Re: [Xen-devel] libxc: fix bug of xc_tbuf_get_size()

[George Dunlap <dunlapg@xxxxxxxxx>]

(Replying to the whole list)

This is changing a function that is only used in one place in the Xen
source tree; the change makes sense.

Acked-by: George Dunlap <george.dunlap@xxxxxxxxxxxxx>

On Tue, Feb 9, 2010 at 10:57 AM, Yu Zhiguo <yuzg@xxxxxxxxxxxxxx> wrote:
> The size in pages of trace buffer should be t_info->tbuf_size
> rather than t_info pages.
>
> Signed-off-by: Yu Zhiguo <yuzg@xxxxxxxxxxxxxx>
>
> diff --git a/tools/libxc/xc_tbuf.c b/tools/libxc/xc_tbuf.c
> --- a/tools/libxc/xc_tbuf.c
> +++ b/tools/libxc/xc_tbuf.c
> @@ -15,6 +15,7 @@
>  */
>
>  #include "xc_private.h"
> +#include <xen/trace.h>
>
>  static int tbuf_enable(int xc_handle, int enable)
>  {
> @@ -44,6 +45,7 @@
>
>  int xc_tbuf_get_size(int xc_handle, unsigned long *size)
>  {
> +    struct t_info *t_info;
>     int rc;
>     DECLARE_SYSCTL;
>
> @@ -52,9 +54,19 @@
>     sysctl.u.tbuf_op.cmd  = XEN_SYSCTL_TBUFOP_get_info;
>
>     rc = xc_sysctl(xc_handle, &sysctl);
> -    if (rc == 0)
> -        *size = sysctl.u.tbuf_op.size;
> -    return rc;
> +    if ( rc != 0 )
> +        return rc;
> +
> +    t_info = xc_map_foreign_range(xc_handle, DOMID_XEN,
> +                    sysctl.u.tbuf_op.size, PROT_READ | PROT_WRITE,
> +                    sysctl.u.tbuf_op.buffer_mfn);
> +
> +    if ( t_info == NULL || t_info->tbuf_size == 0 )
> +        return -1;
> +
> +    *size = t_info->tbuf_size;
> +
> +    return 0;
>  }
>
>  int xc_tbuf_enable(int xc_handle, unsigned long pages, unsigned long *mfn,
>
>
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> http://lists.xensource.com/xen-devel
>

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