[libvirt] [PATCH 0/1] bhyve: Make LPC slot number configurable

[Ivan Mishonov]

Yes, this is totally doable. I just don't know if it's a good idea to 
add a new device type specifically for bhyve LPC and nothing else. Even 
if we do it like this I'll still have to send another patch including 
the bhyve XML namespace as we need to be able to pass extra command line 
options to the bhyve process related to unimplemented MSRs on AMD Zen 
systems. I thought I'd do the 2 things in a similar manner as both of 
them are strictly bhyve specific

Regards,
Ivan

On 08/10/2018 04:58 PM, Daniel P. Berrangé wrote:
> On Fri, Aug 10, 2018 at 03:41:09PM +0300, Ivan Mishonov wrote:
>> This is how it's described in bhyve(8). Basically you need to configure one
>> for each bhyve VM. Otherwise the VM won't boot. I'm not sure if there's an
>> equivalent device in other Hypervisors. I've used KVM for quite some time
>> and didn't need to configure anything similar
>>
>> lpc         LPC PCI-ISA bridge with COM1 and COM2
>>              16550 serial ports and a boot ROM.
>>              The LPC bridge emulation can only be
>>              configured on bus 0.
> Ok, so we have the same thing in QEMU, but it is a built-in part of the
> machine type which we can't move between different PCI slots, so we have
> never had to represent it in the XML.
>
> I think conceptually we'd probably map this to a new controller type eg
>
>    <controller type="isa-bridge" index="0">
>        <address type="pci" domain="0" bus="0" slot="NNN" function="0"/>
>    </controller>
>
> So you'd just need to define the new "isa-bridge" controller type for
> the parser and have the bhyve driver honour the <address>, if provided.
>
> Regards,
> Daniel