Thread (11 messages) 11 messages, 3 authors, 2021-04-08

Re: [PATCH v2 3/3] arm64: Allow nVHE impaired CPUs to boot without CONFIG_ARM64_VHE

From: Will Deacon <will@kernel.org>
Date: 2021-04-07 21:20:38

On Tue, Mar 30, 2021 at 06:39:47PM +0100, Marc Zyngier wrote:
CPUs stuck in VHE mode need some additional care if the kernel
is compiled without CONFIG_ARM64_VHE.

Treat this case as another version of a mismatched boot, and
prevent KVM from being initialised. The machine will boot in
some bizarre state, using TPIDR_EL1 instead of TPIDR_EL2, but
otherwise be functional.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/include/asm/virt.h | 18 +++++++++++++-----
 arch/arm64/kvm/va_layout.c    |  9 +++++++++
 2 files changed, 22 insertions(+), 5 deletions(-)
Hmm, I think we definitely need _something_ here, but it's a bit annoying
to put ourselves into this weird state just for the sake of one stupid
machine.

What if we dropped CONFIG_ARM64_VHE and made the VHE code unconditional
instead? Is there a good reason to allow it to be disabled nowadays?

Will

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