Re: [PATCH] xl: Perform minimal validation of virtual disk file while parsing config file

[Kamala Narasimhan <kamala.narasimhan@gmail.com>]

On Fri, Jan 14, 2011 at 4:05 AM, Ian Campbell <Ian.Campbell@citrix.com> wrote:
> On Thu, 2011-01-13 at 15:35 +0000, Kamala Narasimhan wrote:
>> This patch performs some very basic validation on the virtual disk
>> file passed through the config file.  This validation ensures that we
>> don't go too far with the initialization like spawn qemu and more
>> while there could be some potentially fundamental issues.  Obviously,
>> there is a lot of room for improvement in the kind of validations we
>> could do but the below is a minimal first stab at it.  Please consider
>> this for inclusion or feel free to tweak it as necessary.
>>
>> Signed-off-by: Kamala Narasimhan <kamala.narasimhan@citrix.com>
>
> I wonder if the validation function should be part of libxl?
>

We are better off performing these checks early on as they are very
basic.  Getting far enough to spawn qemu and getting to its block
device initialization code and failing there is a bit of a chase when
it comes to troubleshooting these issues, the cause of which are
rather trivial.  That said, in the long run we might want to move
these validations to upstream qemu as qemu also must perform these
checks especially when run without an accelerator (as there wouldn't
be a toolstack to perform these checks for it in that case).  But,
till that is accomplished these checks need to be somewhere and libxl
seem like a reasonable place in my opinion.

Kamala