# virsh dumpxml fedora34x86_64 | xmllint  -xpath '/domain/devices/console[2]' -
    <serial type="pty">
      <target type="isa-debug">
        <model type="isa-debugcon"/>
      </target>
      <address type="isa" iobase="0x402"/>
    </serial>

 # virsh console --devname console1 fedora34x86_64

Of course you really want to start the guest paused initially to allow
time to connect to the console before resuming CPUs, and thus be able
to catch early firmware output.

In v2:

 - Use <serial> instead of <console>

Daniel P. Berrangé (3):
  conf: validate serial port model in ABI checks
  conf: support firmware ISA debug console
  qemu: add tests for the ISA debug console command line

 docs/formatdomain.rst                         | 14 +++---
 docs/schemas/domaincommon.rng                 |  2 +
 src/conf/domain_conf.c                        | 26 +++++++++--
 src/conf/domain_conf.h                        |  2 +
 src/qemu/qemu_command.c                       |  2 +
 src/qemu/qemu_domain.c                        |  4 ++
 src/qemu/qemu_domain_address.c                |  1 +
 src/qemu/qemu_validate.c                      |  5 +++
 .../serial-debugcon.x86_64-latest.args        | 39 +++++++++++++++++
 tests/qemuxml2argvdata/serial-debugcon.xml    | 29 +++++++++++++
 tests/qemuxml2argvtest.c                      |  1 +
 tests/qemuxml2xmloutdata/serial-debugcon.xml  | 43 +++++++++++++++++++
 tests/qemuxml2xmltest.c                       |  1 +
 13 files changed, 161 insertions(+), 8 deletions(-)
 create mode 100644 tests/qemuxml2argvdata/serial-debugcon.x86_64-latest.args
 create mode 100644 tests/qemuxml2argvdata/serial-debugcon.xml
 create mode 100644 tests/qemuxml2xmloutdata/serial-debugcon.xml

-- 
2.34.1