Re: [Xen-devel] [PATCH] Fix cpumap setting before passing to XEN

[Wei Liu <wei.liu2@xxxxxxxxxx>]

On Mon, Apr 11, 2016 at 09:42:57AM +0800, Zhenzhong Duan wrote:
> It's tool's duty to pass a correct cpumap to XEN. On a host with less than
> 64
> CPUS, it just shows below error.
> 
> [root@localhost /]# xm vcpu-pin 3 all all
> Error: Cannot pin vcpu: 0 to cpu: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12,
> 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31,
> 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50,
> 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63] - (22, 'Invalid
> argument')
> 

This error clearly shows that the upper layer is not passing down the
right cpumap. So this example along won't convince me to that this is a
bug in python binding. It's free to reject input that it deems wrong.

I guess the question is more or less what should it do in such
situation. So ...

> The fix make it same as in xl code.
> 

Is there reference to this? I guess the commit message  or mail thread
will shed more light on the expected behaviour.

BTW please CC relevant maintainers in the future, thanks.

Wei.

> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@xxxxxxxxxx>
> ---
>  tools/python/xen/lowlevel/xc/xc.c |    4 +++-
>  1 files changed, 3 insertions(+), 1 deletions(-)
> 
> diff --git a/tools/python/xen/lowlevel/xc/xc.c
> b/tools/python/xen/lowlevel/xc/xc.c
> index c40a4e9..2f4898d 100644
> --- a/tools/python/xen/lowlevel/xc/xc.c
> +++ b/tools/python/xen/lowlevel/xc/xc.c
> @@ -243,13 +243,15 @@ static PyObject *pyxc_vcpu_setaffinity(XcObject *self,
>          for ( i = 0; i < PyList_Size(cpulist); i++ )
>          {
>              long cpu = PyInt_AsLong(PyList_GetItem(cpulist, i));
> -            if ( cpu < 0 || cpu >= nr_cpus )
> +            if ( cpu < 0 )
>              {
>                  free(cpumap);
>                  errno = EINVAL;
>                  PyErr_SetFromErrno(xc_error_obj);
>                  return NULL;
>              }
> +            if ( cpu >= nr_cpus )
> +                continue;
>              cpumap[cpu / 8] |= 1 << (cpu % 8);
>          }
>      }
> -- 
> 1.7.3
> 
> 
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> http://lists.xen.org/xen-devel

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