Up to now virt support on guest has been only supported with TCG.
Now it becomes feasible to use it with KVM acceleration.

Check neither in-kernel GICv3 nor aarch64=off is used along with KVM
EL2.

Signed-off-by: Haibo Xu <haibo.xu@linaro.org>
Signed-off-by: Miguel Luis <miguel.luis@oracle.com>
Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20250707164129.1167837-6-eric.auger@redhat.com
[PMM: make "kernel doesn't have EL2 support" error message
 distinct from the old "QEMU doesn't have KVM EL2 support" one]
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 hw/arm/virt.c | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index c9f39919370..8070ff7b113 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -797,6 +797,13 @@ static void create_gic(VirtMachineState *vms, MemoryRegion *mem)
     default:
         g_assert_not_reached();
     }
+
+    if (kvm_enabled() && vms->virt &&
+        (revision != 3 || !kvm_irqchip_in_kernel())) {
+        error_report("KVM EL2 is only supported with in-kernel GICv3");
+        exit(1);
+    }
+
     vms->gic = qdev_new(gictype);
     qdev_prop_set_uint32(vms->gic, "revision", revision);
     qdev_prop_set_uint32(vms->gic, "num-cpu", smp_cpus);
@@ -2092,6 +2099,10 @@ static void virt_post_cpus_gic_realized(VirtMachineState *vms,
             memory_region_init_ram(pvtime, NULL, "pvtime", pvtime_size, NULL);
             memory_region_add_subregion(sysmem, pvtime_reg_base, pvtime);
         }
+        if (!aarch64 && vms->virt) {
+            error_report("KVM does not support EL2 on an AArch32 vCPU");
+            exit(1);
+        }
 
         CPU_FOREACH(cpu) {
             if (pmu) {
@@ -2237,7 +2248,13 @@ static void machvirt_init(MachineState *machine)
         exit(1);
     }
 
-    if (vms->virt && !tcg_enabled() && !qtest_enabled()) {
+    if (vms->virt && kvm_enabled() && !kvm_arm_el2_supported()) {
+        error_report("mach-virt: host kernel KVM does not support providing "
+                     "Virtualization extensions to the guest CPU");
+        exit(1);
+    }
+
+    if (vms->virt && !kvm_enabled() && !tcg_enabled() && !qtest_enabled()) {
         error_report("mach-virt: %s does not support providing "
                      "Virtualization extensions to the guest CPU",
                      current_accel_name());
-- 
2.43.0