From: Fuad Tabba <tabba@google.com>
Date: Thu, 14 Dec 2023 10:01:57 +0000 (+0000)
Subject: KVM: arm64: Trap external trace for protected VMs
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=9d52612690985fc0ee1ae1fbad61530a4f6bbb53;p=linux.git

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 9d23a51d7f752..84b5c3f387d80 100644
--- 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;