Re: [PATCH] clarify SHUTDOWN_suspend additional argument

[David Vrabel <david.vrabel@citrix.com>]

On 07/05/14 14:05, Stefano Stabellini wrote:
> SCHEDOP_shutdown has a third argument that is unused on HVM and ARM
> guests. Those guests pass 0 instead. Clarify the behaviour in the
> hypercall description.
> 
> Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> 
> diff --git a/xen/include/public/sched.h b/xen/include/public/sched.h
> index a30b11d..c170556 100644
> --- a/xen/include/public/sched.h
> +++ b/xen/include/public/sched.h
> @@ -77,8 +77,9 @@
>   * @arg == pointer to sched_shutdown_t structure.
>   *
>   * If the sched_shutdown_t reason is SHUTDOWN_suspend then this
> - * hypercall takes an additional extra argument which should be the
> - * MFN of the guest's start_info_t.
> + * hypercall takes an additional extra argument which should be:
> + *  - the MFN of the guest's start_info_t for x86 PV guests;
> + *  - 0 for x86 HVM guests and arm and arm64 guests.

Perhaps word this to reflect what the toolstack actually does?

* x86 PV guest must also set RDX (EDX for 32-bit guests) to the MFN
* of the guest's start info page.  RDX/EDX is the third hypercall
* argument.

David