As we now keep information in the S2PT, we must be careful not
to keep it across a VM reboot, which could otherwise lead to
interesting problems.
Make sure that the S2 is completely discarded on reset of
a vcpu, and remove the flag that enforces the MMIO check.
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
---
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 97ab1512c44f..b0d2225190d2 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -1096,12 +1096,18 @@ static int kvm_arch_vcpu_ioctl_vcpu_init(struct kvm_vcpu *vcpu,
* ensuring that the data side is always coherent. We still
* need to invalidate the I-cache though, as FWB does *not*
* imply CTR_EL0.DIC.
+ *
+ * If the MMIO guard was enabled, we pay the price of a full
+ * unmap to get back to a sane state (and clear the flag).
*/
if (vcpu->arch.has_run_once) {
- if (!cpus_have_final_cap(ARM64_HAS_STAGE2_FWB))
+ if (!cpus_have_final_cap(ARM64_HAS_STAGE2_FWB) ||
+ test_bit(KVM_ARCH_FLAG_MMIO_GUARD, &vcpu->kvm->arch.flags))
stage2_unmap_vm(vcpu->kvm);
else
icache_inval_all_pou();
+
+ clear_bit(KVM_ARCH_FLAG_MMIO_GUARD, &vcpu->kvm->arch.flags);
}
vcpu_reset_hcr(vcpu);
--
2.30.2
