Re: [Xen-devel] [PATCH v2 1/6] xen: xensyms support

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 10.06.14 at 17:45, <boris.ostrovsky@xxxxxxxxxx> wrote:
> On 06/10/2014 11:21 AM, Jan Beulich wrote:
>>>>> On 10.06.14 at 17:03, <boris.ostrovsky@xxxxxxxxxx> wrote:
>>> On 06/10/2014 10:51 AM, Jan Beulich wrote:
>>>>>>> On 10.06.14 at 16:49, <boris.ostrovsky@xxxxxxxxxx> wrote:
>>>>> On 06/10/2014 09:31 AM, David Vrabel wrote:
>>>>>>> --- /dev/null
>>>>>>> +++ b/drivers/xen/xenfs/xensyms.c
>>>>>>> @@ -0,0 +1,124 @@
>>>>>>> +#include <linux/module.h>
>>>>>>> +#include <linux/init.h>
>>>>>>> +#include <linux/seq_file.h>
>>>>>>> +#include <linux/fs.h>
>>>>>>> +#include <linux/mm.h>
>>>>>>> +#include <linux/proc_fs.h>
>>>>>>> +#include <linux/slab.h>
>>>>>>> +#include <xen/interface/platform.h>
>>>>>>> +#include <asm/xen/hypercall.h>
>>>>>>> +#include <xen/xen-ops.h>
>>>>>>> +#include "xenfs.h"
>>>>>>> +
>>>>>>> +
>>>>>>> +#define XEN_KSYM_NAME_LEN 127 /* Hypervisor may have different name 
>>>>>>> length
>>>>> */
>>>>>> Shouldn't this be exported in the hypervisor headers then?
>>>>> Jan objected to having this as part of the interface so now we pass this
>>>>> as a parameter to the hypervisor. I may return Xen's symbol length and,
>>>>> if it is larger than XEN_KSYM_NAME_LEN, do a WARN_ONCE() (in the next
>>>>> spin of the patch).
>>>> The result of my objection should be you not hardcoding any number...
>>> I guess I can query hypervisor's symbol size by passing to
>>> XENPF_get_symbol current symbol number as -1 (or some other token).
>> No - just don't assume any particular length.
> 
> I don't follow. I need to start with something and if I don't query 
> hypervisor --- how would I get going?

Just use a reasonable number as a start, and e.g. double the buffer
each time you get indication of a longer symbol.

Jan


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