[PATCHv12,00/16] Linear Address Masking enabling

  Linear Address Masking[1] (LAM) modifies the checking that is applied to
64-bit linear addresses, allowing software to use of the untranslated
address bits for metadata.

The capability can be used for efficient address sanitizers (ASAN)
implementation and for optimizations in JITs and virtual machines.

The patchset brings support for LAM for userspace addresses. Only LAM_U57 at
this time.

Please review and consider applying.

Results for the self-tests:

   ok 1 MALLOC: LAM_U57. Dereferencing pointer with metadata
   # Get segmentation fault(11).ok 2 MALLOC:[Negative] Disable LAM. Dereferencing pointer with metadata.
   ok 3 BITS: Check default tag bits
   ok 4 # SKIP MMAP: First mmap high address, then set LAM_U57.
   ok 5 # SKIP MMAP: First LAM_U57, then High address.
   ok 6 MMAP: First LAM_U57, then Low address.
   ok 7 SYSCALL: LAM_U57. syscall with metadata
   ok 8 SYSCALL:[Negative] Disable LAM. Dereferencing pointer with metadata.
   ok 9 URING: LAM_U57. Dereferencing pointer with metadata
   ok 10 URING:[Negative] Disable LAM. Dereferencing pointer with metadata.
   ok 11 FORK: LAM_U57, child process should get LAM mode same as parent
   ok 12 EXECVE: LAM_U57, child process should get disabled LAM mode
   open: Device or resource busy
   ok 13 PASID: [Negative] Execute LAM, PASID, SVA in sequence
   ok 14 PASID: Execute LAM, SVA, PASID in sequence
   ok 15 PASID: [Negative] Execute PASID, LAM, SVA in sequence
   ok 16 PASID: Execute PASID, SVA, LAM in sequence
   ok 17 PASID: Execute SVA, LAM, PASID in sequence
   ok 18 PASID: Execute SVA, PASID, LAM in sequence
   1..18

git://git.kernel.org/pub/scm/linux/kernel/git/kas/linux.git lam

v12:
  - Rebased onto tip/x86/mm;
  - Drop VM_WARN_ON() that may produce false-positive on race between context
    switch and LAM enabling;
  - Adjust comments explain possible race;
  - User READ_ONCE() in mm_lam_cr3_mask();
  - Do not assume &init_mm == mm in initialize_tlbstate_and_flush();
  - Ack by Andy;
v11:
  - Move untag_mask to /proc/$PID/status;
  - s/SVM/SVA/g;
  - static inline arch_pgtable_dma_compat() instead of macros;
  - Replace pasid_valid() with mm_valid_pasid();
  - Acks from Ashok and Jacob (forgot to apply from v9);
v10:
  - Rebased to v6.1-rc1;
  - Add selftest for SVM vs LAM;
v9:
  - Fix race between LAM enabling and check that KVM memslot address doesn't
    have any tags;
  - Reduce untagged_addr() overhead until the first LAM user;
  - Clarify SVM vs. LAM semantics;
  - Use mmap_lock to serialize LAM enabling;
v8:
  - Drop redundant smb_mb() in prctl_enable_tagged_addr();
  - Cleanup code around build_cr3();
  - Fix commit messages;
  - Selftests updates;
  - Acked/Reviewed/Tested-bys from Alexander and Peter;
v7:
  - Drop redundant smb_mb() in prctl_enable_tagged_addr();
  - Cleanup code around build_cr3();
  - Fix commit message;
  - Fix indentation;
v6:
  - Rebased onto v6.0-rc1
  - LAM_U48 excluded from the patchet. Still available in the git tree;
  - add ARCH_GET_MAX_TAG_BITS;
  - Fix build without CONFIG_DEBUG_VM;
  - Update comments;
  - Reviewed/Tested-by from Alexander;
v5:
  - Do not use switch_mm() in enable_lam_func()
  - Use mb()/READ_ONCE() pair on LAM enabling;
  - Add self-test by Weihong Zhang;
  - Add comments;
v4:
  - Fix untagged_addr() for LAM_U48;
  - Remove no-threads restriction on LAM enabling;
  - Fix mm_struct access from /proc/$PID/arch_status
  - Fix LAM handling in initialize_tlbstate_and_flush()
  - Pack tlb_state better;
  - Comments and commit messages;
v3:
  - Rebased onto v5.19-rc1
  - Per-process enabling;
  - API overhaul (again);
  - Avoid branches and costly computations in the fast path;
  - LAM_U48 is in optional patch.
v2:
  - Rebased onto v5.18-rc1
  - New arch_prctl(2)-based API
  - Expose status of LAM (or other thread features) in
    /proc/$PID/arch_status

[1] ISE, Chapter 10. https://cdrdv2.intel.com/v1/dl/getContent/671368
Kirill A. Shutemov (11):
  x86/mm: Fix CR3_ADDR_MASK
  x86: CPUID and CR3/CR4 flags for Linear Address Masking
  mm: Pass down mm_struct to untagged_addr()
  x86/mm: Handle LAM on context switch
  x86/uaccess: Provide untagged_addr() and remove tags before address
    check
  KVM: Serialize tagged address check against tagging enabling
  x86/mm: Provide arch_prctl() interface for LAM
  x86/mm: Reduce untagged_addr() overhead until the first LAM user
  mm: Expose untagging mask in /proc/$PID/status
  iommu/sva: Replace pasid_valid() helper with mm_valid_pasid()
  x86/mm, iommu/sva: Make LAM and SVA mutually exclusive

Weihong Zhang (5):
  selftests/x86/lam: Add malloc and tag-bits test cases for
    linear-address masking
  selftests/x86/lam: Add mmap and SYSCALL test cases for linear-address
    masking
  selftests/x86/lam: Add io_uring test cases for linear-address masking
  selftests/x86/lam: Add inherit test cases for linear-address masking
  selftests/x86/lam: Add ARCH_FORCE_TAGGED_SVA test cases for
    linear-address masking

 arch/arm64/include/asm/memory.h               |    4 +-
 arch/arm64/include/asm/mmu_context.h          |    6 +
 arch/arm64/include/asm/signal.h               |    2 +-
 arch/arm64/include/asm/uaccess.h              |    2 +-
 arch/arm64/kernel/hw_breakpoint.c             |    2 +-
 arch/arm64/kernel/traps.c                     |    4 +-
 arch/arm64/mm/fault.c                         |   10 +-
 arch/sparc/include/asm/mmu_context_64.h       |    6 +
 arch/sparc/include/asm/pgtable_64.h           |    2 +-
 arch/sparc/include/asm/uaccess_64.h           |    2 +
 arch/x86/include/asm/cpufeatures.h            |    1 +
 arch/x86/include/asm/mmu.h                    |   12 +-
 arch/x86/include/asm/mmu_context.h            |   47 +
 arch/x86/include/asm/processor-flags.h        |    4 +-
 arch/x86/include/asm/tlbflush.h               |   34 +
 arch/x86/include/asm/uaccess.h                |   46 +-
 arch/x86/include/uapi/asm/prctl.h             |    5 +
 arch/x86/include/uapi/asm/processor-flags.h   |    6 +
 arch/x86/kernel/process.c                     |    3 +
 arch/x86/kernel/process_64.c                  |   87 +-
 arch/x86/kernel/traps.c                       |    6 +-
 arch/x86/mm/tlb.c                             |   53 +-
 .../gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c  |    2 +-
 drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c       |    2 +-
 drivers/gpu/drm/radeon/radeon_gem.c           |    2 +-
 drivers/infiniband/hw/mlx4/mr.c               |    2 +-
 drivers/iommu/iommu-sva-lib.c                 |   16 +-
 drivers/media/common/videobuf2/frame_vector.c |    2 +-
 drivers/media/v4l2-core/videobuf-dma-contig.c |    2 +-
 .../staging/media/atomisp/pci/hmm/hmm_bo.c    |    2 +-
 drivers/tee/tee_shm.c                         |    2 +-
 drivers/vfio/vfio_iommu_type1.c               |    2 +-
 fs/proc/array.c                               |    6 +
 fs/proc/task_mmu.c                            |    2 +-
 include/linux/ioasid.h                        |    9 -
 include/linux/mm.h                            |   11 -
 include/linux/mmu_context.h                   |   14 +
 include/linux/sched/mm.h                      |    8 +-
 include/linux/uaccess.h                       |   15 +
 lib/strncpy_from_user.c                       |    2 +-
 lib/strnlen_user.c                            |    2 +-
 mm/gup.c                                      |    6 +-
 mm/madvise.c                                  |    2 +-
 mm/mempolicy.c                                |    6 +-
 mm/migrate.c                                  |    2 +-
 mm/mincore.c                                  |    2 +-
 mm/mlock.c                                    |    4 +-
 mm/mmap.c                                     |    2 +-
 mm/mprotect.c                                 |    2 +-
 mm/mremap.c                                   |    2 +-
 mm/msync.c                                    |    2 +-
 tools/testing/selftests/x86/Makefile          |    2 +-
 tools/testing/selftests/x86/lam.c             | 1149 +++++++++++++++++
 virt/kvm/kvm_main.c                           |   14 +-
 54 files changed, 1550 insertions(+), 92 deletions(-)
 create mode 100644 tools/testing/selftests/x86/lam.c