qemu: refactor maximum vcpus supported in aarch64

on aarch64, we support different gic interrupt controllers. The maximum number of vCPUs depends on the GIC version, or on how many redistributors we can fit into the memory map. Fixes: kata-containers#584 Signed-off-by: Penny Zheng <[email protected]> Signed-off-by: Wei Chen <[email protected]>
Pennyzct · Aug 27, 2018 · a14cf06 · a14cf06
1 parent cc29b8d
commit a14cf06
Showing 1 changed file with 16 additions and 1 deletion.
diff --git a/virtcontainers/qemu_arm64.go b/virtcontainers/qemu_arm64.go
@@ -107,9 +107,24 @@ func getGuestGICVersion() (version string) {
 	return "host"
 }
 
+//In qemu, maximum number of vCPUs depends on the GIC version, or on how
+//many redistributors we can fit into the memory map.
+//related codes are under github.com/qemu/qemu/hw/arm/virt.c(Line 135 and 1306 in stable-2.11)
+//for now, qemu only supports v2 and v3, we treat v4 as v3 based on
+//backward compatibility.
+var gicList = map[uint32]uint32{
+	uint32(2): uint32(8),
+	uint32(3): uint32(123),
+	uint32(4): uint32(123),
+}
+
 // MaxQemuVCPUs returns the maximum number of vCPUs supported
 func MaxQemuVCPUs() uint32 {
-	return uint32(runtime.NumCPU())
+	if hostGICVersion != 0 {
+		return gicList[hostGICVersion]
+	} else {
+		return uint32(runtime.NumCPU())
+	}
 }
 
 func newQemuArch(config HypervisorConfig) qemuArch {