livemedia-creator: Use /usr/libexec/qemu-kvm on supported arches

For RHEL qemu support is limited, and only qemu-kvm is supported. This
updates lmc to only support it on x86 and aarch64.
It also disables cross-arch building, it is only supported on the same
arch as the host.

Related: RHEL-31830

src/pylorax/creator.py

@@ -48,7 +48,7 @@
 
 
 # Default parameters for rebuilding initramfs, override with --dracut-arg or --dracut-conf
-DRACUT_DEFAULT = ["--xz", "--add", "livenet dmsquash-live dmsquash-live-ntfs convertfs pollcdrom qemu qemu-net",
+DRACUT_DEFAULT = ["--xz", "--add", "livenet dmsquash-live convertfs pollcdrom qemu qemu-net",
                   "--no-hostonly", "--debug", "--no-early-microcode"]
 
 RUNTIME = "images/install.img"

src/pylorax/installer.py

@@ -137,36 +137,21 @@ class QEMUInstall(object):
     """
     # Mapping of arch to qemu command and options
     QEMU = {"x86_64": {
-                "cmd": "qemu-system-x86_64",
-                "arches": ["x86_64", "i386"],
+                "cmd": "/usr/libexec/qemu-kvm",
+                "arches": ["x86_64"],
                 "machine": "q35",
                 "uefi": ["ovmf/OVMF_CODE.secboot.fd", "ovmf/OVMF_VARS.secboot.fd"],
                 "uefi_machine": "q35,smm=on",
                 "uefi_args": ["-global", "driver=cfi.pflash01,property=secure,value=on"],
                 },
-            "i386": {
-                "cmd": "qemu-system-i386",
-                "arches": ["i386"],
-                "machine": "q35",
-                },
-            "arm": {
-                "cmd": "qemu-system-arm",
-                "arches": ["arm"],
-                "machine": "virt",
-                },
             "aarch64": {
-                "cmd": "qemu-system-aarch64",
-                "arches": ["aarch64", "arm"],
+                "cmd": "/usr/libexec/qemu-kvm",
+                "arches": ["aarch64"],
                 "machine": "virt",
                 "uefi": ["aarch64/QEMU_EFI-pflash.raw", "aarch64/vars-template-pflash.raw"],
                 "uefi_machine": "virt",
                 "uefi_args": ["-global", "driver=cfi.pflash01,property=secure,value=off"],
                 },
-            "ppc64le": {
-                "cmd": "qemu-system-ppc64",
-                "arches": ["ppc64le"],
-                "machine": "pseries",
-                },
         }
 
     def __init__(self, opts, iso, ks_paths, disk_img, img_size=2048,
@@ -186,7 +171,7 @@ def __init__(self, opts, iso, ks_paths, disk_img, img_size=2048,
         :param int memory: Amount of RAM to assign to the virt, in MiB
         :param int vcpus: Number of virtual cpus
         :param str vnc: Arguments to pass to qemu -display
-        :param str arch: Optional architecture to use in the virt
+        :param str arch: Unsupported on RHEL10
         :param cancel_func: Function that returns True if the installation fails
         :type cancel_func: function
         :param str virtio_host: Hostname to connect virtio log to
@@ -197,12 +182,10 @@ def __init__(self, opts, iso, ks_paths, disk_img, img_size=2048,
         """
         target_arch = arch or os.uname().machine
         # Lookup qemu-system- for arch if passed, or try to guess using host arch
-        if target_arch in self.QEMU:
+        if target_arch in self.QEMU and os.path.exists(self.QEMU[target_arch]["cmd"]):
             qemu_cmd = [self.QEMU[target_arch]["cmd"]]
-        elif os.path.exists("/usr/bin/"+"qemu-system-"+os.uname().machine):
-            qemu_cmd = ["/usr/bin/qemu-system-"+os.uname().machine]
         else:
-            raise InstallError("/usr/bin/qemu-system-%s does not exist, cannot run qemu" % os.uname().machine)
+            raise InstallError("RHEL10 does not support running qemu on %s" % os.uname().machine)
 
         # Default to using the host cpu capabilities
         qemu_cmd += ["-cpu", opts.cpu or "host"]
@@ -269,6 +252,9 @@ def __init__(self, opts, iso, ks_paths, disk_img, img_size=2048,
         log.info("qemu %s", display_args)
         qemu_cmd += ["-nographic", "-monitor", "none", "-serial", "null", "-display", display_args ]
 
+        # Setup virtio networking
+        qemu_cmd += ["-netdev", "user,id=n1", "-device", "virtio-net-pci,netdev=n1"]
+
         # Setup the virtio log port
         qemu_cmd += ["-device", "virtio-serial-pci,id=virtio-serial0"]
         qemu_cmd += ["-device", "virtserialport,bus=virtio-serial0.0,nr=1,chardev=charchannel0"

src/sbin/livemedia-creator

@@ -20,7 +20,6 @@
 import logging
 log = logging.getLogger("livemedia-creator")
 
-import glob
 import os
 import sys
 import tempfile
@@ -87,8 +86,8 @@ def main():
         errors.append("the volume id cannot be longer than 32 characters")
 
     if is_install and not opts.no_virt \
-       and not any(glob.glob("/usr/bin/qemu-system-*")):
-        errors.append("qemu needs to be installed.")
+       and not os.path.exists("/usr/libexec/qemu-kvm"):
+        errors.append("qemu-kvm needs to be installed.")
 
     if is_install and opts.no_virt \
        and not os.path.exists("/usr/sbin/anaconda"):
@@ -147,6 +146,9 @@ def main():
     if opts.domacboot and not os.path.exists("/usr/sbin/mkfs.hfsplus"):
         errors.append("mkfs.hfsplus is missing. Install hfsplus-tools, or pass --nomacboot")
 
+    if opts.arch != None:
+        errors.append("RHEL10 only supports virt for the host arch.")
+
     if os.getuid() != 0:
         errors.append("You need to run this as root")