Re: [PATCH v5 0/3] arm64: Workaround for Cortex-A55 erratum 1530923

From: Marc Zyngier
Date: Thu Jan 16 2020 - 02:28:53 EST


On 2020-01-14 16:45, Will Deacon wrote:
On Mon, Dec 16, 2019 at 11:56:28AM +0000, Steven Price wrote:
Version 5 is a rebasing of version 4 (no changes).

This series enables a workaround for Cortex-A55 erratum 1530923. The
erratum potentially allows TLB entries to be allocated as a result of a
speculative AT instruction. This may happen in the middle of a guest
world switch while the relevant VMSA configuration is in an inconsistent
state, leading to erroneous content being allocated into TLBs.

There are existing workarounds for similar issues, 1165522 is
effectively the same, and 1319367/1319537 is similar but without VHE
support. Rather than add to the selection of errata, the first patch
renames 1165522 to WORKAROUND_SPECULATIVE_AT which can be reused (in the
final patch) for 1530923.

The workaround for errata 1319367 and 1319537 although similar cannot
use VHE (not available on those CPUs) so cannot share the workaround.
However, to keep some sense of symmetry the workaround is renamed to
SPECULATIVE_AT_NVHE.

Changes since v4:
* Rebased to v5.5-rc1

Looks fine to me. Marc, are you ok with me queueing this via arm64 (that's
where the existing workarounds came from), or would you prefer to take them
via kvm-arm?

Please go ahead and take it (with my ack) via the arm64 tree.

Thanks,

M.
--
Jazz is not dead. It just smells funny...