Re: [PATCH v2 00/35] Introduce NS8250 UART emulator

[Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>]

On Thu, Dec 05, 2024 at 08:41:30PM -0800, Denis Mukhin via B4 Relay wrote:
> The patch series introduces initial in-hypervisor emulator for
> NS8250/NS16x50-compatible UARTs under CONFIG_HAS_VUART_NS8250.
> 
> In parallel domain creation scenario (hyperlaunch), NS8520 emulator helps
> early guest OS bringup debugging, because it eliminates dependency on the
> external emulator being operational by the time domains are created. Also,
> there's no early console facility similar to vpl011 to support x86 guest OS
> bring up.
> 
> The NS8250 emulator is disabled by default.

On a high level, why the mechanism used by earlyprintk=xen (IIUC i/o
port 0xe9) isn't enough?
Hyperlaunch can't start full (Xen-unaware) HVM domains anyway, so
a requirement to use a Xen-specific interface for the console shouldn't be
an issue, no?

-- 
Best Regards,
Marek Marczykowski-Górecki
Invisible Things Lab

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