Re: [PATCH 10/14] libxl: Check xc_maximum_ram_page for negative return values.

[Ian Campbell <ian.campbell@citrix.com>]

On Mon, 2015-03-16 at 11:39 -0400, Konrad Rzeszutek Wilk wrote:
> Instead of assuming everything is always OK.
> 
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> ---
>  tools/libxc/xg_save_restore.h | 3 +++
>  tools/misc/xen-mfndump.c      | 2 +-
>  2 files changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/libxc/xg_save_restore.h b/tools/libxc/xg_save_restore.h
> index bdd9009..6d26a0a 100644
> --- a/tools/libxc/xg_save_restore.h
> +++ b/tools/libxc/xg_save_restore.h
> @@ -313,6 +313,9 @@ static inline int get_platform_info(xc_interface *xch, uint32_t dom,
>  
>      *max_mfn = xc_maximum_ram_page(xch);
>  
> +    if (*max_mfn < 0)
> +        return 0;

*max_mfn is unsigned, so the negative would have been lost already.
Perhaps do the same sort of thing with a helper as the last patch?

> +
>      *hvirt_start = xen_params.virt_start;
>  
>      if ( xc_domain_get_guest_width(xch, dom, guest_width) != 0)
> diff --git a/tools/misc/xen-mfndump.c b/tools/misc/xen-mfndump.c
> index 0761f6e..81ef448 100644
> --- a/tools/misc/xen-mfndump.c
> +++ b/tools/misc/xen-mfndump.c
> @@ -184,7 +184,7 @@ int dump_ptes_func(int argc, char *argv[])
>  
>      /* Map M2P and obtain gpfn */
>      max_mfn = xc_maximum_ram_page(xch);
> -    if ( (mfn > max_mfn) ||
> +    if ( (max_mfn < 0 ) || (mfn > max_mfn) ||

Same here.

>           !(m2p_table = xc_map_m2p(xch, max_mfn, PROT_READ, NULL)) )
>      {
>          xc_unmap_domain_meminfo(xch, &minfo);