[PATCH v4 18/18] hw/arm/virt: Disable LPA2 for -machine virt-6.2

[Richard Henderson]

There is a Linux kernel bug present until v5.12 that prevents
booting with FEAT_LPA2 enabled.  As a workaround for TCG,
disable this feature for machine versions prior to 7.0.

Cc: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 include/hw/arm/virt.h | 1 +
 hw/arm/virt.c         | 7 +++++++
 2 files changed, 8 insertions(+)

diff --git a/include/hw/arm/virt.h b/include/hw/arm/virt.h
index c1ea17d0de..7e76ee2619 100644
--- a/include/hw/arm/virt.h
+++ b/include/hw/arm/virt.h
@@ -132,6 +132,7 @@ struct VirtMachineClass {
     bool no_secure_gpio;
     /* Machines < 6.2 have no support for describing cpu topology to guest */
     bool no_cpu_topology;
+    bool no_tcg_lpa2;
 };
 
 struct VirtMachineState {
diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index 46bf7ceddf..46a42502bc 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -2102,6 +2102,10 @@ static void machvirt_init(MachineState *machine)
             object_property_set_bool(cpuobj, "pmu", false, NULL);
         }
 
+        if (vmc->no_tcg_lpa2 && object_property_find(cpuobj, "lpa2")) {
+            object_property_set_bool(cpuobj, "lpa2", false, NULL);
+        }
+
         if (object_property_find(cpuobj, "reset-cbar")) {
             object_property_set_int(cpuobj, "reset-cbar",
                                     vms->memmap[VIRT_CPUPERIPHS].base,
@@ -3020,8 +3024,11 @@ DEFINE_VIRT_MACHINE_AS_LATEST(7, 0)
 
 static void virt_machine_6_2_options(MachineClass *mc)
 {
+    VirtMachineClass *vmc = VIRT_MACHINE_CLASS(OBJECT_CLASS(mc));
+
     virt_machine_7_0_options(mc);
     compat_props_add(mc->compat_props, hw_compat_6_2, hw_compat_6_2_len);
+    vmc->no_tcg_lpa2 = true;
 }
 DEFINE_VIRT_MACHINE(6, 2)
 
-- 
2.25.1