s390x: add support for IBM Z DASD disks

Support formatting, creating partitions, and installing onto s390x
DASD disks.

Co-authored-by: Benjamin Gilbert <bgilbert@redhat.com>

.travis.yml

@@ -6,9 +6,16 @@ rust:
   - beta
   - nightly
 
+arch:
+  - amd64
+  - s390x
+
 matrix:
   allow_failures:
     - rust: nightly
+    # VM apparently has broken network access
+    - rust: 1.41.0
+      arch: s390x
 
 env:
   global:

Cargo.toml

@@ -23,6 +23,9 @@ path = "src/main.rs"
 [profile.release]
 lto = true
 
+[target.'cfg(target_arch = "s390x")'.dependencies]
+gptman = { version = "^0.6", default-features = false }
+
 [dependencies]
 bincode = "^1.3"
 byte-unit = "^4.0"

scripts/coreos-installer-service

@@ -10,6 +10,9 @@ PERSIST_KERNEL_NET_PARAMS=("ipv6.disable" "net.ifnames" "net.naming-scheme")
 # List from https://www.mankier.com/7/dracut.cmdline#Description-Network
 PERSIST_DRACUT_NET_PARAMS=("ip" "ifname" "rd.route" "bootdev" "BOOTIF" "rd.bootif" "nameserver" "rd.peerdns" "biosdevname" "vlan" "bond" "team" "bridge" "rd.net.timeout.carrier" "coreos.no_persist_ip")
 
+# IBM S390X params to persist
+PERSIST_S390X_PARAMS=("rd.dasd" "rd.zfcp" "rd.znet" "zfcp.allow_lun_scan" "cio_ignore")
+
 args=("install")
 
 cmdline=( $(</proc/cmdline) )
@@ -61,19 +64,24 @@ if [ -n "${ignition_url}" -a "${ignition_url}" != "skip" ]; then
     args+=("--ignition-url" "${ignition_url}" "--insecure-ignition")
 fi
 
-# First-boot kernel arguments. Filter out any args that aren't in our
-# list of networking arguments to forward and store them in $firstboot_args
+# Forward whitelisted kernel arguments to the installed system. We have
+# separate sets of whitelists for first-boot kargs and persistent kargs.
+# Only pass --firstboot-kargs if additional networking options have been
+# specified, since the default in coreos-assembler specifies
+# `rd.neednet=1 ip=dhcp` when no options are persisted.
 firstboot_args=""
 for item in "${cmdline[@]}"; do
     for param in "${PERSIST_KERNEL_NET_PARAMS[@]}" "${PERSIST_DRACUT_NET_PARAMS[@]}"; do
         if [[ $item =~ ^$param(=.*)?$ ]]; then
             firstboot_args+="${item} "
         fi
     done
+    for param in "${PERSIST_S390X_PARAMS[@]}"; do
+        if [[ $item =~ ^$param(=.*)?$ ]]; then
+            args+=("--append-karg" "${item}")
+        fi
+    done
 done
-# Only pass firstboot-kargs if additional networking options have been
-# specified, since the default in ignition-dracut specifies
-# `rd.neednet=1 ip=dhcp` when no options are persisted
 if [ -n "${firstboot_args}" ]; then
     args+=("--firstboot-args" "rd.neednet=1 ${firstboot_args}")
 fi
@@ -94,4 +102,3 @@ udevadm settle
 # Install
 echo "coreos-installer ${args[@]}"
 coreos-installer "${args[@]}"
-

src/blockdev.rs

@@ -569,7 +569,7 @@ mod ioctl {
     ioctl_read!(blkgetsize64, 0x12, 114, libc::size_t);
 }
 
-fn udev_settle() -> Result<()> {
+pub fn udev_settle() -> Result<()> {
     // "udevadm settle" silently no-ops if the udev socket is missing, and
     // then lsblk can't find partition labels.  Catch this early.
     if !Path::new("/run/udev/control").exists() {

src/install.rs

@@ -24,6 +24,8 @@ use crate::cmdline::*;
 use crate::download::*;
 use crate::errors::*;
 use crate::io::*;
+#[cfg(target_arch = "s390x")]
+use crate::s390x;
 use crate::source::*;
 
 /// Integrity verification hash for an Ignition config.
@@ -99,6 +101,13 @@ pub fn install(config: &InstallConfig) -> Result<()> {
         }
     }
 
+    #[cfg(target_arch = "s390x")]
+    {
+        if is_dasd(config)? {
+            s390x::prepare_dasd(&config)?;
+        }
+    }
+
     // open output; ensure it's a block device and we have exclusive access
     let mut dest = OpenOptions::new()
         .write(true)
@@ -179,11 +188,17 @@ fn write_disk(
     let sector_size = get_sector_size(dest)?;
 
     // copy the image
+    #[allow(clippy::match_bool, clippy::match_single_binding)]
+    let image_copy = match is_dasd(config)? {
+        #[cfg(target_arch = "s390x")]
+        true => s390x::image_copy_s390x,
+        _ => image_copy_default,
+    };
     write_image(
         source,
         dest,
         Path::new(&config.device),
-        image_copy_default,
+        image_copy,
         true,
         Some(sector_size),
     )?;
@@ -196,6 +211,7 @@ fn write_disk(
         || config.delete_kargs.is_some()
         || config.platform.is_some()
         || config.network_config.is_some()
+        || cfg!(target_arch = "s390x")
     {
         let mount =
             Disk::new(&config.device).mount_partition_by_label("boot", mount::MsFlags::empty())?;
@@ -225,6 +241,8 @@ fn write_disk(
         if let Some(network_config) = config.network_config.as_ref() {
             copy_network_config(mount.mountpoint(), network_config)?;
         }
+        #[cfg(target_arch = "s390x")]
+        s390x::install_bootloader(mount.mountpoint(), &config.device)?;
     }
 
     Ok(())
@@ -463,6 +481,11 @@ fn clear_partition_table(dest: &mut File, table: &mut dyn PartTable) -> Result<(
     Ok(())
 }
 
+fn is_dasd(config: &InstallConfig) -> Result<bool> {
+    let (target, _) = resolve_link(&config.device)?;
+    Ok(target.to_string_lossy().starts_with("/dev/dasd"))
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

src/main.rs

@@ -20,6 +20,8 @@ mod install;
 mod io;
 mod iso;
 mod osmet;
+#[cfg(target_arch = "s390x")]
+mod s390x;
 mod source;
 mod verify;
 

src/s390x/README.md

@@ -0,0 +1,11 @@
+# CoreOS installation on IBM Z
+
+IBM s390x machines usually have DASD (Direct Access Storage Device) disks.
+
+To use DASD as a Linux hard disk we have to perform several steps:
+
+1. Low-level format it using `dasdfmt` tool
+2. Create partitions on it using `fdasd` tool
+3. Copy each partition from CoreOS image to corresponding partition on DASD
+4. Install boot loader using `zipl` tool
+5. Mark DASD as next boot device using `chreipl` tool