Hello, This patchset builds upon the memfd_restricted() system call that was discussed in the 'KVM: mm: fd-based approach for supporting KVM' patch series, at https://lore.kernel.org/lkml/20221202061347.1070246-1-chao.p.peng@xxxxxxxxxxxxxxx/T/#m7e944d7892afdd1d62a03a287bd488c56e377b0c The tree can be found at: https://github.com/googleprodkernel/linux-cc/tree/restrictedmem-provide-mount-fd In this patchset, a modification to the memfd_restricted() syscall is proposed, which allows userspace to provide a mount, on which the restrictedmem file will be created and returned from the memfd_restricted(). Allowing userspace to provide a mount allows userspace to control various memory binding policies via tmpfs mount options, such as Transparent HugePage memory allocation policy through 'huge=always/never' and NUMA memory allocation policy through 'mpol=local/bind:*'. Changes since RFCv1: + Use fd to represent mount instead of path string, as Kirill suggested. I believe using fds makes this syscall interface more aligned with the other syscalls like fsopen(), fsconfig(), and fsmount() in terms of using and passing around fds + Remove unused variable char *orig_shmem_enabled from selftests Dependencies: + Sean's iteration of the ‘KVM: mm: fd-based approach for supporting KVM’ patch series at https://github.com/sean-jc/linux/tree/x86/upm_base_support + Proposed fixes for these issues mentioned on the mailing list: + https://lore.kernel.org/lkml/diqzzga0fv96.fsf@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/ Links to earlier patch series: + RFC v1: https://lore.kernel.org/lkml/cover.1676507663.git.ackerleytng@xxxxxxxxxx/T/ Ackerley Tng (2): mm: restrictedmem: Allow userspace to specify mount for memfd_restricted selftests: restrictedmem: Check hugepage-ness of shmem file backing restrictedmem fd include/linux/syscalls.h | 2 +- include/uapi/linux/restrictedmem.h | 8 + mm/restrictedmem.c | 63 ++- tools/testing/selftests/Makefile | 1 + .../selftests/restrictedmem/.gitignore | 3 + .../testing/selftests/restrictedmem/Makefile | 15 + .../testing/selftests/restrictedmem/common.c | 9 + .../testing/selftests/restrictedmem/common.h | 8 + .../restrictedmem_hugepage_test.c | 459 ++++++++++++++++++ 9 files changed, 561 insertions(+), 7 deletions(-) create mode 100644 include/uapi/linux/restrictedmem.h create mode 100644 tools/testing/selftests/restrictedmem/.gitignore create mode 100644 tools/testing/selftests/restrictedmem/Makefile create mode 100644 tools/testing/selftests/restrictedmem/common.c create mode 100644 tools/testing/selftests/restrictedmem/common.h create mode 100644 tools/testing/selftests/restrictedmem/restrictedmem_hugepage_test.c -- 2.40.0.rc2.332.ga46443480c-goog
