libvirt: Add podvm instance cpu and mem size support for libvirt

Use io.katacontainers.config.hypervisor.default_vcpus and io.katacontainers.config.hypervisor.default_memory annotations to set the libvirt podvm instance. Use the default values if no annotations are provided.

Fixes: confidential-containers#1650

Signed-off-by : savitrilh <[email protected]>

Author: savitrilh

src/cloud-providers/libvirt/libvirt.go

@@ -27,6 +27,12 @@ const (
 	GetDomainIPsRetries = 20
 	// The sleep time between retries to get the domain IP addresses
 	GetDomainIPsSleep = time.Second * 3
+	// Default Memory size
+	LIBVIRT_DEF_MEM_SIZE = uint(8)
+	// Default CPU size
+	LIBVIRT_DEF_CPU_SIZE = uint(2)
+	// Convert Memory size from MegaBytes to GigaBytes
+	LIBVIRT_CONV_MEM = 1000
 )
 
 type domainConfig struct {
@@ -529,8 +535,14 @@ func getDomainIPs(dom *libvirt.Domain) ([]netip.Addr, error) {
 
 func CreateDomain(ctx context.Context, libvirtClient *libvirtClient, v *vmConfig) (result *createDomainOutput, err error) {
 
-	v.cpu = uint(2)
-	v.mem = uint(8)
+	// Assign the default CPU size and memory when no default memory and
+	// CPU are provided through annotations
+	if v.cpu == 0 {
+		v.cpu = LIBVIRT_DEF_CPU_SIZE
+	}
+	if v.mem == 0 {
+		v.mem = LIBVIRT_DEF_MEM_SIZE
+	}
 	v.rootDiskSize = uint64(10)
 
 	exists, err := checkDomainExistsByName(v.name, libvirtClient)

src/cloud-providers/libvirt/provider.go

@@ -56,9 +56,12 @@ func (p *libvirtProvider) CreateInstance(ctx context.Context, podName, sandboxID
 		return nil, err
 	}
 
-	// TODO: Specify the maximum instance name length in Libvirt
-	vm := &vmConfig{name: instanceName, userData: userData, firmware: p.serviceConfig.Firmware}
+	// Convert the memory units in gigabytes
+	instanceMemory := uint(spec.Memory / LIBVIRT_CONV_MEM)
+	instanceVCPUs := uint(spec.VCPUs)
 
+	// TODO: Specify the maximum instance name length in Libvirt
+	vm := &vmConfig{name: instanceName, cpu: instanceVCPUs, mem: instanceMemory, userData: userData, firmware: p.serviceConfig.Firmware}
 	if p.serviceConfig.DisableCVM {
 		vm.launchSecurityType = NoLaunchSecurity
 	} else if p.serviceConfig.LaunchSecurity != "" {