Re: [Xen-devel] [PATCH] xen/arm: map_domain_page: reuse slots with avail == 0

[Tim Deegan <tim@xxxxxxx>]

At 18:45 +0100 on 27 Sep (1380307517), Stefano Stabellini wrote:
> If a slot has avail == 0 but still points to the right mfn, reuse it.
> 
> Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
> ---
>  xen/arch/arm/mm.c |   15 ++++++++-------
>  1 files changed, 8 insertions(+), 7 deletions(-)
> 
> diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
> index 44ec0e3..cbcb769 100644
> --- a/xen/arch/arm/mm.c
> +++ b/xen/arch/arm/mm.c
> @@ -232,7 +232,13 @@ void *map_domain_page(unsigned long mfn)
>            i < DOMHEAP_ENTRIES;
>            slot = (slot + 1) % DOMHEAP_ENTRIES, i++ )
>      {
> -        if ( map[slot].pt.avail == 0 )
> +        if ( map[slot].pt.avail < 0xf && map[slot].pt.base == slot_mfn )

This needs to check pt.valid as well, in case this path is ever used to
map frame 0.

Tim.

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