Re: [PATCH v6 01/15] emul/vuart: introduce framework for UART emulators

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Fri, 5 Sep 2025, dmukhin@xxxxxxx wrote:
> From: Denis Mukhin <dmukhin@xxxxxxxx> 
> 
> Introduce a driver framework to abstract UART emulators in the hypervisor.
> 
> That allows for architecture-independent handling of virtual UARTs in the
> console driver and simplifies enabling new UART emulators.
> 
> The framework is built under CONFIG_VUART_FRAMEWORK, which will be
> automatically enabled once the user enables any UART emulator.
> 
> Current implementation supports maximum of one vUART of each kind per domain.
> 
> Use new domain_has_vuart() in the console driver code to check whether to
> forward console input to the domain using vUART.
> 
> Enable console forwarding over vUART for hardware domains with a vUART. That
> enables console forwarding to dom0 on x86, since console can be forwarded only
> to Xen, dom0 and pvshim on x86 as of now.
> 
> Note: existing vUARTs are deliberately *not* hooked to the new framework to
> minimize the scope of the patch: vpl011 (i.e. SBSA) emulator and "vuart" (i.e.
> minimalistic MMIO-mapped dtuart for hwdoms on Arm) are kept unmodified.
> 
> No functional changes for non-x86 architectures.
> 
> Signed-off-by: Denis Mukhin <dmukhin@xxxxxxxx>

Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>