Re: [Qemu-devel] Funny -m arguments can crash

[Markus Armbruster <armbru@redhat.com>]

Blue Swirl <blauwirbel@gmail.com> writes:

> On Mon, Jul 30, 2012 at 12:56 PM, Markus Armbruster <armbru@redhat.com> wrote:
>> Blue Swirl <blauwirbel@gmail.com> writes:
>>
>>> On Sat, Jul 28, 2012 at 6:41 AM, Markus Armbruster <armbru@redhat.com> wrote:
>>>> Blue Swirl <blauwirbel@gmail.com> writes:
>>>>
>>>>> On Wed, Jul 25, 2012 at 11:49 AM, Markus Armbruster
>>>>> <armbru@redhat.com> wrote:
>>>>>> Asking for "funny" memory sizes sometimes crashes for me.  For instance
>>>>>> -m 0.8 or the equivalent -m 838860b.  -m 0.7 appears to work.
>>>>>>
>>>>>> Should we round memory sizes?  How?  Where?
>>>>>
>>>>> We had a discussion about this recently:
>>>>> http://lists.nongnu.org/archive/html/qemu-devel/2012-06/msg02800.html
>>>>
>>>> I missed that, thanks!
>>>>
>>>> Unfortunately, the thread petered out without a conclusion.  What now?
>>>
>>> There's no patch to do the check in vl.c for 8k. Lacking the patch, we
>>> don't know exactly what is the charge level of megaphone batteries:
>>> like Schrödinger's cat, they may be dead or fully charged.
>>
>> What would you like me to do?  Round argument of -m up to next multiple
>> of 8KiB?
>
> Yes please, maybe with a notice to the user.

Next problem: minimum RAM size.

For instance, -M pc -m X, where X < 32KiB dies "qemu: fatal: Trying to
execute code outside RAM or ROM at [...] Aborted (core dumped)" with
TCG, and "KVM internal error. Suberror: 1" with KVM.

Should a minimum RAM size be enforced?  Board-specific?

I'm inclined to declare this one a feature...