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Message-ID: <0108ab72-efca-1027-23e8-e5d445929943@kernel.org>
Date: Mon, 7 Nov 2022 06:59:42 -0800
From: Andy Lutomirski <luto@...nel.org>
To: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
Dave Hansen <dave.hansen@...ux.intel.com>,
Peter Zijlstra <peterz@...radead.org>
Cc: x86@...nel.org, Kostya Serebryany <kcc@...gle.com>,
Andrey Ryabinin <ryabinin.a.a@...il.com>,
Andrey Konovalov <andreyknvl@...il.com>,
Alexander Potapenko <glider@...gle.com>,
Taras Madan <tarasmadan@...gle.com>,
Dmitry Vyukov <dvyukov@...gle.com>,
"H . J . Lu" <hjl.tools@...il.com>,
Andi Kleen <ak@...ux.intel.com>,
Rick Edgecombe <rick.p.edgecombe@...el.com>,
Bharata B Rao <bharata@....com>,
Jacob Pan <jacob.jun.pan@...ux.intel.com>,
Ashok Raj <ashok.raj@...el.com>, linux-mm@...ck.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCHv11 00/16] Linear Address Masking enabling
On 10/24/22 17:17, Kirill A. Shutemov 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 JITs and virtual machines.
>
> The patchset brings support for LAM for userspace addresses. Only LAM_U57 at
> this time.
>
> Please review and consider applying.
I'm pretty happy with this series other than my two comments (switch_mm
race and explaining why untagged_addr needs to preserve kernel addresses).
>
> 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
>
> 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 | 81 +-
> arch/x86/kernel/traps.c | 6 +-
> 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 | 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, 1539 insertions(+), 92 deletions(-)
> create mode 100644 tools/testing/selftests/x86/lam.c
>
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