runtime: Add option "enable_guest_swap" to config hypervisor.qemu

This commit add option "enable_guest_swap" to config hypervisor.qemu.
It will enable swap in the guest. Default false.
When enable_guest_swap is enabled, insert a raw file to the guest as the
swap device if the swappiness of a container (set by annotation
"io.katacontainers.container.resource.swappiness") is bigger than 0.
The size of the swap device should be
swap_in_bytes (set by annotation
"io.katacontainers.container.resource.swap_in_bytes") - memory_limit_in_bytes.
If swap_in_bytes is not set, the size should be memory_limit_in_bytes.
If swap_in_bytes and memory_limit_in_bytes is not set, the size should be
default_memory.

Fixes: #2201

Signed-off-by: Hui Zhu <teawater@antfin.com>

src/runtime/pkg/katautils/config.go

@@ -133,6 +133,7 @@ type hypervisor struct {
 	DisableVhostNet         bool     `toml:"disable_vhost_net"`
 	GuestMemoryDumpPaging   bool     `toml:"guest_memory_dump_paging"`
 	ConfidentialGuest       bool     `toml:"confidential_guest"`
+	GuestSwap               bool     `toml:"enable_guest_swap"`
 }
 
 type runtime struct {
@@ -711,6 +712,7 @@ func newQemuHypervisorConfig(h hypervisor) (vc.HypervisorConfig, error) {
 		GuestMemoryDumpPath:     h.GuestMemoryDumpPath,
 		GuestMemoryDumpPaging:   h.GuestMemoryDumpPaging,
 		ConfidentialGuest:       h.ConfidentialGuest,
+		GuestSwap:               h.GuestSwap,
 	}, nil
 }
 
@@ -1066,6 +1068,7 @@ func GetDefaultHypervisorConfig() vc.HypervisorConfig {
 		TxRateLimiterMaxRate:    defaultTxRateLimiterMaxRate,
 		SGXEPCSize:              defaultSGXEPCSize,
 		ConfidentialGuest:       defaultConfidentialGuest,
+		GuestSwap:               defaultGuestSwap,
 	}
 }