On 13.10.2025 12:01, Alejandro Vallejo wrote:
> On Wed Oct 8, 2025 at 6:04 PM CEST, Jan Beulich wrote:
>> On 30.09.2025 14:52, Grygorii Strashko wrote:
>>> --- a/xen/arch/x86/hvm/Kconfig
>>> +++ b/xen/arch/x86/hvm/Kconfig
>>> @@ -62,6 +62,16 @@ config ALTP2M
>>>  
>>>       If unsure, stay with defaults.
>>>  
>>> +config VIRIDIAN
>>> +   bool "Hyper-V enlightenments for guests" if EXPERT
>>> +   default y
>>> +   help
>>> +     Support optimizations for Hyper-V guests such as faster hypercalls,
>>> +     efficient timer and interrupt handling, and enhanced paravirtualized
>>> +     I/O. This is to improve performance and compatibility of Windows VMs.
>>
>> What is "paravirtualized I/O" about in this context?
> 
> Hypervisor-assisted IPIs, TLB flushes, etc. Or so I understood back when I 
> said
> that looked ok.

Just to clarify my take: IPIs fall under "interrupt handling", and TLB flushes
to me fall under memory management, not I/O.

> I see there could be confusion with Xen PV device protocols,
> but as far as the user of the help message is concerned it makes no 
> difference.

Does it not? To me it does.

> One could even remove the examples and leave it as "... for Hyper-V guests. 
> This
> is to...". They are truly inconsequential.
> 
> All that matters is that (modern) Windows won't run without it, and that it
> provides some indeterminate hypervisor-provided assists to try to reduce some
> virtualization overheads.

I think I'm happy for the other examples to stay, as they provide some extra
context for less aware users.

Jan

Reply via email to