config: don't exceed the number of physical cores

the maximum number of vCPUs per VM shouldn't not exceed the number of physical cores, otherwise we could face issues with KVM and other architectures fixes #1028 Signed-off-by: Julio Montes <[email protected]>
clearcontainers · Feb 23, 2018 · f6da537 · f6da537
1 parent 7067e6d
commit f6da537
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Showing 3 changed files with 12 additions and 13 deletions.
diff --git a/config.go b/config.go
@@ -185,15 +185,14 @@ func (h hypervisor) machineType() string {
 }
 
 func (h hypervisor) defaultVCPUs() uint32 {
-	if h.DefaultVCPUs < 0 {
-		return uint32(goruntime.NumCPU())
+	numCPUs := goruntime.NumCPU()
+
+	if h.DefaultVCPUs < 0 || h.DefaultVCPUs > int32(numCPUs) {
+		return uint32(numCPUs)
 	}
 	if h.DefaultVCPUs == 0 { // or unspecified
 		return defaultVCPUCount
 	}
-	if h.DefaultVCPUs > 255 { // qemu supports max 255
-		return 255
-	}
 
 	return uint32(h.DefaultVCPUs)
 }

diff --git a/config/configuration.toml.in b/config/configuration.toml.in
@@ -33,10 +33,10 @@ firmware = "@FIRMWAREPATH@"
 machine_accelerators="@MACHINEACCELERATORS@"
 
 # Default number of vCPUs per POD/VM:
-# unspecified or 0 --> will be set to @DEFVCPUS@
-# < 0              --> will be set to the actual number of physical cores
-# > 0 <= 255       --> will be set to the specified number
-# > 255            --> will be set to 255
+# unspecified or 0                --> will be set to @DEFVCPUS@
+# < 0                             --> will be set to the actual number of physical cores
+# > 0 <= number of physical cores --> will be set to the specified number
+# > number of physical cores      --> will be set to the actual number of physical cores
 default_vcpus = -1
 
 

diff --git a/config_test.go b/config_test.go
@@ -668,9 +668,9 @@ func TestHypervisorDefaults(t *testing.T) {
 	h.DefaultVCPUs = 2
 	assert.Equal(h.defaultVCPUs(), uint32(2), "default vCPU number is wrong")
 
-	// qemu supports max 255
-	h.DefaultVCPUs = 8086
-	assert.Equal(h.defaultVCPUs(), uint32(255), "default vCPU number is wrong")
+	numCPUs := goruntime.NumCPU()
+	h.DefaultVCPUs = int32(numCPUs) + 1
+	assert.Equal(h.defaultVCPUs(), uint32(numCPUs), "default vCPU number is wrong")
 
 	h.DefaultMemSz = 1024
 	assert.Equal(h.defaultMemSz(), uint32(1024), "default memory size is wrong")
@@ -1017,7 +1017,7 @@ func TestUpdateRuntimeConfiguration(t *testing.T) {
 func TestUpdateRuntimeConfigurationVMConfig(t *testing.T) {
 	assert := assert.New(t)
 
-	vcpus := uint(8)
+	vcpus := uint(2)
 	mem := uint(2048)
 
 	config := oci.RuntimeConfig{}