Re: [Xen-devel] [PATCH v8 14/15] xen: make grant table limits boot parameters dom0 only

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 20.09.17 at 08:34, <jgross@xxxxxxxx> wrote:
> --- a/xen/arch/arm/domain_build.c
> +++ b/xen/arch/arm/domain_build.c
> @@ -2098,7 +2098,7 @@ static void __init find_gnttab_region(struct domain *d,
>      kinfo->gnttab_size = (_etext - _stext) & PAGE_MASK;
>  
>      /* Make sure the grant table will fit in the region */
> -    if ( (kinfo->gnttab_size >> PAGE_SHIFT) < max_grant_frames )
> +    if ( grant_table_verify_size(d, kinfo->gnttab_size >> PAGE_SHIFT) )
>          panic("Cannot find a space for the grant table region\n");

I can see how this may cause complications with my alternative
proposal for the meaning of the command line options, but that's
solvable for sure.

> @@ -3462,6 +3449,10 @@ grant_table_create(
>      struct domain *d)
>  {
>      struct grant_table *t;
> +    static unsigned int max_grant_frames;
> +    static unsigned int max_maptrack_frames;
> +    integer_param("gnttab_max_frames", max_grant_frames);
> +    integer_param("gnttab_max_maptrack_frames", max_maptrack_frames);
>  
>      if ( (t = xzalloc(struct grant_table)) == NULL )
>          return -ENOMEM;
> @@ -3469,14 +3460,17 @@ grant_table_create(
>      /* Simple stuff. */
>      percpu_rwlock_resource_init(&t->lock, grant_rwlock);
>      spin_lock_init(&t->maptrack_lock);
> -    t->max_grant_frames = max_grant_frames;
> -    t->max_maptrack_frames = max_maptrack_frames;
>  
>      /* Okay, install the structure. */
>      d->grant_table = t;
>  
>      if ( d->domain_id == 0 )
> +    {
> +        t->max_grant_frames = max_grant_frames ? : 
> DEFAULT_MAX_NR_GRANT_FRAMES;
> +        t->max_maptrack_frames =
> +                           max_maptrack_frames ? : 
> DEFAULT_MAX_MAPTRACK_FRAMES;
>          return grant_table_init(t);
> +    }

The use here makes it that in effect the two variables could then
become __initdata. Maybe their definition should then even move
here (if the other proposal would be discarded).

> +bool __init grant_table_verify_size(struct domain *d, unsigned int frames)

const

Jan


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