KVM: arm64: Disable TTBR1_EL2 when using ARM64_KVM_HVHE

When using hVHE, we end-up with two TTBRs at EL2. That's great,
but we're not quite ready for this just yet.

Disable TTBR1_EL2 by setting TCR_EL2.EPD1 so that we only
translate via TTBR0_EL2.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230609162200.2024064-12-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>

Author: Marc Zyngier

arch/arm64/kvm/arm.c

@@ -1666,7 +1666,13 @@ static void __init cpu_prepare_hyp_mode(int cpu, u32 hyp_va_bits)
 
 	params->mair_el2 = read_sysreg(mair_el1);
 
-	tcr = (read_sysreg(tcr_el1) & TCR_EL2_MASK) | TCR_EL2_RES1;
+	tcr = read_sysreg(tcr_el1);
+	if (cpus_have_final_cap(ARM64_KVM_HVHE)) {
+		tcr |= TCR_EPD1_MASK;
+	} else {
+		tcr &= TCR_EL2_MASK;
+		tcr |= TCR_EL2_RES1;
+	}
 	tcr &= ~TCR_T0SZ_MASK;
 	tcr |= TCR_T0SZ(hyp_va_bits);
 	params->tcr_el2 = tcr;