From 07f557f60a9a4e15288c29a2924e19e44200db51 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Wed, 30 Jul 2025 11:18:28 +0100 Subject: [PATCH] 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: 069a05e535496 ("KVM: arm64: nv: Handle VNCR_EL2-triggered faults") Signed-off-by: Marc Zyngier Reviewed-by: Joey Gouly Link: https://lore.kernel.org/r/20250730101828.1168707-1-maz@kernel.org Signed-off-by: Oliver Upton --- arch/arm64/kvm/nested.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm64/kvm/nested.c b/arch/arm64/kvm/nested.c index efb37aad11ece..74a2a94dad9ba 100644 --- a/arch/arm64/kvm/nested.c +++ b/arch/arm64/kvm/nested.c @@ -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); -- 2.51.0