[PATCH 0/3] arm64: kvm: avoid referencing cpu_hwcaps from hyp

[Mark Rutland]

In a few places we use cpus_have_const_cap() in hyp code, usually
because this is hidden within a helper that's also used in regular
kernel context. As cpus_have_const_cap() generates code to read the
cpu_hwcaps array before capabilities are finalized, this means we
generate some potentially-unsound references to regular kernel VAs, but
this these are redundant as capabilities are finalized before we
initialize the kvm hyp code.

This series gets rid of the redundant code by automatically upgrading
cpust_have_const_cap() to cpus_have_final_cap() when used in hyp code.
This allows us to avoid creating an NVHE alias for the cpu_hwcaps array,
so we can catch if we accidentally introduce an runtime reference to
this (e.g. via cpus_have_cap()).

Thees patches are based on the kvmarm next branch [1].

[1] git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm.git next

Thanks,
Mark.

Mark Rutland (3):
  arm64: kvm: factor out is_{vhe,nvhe}_hyp_code()
  arm64: cpufeature: reorder cpus_have_{const,final}_cap()
  arm64: cpufeature: upgrade hyp caps to final

 arch/arm64/include/asm/cpufeature.h | 40 ++++++++++++++++++++++++++++---------
 arch/arm64/include/asm/virt.h       |  9 ++++-----
 arch/arm64/kernel/image-vars.h      |  1 -
 3 files changed, 35 insertions(+), 15 deletions(-)

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2.11.0