[PATCH 11/17] KVM: arm64: Disable TTBR1_EL2 when using ARM64_KVM_HVHE

Marc Zyngier maz at kernel.org
Thu Oct 20 02:07:21 PDT 2022


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 at kernel.org>
---
 arch/arm64/kvm/arm.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 85df7ce0b051..cf0f15f4d69a 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -1548,7 +1548,13 @@ static void cpu_prepare_hyp_mode(int cpu)
 	 *
 	 * So use the same T0SZ value we use for the ID map.
 	 */
-	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 |= (idmap_t0sz & GENMASK(TCR_TxSZ_WIDTH - 1, 0)) << TCR_T0SZ_OFFSET;
 	params->tcr_el2 = tcr;
-- 
2.34.1




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