Re: [PATCHv9 00/14] Linear Address Masking enabling

From: Alexander Potapenko
Date: Thu Oct 06 2022 - 09:59:07 EST

On Fri, Sep 30, 2022 at 4:48 PM Kirill A. Shutemov
<kirill.shutemov@xxxxxxxxxxxxxxx> wrote:
>
> 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 virtual machines.
>
> The patchset brings support for LAM for userspace addresses. Only LAM_U57 at
> this time.
>
> Please review and consider applying.
>
> git://git.kernel.org/pub/scm/linux/kernel/git/kas/linux.git lam

Not a big deal, but this tree contains LAM_U48 patches, and after
skipping those the SVM patch does not apply cleanly.

> 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 (10):
> 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
> x86: Expose untagging mask in /proc/$PID/arch_status
> x86/mm, iommu/sva: Make LAM and SVM mutually exclusive
>
> Weihong Zhang (4):
> 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
>
> arch/arm64/include/asm/memory.h | 4 +-
> arch/arm64/include/asm/signal.h | 2 +-
> arch/arm64/include/asm/uaccess.h | 4 +-
> arch/arm64/kernel/hw_breakpoint.c | 2 +-
> arch/arm64/kernel/traps.c | 4 +-
> arch/arm64/mm/fault.c | 10 +-
> 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 | 35 +
> 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/Makefile | 2 +
> arch/x86/kernel/fpu/xstate.c | 47 -
> arch/x86/kernel/proc.c | 60 ++
> arch/x86/kernel/process.c | 3 +
> arch/x86/kernel/process_64.c | 82 +-
> arch/x86/mm/tlb.c | 48 +-
> .../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 | 12 +
> 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/task_mmu.c | 2 +-
> include/linux/mm.h | 11 -
> include/linux/mmu_context.h | 4 +
> 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 | 916 ++++++++++++++++++
> virt/kvm/kvm_main.c | 14 +-
> 51 files changed, 1331 insertions(+), 125 deletions(-)
> create mode 100644 arch/x86/kernel/proc.c
> create mode 100644 tools/testing/selftests/x86/lam.c
>
> --
> 2.35.1
>


--
Alexander Potapenko
Software Engineer

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