Re: [RFC PATCH v1 0/3] arm64: tlb: add support for TTL field

From: Marc Zyngier
Date: Wed Mar 11 2020 - 05:12:58 EST


Zhenyu,

On 2020-03-11 02:53, Zhenyu Ye wrote:
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.

This set of patches adds TTL field to __TLBI_ADDR, and uses
Architecture-specific MM context to pass the TTL value to tlb interface.

The default value of TTL is 0, which will not have any impact on the
TLB maintenance instructions. The last patch trys to use TTL field in
some obviously tlb-flush interface.

I have already posted some support for ARMv8.4-TTL as part of my NV series [1],
patches 62, 67, 68 and 69. This only deals with Stage-2 translation so far.
If you intend to add Stage-1, please build on top of what I have already posted
(I can extract the patches on a separate branch if you want).

Thanks,

M.

[1] https://lore.kernel.org/linux-arm-kernel/20200211174938.27809-1-maz@xxxxxxxxxx/
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