Add support for IBM s390x dasd disks

Installation on s390 dasd disks is a bit tricky,
this patch makes coreos-installer able to format,
create partitions, and finally install CoreOS on s390.

Signed-off-by: Nikita Dubrovskii <nikita@linux.ibm.com>

Cargo.toml

@@ -23,6 +23,12 @@ path = "src/main.rs"
 [profile.release]
 lto = true
 
+[target.'cfg(target_arch = "s390x")'.dependencies]
+dd-lib = "0.2.1"
+walkdir = "2.3.1"
+fdisk="^0.1.0"
+tempfile = "^3.1.0"
+
 [dependencies]
 byte-unit = "^3.0"
 clap = "^2.33"

src/install.rs

@@ -102,16 +102,25 @@ fn write_disk(
     dest: &mut File,
     ignition: Option<File>,
 ) -> Result<()> {
-    // Get sector size of destination, for comparing with image
-    let sector_size = get_sector_size(dest)?;
-
     // copy the image
-    write_image(source, dest, true, Some(sector_size))?;
+    if cfg!(target_arch = "s390x") && config.device.contains("dasd") {
+        #[cfg(target_arch = "s390x")]
+        crate::s390x::dasd::write_image_s390(config, source)?;
+    } else {
+        // Get sector size of destination, for comparing with image
+        let sector_size = get_sector_size(dest)?;
+        write_image(source, dest, true, Some(sector_size))?;
+    }
+
     reread_partition_table(dest)?;
     udev_settle()?;
 
     // postprocess
-    if ignition.is_some() || config.firstboot_kargs.is_some() || config.platform.is_some() {
+    if ignition.is_some()
+        || config.firstboot_kargs.is_some()
+        || config.platform.is_some()
+        || cfg!(target_arch = "s390x")
+    {
         let mount = mount_partition_by_label(&config.device, "boot", mount::MsFlags::empty())?;
         if let Some(ignition) = ignition {
             write_ignition(mount.mountpoint(), ignition)?;
@@ -122,6 +131,12 @@ fn write_disk(
         if let Some(platform) = config.platform.as_ref() {
             write_platform(mount.mountpoint(), platform)?;
         }
+        #[cfg(target_arch = "s390x")]
+        crate::s390x::zipl::install_bootloader(
+            mount.mountpoint(),
+            &config.device,
+            &config.firstboot_kargs,
+        )?;
     }
 
     Ok(())

src/main.rs

@@ -18,6 +18,8 @@ mod download;
 mod errors;
 mod install;
 mod iso;
+#[cfg(target_arch = "s390x")]
+mod s390x;
 mod source;
 mod verify;
 

src/s390x/README.md

@@ -0,0 +1,10 @@
+# CoreOS installation on IBM Z
+
+IBM s390x machines usually have DASD (Direct Access Storage Devices) disks.
+
+To use DASD as a Linux harddisk we have to pass thru several steps:
+  1) Using `dasdfmt` tool we have to low-level format it
+  2) Using `fdasd` tool we have to create partition(s) on it
+  3) Copy each partition from CoreOS image to corresponding partition on DASD)
+  4) Using `zipl` tool install  boot loader 
+  5) Using `chreipl` tool mark DASD as next boot devcie