target/arm/kvm: Let kvm_arm_vgic_probe() return a bitmap

Convert kvm_arm_vgic_probe() so that it returns a
bitmap of supported in-kernel emulation VGIC versions instead
of the max version: at the moment values can be v2 and v3.
This allows to expose the case where the host GICv3 also
supports GICv2 emulation. This will be useful to choose the
default version in KVM accelerated mode.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200311131618.7187-5-eric.auger@redhat.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index e55cafa014b55045f61f6e5c6412f0c6818521c6..a94bc5ddae5acea05f6611d98c34f3a631c6913e 100644 (file)
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -1554,11 +1554,18 @@ static void finalize_gic_version(VirtMachineState *vms)
                 vms->gic_version = VIRT_GIC_VERSION_3;
             }
         } else {
-            vms->gic_version = kvm_arm_vgic_probe();
-            if (!vms->gic_version) {
+            int probe_bitmap = kvm_arm_vgic_probe();
+
+            if (!probe_bitmap) {
                 error_report(
                     "Unable to determine GIC version supported by host");
                 exit(1);
+            } else {
+                if (probe_bitmap & KVM_ARM_VGIC_V3) {
+                    vms->gic_version = VIRT_GIC_VERSION_3;
+                } else {
+                    vms->gic_version = VIRT_GIC_VERSION_2;
+                }
             }
         }
     } else if (vms->gic_version == VIRT_GIC_VERSION_NOSEL) {

diff --git a/target/arm/kvm.c b/target/arm/kvm.c
index 85860e6f954cb45560ef7cbd73f178f0e7184a7b..390077c51823a5fac867252fbd4bc489aa330e21 100644 (file)
--- a/target/arm/kvm.c
+++ b/target/arm/kvm.c
@@ -874,15 +874,17 @@ int kvm_arch_irqchip_create(KVMState *s)
 
 int kvm_arm_vgic_probe(void)
 {
+    int val = 0;
+
     if (kvm_create_device(kvm_state,
                           KVM_DEV_TYPE_ARM_VGIC_V3, true) == 0) {
-        return 3;
-    } else if (kvm_create_device(kvm_state,
-                                 KVM_DEV_TYPE_ARM_VGIC_V2, true) == 0) {
-        return 2;
-    } else {
-        return 0;
+        val |= KVM_ARM_VGIC_V3;
+    }
+    if (kvm_create_device(kvm_state,
+                          KVM_DEV_TYPE_ARM_VGIC_V2, true) == 0) {
+        val |= KVM_ARM_VGIC_V2;
     }
+    return val;
 }
 
 int kvm_arm_set_irq(int cpu, int irqtype, int irq, int level)

diff --git a/target/arm/kvm_arm.h b/target/arm/kvm_arm.h
index ae9e075d75454762e45a2008b0623e89c8abee63..48bf5e16d58bbfa11480c27a252f9115d45295ac 100644 (file)
--- a/target/arm/kvm_arm.h
+++ b/target/arm/kvm_arm.h
@@ -15,6 +15,9 @@
 #include "exec/memory.h"
 #include "qemu/error-report.h"
 
+#define KVM_ARM_VGIC_V2   (1 << 0)
+#define KVM_ARM_VGIC_V3   (1 << 1)
+
 /**
  * kvm_arm_vcpu_init:
  * @cs: CPUState