[PATCH 2/2] KVM: arm64: Reenable MTE tag checking on exit from guest when running VHE

[Marc Zyngier]

Once we're back from running a guest, it is important to set TCO to
zero so that MTE is functional again.

Signed-off-by: Marc Zyngier <maz at kernel.org>
---
 arch/arm64/kvm/hyp/vhe/switch.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/arm64/kvm/hyp/vhe/switch.c b/arch/arm64/kvm/hyp/vhe/switch.c
index 4c965f9b1e1de..73c2dd61e6c69 100644
--- a/arch/arm64/kvm/hyp/vhe/switch.c
+++ b/arch/arm64/kvm/hyp/vhe/switch.c
@@ -193,6 +193,13 @@ static void __deactivate_traps(struct kvm_vcpu *vcpu)
 	if (!arm64_kernel_unmapped_at_el0())
 		host_vectors = __this_cpu_read(this_cpu_vector);
 	write_sysreg(host_vectors, vbar_el1);
+
+	/*
+	 * We're now able to take MTE exceptions, make sure the VBAR_EL2 is
+	 * set to the correct value.
+	 */
+	if (mte_disable_tco_entry(current))
+		isb();
 }
 NOKPROBE_SYMBOL(__deactivate_traps);
 
-- 
2.47.3