[Qemu-devel] [PATCH v6 4/4] arm: implement query-gic-capabilities

[Peter Xu <peterx@redhat.com>]

For emulated GIC capabilities, currently only gicv2 is supported. We
need to add gicv3 in when emulated gicv3 ready. For KVM accelerated ARM
VM, we detect the capability bits by creating a scratch VM.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 target-arm/monitor.c | 60 +++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 59 insertions(+), 1 deletion(-)

diff --git a/target-arm/monitor.c b/target-arm/monitor.c
index 254a9c9..4a2db59 100644
--- a/target-arm/monitor.c
+++ b/target-arm/monitor.c
@@ -21,8 +21,66 @@
  */
 #include "qemu/osdep.h"
 #include "qmp-commands.h"
+#include "hw/boards.h"
+#include "kvm_arm.h"
+
+static GICCapability *gic_cap_new(int version)
+{
+    GICCapability *cap = g_new0(GICCapability, 1);
+    cap->version = version;
+    /* by default, support none */
+    cap->emulated = false;
+    cap->kernel = false;
+    return cap;
+}
+
+static GICCapabilityList *gic_cap_list_add(GICCapabilityList *head,
+                                           GICCapability *cap)
+{
+    GICCapabilityList *item = g_new0(GICCapabilityList, 1);
+    item->value = cap;
+    item->next = head;
+    return item;
+}
 
 GICCapabilityResult *qmp_query_gic_capabilities(Error **errp)
 {
-    return NULL;
+    GICCapabilityResult *result = g_new0(GICCapabilityResult, 1);
+    GICCapabilityList *head = NULL;
+    GICCapability *v2 = gic_cap_new(2), *v3 = gic_cap_new(3);
+
+    v2->emulated = true;
+    /* FIXME: we'd change to true after we get emulated GICv3. */
+    v3->emulated = false;
+
+#ifdef CONFIG_KVM
+    {
+        int fdarray[3];
+
+        if (!kvm_arm_create_scratch_host_vcpu(NULL, fdarray, NULL)) {
+            goto out;
+        }
+
+        /* Test KVM GICv2 */
+        if (kvm_support_device(fdarray[1], KVM_DEV_TYPE_ARM_VGIC_V2)) {
+            v2->kernel = true;
+        }
+
+        /* Test KVM GICv3 */
+        if (kvm_support_device(fdarray[1], KVM_DEV_TYPE_ARM_VGIC_V3)) {
+            v3->kernel = true;
+        }
+
+        kvm_arm_destroy_scratch_host_vcpu(fdarray);
+out:
+        ;
+    }
+#endif
+
+    head = gic_cap_list_add(head, v2);
+    head = gic_cap_list_add(head, v3);
+
+    result->capabilities = head;
+
+    return result;
 }
-- 
2.4.3