qemu: explicitly pass the basedisk format to QEMU

Signed-off-by: Akihiro Suda <[email protected]>

pkg/qemu/qemu.go

@@ -570,14 +570,21 @@ func Cmdline(cfg Config) (string, []string, error) {
 	}
 	if isBaseDiskCDROM {
 		args = appendArgsIfNoConflict(args, "-boot", "order=d,splash-time=0,menu=on")
-		args = append(args, "-drive", fmt.Sprintf("file=%s,media=cdrom,readonly=on", baseDisk))
+		args = append(args, "-drive", fmt.Sprintf("file=%s,format=raw,media=cdrom,readonly=on", baseDisk))
 	} else {
 		args = appendArgsIfNoConflict(args, "-boot", "order=c,splash-time=0,menu=on")
 	}
 	if diskSize, _ := units.RAMInBytes(*cfg.LimaYAML.Disk); diskSize > 0 {
 		args = append(args, "-drive", fmt.Sprintf("file=%s,if=virtio,discard=on", diffDisk))
 	} else if !isBaseDiskCDROM {
-		args = append(args, "-drive", fmt.Sprintf("file=%s,if=virtio,discard=on", baseDisk))
+		baseDiskInfo, err := imgutil.GetInfo(baseDisk)
+		if err != nil {
+			return "", nil, fmt.Errorf("failed to get the information of %q: %w", baseDisk, err)
+		}
+		if baseDiskInfo.Format == "" {
+			return "", nil, fmt.Errorf("failed to inspect the format of %q", baseDisk)
+		}
+		args = append(args, "-drive", fmt.Sprintf("file=%s,format=%s,if=virtio,discard=on", baseDisk, baseDiskInfo.Format))
 	}
 	for _, extraDisk := range extraDisks {
 		args = append(args, "-drive", fmt.Sprintf("file=%s,if=virtio,discard=on", extraDisk))