Re: [PATCH] x86/hvm: reserve another HVM context save record ID for Amazon

[Jan Beulich <jbeulich@xxxxxxxx>]

On 07.01.2022 13:55, David Vrabel wrote:
> Amazon's guest transparent live migration work needs another save
> record (for event channel upcall vectors). Reserve another HVM context
> save record ID for this.

I have to admit that I have reservations: I didn't really like seeing
the original range getting reserved. Even less so I'd like to see
extensions / further such reservations. The more that iirc the
original reservation was accepted based on a (perhaps vague) promise
of the respective uses actually getting upstreamed. Yet that hasn't
happened (nor even started to happen) in slightly over 2 years time,
iirc.

What I could see as a compromise is to have, say, vendor ranges
higher up in number space.

Jan

> Signed-off-by: David Vrabel <dvrabel@xxxxxxxxxxxx>
> ---
> I've added it to the end, keeping the unused ID at 21.
> ---
>  xen/include/public/arch-x86/hvm/save.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/xen/include/public/arch-x86/hvm/save.h 
> b/xen/include/public/arch-x86/hvm/save.h
> index 773a380bc2..2de3dfd9bb 100644
> --- a/xen/include/public/arch-x86/hvm/save.h
> +++ b/xen/include/public/arch-x86/hvm/save.h
> @@ -641,7 +641,7 @@ struct hvm_msr {
>  
>  #define CPU_MSR_CODE  20
>  
> -/* Range 22 - 34 (inclusive) reserved for Amazon */
> +/* Range 22 - 35 (inclusive) reserved for Amazon */
>  
>  /*
>   * Largest type-code in use