Merge pull request #585 from Pennyzct/smp

qemu: refactor maximum vcpus supported in aarch64

virtcontainers/qemu_arm64.go

@@ -107,8 +107,22 @@ 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 {
+	if hostGICVersion != 0 {
+		return gicList[hostGICVersion]
+	}
 	return uint32(runtime.NumCPU())
 }
 

virtcontainers/qemu_arm64_test.go

@@ -7,6 +7,10 @@ package virtcontainers
 
 import (
 	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"runtime"
 	"testing"
 
 	govmmQemu "github.com/intel/govmm/qemu"
@@ -50,3 +54,52 @@ func TestQemuArm64MemoryTopology(t *testing.T) {
 	m := arm64.memoryTopology(mem, hostMem)
 	assert.Equal(expectedMemory, m)
 }
+
+func TestMaxQemuVCPUs(t *testing.T) {
+	assert := assert.New(t)
+
+	type testData struct {
+		contents       string
+		expectedResult uint32
+	}
+
+	data := []testData{
+		{"", uint32(runtime.NumCPU())},
+		{"  1:          0          0     GICv2  25 Level     vgic \n", uint32(8)},
+		{"  1:          0          0     GICv3  25 Level     vgic \n", uint32(123)},
+		{"  1:          0          0     GICv4  25 Level     vgic \n", uint32(123)},
+	}
+
+	tmpdir, err := ioutil.TempDir("", "")
+	if err != nil {
+		panic(err)
+	}
+	defer os.RemoveAll(tmpdir)
+
+	savedGicProfile := gicProfile
+
+	testGicProfile := filepath.Join(tmpdir, "interrupts")
+
+	// override
+	gicProfile = testGicProfile
+
+	defer func() {
+		gicProfile = savedGicProfile
+	}()
+
+	savedHostGICVersion := hostGICVersion
+
+	defer func() {
+		hostGICVersion = savedHostGICVersion
+	}()
+
+	for _, d := range data {
+		err := ioutil.WriteFile(gicProfile, []byte(d.contents), os.FileMode(0640))
+		assert.NoError(err)
+
+		hostGICVersion = getHostGICVersion()
+		vCPUs := MaxQemuVCPUs()
+
+		assert.Equal(d.expectedResult, vCPUs)
+	}
+}