Thread (6 messages) flat view 6 messages, 3 authors, 2019-11-11

Re: [PATCH 1/2] arm64: Rename WORKAROUND_1165522 to SPECULATIVE_AT

From: Marc Zyngier <maz@kernel.org>
Date: 2019-11-11 15:42:27
Also in: kvmarm, lkml

Hi Steven,

On 2019-11-11 15:21, Steven Price wrote:
Cortex-A55 is affected by a similar erratum, so rename the existing
workaround for errarum 1165522 so it can be used for both errata.
nit: erratum
quoted hunk ↗ jump to hunk
Signed-off-by: Steven Price <steven.price@arm.com>
---
 arch/arm64/Kconfig                |  4 ++++
 arch/arm64/include/asm/cpucaps.h  |  2 +-
 arch/arm64/include/asm/kvm_host.h |  2 +-
 arch/arm64/include/asm/kvm_hyp.h  |  3 +--
 arch/arm64/kernel/cpu_errata.c    | 17 +++++++++++++----
 arch/arm64/kvm/hyp/switch.c       |  2 +-
 arch/arm64/kvm/hyp/tlb.c          |  4 ++--
 7 files changed, 23 insertions(+), 11 deletions(-)
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 3f047afb982c..6cb4eff602c6 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -510,9 +510,13 @@ config ARM64_ERRATUM_1418040

 	  If unsure, say Y.

+config ARM64_WORKAROUND_SPECULATIVE_AT
+	bool
+
 config ARM64_ERRATUM_1165522
 	bool "Cortex-A76: Speculative AT instruction using out-of-context
translation regime could cause subsequent request to generate an
incorrect translation"
 	default y
+	select ARM64_WORKAROUND_SPECULATIVE_AT
I'd object that ARM64_ERRATUM_1319367 (and its big brother 1319537)
are also related to speculative AT execution, and yet are not covered
by this configuration symbol.

I can see three solutions to this:

- Either you call it SPECULATIVE_AT_VHE and introduce 
SPECULATIVE_AT_NVHE
   for symmetry

- Or you make SPECULATIVE_AT cover all the speculative AT errata, which
   may or may not work...

- Or even better, you just ammend the documentation to say that 1165522
   also covers the newly found A55 one (just like we have for A57/A72)

What do you think?

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

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