From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Jan Beulich" <JBeulich@suse.com>
Subject: Re: [PATCH 04/18] xen: Preserve reserved grant entries
 when switching versions
Date: Fri, 13 Jan 2012 08:07:35 +0000
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To: Daniel De Graaf <dgdegra@tycho.nsa.gov>
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>>> On 13.01.12 at 00:35, Daniel De Graaf <dgdegra@tycho.nsa.gov> wrote:
> --- a/xen/include/public/grant_table.h
> +++ b/xen/include/public/grant_table.h
> @@ -117,6 +117,12 @@ struct grant_entry_v1 {
>  };
>  typedef struct grant_entry_v1 grant_entry_v1_t;
>  
> +/* External tools reserve first few grant table entries. */

This reads as if they must not be used (but could without taking extra
care) by other than the tools themselves, which would be an
incompatible change. As my understanding is that the change is
backwards compatible, I would suggest adjusting the comment.

Jan

> +#define GNTTAB_NR_RESERVED_ENTRIES     8
> +#define GNTTAB_RESERVED_CONSOLE        0
> +#define GNTTAB_RESERVED_XENSTORE       1
> +/* (the next 6 are reserved for future use) */
> +
>  /*
>   * Type of grant entry.
>   *  GTF_invalid: This grant entry grants no privileges.