KVM: arm64: nv: Don't erroneously claim FEAT_DoubleLock for NV VMs

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ID_AA64DFR0_EL1.DoubleLock is one of those annoying signed feature
fields where a non-negative value implies that a feature is implemented
and a negative value implies that it is not. While the intention of
masking this field was likely to hide the feature, KVM actually
advertises it, even on unsupporting hardware.

Remove FEAT_DoubleLock from the mask, making the NI value visible to the
VM. Take care to accept the old, incorrect values for this field as
we've lied to userspace.

Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>

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Oliver Upton 2025-09-12 14:22:49 -07:00 • committed by Marc Zyngier

parent d3c35b7c57

commit 49da9872a6

2 changed files with 25 additions and 1 deletions

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arch/arm64/kvm/nested.c

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arch/arm64/kvm/sys_regs.c

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