Re: [PATCH] x86: wrap kexec feature with CONFIG_KEXEC

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 01/09/15 11:54, Jan Beulich wrote:
>>>> On 01.09.15 at 12:44, <andrew.cooper3@citrix.com> wrote:
>> On 01/09/15 11:36, Ian Campbell wrote:
>>> In general (i.e. not 100% consistently, I think) we have tended to avoid
>>> making things user-facing compile time options. Many of the existing
>>> CONFIG_* and HAVE_* are really about things which are arch dependent, or
>>> require specific porting to each arch etc. I think the KEXEC flag is one of
>>> those.
>>>
>>> This keeps the test matrix more reasonable (unlike e.g. Linux's Kconfig)
>>> and also helps us by ensuring that users are mostly running one of a small
>>> number of possible configs.
>>>
>>> I slightly fear that after Kexec you are going to want to strip out more
>>> and more stuff...
>> I for one welcome a Kconfig style approach.  We will never be in the
>> same order of magnitude of options as Linux, and it will help to
>> properly modularise the code.
> Indeed the idea was brought up a few times already, and I would
> also welcome such a step (accepting the downside of the larger
> test matrix). Not the least considering the "no shadow mode" and
> "big memory" build options that got introduced not so long ago.

>From a large attack surface point of view, support for 32bit ABI on
64bit Xen is a welcome candidate for more controlled environments.

>From a code volume point of view, having things like PV or support
configurable would be interesting.

~Andrew