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[PATCH V9 0/7] Add NUMA mempolicy support for KVM guest-memfd

by Shivank Garg

This series introduces NUMA-aware memory placement support for KVM guests with guest_memfd memory backends. It builds upon Fuad Tabba's work that enabled host-mapping for guest_memfd memory [1]. == Background == KVM's guest-memfd memory backend currently lacks support for NUMA policy enforcement, causing guest memory allocations to be distributed across host nodes according to kernel's default behavior, irrespective of any policy specified by the VMM. This limitation arises because conventional userspace NUMA control mechanisms like mbind(2) don't work since the memory isn't directly mapped to userspace when allocations occur. Fuad's work [1] provides the necessary mmap capability, and this series leverages it to enable mbind(2). == Implementation == This series implements proper NUMA policy support for guest-memfd by: 1. Adding mempolicy-aware allocation APIs to the filemap layer. 2. Introducing custom inodes (via a dedicated slab-allocated inode cache, kvm_gmem_inode_info) to store NUMA policy and metadata for guest memory. 3. Implementing get/set_policy vm_ops in guest_memfd to support NUMA policy. With these changes, VMMs can now control guest memory placement by mapping guest_memfd file descriptor and using mbind(2) to specify: - Policy modes: default, bind, interleave, or preferred - Host NUMA nodes: List of target nodes for memory allocation These Policies affect only future allocations and do not migrate existing memory. This matches mbind(2)'s default behavior which affects only new allocations unless overridden with MPOL_MF_MOVE/MPOL_MF_MOVE_ALL flags (Not supported for guest_memfd as it is unmovable by design). == Upstream Plan == Phased approach as per David's guest_memfd extension overview [2] and community calls [3]: Phase 1 (this series): 1. Focuses on shared guest_memfd support (non-CoCo VMs). 2. Builds on Fuad's host-mapping work. Phase2 (future work): 1. NUMA support for private guest_memfd (CoCo VMs). 2. Depends on SNP in-place conversion support [4]. This series provides a clean integration path for NUMA-aware memory management for guest_memfd and lays the groundwork for future confidential computing NUMA capabilities. Please review and provide feedback! Thanks, Shivank == Changelog == - v1,v2: Extended the KVM_CREATE_GUEST_MEMFD IOCTL to pass mempolicy. - v3: Introduced fbind() syscall for VMM memory-placement configuration. - v4-v6: Current approach using shared_policy support and vm_ops (based on suggestions from David [5] and guest_memfd bi-weekly upstream call discussion [6]). - v7: Use inodes to store NUMA policy instead of file [7]. - v8: Rebase on top of Fuad's V12: Host mmaping for guest_memfd memory. - v9: Rebase on top of Fuad's V13 and incorporate review comments [1] https://lore.kernel.org/all/20250709105946.4009897-1-tabba@google.com [2] https://lore.kernel.org/all/c1c9591d-218a-495c-957b-ba356c8f8e09@redhat.com [3] https://docs.google.com/document/d/1M6766BzdY1Lhk7LiR5IqVR8B8mG3cr-cxTxOrAo… [4] https://lore.kernel.org/all/20250613005400.3694904-1-michael.roth@amd.com [5] https://lore.kernel.org/all/6fbef654-36e2-4be5-906e-2a648a845278@redhat.com [6] https://lore.kernel.org/all/2b77e055-98ac-43a1-a7ad-9f9065d7f38f@amd.com [7] https://lore.kernel.org/all/diqzbjumm167.fsf@ackerleytng-ctop.c.googlers.com Ackerley Tng (1): KVM: guest_memfd: Use guest mem inodes instead of anonymous inodes Matthew Wilcox (Oracle) (2): mm/filemap: Add NUMA mempolicy support to filemap_alloc_folio() mm/filemap: Extend __filemap_get_folio() to support NUMA memory policies Shivank Garg (4): mm/mempolicy: Export memory policy symbols KVM: guest_memfd: Add slab-allocated inode cache KVM: guest_memfd: Enforce NUMA mempolicy using shared policy KVM: guest_memfd: selftests: Add tests for mmap and NUMA policy support fs/bcachefs/fs-io-buffered.c | 2 +- fs/btrfs/compression.c | 4 +- fs/btrfs/verity.c | 2 +- fs/erofs/zdata.c | 2 +- fs/f2fs/compress.c | 2 +- include/linux/pagemap.h | 18 +- include/uapi/linux/magic.h | 1 + mm/filemap.c | 23 +- mm/mempolicy.c | 6 + mm/readahead.c | 2 +- tools/testing/selftests/kvm/Makefile.kvm | 1 + .../testing/selftests/kvm/guest_memfd_test.c | 122 ++++++++- virt/kvm/guest_memfd.c | 255 ++++++++++++++++-- virt/kvm/kvm_main.c | 7 +- virt/kvm/kvm_mm.h | 10 +- 15 files changed, 408 insertions(+), 49 deletions(-) -- 2.43.0 --- == Earlier Postings == v8: https://lore.kernel.org/all/20250618112935.7629-1-shivankg@amd.com v7: https://lore.kernel.org/all/20250408112402.181574-1-shivankg@amd.com v6: https://lore.kernel.org/all/20250226082549.6034-1-shivankg@amd.com v5: https://lore.kernel.org/all/20250219101559.414878-1-shivankg@amd.com v4: https://lore.kernel.org/all/20250210063227.41125-1-shivankg@amd.com v3: https://lore.kernel.org/all/20241105164549.154700-1-shivankg@amd.com v2: https://lore.kernel.org/all/20240919094438.10987-1-shivankg@amd.com v1: https://lore.kernel.org/all/20240916165743.201087-1-shivankg@amd.com

3 months

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[PATCH] selftests/coredump: Remove the read() that fails the test

by Nam Cao

Resolve a conflict between commit 6a68d28066b6 ("selftests/coredump: Fix "socket_detect_userspace_client" test failure") and commit 994dc26302ed ("selftests/coredump: fix build") The first commit adds a read() to wait for write() from another thread to finish. But the second commit removes the write(). Now that the two commits are in the same tree, the read() now gets EOF and the test fails. Remove this read() so that the test passes. Signed-off-by: Nam Cao <namcao(a)linutronix.de> --- tools/testing/selftests/coredump/stackdump_test.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/tools/testing/selftests/coredump/stackdump_test.c b/tools/testing/selftests/coredump/stackdump_test.c index 5a5a7a5f7e1d..a4ac80bb1003 100644 --- a/tools/testing/selftests/coredump/stackdump_test.c +++ b/tools/testing/selftests/coredump/stackdump_test.c @@ -446,9 +446,6 @@ TEST_F(coredump, socket_detect_userspace_client) if (info.coredump_mask & PIDFD_COREDUMPED) goto out; - if (read(fd_coredump, &c, 1) < 1) - goto out; - exit_code = EXIT_SUCCESS; out: if (fd_peer_pidfd >= 0) -- 2.39.5

3 months

1
0
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[PATCH v5] kunit: qemu_configs: Add MIPS configurations

by Thomas Weißschuh

Add basic support to run various MIPS variants via kunit_tool using the virtualized malta platform. Signed-off-by: Thomas Weißschuh <thomas.weissschuh(a)linutronix.de> Reviewed-by: David Gow <davidgow(a)google.com> --- Changes in v5: - Rebase on v6.17-rc1 - Drop alreayd applied patch to MIPS core code and related CCs - Link to v4: https://lore.kernel.org/r/20250611-kunit-mips-v4-0-1d8997fb2ae4@linutronix.… Changes in v4: - Rebase on v6.16-rc1 - Pick up reviews from David - Clarify that GIC page is linked to vDSO - Link to v3: https://lore.kernel.org/r/20250415-kunit-mips-v3-0-4ec2461b5a7e@linutronix.… Changes in v3: - Also skip VDSO_RANDOMIZE_SIZE adjustment for kthreads - Link to v2: https://lore.kernel.org/r/20250414-kunit-mips-v2-0-4cf01e1a29e6@linutronix.… Changes in v2: - Fix usercopy kunit test by handling ABI-less tasks in stack_top() - Drop change to mm initialization. The broken test is not built by default anymore. - Link to v1: https://lore.kernel.org/r/20250212-kunit-mips-v1-0-eb49c9d76615@linutronix.… --- tools/testing/kunit/qemu_configs/mips.py | 18 ++++++++++++++++++ tools/testing/kunit/qemu_configs/mips64.py | 19 +++++++++++++++++++ tools/testing/kunit/qemu_configs/mips64el.py | 19 +++++++++++++++++++ tools/testing/kunit/qemu_configs/mipsel.py | 18 ++++++++++++++++++ 4 files changed, 74 insertions(+) diff --git a/tools/testing/kunit/qemu_configs/mips.py b/tools/testing/kunit/qemu_configs/mips.py new file mode 100644 index 0000000000000000000000000000000000000000..8899ac157b30bd2ee847eacd5b90fe6ad4e5fb04 --- /dev/null +++ b/tools/testing/kunit/qemu_configs/mips.py @@ -0,0 +1,18 @@ +# SPDX-License-Identifier: GPL-2.0 + +from ..qemu_config import QemuArchParams + +QEMU_ARCH = QemuArchParams(linux_arch='mips', + kconfig=''' +CONFIG_32BIT=y +CONFIG_CPU_BIG_ENDIAN=y +CONFIG_MIPS_MALTA=y +CONFIG_SERIAL_8250=y +CONFIG_SERIAL_8250_CONSOLE=y +CONFIG_POWER_RESET=y +CONFIG_POWER_RESET_SYSCON=y +''', + qemu_arch='mips', + kernel_path='vmlinuz', + kernel_command_line='console=ttyS0', + extra_qemu_params=['-M', 'malta']) diff --git a/tools/testing/kunit/qemu_configs/mips64.py b/tools/testing/kunit/qemu_configs/mips64.py new file mode 100644 index 0000000000000000000000000000000000000000..1478aed05b94da4914f34c6a8affdcfe34eb88ea --- /dev/null +++ b/tools/testing/kunit/qemu_configs/mips64.py @@ -0,0 +1,19 @@ +# SPDX-License-Identifier: GPL-2.0 + +from ..qemu_config import QemuArchParams + +QEMU_ARCH = QemuArchParams(linux_arch='mips', + kconfig=''' +CONFIG_CPU_MIPS64_R2=y +CONFIG_64BIT=y +CONFIG_CPU_BIG_ENDIAN=y +CONFIG_MIPS_MALTA=y +CONFIG_SERIAL_8250=y +CONFIG_SERIAL_8250_CONSOLE=y +CONFIG_POWER_RESET=y +CONFIG_POWER_RESET_SYSCON=y +''', + qemu_arch='mips64', + kernel_path='vmlinuz', + kernel_command_line='console=ttyS0', + extra_qemu_params=['-M', 'malta', '-cpu', '5KEc']) diff --git a/tools/testing/kunit/qemu_configs/mips64el.py b/tools/testing/kunit/qemu_configs/mips64el.py new file mode 100644 index 0000000000000000000000000000000000000000..300c711d7a82500b2ebcb4cf1467b6f72b5c17aa --- /dev/null +++ b/tools/testing/kunit/qemu_configs/mips64el.py @@ -0,0 +1,19 @@ +# SPDX-License-Identifier: GPL-2.0 + +from ..qemu_config import QemuArchParams + +QEMU_ARCH = QemuArchParams(linux_arch='mips', + kconfig=''' +CONFIG_CPU_MIPS64_R2=y +CONFIG_64BIT=y +CONFIG_CPU_LITTLE_ENDIAN=y +CONFIG_MIPS_MALTA=y +CONFIG_SERIAL_8250=y +CONFIG_SERIAL_8250_CONSOLE=y +CONFIG_POWER_RESET=y +CONFIG_POWER_RESET_SYSCON=y +''', + qemu_arch='mips64el', + kernel_path='vmlinuz', + kernel_command_line='console=ttyS0', + extra_qemu_params=['-M', 'malta', '-cpu', '5KEc']) diff --git a/tools/testing/kunit/qemu_configs/mipsel.py b/tools/testing/kunit/qemu_configs/mipsel.py new file mode 100644 index 0000000000000000000000000000000000000000..3d3543315b45776d0e77fb5c00c8c0a89eafdffd --- /dev/null +++ b/tools/testing/kunit/qemu_configs/mipsel.py @@ -0,0 +1,18 @@ +# SPDX-License-Identifier: GPL-2.0 + +from ..qemu_config import QemuArchParams + +QEMU_ARCH = QemuArchParams(linux_arch='mips', + kconfig=''' +CONFIG_32BIT=y +CONFIG_CPU_LITTLE_ENDIAN=y +CONFIG_MIPS_MALTA=y +CONFIG_SERIAL_8250=y +CONFIG_SERIAL_8250_CONSOLE=y +CONFIG_POWER_RESET=y +CONFIG_POWER_RESET_SYSCON=y +''', + qemu_arch='mipsel', + kernel_path='vmlinuz', + kernel_command_line='console=ttyS0', + extra_qemu_params=['-M', 'malta']) --- base-commit: 5606dd26f0b0d614e64a51e68c86e5066f9a5b71 change-id: 20241014-kunit-mips-e4fe1c265ed7 Best regards, -- Thomas Weißschuh <thomas.weissschuh(a)linutronix.de>

3 months

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[PATCH v2] kunit: Enable PCI on UML without triggering WARN()

by Thomas Weißschuh

Various KUnit tests require PCI infrastructure to work. All normal platforms enable PCI by default, but UML does not. Enabling PCI from .kunitconfig files is problematic as it would not be portable. So in commit 6fc3a8636a7b ("kunit: tool: Enable virtio/PCI by default on UML") PCI was enabled by way of CONFIG_UML_PCI_OVER_VIRTIO=y. However CONFIG_UML_PCI_OVER_VIRTIO requires additional configuration of CONFIG_UML_PCI_OVER_VIRTIO_DEVICE_ID or will otherwise trigger a WARN() in virtio_pcidev_init(). However there is no one correct value for UML_PCI_OVER_VIRTIO_DEVICE_ID which could be used by default. This warning is confusing when debugging test failures. On the other hand, the functionality of CONFIG_UML_PCI_OVER_VIRTIO is not used at all, given that it is completely non-functional as indicated by the WARN() in question. Instead it is only used as a way to enable CONFIG_UML_PCI which itself is not directly configurable. Instead of going through CONFIG_UML_PCI_OVER_VIRTIO, introduce a custom configuration option which enables CONFIG_UML_PCI without triggering warnings or building dead code. Signed-off-by: Thomas Weißschuh <thomas.weissschuh(a)linutronix.de> Reviewed-by: Johannes Berg <johannes(a)sipsolutions.net> --- Changes in v2: - Rebase onto v6.17-rc1 - Pick up review from Johannes - Link to v1: https://lore.kernel.org/r/20250627-kunit-uml-pci-v1-1-a622fa445e58@linutron… --- lib/kunit/Kconfig | 7 +++++++ tools/testing/kunit/configs/arch_uml.config | 5 ++--- 2 files changed, 9 insertions(+), 3 deletions(-) diff --git a/lib/kunit/Kconfig b/lib/kunit/Kconfig index c10ede4b1d2201d5f8cddeb71cc5096e21be9b6a..1823539e96da30e165fa8d395ccbd3f6754c836e 100644 --- a/lib/kunit/Kconfig +++ b/lib/kunit/Kconfig @@ -106,4 +106,11 @@ config KUNIT_DEFAULT_TIMEOUT If unsure, the default timeout of 300 seconds is suitable for most cases. +config KUNIT_UML_PCI + bool "KUnit UML PCI Support" + depends on UML + select UML_PCI + help + Enables the PCI subsystem on UML for use by KUnit tests. + endif # KUNIT diff --git a/tools/testing/kunit/configs/arch_uml.config b/tools/testing/kunit/configs/arch_uml.config index 54ad8972681a2cc724e6122b19407188910b9025..28edf816aa70e6f408d9486efff8898df79ee090 100644 --- a/tools/testing/kunit/configs/arch_uml.config +++ b/tools/testing/kunit/configs/arch_uml.config @@ -1,8 +1,7 @@ # Config options which are added to UML builds by default -# Enable virtio/pci, as a lot of tests require it. -CONFIG_VIRTIO_UML=y -CONFIG_UML_PCI_OVER_VIRTIO=y +# Enable pci, as a lot of tests require it. +CONFIG_KUNIT_UML_PCI=y # Enable FORTIFY_SOURCE for wider checking. CONFIG_FORTIFY_SOURCE=y --- base-commit: 8f5ae30d69d7543eee0d70083daf4de8fe15d585 change-id: 20250626-kunit-uml-pci-a2b687553746 Best regards, -- Thomas Weißschuh <thomas.weissschuh(a)linutronix.de>

3 months

1
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[linus:master] [selftests/fs/mount] c6d9775c20: kernel-selftests.filesystems/mount-notify.make.fail

by kernel test robot

Hello, kernel test robot noticed "kernel-selftests.filesystems/mount-notify.make.fail" on: commit: c6d9775c2066a37385e784ee2e0ce83bd6644610 ("selftests/fs/mount-notify: build with tools include dir") https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master [test failed on linus/master 6e64f4580381e32c06ee146ca807c555b8f73e24] [test failed on linux-next/master 442d93313caebc8ccd6d53f4572c50732a95bc48] in testcase: kernel-selftests version: kernel-selftests-x86_64-186f3edfdd41-1_20250803 with following parameters: group: filesystems config: x86_64-rhel-9.4-kselftests compiler: gcc-12 test machine: 36 threads 1 sockets Intel(R) Core(TM) i9-9980XE CPU @ 3.00GHz (Skylake) with 32G memory (please refer to attached dmesg/kmsg for entire log/backtrace) If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot <oliver.sang(a)intel.com> | Closes: https://lore.kernel.org/oe-lkp/202508110628.65069d92-lkp@intel.com 2025-08-06 18:21:58 make -j36 TARGETS=filesystems/mount-notify make[1]: Entering directory '/usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-c6d9775c2066a37385e784ee2e0ce83bd6644610/tools/testing/selftests/filesystems/mount-notify' CC mount-notify_test mount-notify_test.c:21:3: error: conflicting types for ‘__kernel_fsid_t’; have ‘struct <anonymous>’ 21 | } __kernel_fsid_t; | ^~~~~~~~~~~~~~~ In file included from /usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-c6d9775c2066a37385e784ee2e0ce83bd6644610/usr/include/asm/posix_types_64.h:18, from /usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-c6d9775c2066a37385e784ee2e0ce83bd6644610/usr/include/asm/posix_types.h:7, from /usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-c6d9775c2066a37385e784ee2e0ce83bd6644610/usr/include/linux/posix_types.h:36, from /usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-c6d9775c2066a37385e784ee2e0ce83bd6644610/usr/include/linux/types.h:9, from /usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-c6d9775c2066a37385e784ee2e0ce83bd6644610/usr/include/linux/stat.h:5, from /usr/include/x86_64-linux-gnu/bits/statx.h:31, from /usr/include/x86_64-linux-gnu/sys/stat.h:465, from mount-notify_test.c:9: /usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-c6d9775c2066a37385e784ee2e0ce83bd6644610/usr/include/asm-generic/posix_types.h:81:3: note: previous declaration of ‘__kernel_fsid_t’ with type ‘__kernel_fsid_t’ 81 | } __kernel_fsid_t; | ^~~~~~~~~~~~~~~ make[1]: *** [../../lib.mk:222: /usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-c6d9775c2066a37385e784ee2e0ce83bd6644610/tools/testing/selftests/filesystems/mount-notify/mount-notify_test] Error 1 make[1]: Leaving directory '/usr/src/perf_selftests-x86_64-rhel-9.4-kselftests-c6d9775c2066a37385e784ee2e0ce83bd6644610/tools/testing/selftests/filesystems/mount-notify' make: *** [Makefile:203: all] Error 2 The kernel config and materials to reproduce are available at: https://download.01.org/0day-ci/archive/20250811/202508110628.65069d92-lkp@… -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki

3 months

1
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[PATCH] selftests/mm: do check_huge_anon() with a number been passed in

by Wei Yang

Currently it hard coded the number of hugepage to check for check_huge_anon(), but we already have the number passed in. Do the check based on the number of hugepage passed in is more reasonable. Signed-off-by: Wei Yang <richard.weiyang(a)gmail.com> --- tools/testing/selftests/mm/split_huge_page_test.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/mm/split_huge_page_test.c b/tools/testing/selftests/mm/split_huge_page_test.c index 44a3f8a58806..bf40e6b121ab 100644 --- a/tools/testing/selftests/mm/split_huge_page_test.c +++ b/tools/testing/selftests/mm/split_huge_page_test.c @@ -111,7 +111,7 @@ static void verify_rss_anon_split_huge_page_all_zeroes(char *one_page, int nr_hp unsigned long rss_anon_before, rss_anon_after; size_t i; - if (!check_huge_anon(one_page, 4, pmd_pagesize)) + if (!check_huge_anon(one_page, nr_hpages, pmd_pagesize)) ksft_exit_fail_msg("No THP is allocated\n"); rss_anon_before = rss_anon(); -- 2.34.1

3 months

8
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[PATCH v3 00/13] stackleak: Support Clang stack depth tracking

by Kees Cook

v3: - split up and drop __init vs inline patches that went via arch trees - apply feedback about preferring __init to __always_inline - incorporate Ritesh Harjani's patch for __init cleanups in powerpc - wider build testing on older compilers v2: https://lore.kernel.org/lkml/20250523043251.it.550-kees@kernel.org/ v1: https://lore.kernel.org/lkml/20250507180852.work.231-kees@kernel.org/ Hi, As part of looking at what GCC plugins could be replaced with Clang implementations, this series uses the recently landed stack depth tracking callback in Clang[1] to implement the stackleak feature. Since the Clang feature is now landed, I'm moving this out of RFC to a v1. Since this touches a lot of arch-specific Makefiles, I tried to trim the CC list down to just mailing lists in those cases, otherwise the CC was giant. Thanks! -Kees [1] https://clang.llvm.org/docs/SanitizerCoverage.html#tracing-stack-depth Kees Cook (12): stackleak: Rename STACKLEAK to KSTACK_ERASE stackleak: Rename stackleak_track_stack to __sanitizer_cov_stack_depth stackleak: Split KSTACK_ERASE_CFLAGS from GCC_PLUGINS_CFLAGS x86: Handle KCOV __init vs inline mismatches arm: Handle KCOV __init vs inline mismatches arm64: Handle KCOV __init vs inline mismatches s390: Handle KCOV __init vs inline mismatches mips: Handle KCOV __init vs inline mismatch init.h: Disable sanitizer coverage for __init and __head kstack_erase: Support Clang stack depth tracking configs/hardening: Enable CONFIG_KSTACK_ERASE configs/hardening: Enable CONFIG_INIT_ON_FREE_DEFAULT_ON Ritesh Harjani (IBM) (1): powerpc/mm/book3s64: Move kfence and debug_pagealloc related calls to __init section arch/Kconfig | 4 +- arch/arm/Kconfig | 2 +- arch/arm64/Kconfig | 2 +- arch/riscv/Kconfig | 2 +- arch/s390/Kconfig | 2 +- arch/x86/Kconfig | 2 +- security/Kconfig.hardening | 45 +++++++++------- Makefile | 1 + arch/arm/boot/compressed/Makefile | 2 +- arch/arm/vdso/Makefile | 2 +- arch/arm64/kernel/pi/Makefile | 2 +- arch/arm64/kernel/vdso/Makefile | 3 +- arch/arm64/kvm/hyp/nvhe/Makefile | 2 +- arch/riscv/kernel/pi/Makefile | 2 +- arch/riscv/purgatory/Makefile | 2 +- arch/sparc/vdso/Makefile | 3 +- arch/x86/entry/vdso/Makefile | 3 +- arch/x86/purgatory/Makefile | 2 +- drivers/firmware/efi/libstub/Makefile | 8 +-- drivers/misc/lkdtm/Makefile | 2 +- kernel/Makefile | 10 ++-- lib/Makefile | 2 +- scripts/Makefile.gcc-plugins | 16 +----- scripts/Makefile.kstack_erase | 21 ++++++++ scripts/gcc-plugins/stackleak_plugin.c | 52 +++++++++---------- Documentation/admin-guide/sysctl/kernel.rst | 4 +- Documentation/arch/x86/x86_64/mm.rst | 2 +- Documentation/security/self-protection.rst | 2 +- .../zh_CN/security/self-protection.rst | 2 +- arch/arm64/include/asm/acpi.h | 2 +- arch/mips/include/asm/time.h | 2 +- arch/s390/hypfs/hypfs.h | 2 +- arch/s390/hypfs/hypfs_diag.h | 2 +- arch/x86/entry/calling.h | 4 +- arch/x86/include/asm/acpi.h | 4 +- arch/x86/include/asm/init.h | 2 +- arch/x86/include/asm/realmode.h | 2 +- include/linux/acpi.h | 4 +- include/linux/bootconfig.h | 2 +- include/linux/efi.h | 2 +- include/linux/init.h | 4 +- include/linux/{stackleak.h => kstack_erase.h} | 20 +++---- include/linux/memblock.h | 2 +- include/linux/mfd/dbx500-prcmu.h | 2 +- include/linux/sched.h | 4 +- include/linux/smp.h | 2 +- arch/arm/kernel/entry-common.S | 2 +- arch/arm64/kernel/entry.S | 2 +- arch/riscv/kernel/entry.S | 2 +- arch/s390/kernel/entry.S | 2 +- arch/arm/mm/cache-feroceon-l2.c | 2 +- arch/arm/mm/cache-tauros2.c | 2 +- arch/powerpc/mm/book3s64/hash_utils.c | 6 +-- arch/powerpc/mm/book3s64/radix_pgtable.c | 4 +- arch/s390/mm/init.c | 2 +- arch/x86/kernel/kvm.c | 2 +- arch/x86/mm/init_64.c | 2 +- drivers/clocksource/timer-orion.c | 2 +- .../lkdtm/{stackleak.c => kstack_erase.c} | 26 +++++----- drivers/soc/ti/pm33xx.c | 2 +- fs/proc/base.c | 6 +-- kernel/fork.c | 2 +- kernel/kexec_handover.c | 4 +- kernel/{stackleak.c => kstack_erase.c} | 22 ++++---- tools/objtool/check.c | 4 +- tools/testing/selftests/lkdtm/config | 2 +- MAINTAINERS | 6 ++- kernel/configs/hardening.config | 6 +++ 68 files changed, 204 insertions(+), 172 deletions(-) create mode 100644 scripts/Makefile.kstack_erase rename include/linux/{stackleak.h => kstack_erase.h} (81%) rename drivers/misc/lkdtm/{stackleak.c => kstack_erase.c} (89%) rename kernel/{stackleak.c => kstack_erase.c} (87%) -- 2.34.1

3 months

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[PATCH v8 00/14] riscv: add SBI FWFT misaligned exception delegation support

by Clément Léger

The SBI Firmware Feature extension allows the S-mode to request some specific features (either hardware or software) to be enabled. This series uses this extension to request misaligned access exception delegation to S-mode in order to let the kernel handle it. It also adds support for the KVM FWFT SBI extension based on the misaligned access handling infrastructure. FWFT SBI extension is part of the SBI V3.0 specifications [1]. It can be tested using the qemu provided at [2] which contains the series from [3]. Upstream kvm-unit-tests can be used inside kvm to tests the correct delegation of misaligned exceptions. Upstream OpenSBI can be used. Note: Since SBI V3.0 is not yet ratified, FWFT extension API is split between interface only and implementation, allowing to pick only the interface which do not have hard dependencies on SBI. The tests can be run using the kselftest from series [4]. $ qemu-system-riscv64 \ -cpu rv64,trap-misaligned-access=true,v=true \ -M virt \ -m 1024M \ -bios fw_dynamic.bin \ -kernel Image ... # ./misaligned TAP version 13 1..23 # Starting 23 tests from 1 test cases. # RUN global.gp_load_lh ... # OK global.gp_load_lh ok 1 global.gp_load_lh # RUN global.gp_load_lhu ... # OK global.gp_load_lhu ok 2 global.gp_load_lhu # RUN global.gp_load_lw ... # OK global.gp_load_lw ok 3 global.gp_load_lw # RUN global.gp_load_lwu ... # OK global.gp_load_lwu ok 4 global.gp_load_lwu # RUN global.gp_load_ld ... # OK global.gp_load_ld ok 5 global.gp_load_ld # RUN global.gp_load_c_lw ... # OK global.gp_load_c_lw ok 6 global.gp_load_c_lw # RUN global.gp_load_c_ld ... # OK global.gp_load_c_ld ok 7 global.gp_load_c_ld # RUN global.gp_load_c_ldsp ... # OK global.gp_load_c_ldsp ok 8 global.gp_load_c_ldsp # RUN global.gp_load_sh ... # OK global.gp_load_sh ok 9 global.gp_load_sh # RUN global.gp_load_sw ... # OK global.gp_load_sw ok 10 global.gp_load_sw # RUN global.gp_load_sd ... # OK global.gp_load_sd ok 11 global.gp_load_sd # RUN global.gp_load_c_sw ... # OK global.gp_load_c_sw ok 12 global.gp_load_c_sw # RUN global.gp_load_c_sd ... # OK global.gp_load_c_sd ok 13 global.gp_load_c_sd # RUN global.gp_load_c_sdsp ... # OK global.gp_load_c_sdsp ok 14 global.gp_load_c_sdsp # RUN global.fpu_load_flw ... # OK global.fpu_load_flw ok 15 global.fpu_load_flw # RUN global.fpu_load_fld ... # OK global.fpu_load_fld ok 16 global.fpu_load_fld # RUN global.fpu_load_c_fld ... # OK global.fpu_load_c_fld ok 17 global.fpu_load_c_fld # RUN global.fpu_load_c_fldsp ... # OK global.fpu_load_c_fldsp ok 18 global.fpu_load_c_fldsp # RUN global.fpu_store_fsw ... # OK global.fpu_store_fsw ok 19 global.fpu_store_fsw # RUN global.fpu_store_fsd ... # OK global.fpu_store_fsd ok 20 global.fpu_store_fsd # RUN global.fpu_store_c_fsd ... # OK global.fpu_store_c_fsd ok 21 global.fpu_store_c_fsd # RUN global.fpu_store_c_fsdsp ... # OK global.fpu_store_c_fsdsp ok 22 global.fpu_store_c_fsdsp # RUN global.gen_sigbus ... [12797.988647] misaligned[618]: unhandled signal 7 code 0x1 at 0x0000000000014dc0 in misaligned[4dc0,10000+76000] [12797.988990] CPU: 0 UID: 0 PID: 618 Comm: misaligned Not tainted 6.13.0-rc6-00008-g4ec4468967c9-dirty #51 [12797.989169] Hardware name: riscv-virtio,qemu (DT) [12797.989264] epc : 0000000000014dc0 ra : 0000000000014d00 sp : 00007fffe165d100 [12797.989407] gp : 000000000008f6e8 tp : 0000000000095760 t0 : 0000000000000008 [12797.989544] t1 : 00000000000965d8 t2 : 000000000008e830 s0 : 00007fffe165d160 [12797.989692] s1 : 000000000000001a a0 : 0000000000000000 a1 : 0000000000000002 [12797.989831] a2 : 0000000000000000 a3 : 0000000000000000 a4 : ffffffffdeadbeef [12797.989964] a5 : 000000000008ef61 a6 : 626769735f6e0000 a7 : fffffffffffff000 [12797.990094] s2 : 0000000000000001 s3 : 00007fffe165d838 s4 : 00007fffe165d848 [12797.990238] s5 : 000000000000001a s6 : 0000000000010442 s7 : 0000000000010200 [12797.990391] s8 : 000000000000003a s9 : 0000000000094508 s10: 0000000000000000 [12797.990526] s11: 0000555567460668 t3 : 00007fffe165d070 t4 : 00000000000965d0 [12797.990656] t5 : fefefefefefefeff t6 : 0000000000000073 [12797.990756] status: 0000000200004020 badaddr: 000000000008ef61 cause: 0000000000000006 [12797.990911] Code: 8793 8791 3423 fcf4 3783 fc84 c737 dead 0713 eef7 (c398) 0001 # OK global.gen_sigbus ok 23 global.gen_sigbus # PASSED: 23 / 23 tests passed. # Totals: pass:23 fail:0 xfail:0 xpass:0 skip:0 error:0 With kvm-tools: # lkvm run -k sbi.flat -m 128 Info: # lkvm run -k sbi.flat -m 128 -c 1 --name guest-97 Info: Removed ghost socket file "/root/.lkvm//guest-97.sock". ########################################################################## # kvm-unit-tests ########################################################################## ... [test messages elided] PASS: sbi: fwft: FWFT extension probing no error PASS: sbi: fwft: get/set reserved feature 0x6 error == SBI_ERR_DENIED PASS: sbi: fwft: get/set reserved feature 0x3fffffff error == SBI_ERR_DENIED PASS: sbi: fwft: get/set reserved feature 0x80000000 error == SBI_ERR_DENIED PASS: sbi: fwft: get/set reserved feature 0xbfffffff error == SBI_ERR_DENIED PASS: sbi: fwft: misaligned_deleg: Get misaligned deleg feature no error PASS: sbi: fwft: misaligned_deleg: Set misaligned deleg feature invalid value error PASS: sbi: fwft: misaligned_deleg: Set misaligned deleg feature invalid value error PASS: sbi: fwft: misaligned_deleg: Set misaligned deleg feature value no error PASS: sbi: fwft: misaligned_deleg: Set misaligned deleg feature value 0 PASS: sbi: fwft: misaligned_deleg: Set misaligned deleg feature value no error PASS: sbi: fwft: misaligned_deleg: Set misaligned deleg feature value 1 PASS: sbi: fwft: misaligned_deleg: Verify misaligned load exception trap in supervisor SUMMARY: 50 tests, 2 unexpected failures, 12 skipped This series is available at [5]. Link: https://github.com/riscv-non-isa/riscv-sbi-doc/releases/download/vv3.0-rc2/… [1] Link: https://github.com/rivosinc/qemu/tree/dev/cleger/misaligned [2] Link: https://lore.kernel.org/all/20241211211933.198792-3-fkonrad@amd.com/T/ [3] Link: https://lore.kernel.org/linux-riscv/20250414123543.1615478-1-cleger@rivosin… [4] Link: https://github.com/rivosinc/linux/tree/dev/cleger/fwft [5] --- V8: - Move misaligned_access_speed under CONFIG_RISCV_MISALIGNED and add a separate commit for that. V7: - Fix ifdefery build problems - Move sbi_fwft_is_supported with fwft_set_req struct - Added Atish Reviewed-by - Updated KVM vcpu cfg hedeleg value in set_delegation - Changed SBI ETIME error mapping to ETIMEDOUT - Fixed a few typo reported by Alok V6: - Rename FWFT interface to remove "_local" - Fix test for MEDELEG values in KVM FWFT support - Add __init for unaligned_access_init() - Rebased on master V5: - Return ERANGE as mapping for SBI_ERR_BAD_RANGE - Removed unused sbi_fwft_get() - Fix kernel for sbi_fwft_local_set_cpumask() - Fix indentation for sbi_fwft_local_set() - Remove spurious space in kvm_sbi_fwft_ops. - Rebased on origin/master - Remove fixes commits and sent them as a separate series [4] V4: - Check SBI version 3.0 instead of 2.0 for FWFT presence - Use long for kvm_sbi_fwft operation return value - Init KVM sbi extension even if default_disabled - Remove revert_on_fail parameter for sbi_fwft_feature_set(). - Fix comments for sbi_fwft_set/get() - Only handle local features (there are no globals yet in the spec) - Add new SBI errors to sbi_err_map_linux_errno() V3: - Added comment about kvm sbi fwft supported/set/get callback requirements - Move struct kvm_sbi_fwft_feature in kvm_sbi_fwft.c - Add a FWFT interface V2: - Added Kselftest for misaligned testing - Added get_user() usage instead of __get_user() - Reenable interrupt when possible in misaligned access handling - Document that riscv supports unaligned-traps - Fix KVM extension state when an init function is present - Rework SBI misaligned accesses trap delegation code - Added support for CPU hotplugging - Added KVM SBI reset callback - Added reset for KVM SBI FWFT lock - Return SBI_ERR_DENIED_LOCKED when LOCK flag is set Clément Léger (14): riscv: sbi: add Firmware Feature (FWFT) SBI extensions definitions riscv: sbi: remove useless parenthesis riscv: sbi: add new SBI error mappings riscv: sbi: add FWFT extension interface riscv: sbi: add SBI FWFT extension calls riscv: misaligned: request misaligned exception from SBI riscv: misaligned: use on_each_cpu() for scalar misaligned access probing riscv: misaligned: declare misaligned_access_speed under CONFIG_RISCV_MISALIGNED riscv: misaligned: move emulated access uniformity check in a function riscv: misaligned: add a function to check misalign trap delegability RISC-V: KVM: add SBI extension init()/deinit() functions RISC-V: KVM: add SBI extension reset callback RISC-V: KVM: add support for FWFT SBI extension RISC-V: KVM: add support for SBI_FWFT_MISALIGNED_DELEG arch/riscv/include/asm/cpufeature.h | 14 +- arch/riscv/include/asm/kvm_host.h | 5 +- arch/riscv/include/asm/kvm_vcpu_sbi.h | 12 + arch/riscv/include/asm/kvm_vcpu_sbi_fwft.h | 29 +++ arch/riscv/include/asm/sbi.h | 60 +++++ arch/riscv/include/uapi/asm/kvm.h | 1 + arch/riscv/kernel/sbi.c | 81 ++++++- arch/riscv/kernel/traps_misaligned.c | 112 ++++++++- arch/riscv/kernel/unaligned_access_speed.c | 8 +- arch/riscv/kvm/Makefile | 1 + arch/riscv/kvm/vcpu.c | 4 +- arch/riscv/kvm/vcpu_sbi.c | 54 +++++ arch/riscv/kvm/vcpu_sbi_fwft.c | 257 +++++++++++++++++++++ arch/riscv/kvm/vcpu_sbi_sta.c | 3 +- 14 files changed, 620 insertions(+), 21 deletions(-) create mode 100644 arch/riscv/include/asm/kvm_vcpu_sbi_fwft.h create mode 100644 arch/riscv/kvm/vcpu_sbi_fwft.c -- 2.49.0

3 months

9
38
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[PATCH -rebased 15/15] selftests/sched_ext: Add test for DL server total_bw consistency

by Joel Fernandes

Add a new kselftest to verify that the total_bw value in /sys/kernel/debug/sched/debug remains consistent across all CPUs under different sched_ext BPF program states: 1. Before a BPF scheduler is loaded 2. While a BPF scheduler is loaded and active 3. After a BPF scheduler is unloaded The test runs CPU stress threads to ensure DL server bandwidth values stabilize before checking consistency. This helps catch potential issues with DL server bandwidth accounting during sched_ext transitions. Signed-off-by: Joel Fernandes <joelagnelf(a)nvidia.com> --- tools/testing/selftests/sched_ext/Makefile | 1 + tools/testing/selftests/sched_ext/total_bw.c | 282 +++++++++++++++++++ 2 files changed, 283 insertions(+) create mode 100644 tools/testing/selftests/sched_ext/total_bw.c diff --git a/tools/testing/selftests/sched_ext/Makefile b/tools/testing/selftests/sched_ext/Makefile index f0a8cba3a99f..d48be158b0a1 100644 --- a/tools/testing/selftests/sched_ext/Makefile +++ b/tools/testing/selftests/sched_ext/Makefile @@ -184,6 +184,7 @@ auto-test-targets := \ select_cpu_vtime \ rt_stall \ test_example \ + total_bw \ testcase-targets := $(addsuffix .o,$(addprefix $(SCXOBJ_DIR)/,$(auto-test-targets))) diff --git a/tools/testing/selftests/sched_ext/total_bw.c b/tools/testing/selftests/sched_ext/total_bw.c new file mode 100644 index 000000000000..d70852cee358 --- /dev/null +++ b/tools/testing/selftests/sched_ext/total_bw.c @@ -0,0 +1,282 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Test to verify that total_bw value remains consistent across all CPUs + * in different BPF program states. + * + * Copyright (C) 2025 Nvidia Corporation. + */ +#include <bpf/bpf.h> +#include <errno.h> +#include <pthread.h> +#include <scx/common.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/wait.h> +#include <unistd.h> +#include "minimal.bpf.skel.h" +#include "scx_test.h" + +#define MAX_CPUS 512 +#define STRESS_DURATION_SEC 5 + +struct total_bw_ctx { + struct minimal *skel; + long baseline_bw[MAX_CPUS]; + int nr_cpus; +}; + +static void *cpu_stress_thread(void *arg) +{ + volatile int i; + time_t end_time = time(NULL) + STRESS_DURATION_SEC; + + while (time(NULL) < end_time) { + for (i = 0; i < 1000000; i++); + } + + return NULL; +} + +/* + * The first enqueue on a CPU causes the DL server to start, for that + * reason run stressor threads in the hopes it schedules on all CPUs. + */ +static int run_cpu_stress(int nr_cpus) +{ + pthread_t *threads; + int i, ret = 0; + + threads = calloc(nr_cpus, sizeof(pthread_t)); + if (!threads) + return -ENOMEM; + + /* Create threads to run on each CPU */ + for (i = 0; i < nr_cpus; i++) { + if (pthread_create(&threads[i], NULL, cpu_stress_thread, NULL)) { + ret = -errno; + fprintf(stderr, "Failed to create thread %d: %s\n", i, strerror(-ret)); + break; + } + } + + /* Wait for all threads to complete */ + for (i = 0; i < nr_cpus; i++) { + if (threads[i]) + pthread_join(threads[i], NULL); + } + + free(threads); + return ret; +} + +static int read_total_bw_values(long *bw_values, int max_cpus) +{ + FILE *fp; + char line[256]; + int cpu_count = 0; + + fp = fopen("/sys/kernel/debug/sched/debug", "r"); + if (!fp) { + SCX_ERR("Failed to open debug file"); + return -1; + } + + while (fgets(line, sizeof(line), fp)) { + char *bw_str = strstr(line, "total_bw"); + if (bw_str) { + bw_str = strchr(bw_str, ':'); + if (bw_str) { + /* Only store up to max_cpus values */ + if (cpu_count < max_cpus) { + bw_values[cpu_count] = atol(bw_str + 1); + } + cpu_count++; + } + } + } + + fclose(fp); + return cpu_count; +} + +static bool verify_total_bw_consistency(long *bw_values, int count) +{ + int i; + long first_value; + + if (count <= 0) + return false; + + first_value = bw_values[0]; + + for (i = 1; i < count; i++) { + if (bw_values[i] != first_value) { + SCX_ERR("Inconsistent total_bw: CPU0=%ld, CPU%d=%ld", + first_value, i, bw_values[i]); + return false; + } + } + + return true; +} + +static int fetch_verify_total_bw(long *bw_values, int nr_cpus) +{ + int attempts = 0; + int max_attempts = 10; + int count; + + /* + * The first enqueue on a CPU causes the DL server to start, for that + * reason run stressor threads in the hopes it schedules on all CPUs. + */ + if (run_cpu_stress(nr_cpus) < 0) { + SCX_ERR("Failed to run CPU stress"); + return -1; + } + + /* Try multiple times to get stable values */ + while (attempts < max_attempts) { + count = read_total_bw_values(bw_values, nr_cpus); + fprintf(stderr, "Read %d total_bw values (testing %d CPUs)\n", count, nr_cpus); + /* If system has more CPUs than we're testing, that's OK */ + if (count < nr_cpus) { + SCX_ERR("Expected at least %d CPUs, got %d", nr_cpus, count); + attempts++; + sleep(1); + continue; + } + + /* Only verify the CPUs we're testing */ + if (verify_total_bw_consistency(bw_values, nr_cpus)) { + fprintf(stderr, "Values are consistent: %ld\n", bw_values[0]); + return 0; + } + + attempts++; + sleep(1); + } + + return -1; +} + +static enum scx_test_status setup(void **ctx) +{ + struct total_bw_ctx *test_ctx; + + if (access("/sys/kernel/debug/sched/debug", R_OK) != 0) { + fprintf(stderr, "Skipping test: debugfs sched/debug not accessible\n"); + return SCX_TEST_SKIP; + } + + test_ctx = calloc(1, sizeof(*test_ctx)); + if (!test_ctx) + return SCX_TEST_FAIL; + + test_ctx->nr_cpus = sysconf(_SC_NPROCESSORS_ONLN); + if (test_ctx->nr_cpus <= 0) { + free(test_ctx); + return SCX_TEST_FAIL; + } + + /* If system has more CPUs than MAX_CPUS, just test the first MAX_CPUS */ + if (test_ctx->nr_cpus > MAX_CPUS) { + test_ctx->nr_cpus = MAX_CPUS; + } + + /* Test scenario 1: BPF program not loaded */ + /* Read and verify baseline total_bw before loading BPF program */ + fprintf(stderr, "BPF prog initially not loaded, reading total_bw values\n"); + if (fetch_verify_total_bw(test_ctx->baseline_bw, test_ctx->nr_cpus) < 0) { + SCX_ERR("Failed to get stable baseline values"); + free(test_ctx); + return SCX_TEST_FAIL; + } + + /* Load the BPF skeleton */ + test_ctx->skel = minimal__open(); + if (!test_ctx->skel) { + free(test_ctx); + return SCX_TEST_FAIL; + } + + SCX_ENUM_INIT(test_ctx->skel); + if (minimal__load(test_ctx->skel)) { + minimal__destroy(test_ctx->skel); + free(test_ctx); + return SCX_TEST_FAIL; + } + + *ctx = test_ctx; + return SCX_TEST_PASS; +} + +static enum scx_test_status run(void *ctx) +{ + struct total_bw_ctx *test_ctx = ctx; + struct bpf_link *link; + long loaded_bw[MAX_CPUS]; + long unloaded_bw[MAX_CPUS]; + int i; + + /* Test scenario 2: BPF program loaded */ + link = bpf_map__attach_struct_ops(test_ctx->skel->maps.minimal_ops); + if (!link) { + SCX_ERR("Failed to attach scheduler"); + return SCX_TEST_FAIL; + } + + fprintf(stderr, "BPF program loaded, reading total_bw values\n"); + if (fetch_verify_total_bw(loaded_bw, test_ctx->nr_cpus) < 0) { + SCX_ERR("Failed to get stable values with BPF loaded"); + bpf_link__destroy(link); + return SCX_TEST_FAIL; + } + bpf_link__destroy(link); + + /* Test scenario 3: BPF program unloaded */ + fprintf(stderr, "BPF program unloaded, reading total_bw values\n"); + if (fetch_verify_total_bw(unloaded_bw, test_ctx->nr_cpus) < 0) { + SCX_ERR("Failed to get stable values after BPF unload"); + return SCX_TEST_FAIL; + } + + /* Verify all three scenarios have the same total_bw values */ + for (i = 0; i < test_ctx->nr_cpus; i++) { + if (test_ctx->baseline_bw[i] != loaded_bw[i]) { + SCX_ERR("CPU%d: baseline_bw=%ld != loaded_bw=%ld", + i, test_ctx->baseline_bw[i], loaded_bw[i]); + return SCX_TEST_FAIL; + } + + if (test_ctx->baseline_bw[i] != unloaded_bw[i]) { + SCX_ERR("CPU%d: baseline_bw=%ld != unloaded_bw=%ld", + i, test_ctx->baseline_bw[i], unloaded_bw[i]); + return SCX_TEST_FAIL; + } + } + + fprintf(stderr, "All total_bw values are consistent across all scenarios\n"); + return SCX_TEST_PASS; +} + +static void cleanup(void *ctx) +{ + struct total_bw_ctx *test_ctx = ctx; + + if (test_ctx) { + if (test_ctx->skel) + minimal__destroy(test_ctx->skel); + free(test_ctx); + } +} + +struct scx_test total_bw = { + .name = "total_bw", + .description = "Verify total_bw consistency across BPF program states", + .setup = setup, + .run = run, + .cleanup = cleanup, +}; +REGISTER_SCX_TEST(&total_bw) -- 2.34.1

3 months

1
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[PATCH -rebased 14/15] selftests/sched_ext: Add test for sched_ext dl_server

by Joel Fernandes

From: Andrea Righi <arighi(a)nvidia.com> Add a selftest to validate the correct behavior of the deadline server for the ext_sched_class. [ Joel: Replaced occurences of CFS in the test with EXT. ] Signed-off-by: Joel Fernandes <joelagnelf(a)nvidia.com> Signed-off-by: Andrea Righi <arighi(a)nvidia.com> --- tools/testing/selftests/sched_ext/Makefile | 1 + .../selftests/sched_ext/rt_stall.bpf.c | 23 ++ tools/testing/selftests/sched_ext/rt_stall.c | 213 ++++++++++++++++++ 3 files changed, 237 insertions(+) create mode 100644 tools/testing/selftests/sched_ext/rt_stall.bpf.c create mode 100644 tools/testing/selftests/sched_ext/rt_stall.c diff --git a/tools/testing/selftests/sched_ext/Makefile b/tools/testing/selftests/sched_ext/Makefile index 9d9d6b4c38b0..f0a8cba3a99f 100644 --- a/tools/testing/selftests/sched_ext/Makefile +++ b/tools/testing/selftests/sched_ext/Makefile @@ -182,6 +182,7 @@ auto-test-targets := \ select_cpu_dispatch_bad_dsq \ select_cpu_dispatch_dbl_dsp \ select_cpu_vtime \ + rt_stall \ test_example \ testcase-targets := $(addsuffix .o,$(addprefix $(SCXOBJ_DIR)/,$(auto-test-targets))) diff --git a/tools/testing/selftests/sched_ext/rt_stall.bpf.c b/tools/testing/selftests/sched_ext/rt_stall.bpf.c new file mode 100644 index 000000000000..80086779dd1e --- /dev/null +++ b/tools/testing/selftests/sched_ext/rt_stall.bpf.c @@ -0,0 +1,23 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * A scheduler that verified if RT tasks can stall SCHED_EXT tasks. + * + * Copyright (c) 2025 NVIDIA Corporation. + */ + +#include <scx/common.bpf.h> + +char _license[] SEC("license") = "GPL"; + +UEI_DEFINE(uei); + +void BPF_STRUCT_OPS(rt_stall_exit, struct scx_exit_info *ei) +{ + UEI_RECORD(uei, ei); +} + +SEC(".struct_ops.link") +struct sched_ext_ops rt_stall_ops = { + .exit = (void *)rt_stall_exit, + .name = "rt_stall", +}; diff --git a/tools/testing/selftests/sched_ext/rt_stall.c b/tools/testing/selftests/sched_ext/rt_stall.c new file mode 100644 index 000000000000..d4cb545ebfd8 --- /dev/null +++ b/tools/testing/selftests/sched_ext/rt_stall.c @@ -0,0 +1,213 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2025 NVIDIA Corporation. + */ +#define _GNU_SOURCE +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +#include <sched.h> +#include <sys/prctl.h> +#include <sys/types.h> +#include <sys/wait.h> +#include <time.h> +#include <linux/sched.h> +#include <signal.h> +#include <bpf/bpf.h> +#include <scx/common.h> +#include <sys/wait.h> +#include <unistd.h> +#include "rt_stall.bpf.skel.h" +#include "scx_test.h" +#include "../kselftest.h" + +#define CORE_ID 0 /* CPU to pin tasks to */ +#define RUN_TIME 5 /* How long to run the test in seconds */ + +/* Simple busy-wait function for test tasks */ +static void process_func(void) +{ + while (1) { + /* Busy wait */ + for (volatile unsigned long i = 0; i < 10000000UL; i++); + } +} + +/* Set CPU affinity to a specific core */ +static void set_affinity(int cpu) +{ + cpu_set_t mask; + + CPU_ZERO(&mask); + CPU_SET(cpu, &mask); + if (sched_setaffinity(0, sizeof(mask), &mask) != 0) { + perror("sched_setaffinity"); + exit(EXIT_FAILURE); + } +} + +/* Set task scheduling policy and priority */ +static void set_sched(int policy, int priority) +{ + struct sched_param param; + + param.sched_priority = priority; + if (sched_setscheduler(0, policy, &param) != 0) { + perror("sched_setscheduler"); + exit(EXIT_FAILURE); + } +} + +/* Get process runtime from /proc/<pid>/stat */ +static float get_process_runtime(int pid) +{ + char path[256]; + FILE *file; + long utime, stime; + int fields; + + snprintf(path, sizeof(path), "/proc/%d/stat", pid); + file = fopen(path, "r"); + if (file == NULL) { + perror("Failed to open stat file"); + return -1; + } + + /* Skip the first 13 fields and read the 14th and 15th */ + fields = fscanf(file, + "%*d %*s %*c %*d %*d %*d %*d %*d %*u %*u %*u %*u %*u %lu %lu", + &utime, &stime); + fclose(file); + + if (fields != 2) { + fprintf(stderr, "Failed to read stat file\n"); + return -1; + } + + /* Calculate the total time spent in the process */ + long total_time = utime + stime; + long ticks_per_second = sysconf(_SC_CLK_TCK); + float runtime_seconds = total_time * 1.0 / ticks_per_second; + + return runtime_seconds; +} + +static enum scx_test_status setup(void **ctx) +{ + struct rt_stall *skel; + + skel = rt_stall__open(); + SCX_FAIL_IF(!skel, "Failed to open"); + SCX_ENUM_INIT(skel); + SCX_FAIL_IF(rt_stall__load(skel), "Failed to load skel"); + + *ctx = skel; + + return SCX_TEST_PASS; +} + +static bool sched_stress_test(void) +{ + float cfs_runtime, rt_runtime; + int cfs_pid, rt_pid; + float expected_min_ratio = 0.04; /* 4% */ + + ksft_print_header(); + ksft_set_plan(1); + + /* Create and set up a EXT task */ + cfs_pid = fork(); + if (cfs_pid == 0) { + set_affinity(CORE_ID); + process_func(); + exit(0); + } else if (cfs_pid < 0) { + perror("fork for EXT task"); + ksft_exit_fail(); + } + + /* Create an RT task */ + rt_pid = fork(); + if (rt_pid == 0) { + set_affinity(CORE_ID); + set_sched(SCHED_FIFO, 50); + process_func(); + exit(0); + } else if (rt_pid < 0) { + perror("fork for RT task"); + ksft_exit_fail(); + } + + /* Let the processes run for the specified time */ + sleep(RUN_TIME); + + /* Get runtime for the EXT task */ + cfs_runtime = get_process_runtime(cfs_pid); + if (cfs_runtime != -1) + ksft_print_msg("Runtime of EXT task (PID %d) is %f seconds\n", cfs_pid, cfs_runtime); + else + ksft_exit_fail_msg("Error getting runtime for EXT task (PID %d)\n", cfs_pid); + + /* Get runtime for the RT task */ + rt_runtime = get_process_runtime(rt_pid); + if (rt_runtime != -1) + ksft_print_msg("Runtime of RT task (PID %d) is %f seconds\n", rt_pid, rt_runtime); + else + ksft_exit_fail_msg("Error getting runtime for RT task (PID %d)\n", rt_pid); + + /* Kill the processes */ + kill(cfs_pid, SIGKILL); + kill(rt_pid, SIGKILL); + waitpid(cfs_pid, NULL, 0); + waitpid(rt_pid, NULL, 0); + + /* Verify that the scx task got enough runtime */ + float actual_ratio = cfs_runtime / (cfs_runtime + rt_runtime); + ksft_print_msg("EXT task got %.2f%% of total runtime\n", actual_ratio * 100); + + if (actual_ratio >= expected_min_ratio) { + ksft_test_result_pass("PASS: EXT task got more than %.2f%% of runtime\n", + expected_min_ratio * 100); + return true; + } else { + ksft_test_result_fail("FAIL: EXT task got less than %.2f%% of runtime\n", + expected_min_ratio * 100); + return false; + } +} + +static enum scx_test_status run(void *ctx) +{ + struct rt_stall *skel = ctx; + struct bpf_link *link; + bool res; + + link = bpf_map__attach_struct_ops(skel->maps.rt_stall_ops); + SCX_FAIL_IF(!link, "Failed to attach scheduler"); + + res = sched_stress_test(); + + SCX_EQ(skel->data->uei.kind, EXIT_KIND(SCX_EXIT_NONE)); + bpf_link__destroy(link); + + if (!res) + ksft_exit_fail(); + + return SCX_TEST_PASS; +} + +static void cleanup(void *ctx) +{ + struct rt_stall *skel = ctx; + + rt_stall__destroy(skel); +} + +struct scx_test rt_stall = { + .name = "rt_stall", + .description = "Verify that RT tasks cannot stall SCHED_EXT tasks", + .setup = setup, + .run = run, + .cleanup = cleanup, +}; +REGISTER_SCX_TEST(&rt_stall) -- 2.34.1

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