +- mm/memory.c | 27 +- tools/include/uapi/linux/fs.h | 55 + tools/testing/selftests/mm/.gitignore | 2 + tools/testing/selftests/mm/Makefile | 3 +- tools/testing/selftests/mm/config | 1 + tools/testing/selftests/mm/pagemap_ioctl.c | 1464 ++++++++++++++++++ tools/testing/selftests/mm/run_vmtests.sh | 4 + 16 files changed, 2362 insertions(+), 24 deletions(-) create mode 100644 tools/testing/selftests/mm/pagemap_ioctl.c mode change 100644 => 100755 tools/testing/selftests/mm/run_vmtests.sh -- 2.39.2

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