Commit 07f557f6 authored by Marc Zyngier's avatar Marc Zyngier Committed by Oliver Upton
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KVM: arm64: nv: Properly check ESR_EL2.VNCR on taking a VNCR_EL2 related fault 



Instead of checking for the ESR_EL2.VNCR bit being set (the only case
we should be here), we are actually testing random bits in ESR_EL2.DFSC.

13 obviously being a lucky number, it matches both permission and
translation fault status codes, which explains why we never saw it
failing. This was found by inspection, while reviewing a vaguely
related patch.

Whilst we're at it, turn the BUG_ON() into a WARN_ON_ONCE(), as
exploding here is just silly.

Fixes: 069a05e5 ("KVM: arm64: nv: Handle VNCR_EL2-triggered faults")
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Reviewed-by: default avatarJoey Gouly <joey.gouly@arm.com>
Link: https://lore.kernel.org/r/20250730101828.1168707-1-maz@kernel.org


Signed-off-by: default avatarOliver Upton <oliver.upton@linux.dev>
parent 7b8346bd

arch/arm64/kvm/nested.c

+1 −1
Original line number Diff line number Diff line
@@ -1287,7 +1287,7 @@ int kvm_handle_vncr_abort(struct kvm_vcpu *vcpu) 
	struct vncr_tlb *vt = vcpu->arch.vncr_tlb;

	u64 esr = kvm_vcpu_get_esr(vcpu);



	BUG_ON(!(esr & ESR_ELx_VNCR_SHIFT));

	WARN_ON_ONCE(!(esr & ESR_ELx_VNCR));



	if (esr_fsc_is_permission_fault(esr)) {

		inject_vncr_perm(vcpu);