Re: [Xen-devel] [PATCH v2] xen/arm: create_xen_entries has to flush TLBs on every CPU

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Wed, 2014-04-23 at 12:36 +0100, Julien Grall wrote:
> The function create_xen_entries creates mappings in second-level page tables
> which is shared between every CPU.
> 
> Only flushing TLBs on local processor may result to wrong behaviour
> when io{re,un}map is used.
> 
> Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>

Acked + applied.

> ---
> 
> This patch is candidate to be backported to Xen 4.4.

Noted. I think you said this would need some backporting? Given that I'm
inclined to hold off on backporting this until someone who is using 4.4
and tripping over the issue reports/requests it.

> 
> create_p2m_entries is only used by vmap ( iore{,un}map functions.
> 
> Upstream Xen 4.4 calls these functions only when 1 CPU is online so it's
> "safe". But people who make product based on Xen 4.4 might want to use theses
> functions when all CPUs are UP.
> 
>     Changes in v2:
>         - The patch change create_xen_entries not create_p2m_entries
> ---
>  xen/arch/arm/mm.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
> index 362bc8d..eac228c 100644
> --- a/xen/arch/arm/mm.c
> +++ b/xen/arch/arm/mm.c
> @@ -845,7 +845,7 @@ static int create_xen_entries(enum xenmap_operation op,
>                  BUG();
>          }
>      }
> -    flush_xen_data_tlb_range_va_local(virt, PAGE_SIZE * nr_mfns);
> +    flush_xen_data_tlb_range_va(virt, PAGE_SIZE * nr_mfns);
>  
>      rc = 0;
>  




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