Re: [Draft B] Boot ABI for HVM guests without a device-model

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

On 27/08/15 09:04, Jan Beulich wrote:
>>>> On 26.08.15 at 16:44, <roger.pau@citrix.com> wrote:
>> El 26/08/15 a les 14.12, Andrew Cooper ha escrit:
>>> On 26/08/15 13:00, Jan Beulich wrote:
>>>>> This structure is guaranteed to always be placed in memory after the
>>>> DYM "These structures are ..."?
>>>>
>>>>> loaded kernel and modules.
>>> There is no requirement for the command line/module information to be
>>> after the loaded kernel.  All it needs to do is not overlap.
>> IMHO, this is helpful in order to get last used physical address, after
>> which free memory starts. Current FreeBSD implementation relies on this,
>> if we didn't do it that way I would have to calculate where the symtab +
>> strtab ends, which is more complex.
> But the statement leaves open whether there is any free memory at
> all after those structures, or whether instead all free memory lives
> at lower addresses. Nor do I consider it appropriate to take a present
> (one might say overly simplistic) implementation as a basis for setting
> arbitrary restrictions.

I agree.  This sounds like a FreeBSD bug, and absolutely shouldn't be a
written restriction in the boot ABI.

~Andrew