[PATCH v1 1/8] KVM: arm64: Route MOPS exceptions to EL2 when guest lacks support

[Fuad Tabba]

MOPS exceptions must be routed to the hypervisor (EL2) when the guest
does not support the feature. If the guest does support MOPS, exceptions
should be handled by the guest at EL1.

The existing logic was inverted: exceptions were trapped to EL2 (by
setting HCRX_EL2_MCE2) when the guest supported MOPS, and left to be
handled at EL1 when it did not.

Fix this by moving the setting of HCRX_EL2_MCE2 from the feature-check
block to the 'else' block, ensuring exceptions are only trapped to EL2
when the guest cannot handle them.

Fixes: 84de212d739e ("KVM: arm64: Make FEAT_MOPS UNDEF if not advertised to the guest")
Signed-off-by: Fuad Tabba <tabba at google.com>
---
 arch/arm64/include/asm/kvm_emulate.h | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h
index c9eab316398e..0f8311263edf 100644
--- a/arch/arm64/include/asm/kvm_emulate.h
+++ b/arch/arm64/include/asm/kvm_emulate.h
@@ -684,7 +684,9 @@ static inline void vcpu_set_hcrx(struct kvm_vcpu *vcpu)
 		vcpu->arch.hcrx_el2 = HCRX_EL2_SMPME;
 
 		if (kvm_has_feat(kvm, ID_AA64ISAR2_EL1, MOPS, IMP))
-			vcpu->arch.hcrx_el2 |= (HCRX_EL2_MSCEn | HCRX_EL2_MCE2);
+			vcpu->arch.hcrx_el2 |= HCRX_EL2_MSCEn;
+		else
+			vcpu->arch.hcrx_el2 |= HCRX_EL2_MCE2;
 
 		if (kvm_has_tcr2(kvm))
 			vcpu->arch.hcrx_el2 |= HCRX_EL2_TCR2En;
-- 
2.51.2.997.g839fc31de9-goog