Re: [Xen-devel] [PATCH] PVH linux: Use ballooning to allocate grant table pages

[Konrad Rzeszutek Wilk <konrad@xxxxxxxxxx>]

On Thu, Jan 31, 2013 at 06:30:15PM -0800, Mukesh Rathor wrote:
> This patch fixes a fixme in Linux to use alloc_xenballooned_pages() to
> allocate pfns for grant table pages instead of kmalloc. This also
> simplifies add to physmap on the xen side a bit.

Pulled this.
> 
> Signed-off-by: Mukesh Rathor <mukesh.rathor@xxxxxxxxxx>
> 
> ---
>  drivers/xen/grant-table.c |   37 ++++++++++++++++++++++++++-----------
>  1 files changed, 26 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
> index 9c0019d..d731f39 100644
> --- a/drivers/xen/grant-table.c
> +++ b/drivers/xen/grant-table.c
> @@ -47,6 +47,7 @@
>  #include <xen/grant_table.h>
>  #include <xen/interface/memory.h>
>  #include <xen/hvc-console.h>
> +#include <xen/balloon.h>
>  #include <asm/xen/hypercall.h>
>  #include <asm/xen/interface.h>
>  
> @@ -1138,27 +1139,41 @@ static void gnttab_request_version(void)
>               grant_table_version);
>  }
>  
> +static int xlated_setup_gnttab_pages(int numpages, void **addr)
> +{
> +     int i, rc;
> +     unsigned long pfns[numpages];
> +     struct page *pages[numpages];
> +
> +     rc = alloc_xenballooned_pages(numpages, pages, 0);
> +     if (rc != 0) {
> +             pr_warn("%s Could not balloon alloc %d pfns rc:%d\n", __func__,
> +                     numpages, rc);
> +             return -ENOMEM;
> +     }
> +     for (i = 0; i < numpages; i++)
> +             pfns[i] = page_to_pfn(pages[i]);
> +
> +     rc = arch_gnttab_map_shared(pfns, numpages, numpages, addr);
> +     return rc;
> +}
> +
>  int gnttab_resume(void)
>  {
> -     unsigned int max_nr_gframes;
> -     char *kmsg = "Failed to kmalloc pages for pv in hvm grant frames\n";
> +     unsigned int rc, max_nr_gframes;
>  
>       gnttab_request_version();
>       max_nr_gframes = gnttab_max_grant_frames();
>       if (max_nr_gframes < nr_grant_frames)
>               return -ENOSYS;
>  
> -     /* PVH note: xen will free existing kmalloc'd mfn in
> -      * XENMEM_add_to_physmap. TBD/FIXME: use xen ballooning instead of
> -      * kmalloc(). */
>       if (xen_pv_domain() && xen_feature(XENFEAT_auto_translated_physmap) &&
>           !gnttab_shared.addr) {
> -             gnttab_shared.addr =
> -                     kmalloc(max_nr_gframes * PAGE_SIZE, GFP_KERNEL);
> -             if (!gnttab_shared.addr) {
> -                     pr_warn("%s", kmsg);
> -                     return -ENOMEM;
> -             }
> +
> +             rc = xlated_setup_gnttab_pages(max_nr_gframes,
> +                                            &gnttab_shared.addr);
> +             if (rc != 0)
> +                     return rc;
>       }
>       if (xen_pv_domain())
>               return gnttab_map(0, nr_grant_frames - 1);
> -- 
> 1.7.2.3
> 

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