Re: [Xen-devel] [PATCH 14/14] arm: implement foreign mapping using XENMEM_add_to_physmap_range

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Thu, 4 Oct 2012, Ian Campbell wrote:
> This interface is prefered for foreign mappings.

So now we have XENMEM_add_to_physmap_range but we only have
XENMEM_remove_from_physmap. Would it be worth to introduce a
XENMEM_remove_from_physmap_range too?


> Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
> ---
>  arch/arm/xen/enlighten.c       |   14 +++++++++-----
>  include/xen/interface/memory.h |   18 ++++++++++++++++++
>  2 files changed, 27 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
> index 9956af5..a9946aa 100644
> --- a/arch/arm/xen/enlighten.c
> +++ b/arch/arm/xen/enlighten.c
> @@ -51,15 +51,19 @@ static int map_foreign_page(unsigned long lpfn, unsigned 
> long fgmfn,
>                           unsigned int domid)
>  {
>       int rc;
> -     struct xen_add_to_physmap xatp = {
> +     struct xen_add_to_physmap_range xatp = {
>               .domid = DOMID_SELF,
> -             .u.foreign_domid = domid,
> +             .foreign_domid = domid,
> +             .size = 1,
>               .space = XENMAPSPACE_gmfn_foreign,
> -             .idx = fgmfn,
> -             .gpfn = lpfn,
>       };
> +     unsigned long idx = fgmfn;
> +     xen_pfn_t gpfn = lpfn;
>  
> -     rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp);
> +     set_xen_guest_handle(xatp.idxs, &idx);
> +     set_xen_guest_handle(xatp.gpfns, &gpfn);
> +
> +     rc = HYPERVISOR_memory_op(XENMEM_add_to_physmap_range, &xatp);
>       if (rc) {
>               pr_warn("Failed to map pfn to mfn rc:%d pfn:%lx mfn:%lx\n",
>                       rc, lpfn, fgmfn);

Wouldn't it make sense to call XENMEM_add_to_physmap_range only once for
the whole range, rather than once per page?


> diff --git a/include/xen/interface/memory.h b/include/xen/interface/memory.h
> index d38bdc1..e5675bc 100644
> --- a/include/xen/interface/memory.h
> +++ b/include/xen/interface/memory.h
> @@ -188,6 +188,24 @@ struct xen_add_to_physmap {
>  };
>  DEFINE_GUEST_HANDLE_STRUCT(xen_add_to_physmap);
>  
> +#define XENMEM_add_to_physmap_range 23
> +struct xen_add_to_physmap_range {
> +    /* Which domain to change the mapping for. */
> +    domid_t domid;
> +    uint16_t space; /* => enum phys_map_space */
> +
> +    /* Number of pages to go through */
> +    uint16_t size;
> +    domid_t foreign_domid; /* IFF gmfn_foreign */
> +
> +    /* Indexes into space being mapped. */
> +    GUEST_HANDLE(ulong) idxs;
> +
> +    /* GPFN in domid where the source mapping page should appear. */
> +    GUEST_HANDLE(xen_pfn_t) gpfns;
> +};
> +DEFINE_GUEST_HANDLE_STRUCT(xen_add_to_physmap_range);
> +
>  /*
>   * Translates a list of domain-specific GPFNs into MFNs. Returns a -ve error
>   * code on failure. This call only works for auto-translated guests.
> -- 
> 1.7.2.5
> 

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel