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

Re: [PATCH v4 15/17] iommufd: Add a selftest

by Matthew Rosato

On 11/7/22 7:49 PM, Jason Gunthorpe wrote: > Cover the essential functionality of the iommufd with a directed > test. This aims to achieve reasonable functional coverage using the > in-kernel self test framework. > > It provides a mock kernel module for the iommu_domain that allows it to > run without any HW and the mocking provides a way to directly validate > that the PFNs loaded into the iommu_domain are correct. > > The mock also simulates the rare case of PAGE_SIZE > iommu page size as > the mock will operate at a 2K iommu page size. This allows exercising all > of the calculations to support this mismatch. > > This allows achieving high coverage of the corner cases in the iopt_pages. > > However, it is an unusually invasive config option to enable all of > this. The config option should not be enabled in a production kernel. > > Tested-by: Nicolin Chen <nicolinc(a)nvidia.com> > Signed-off-by: Jason Gunthorpe <jgg(a)nvidia.com> > Signed-off-by: Nicolin Chen <nicolinc(a)nvidia.com> > Signed-off-by: Yi Liu <yi.l.liu(a)intel.com> Ran the selftests on s390 in both LPAR (z16) and a QEMU kvm guest using 1M hugepages, all tests are passing. Tested-by: Matthew Rosato <mjrosato(a)linux.ibm.com> # s390

3 years

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[PATCH] selftests: proc: Fix proc-empty-vm build error on non x86_64

by Punit Agrawal

The proc-empty-vm test is implemented for x86_64 and fails to build for other architectures. Rather then emitting a compiler error it would be preferable to only build the test on supported architectures. Mark proc-empty-vm as a test for x86_64 and customise to the Makefile to build it only when building for this target architecture. Fixes: 5bc73bb3451b ("proc: test how it holds up with mapping'less process") Signed-off-by: Punit Agrawal <punit.agrawal(a)bytedance.com> --- tools/testing/selftests/proc/Makefile | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/proc/Makefile b/tools/testing/selftests/proc/Makefile index cd95369254c0..6b31439902af 100644 --- a/tools/testing/selftests/proc/Makefile +++ b/tools/testing/selftests/proc/Makefile @@ -1,14 +1,18 @@ # SPDX-License-Identifier: GPL-2.0-only + +# When ARCH not overridden for crosscompiling, lookup machine +ARCH ?= $(shell uname -m 2>/dev/null || echo not) + CFLAGS += -Wall -O2 -Wno-unused-function CFLAGS += -D_GNU_SOURCE LDFLAGS += -pthread -TEST_GEN_PROGS := +TEST_GEN_PROGS_x86_64 += proc-empty-vm + TEST_GEN_PROGS += fd-001-lookup TEST_GEN_PROGS += fd-002-posix-eq TEST_GEN_PROGS += fd-003-kthread TEST_GEN_PROGS += proc-loadavg-001 -TEST_GEN_PROGS += proc-empty-vm TEST_GEN_PROGS += proc-pid-vm TEST_GEN_PROGS += proc-self-map-files-001 TEST_GEN_PROGS += proc-self-map-files-002 -- 2.30.2

3 years

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[PATCH] selftests/bpf: Fix test_progs compilation failure in 32-bit arch

by Yang Jihong

test_progs fails to be compiled in the 32-bit arch, log is as follows: test_progs.c:1013:52: error: format '%ld' expects argument of type 'long int', but argument 3 has type 'size_t' {aka 'unsigned int'} [-Werror=format=] 1013 | sprintf(buf, "MSG_TEST_LOG (cnt: %ld, last: %d)", | ~~^ | | | long int | %d 1014 | strlen(msg->test_log.log_buf), | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | | | size_t {aka unsigned int} Fix it. Fixes: 91b2c0afd00c ("selftests/bpf: Add parallelism to test_progs") Signed-off-by: Yang Jihong <yangjihong1(a)huawei.com> --- tools/testing/selftests/bpf/test_progs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/bpf/test_progs.c b/tools/testing/selftests/bpf/test_progs.c index 0e9a47f97890..3fef451d8831 100644 --- a/tools/testing/selftests/bpf/test_progs.c +++ b/tools/testing/selftests/bpf/test_progs.c @@ -1010,7 +1010,7 @@ static inline const char *str_msg(const struct msg *msg, char *buf) msg->subtest_done.have_log); break; case MSG_TEST_LOG: - sprintf(buf, "MSG_TEST_LOG (cnt: %ld, last: %d)", + sprintf(buf, "MSG_TEST_LOG (cnt: %zu, last: %d)", strlen(msg->test_log.log_buf), msg->test_log.is_last); break; -- 2.30.GIT

3 years

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[PATCH v1 0/6] arm64: Support for 2022 data processing instructions

by Mark Brown

The 2022 update to the Arm architecture includes a number of additions of generic data processing features, covering the base architecture, SVE and SME. Other than SME these are all simple features which introduce no architectural state so we simply need to expose hwcaps for them. This series covers these simple features. Since the SME updates do introduce new architectural state for which we must add new ABI they will be handled in a separate series. Mark Brown (6): arm64/hwcap: Add support for FEAT_CSSC kselftest/arm64: Add FEAT_CSSC to the hwcap selftest arm64/hwcap: Add support for FEAT_RPRFM kselftest/arm64: Add FEAT_RPRFM to the hwcap test arm64/hwcap: Add support for SVE 2.1 kselftest/arm64: Add SVE 2.1 to hwcap test Documentation/arm64/elf_hwcaps.rst | 9 +++++++ Documentation/arm64/sve.rst | 1 + arch/arm64/include/asm/hwcap.h | 3 +++ arch/arm64/include/uapi/asm/hwcap.h | 3 +++ arch/arm64/kernel/cpufeature.c | 5 ++++ arch/arm64/kernel/cpuinfo.c | 3 +++ arch/arm64/tools/sysreg | 12 ++++++++- tools/testing/selftests/arm64/abi/hwcap.c | 32 +++++++++++++++++++++++ 8 files changed, 67 insertions(+), 1 deletion(-) base-commit: 9abf2313adc1ca1b6180c508c25f22f9395cc780 -- 2.30.2

3 years

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[RFC PATCH v1 0/2] Fix offset when fault occurs in strncpy_from_kernel_nofault()

by Francis Laniel

Hi. First of all, I hope you are fine and the same for your relatives. This contribution fixes a bug where the byte before the destination address can be reset when a page fault occurs in strncpy_from_kernel_nofault() while copying the first byte from the source address. This bug leaded to kernel panic if a pointer containing the modified address is dereferenced as the pointer does not contain a correct addresss. To fix this bug, we simply reset the current destination byte in a case of a page fault. The proposed fix was tested and validated inside a VM: root@vm-amd64:~# ./share/linux/tools/testing/selftests/bpf/test_progs --name varlen ... #222 varlen:OK Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED Without the patch, the test will fail: root@vm-amd64:~# ./share/linux/tools/testing/selftests/bpf/test_progs --name varlen ... #222 varlen:FAIL Summary: 0/0 PASSED, 0 SKIPPED, 1 FAILED If you see any way to improve this contribution, feel free to share. Alban Crequy (2): maccess: fix writing offset in case of fault in strncpy_from_kernel_nofault() selftests: bpf: add a test when bpf_probe_read_kernel_str() returns EFAULT mm/maccess.c | 2 +- tools/testing/selftests/bpf/prog_tests/varlen.c | 7 +++++++ tools/testing/selftests/bpf/progs/test_varlen.c | 5 +++++ 3 files changed, 13 insertions(+), 1 deletion(-) Best regards and thank you in advance. -- 2.25.1

3 years

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[PATCH v3 00/15] IOMMUFD Generic interface

by Jason Gunthorpe

[ At this point everything is done and I will start putting this work into a git tree and into linux-next with the intention of sending it during the next merge window. I intend to focus the next several weeks on more intensive QA to look at error flows and other things. Hopefully including syzkaller if I'm lucky ] iommufd is the user API to control the IOMMU subsystem as it relates to managing IO page tables that point at user space memory. It takes over from drivers/vfio/vfio_iommu_type1.c (aka the VFIO container) which is the VFIO specific interface for a similar idea. We see a broad need for extended features, some being highly IOMMU device specific: - Binding iommu_domain's to PASID/SSID - Userspace IO page tables, for ARM, x86 and S390 - Kernel bypassed invalidation of user page tables - Re-use of the KVM page table in the IOMMU - Dirty page tracking in the IOMMU - Runtime Increase/Decrease of IOPTE size - PRI support with faults resolved in userspace Many of these HW features exist to support VM use cases - for instance the combination of PASID, PRI and Userspace IO Page Tables allows an implementation of DMA Shared Virtual Addressing (vSVA) within a guest. Dirty tracking enables VM live migration with SRIOV devices and PASID support allow creating "scalable IOV" devices, among other things. As these features are fundamental to a VM platform they need to be uniformly exposed to all the driver families that do DMA into VMs, which is currently VFIO and VDPA. The pre-v1 series proposed re-using the VFIO type 1 data structure, however it was suggested that if we are doing this big update then we should also come with an improved data structure that solves the limitations that VFIO type1 has. Notably this addresses: - Multiple IOAS/'containers' and multiple domains inside a single FD - Single-pin operation no matter how many domains and containers use a page - A fine grained locking scheme supporting user managed concurrency for multi-threaded map/unmap - A pre-registration mechanism to optimize vIOMMU use cases by pre-pinning pages - Extended ioctl API that can manage these new objects and exposes domains directly to user space - domains are sharable between subsystems, eg VFIO and VDPA The bulk of this code is a new data structure design to track how the IOVAs are mapped to PFNs. iommufd intends to be general and consumable by any driver that wants to DMA to userspace. From a driver perspective it can largely be dropped in in-place of iommu_attach_device() and provides a uniform full feature set to all consumers. As this is a larger project this series is the first step. This series provides the iommfd "generic interface" which is designed to be suitable for applications like DPDK and VMM flows that are not optimized to specific HW scenarios. It is close to being a drop in replacement for the existing VFIO type 1 and supports existing qemu based VM flows. Several follow-on series are being prepared: - Patches integrating with qemu in native mode: https://github.com/yiliu1765/qemu/commits/qemu-iommufd-6.0-rc2 - A completed integration with VFIO now exists that covers "emulated" mdev use cases now, and can pass testing with qemu/etc in compatability mode: https://github.com/jgunthorpe/linux/commits/vfio_iommufd - A draft providing system iommu dirty tracking on top of iommufd, including iommu driver implementations: https://github.com/jpemartins/linux/commits/x86-iommufd This pairs with patches for providing a similar API to support VFIO-device tracking to give a complete vfio solution: https://lore.kernel.org/kvm/20220901093853.60194-1-yishaih@nvidia.com/ - Userspace page tables aka 'nested translation' for ARM and Intel iommu drivers: https://github.com/nicolinc/iommufd/commits/iommufd_nesting - "device centric" vfio series to expose the vfio_device FD directly as a normal cdev, and provide an extended API allowing dynamically changing the IOAS binding: https://github.com/yiliu1765/iommufd/commits/iommufd-v6.0-rc2-nesting-0901 - Drafts for PASID and PRI interfaces are included above as well Overall enough work is done now to show the merit of the new API design and at least draft solutions to many of the main problems. Several people have contributed directly to this work: Eric Auger, Joao Martins, Kevin Tian, Lu Baolu, Nicolin Chen, Yi L Liu. Many more have participated in the discussions that lead here, and provided ideas. Thanks to all! The v1/v2 iommufd series has been used to guide a large amount of preparatory work that has now been merged. The general theme is to organize things in a way that makes injecting iommufd natural: - VFIO live migration support with mlx5 and hisi_acc drivers. These series need a dirty tracking solution to be really usable. https://lore.kernel.org/kvm/20220224142024.147653-1-yishaih@nvidia.com/ https://lore.kernel.org/kvm/20220308184902.2242-1-shameerali.kolothum.thodi… - Significantly rework the VFIO gvt mdev and remove struct mdev_parent_ops https://lore.kernel.org/lkml/20220411141403.86980-1-hch@lst.de/ - Rework how PCIe no-snoop blocking works https://lore.kernel.org/kvm/0-v3-2cf356649677+a32-intel_no_snoop_jgg@nvidia… - Consolidate dma ownership into the iommu core code https://lore.kernel.org/linux-iommu/20220418005000.897664-1-baolu.lu@linux.… - Make all vfio driver interfaces use struct vfio_device consistently https://lore.kernel.org/kvm/0-v4-8045e76bf00b+13d-vfio_mdev_no_group_jgg@nv… - Remove the vfio_group from the kvm/vfio interface https://lore.kernel.org/kvm/0-v3-f7729924a7ea+25e33-vfio_kvm_no_group_jgg@n… - Simplify locking in vfio https://lore.kernel.org/kvm/0-v2-d035a1842d81+1bf-vfio_group_locking_jgg@nv… - Remove the vfio notifiter scheme that faces drivers https://lore.kernel.org/kvm/0-v4-681e038e30fd+78-vfio_unmap_notif_jgg@nvidi… - Improve the driver facing API for vfio pin/unpin pages to make the presence of struct page clear https://lore.kernel.org/kvm/20220723020256.30081-1-nicolinc@nvidia.com/ - Clean up in the Intel IOMMU driver https://lore.kernel.org/linux-iommu/20220301020159.633356-1-baolu.lu@linux.… https://lore.kernel.org/linux-iommu/20220510023407.2759143-1-baolu.lu@linux… https://lore.kernel.org/linux-iommu/20220514014322.2927339-1-baolu.lu@linux… https://lore.kernel.org/linux-iommu/20220706025524.2904370-1-baolu.lu@linux… https://lore.kernel.org/linux-iommu/20220702015610.2849494-1-baolu.lu@linux… - Rework s390 vfio drivers https://lore.kernel.org/kvm/20220707135737.720765-1-farman@linux.ibm.com/ - Normalize vfio ioctl handling https://lore.kernel.org/kvm/0-v2-0f9e632d54fb+d6-vfio_ioctl_split_jgg@nvidi… - VFIO API for dirty tracking (aka dma logging) managed inside a PCI device, with mlx5 implementation https://lore.kernel.org/kvm/20220901093853.60194-1-yishaih@nvidia.com - Introduce a struct device sysfs presence for struct vfio_device https://lore.kernel.org/kvm/20220901143747.32858-1-kevin.tian@intel.com/ - Complete restructuring the vfio mdev model https://lore.kernel.org/kvm/20220822062208.152745-1-hch@lst.de/ - Isolate VFIO container code in preperation for iommufd to provide an alternative implementation of it all https://lore.kernel.org/kvm/0-v1-a805b607f1fb+17b-vfio_container_split_jgg@… This is about 215 patches applied since March, thank you to everyone involved in all this work! Currently there are a number of supporting series still in progress: - Simplify and consolidate iommu_domain/device compatability checking https://lore.kernel.org/linux-iommu/20220815181437.28127-1-nicolinc@nvidia.… - Align iommu SVA support with the domain-centric model https://lore.kernel.org/linux-iommu/20220826121141.50743-1-baolu.lu@linux.i… - DMABUF exporter support for VFIO to allow PCI P2P with VFIO https://lore.kernel.org/r/0-v2-472615b3877e+28f7-vfio_dma_buf_jgg@nvidia.com - Start to provide iommu_domain ops for power https://lore.kernel.org/all/20220714081822.3717693-1-aik@ozlabs.ru/ However, these are not necessary for this series to advance. This is on github: https://github.com/jgunthorpe/linux/commits/iommufd v3: - Rebase to v6.1-rc1 - Improve documentation - Use EXPORT_SYMBOL_NS - Fix W1, checkpatch stuff - Revise pages.c to resolve the FIXMEs. Create a interval_tree_double_span_iter which allows a simple expression of the previously problematic algorithms - Consistently use the word 'access' instead of user to refer to an access from an in-kernel user (eg vfio mdev) - Support two forms of rlimit accounting and make the vfio compatible one the default in compatability mode (following series) - Support old VFIO type1 by disabling huge pages and implementing a simple algorithm to split a struct iopt_area - Full implementation of access support, test coverage and optimizations - Complete COPY to be able to copy across contiguous areas. Improve all the algorithms around contiguous areas with a dedicated iterator - Functional ENFORCED_COHERENT support - Support multi-device groups - Lots of smaller changes (the interdiff is 5k lines) v2: https://lore.kernel.org/r/0-v2-f9436d0bde78+4bb-iommufd_jgg@nvidia.com - Rebase to v6.0-rc3 - Improve comments - Change to an iterative destruction approach to avoid cycles - Near rewrite of the vfio facing implementation, supported by a complete implementation on the vfio side - New IOMMU_IOAS_ALLOW_IOVAS API as discussed. Allows userspace to assert that ranges of IOVA must always be mappable. To be used by a VMM that has promised a guest a certain availability of IOVA. May help guide PPC's multi-window implementation. - Rework how unmap_iova works, user can unmap the whole ioas now - The no-snoop / wbinvd support is implemented - Bug fixes - Test suite improvements - Lots of smaller changes (the interdiff is 3k lines) v1: https://lore.kernel.org/r/0-v1-e79cd8d168e8+6-iommufd_jgg@nvidia.com Jason Gunthorpe (13): iommu: Add IOMMU_CAP_ENFORCE_CACHE_COHERENCY interval-tree: Add a utility to iterate over spans in an interval tree iommufd: File descriptor, context, kconfig and makefiles kernel/user: Allow user::locked_vm to be usable for iommufd iommufd: PFN handling for iopt_pages iommufd: Algorithms for PFN storage iommufd: Data structure to provide IOVA to PFN mapping iommufd: IOCTLs for the io_pagetable iommufd: Add a HW pagetable object iommufd: Add kAPI toward external drivers for physical devices iommufd: Add kAPI toward external drivers for kernel access iommufd: vfio container FD ioctl compatibility iommufd: Add a selftest Kevin Tian (1): iommufd: Overview documentation Lu Baolu (1): iommu: Add device-centric DMA ownership interfaces .clang-format | 3 + Documentation/userspace-api/index.rst | 1 + .../userspace-api/ioctl/ioctl-number.rst | 1 + Documentation/userspace-api/iommufd.rst | 222 ++ MAINTAINERS | 10 + drivers/iommu/Kconfig | 1 + drivers/iommu/Makefile | 2 +- drivers/iommu/amd/iommu.c | 2 + drivers/iommu/intel/iommu.c | 4 + drivers/iommu/iommu.c | 116 +- drivers/iommu/iommufd/Kconfig | 24 + drivers/iommu/iommufd/Makefile | 13 + drivers/iommu/iommufd/device.c | 744 +++++++ drivers/iommu/iommufd/double_span.h | 98 + drivers/iommu/iommufd/hw_pagetable.c | 57 + drivers/iommu/iommufd/io_pagetable.c | 1143 +++++++++++ drivers/iommu/iommufd/io_pagetable.h | 240 +++ drivers/iommu/iommufd/ioas.c | 390 ++++ drivers/iommu/iommufd/iommufd_private.h | 273 +++ drivers/iommu/iommufd/iommufd_test.h | 85 + drivers/iommu/iommufd/main.c | 417 ++++ drivers/iommu/iommufd/pages.c | 1803 +++++++++++++++++ drivers/iommu/iommufd/selftest.c | 711 +++++++ drivers/iommu/iommufd/vfio_compat.c | 443 ++++ include/linux/interval_tree.h | 50 + include/linux/iommu.h | 18 + include/linux/iommufd.h | 101 + include/linux/sched/user.h | 2 +- include/uapi/linux/iommufd.h | 330 +++ kernel/user.c | 1 + lib/Kconfig | 4 + lib/interval_tree.c | 132 ++ tools/testing/selftests/Makefile | 1 + tools/testing/selftests/iommu/.gitignore | 2 + tools/testing/selftests/iommu/Makefile | 11 + tools/testing/selftests/iommu/config | 2 + tools/testing/selftests/iommu/iommufd.c | 1715 ++++++++++++++++ 37 files changed, 9145 insertions(+), 27 deletions(-) create mode 100644 Documentation/userspace-api/iommufd.rst create mode 100644 drivers/iommu/iommufd/Kconfig create mode 100644 drivers/iommu/iommufd/Makefile create mode 100644 drivers/iommu/iommufd/device.c create mode 100644 drivers/iommu/iommufd/double_span.h create mode 100644 drivers/iommu/iommufd/hw_pagetable.c create mode 100644 drivers/iommu/iommufd/io_pagetable.c create mode 100644 drivers/iommu/iommufd/io_pagetable.h create mode 100644 drivers/iommu/iommufd/ioas.c create mode 100644 drivers/iommu/iommufd/iommufd_private.h create mode 100644 drivers/iommu/iommufd/iommufd_test.h create mode 100644 drivers/iommu/iommufd/main.c create mode 100644 drivers/iommu/iommufd/pages.c create mode 100644 drivers/iommu/iommufd/selftest.c create mode 100644 drivers/iommu/iommufd/vfio_compat.c create mode 100644 include/linux/iommufd.h create mode 100644 include/uapi/linux/iommufd.h create mode 100644 tools/testing/selftests/iommu/.gitignore create mode 100644 tools/testing/selftests/iommu/Makefile create mode 100644 tools/testing/selftests/iommu/config create mode 100644 tools/testing/selftests/iommu/iommufd.c base-commit: 247f34f7b80357943234f93f247a1ae6b6c3a740 -- 2.38.0

3 years

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Słowa kluczowe do wypozycjonowania

by Adam Charachuta

Dzień dobry, zapoznałem się z Państwa ofertą i z przyjemnością przyznaję, że przyciąga uwagę i zachęca do dalszych rozmów. Pomyślałem, że może mógłbym mieć swój wkład w Państwa rozwój i pomóc dotrzeć z tą ofertą do większego grona odbiorców. Pozycjonuję strony www, dzięki czemu generują świetny ruch w sieci. Możemy porozmawiać w najbliższym czasie? Pozdrawiam Adam Charachuta

3 years

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[PATCH linux-next] selftests/vm: calculate variables in correct order

by Joel Savitz

commit b5ba705c2608 ("selftests/vm: enable running select groups of tests") unintentionally reversed the ordering of some of the lines of run_vmtests.sh that calculate values based on system configuration. Importantly, $hpgsize_MB is determined from $hpgsize_KB, but this later value is not read from /proc/meminfo until later, causing userfaultfd tests to incorrectly fail since $half_ufd_size_MB will always be 0. Switch these statements around into proper order to fix the invocation of the userfaultfd tests that use $half_ufd_size_MB. Suggested-by: Nico Pache <npache(a)redhat.com> Signed-off-by: Joel Savitz <jsavitz(a)redhat.com> --- tools/testing/selftests/vm/run_vmtests.sh | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/tools/testing/selftests/vm/run_vmtests.sh b/tools/testing/selftests/vm/run_vmtests.sh index fff00bb77086..ce52e4f5ff21 100755 --- a/tools/testing/selftests/vm/run_vmtests.sh +++ b/tools/testing/selftests/vm/run_vmtests.sh @@ -82,16 +82,6 @@ test_selected() { fi } -# Simple hugetlbfs tests have a hardcoded minimum requirement of -# huge pages totaling 256MB (262144KB) in size. The userfaultfd -# hugetlb test requires a minimum of 2 * nr_cpus huge pages. Take -# both of these requirements into account and attempt to increase -# number of huge pages available. -nr_cpus=$(nproc) -hpgsize_MB=$((hpgsize_KB / 1024)) -half_ufd_size_MB=$((((nr_cpus * hpgsize_MB + 127) / 128) * 128)) -needmem_KB=$((half_ufd_size_MB * 2 * 1024)) - # get huge pagesize and freepages from /proc/meminfo while read -r name size unit; do if [ "$name" = "HugePages_Free:" ]; then @@ -102,6 +92,16 @@ while read -r name size unit; do fi done < /proc/meminfo +# Simple hugetlbfs tests have a hardcoded minimum requirement of +# huge pages totaling 256MB (262144KB) in size. The userfaultfd +# hugetlb test requires a minimum of 2 * nr_cpus huge pages. Take +# both of these requirements into account and attempt to increase +# number of huge pages available. +nr_cpus=$(nproc) +hpgsize_MB=$((hpgsize_KB / 1024)) +half_ufd_size_MB=$((((nr_cpus * hpgsize_MB + 127) / 128) * 128)) +needmem_KB=$((half_ufd_size_MB * 2 * 1024)) + # set proper nr_hugepages if [ -n "$freepgs" ] && [ -n "$hpgsize_KB" ]; then nr_hugepgs=$(cat /proc/sys/vm/nr_hugepages) -- 2.31.1

3 years

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[PATCH v5 0/3] Implement IOCTL to get and/or the clear info about PTEs

by Muhammad Usama Anjum

Hello, This patch series implements IOCTL on the pagemap procfs file to get the information about the page table entries (PTEs). The following operations are supported in this ioctl: - Get the information if the pages are soft-dirty, file mapped, present or swapped. - Clear the soft-dirty PTE bit of the pages. - Get and clear the soft-dirty PTE bit of the pages atomically. Soft-dirty PTE bit of the memory pages can be read by using the pagemap procfs file. The soft-dirty PTE bit for the whole memory range of the process can be cleared by writing to the clear_refs file. There are other methods to mimic this information entirely in userspace with poor performance: - The mprotect syscall and SIGSEGV handler for bookkeeping - The userfaultfd syscall 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 PTE bit status and clear operation possible. - The soft-dirty PTE bit of only a part of memory cannot be cleared. 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. This syscall is used by games to keep track of dirty pages to process only the dirty pages. The information related to pages if the page is file mapped, present and swapped is required for the CRIU project[2][3]. The addition of the required mask, any mask, excluded mask and return masks are also required for the CRIU project[2]. 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. Some non-dirty pages get marked as dirty because of the kernel's internal activity (such as VMA merging as soft-dirty bit difference isn't considered while deciding to merge VMAs). The dirty bit of the pages is stored in the VMA flags and in the per page flags. If any of these two bits are set, the page is considered to be soft dirty. Suppose you have cleared the soft dirty bit of half of VMA which will be done by splitting the VMA and clearing soft dirty bit flag in the half VMA and the pages in it. Now kernel may decide to merge the VMAs again. So the half VMA becomes dirty again. This splitting/merging costs performance. The application receives a lot of pages which aren't dirty in reality but marked as dirty. Performance is lost again here. Also sometimes user doesn't want the newly allocated memory to be marked as dirty. PAGEMAP_NO_REUSED_REGIONS flag solves both the problems. It is used to not depend on the soft dirty flag in the VMA flags. So VMA splitting and merging doesn't happen. It only depends on the soft dirty bit of the individual pages. Thus by using this flag, there may be a scenerio such that the new memory regions which are just created, doesn't look dirty when seen with the IOCTL, but look dirty when seen from procfs. This seems okay as the user of this flag know the implication of using it. [1] https://lore.kernel.org/lkml/54d4c322-cd6e-eefd-b161-2af2b56aae24@collabora… [2] https://lore.kernel.org/all/YyiDg79flhWoMDZB@gmail.com/ [3] https://lore.kernel.org/all/20221014134802.1361436-1-mdanylo@google.com/ Regards, Muhammad Usama Anjum Muhammad Usama Anjum (3): fs/proc/task_mmu: update functions to clear the soft-dirty PTE bit fs/proc/task_mmu: Implement IOCTL to get and/or the clear info about PTEs selftests: vm: add pagemap ioctl tests fs/proc/task_mmu.c | 396 +++++++++++- include/uapi/linux/fs.h | 53 ++ tools/include/uapi/linux/fs.h | 53 ++ tools/testing/selftests/vm/.gitignore | 1 + tools/testing/selftests/vm/Makefile | 5 +- tools/testing/selftests/vm/pagemap_ioctl.c | 681 +++++++++++++++++++++ 6 files changed, 1156 insertions(+), 33 deletions(-) create mode 100644 tools/testing/selftests/vm/pagemap_ioctl.c -- 2.30.2

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[PATCH] kselftest/arm64: fix array_size.cocci warning

by Kang Minchul

Use ARRAY_SIZE to fix the following coccicheck warnings: tools/testing/selftests/arm64/mte/check_buffer_fill.c:341:20-21: WARNING: Use ARRAY_SIZE tools/testing/selftests/arm64/mte/check_buffer_fill.c:35:20-21: WARNING: Use ARRAY_SIZE tools/testing/selftests/arm64/mte/check_buffer_fill.c:168:20-21: WARNING: Use ARRAY_SIZE tools/testing/selftests/arm64/mte/check_buffer_fill.c:72:20-21: WARNING: Use ARRAY_SIZE tools/testing/selftests/arm64/mte/check_buffer_fill.c:369:25-26: WARNING: Use ARRAY_SIZE Signed-off-by: Kang Minchul <tegongkang(a)gmail.com> --- .../testing/selftests/arm64/mte/check_buffer_fill.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/tools/testing/selftests/arm64/mte/check_buffer_fill.c b/tools/testing/selftests/arm64/mte/check_buffer_fill.c index 75fc482d63b6..1dbbbd47dd50 100644 --- a/tools/testing/selftests/arm64/mte/check_buffer_fill.c +++ b/tools/testing/selftests/arm64/mte/check_buffer_fill.c @@ -32,7 +32,7 @@ static int check_buffer_by_byte(int mem_type, int mode) bool err; mte_switch_mode(mode, MTE_ALLOW_NON_ZERO_TAG); - item = sizeof(sizes)/sizeof(int); + item = ARRAY_SIZE(sizes); for (i = 0; i < item; i++) { ptr = (char *)mte_allocate_memory(sizes[i], mem_type, 0, true); @@ -69,7 +69,7 @@ static int check_buffer_underflow_by_byte(int mem_type, int mode, char *und_ptr = NULL; mte_switch_mode(mode, MTE_ALLOW_NON_ZERO_TAG); - item = sizeof(sizes)/sizeof(int); + item = ARRAY_SIZE(sizes); for (i = 0; i < item; i++) { ptr = (char *)mte_allocate_memory_tag_range(sizes[i], mem_type, 0, underflow_range, 0); @@ -165,7 +165,7 @@ static int check_buffer_overflow_by_byte(int mem_type, int mode, char *over_ptr = NULL; mte_switch_mode(mode, MTE_ALLOW_NON_ZERO_TAG); - item = sizeof(sizes)/sizeof(int); + item = ARRAY_SIZE(sizes); for (i = 0; i < item; i++) { ptr = (char *)mte_allocate_memory_tag_range(sizes[i], mem_type, 0, 0, overflow_range); @@ -338,7 +338,7 @@ static int check_buffer_by_block(int mem_type, int mode) int i, item, result = KSFT_PASS; mte_switch_mode(mode, MTE_ALLOW_NON_ZERO_TAG); - item = sizeof(sizes)/sizeof(int); + item = ARRAY_SIZE(sizes); cur_mte_cxt.fault_valid = false; for (i = 0; i < item; i++) { result = check_buffer_by_block_iterate(mem_type, mode, sizes[i]); @@ -366,7 +366,7 @@ static int check_memory_initial_tags(int mem_type, int mode, int mapping) { char *ptr; int run, fd; - int total = sizeof(sizes)/sizeof(int); + int total = ARRAY_SIZE(sizes); mte_switch_mode(mode, MTE_ALLOW_NON_ZERO_TAG); for (run = 0; run < total; run++) { @@ -404,7 +404,7 @@ int main(int argc, char *argv[]) { int err; size_t page_size = getpagesize(); - int item = sizeof(sizes)/sizeof(int); + int item = ARRAY_SIZE(sizes); sizes[item - 3] = page_size - 1; sizes[item - 2] = page_size; -- 2.34.1

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