Re: [RFC PATCH v3 0/4] arm64: tlb: add support for TTL field

[Zenghui Yu]

Hi Zhenyu,

On 2020/3/21 20:16, Zhenyu Ye wrote:
> --
> ChangeList:
> v3:
> use vma->vm_flags to replace mm->context.flags.
>
> v2:
> build the patch on Marc's NV series[1].
>
> v1:
> add support for TTL field in arm64.
>
> --
> ARMv8.4-TTL provides the TTL field in tlbi instruction to indicate
> the level of translation table walk holding the leaf entry for the
> address that is being invalidated. Hardware can use this information
> to determine if there was a risk of splintering.
>
> Marc has provided basic support for ARM64-TTL features on his
> NV series[1] patches. NV is a large feature, however, only
> patches 62[2] and 67[3] are need by this patch set.
> ** You only need read those two patches before review this patch. **

It'd be good if you can put the whole thing into a series, otherwise
people will have difficulty when reviewing and testing it...

I haven't tracked the previous versions. If Marc is OK to share the
two patches below [2][3], I'd suggest you to pick them up, add them
in your series, rebase on top of mainline and resend it.


Thanks,
Zenghui

> Some of this patch depends on a feature powered by @Will Deacon
> two years ago, which tracking the level of page tables in mm_gather.
> See more in commit a6d60245.
>
> [1] git://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git kvm-arm64/nv-5.6-rc1
> [2] https://lore.kernel.org/linux-arm-kernel/20200211174938.27809-63-maz@xxxxxxxxxx/
> [3] https://lore.kernel.org/linux-arm-kernel/20200211174938.27809-68-maz@xxxxxxxxxx/
>
> Zhenyu Ye (4):
>    arm64: Add level-hinted TLB invalidation helper to tlbi_user
>    mm: Add page table level flags to vm_flags
>    arm64: tlb: Use translation level hint in vm_flags
>    mm: Set VM_LEVEL flags in some tlb_flush functions
>
>   arch/arm64/include/asm/mmu.h      |  2 ++
>   arch/arm64/include/asm/tlb.h      | 12 +++++++++
>   arch/arm64/include/asm/tlbflush.h | 44 ++++++++++++++++++++++++++-----
>   arch/arm64/mm/hugetlbpage.c       |  4 +--
>   arch/arm64/mm/mmu.c               | 14 ++++++++++
>   include/asm-generic/pgtable.h     | 16 +++++++++--
>   include/linux/mm.h                | 10 +++++++
>   include/trace/events/mmflags.h    | 15 ++++++++++-
>   mm/huge_memory.c                  |  8 +++++-
>   9 files changed, 113 insertions(+), 12 deletions(-)