KVM: arm64: Trap external trace for protected VMs

pKVM does not support external trace for protected VMs. Trap
external trace, and add the ExtTrcBuff to make it possible to
check for the feature.

Signed-off-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20231214100158.2305400-18-tabba@google.com

diff --git a/arch/arm64/kvm/hyp/nvhe/pkvm.c b/arch/arm64/kvm/hyp/nvhe/pkvm.c
index 9d23a51d7f7525d50558adefdc402c906ea2b82a..84b5c3f387d80cc894cb61e0f967561d55fcfffa 100644 (file)
--- a/arch/arm64/kvm/hyp/nvhe/pkvm.c
+++ b/arch/arm64/kvm/hyp/nvhe/pkvm.c
@@ -136,6 +136,10 @@ static void pvm_init_traps_aa64dfr0(struct kvm_vcpu *vcpu)
                        cptr_set |= CPTR_EL2_TTA;
        }
 
+       /* Trap External Trace */
+       if (!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_ExtTrcBuff), feature_ids))
+               mdcr_clear |= MDCR_EL2_E2TB_MASK << MDCR_EL2_E2TB_SHIFT;
+
        vcpu->arch.mdcr_el2 |= mdcr_set;
        vcpu->arch.mdcr_el2 &= ~mdcr_clear;
        vcpu->arch.cptr_el2 |= cptr_set;