Re: [libvirt PATCH v2 2/3] conf: support firmware ISA debug console
On Wed, Feb 02, 2022 at 12:44:44PM +0000, Daniel P. Berrangé wrote:
Introduce support for
<serial type='pty'>
<target type='isa-debug'>
<model type='isa-debugcon'/>
</target>
<address type='isa' iobase='0x402'/>
</console>
which is used as a way to receive debug messages from the
firmware on x86 platforms.
Note that the default port is 0x0xe9 since that's the original
Bochs debug port. Thus for use with SeaBIOS/OVMF, the iobase
port needs to be explicitly set to 0x402.
The default is not set anywhere in the code, so I guess we're relying
on the fact that QEMU has that as the current default. Wouldn't it
make sense to have it reflected in the XML as well?
The previous version used 0x402 as the default, which apparently
doesn't match QEMU's own but is what most people will want in
practice. Wouldn't that be a better default for us? People who care
about Bochs compatibility can always explicitly set the appropriate
value themselves.
The rest of the changes look good.
--
Andrea Bolognani / Red Hat / Virtualization