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bochs & mp tables

Posted: Sat Jun 14, 2008 11:06 pm
by blound
I read some posts on here and brendan imparticular had some from 2006 highlighting boch's and its problems with the apic & smp; Today I read through the mp specs and wrote some code that to find the tables in memory but I am not having any luck under bochs.

I scanned the 4 areas designated in the spec and I checked the linux source and they scan the same regions. I have a full check for a proper structure but also one liners for _MP_ and _PM_ in memory, but nothing is found in the regions. Does Bochs not provide an mp table? or what do you have to do to make it provide one? Here are my configure options to bochs:

Code: Select all

--enable-smp --enable-apic --enable-pci --enable-global-pages --enable-mtrr --enable-debugger --enable-disasm --enable-readline --enable-logging --enable-sep --with-x --with-gnu-ld --enable-4meg-pages
I tried with varying number of processors and the tables never showed up. I also looked again through the bochsrc man page sort of thing and nothing stuck out that I was missing.

Re: bochs & mp tables

Posted: Sat Sep 20, 2008 3:42 am
by Kicer
i have the same problem. in bochs newer than 2.3, there (probably) is no mp table. I wrote to bochs developers and i hope they will fix this.
actually i just use apic to find other processors :)

Re: bochs & mp tables

Posted: Sat Sep 20, 2008 6:52 am
by Combuster
The absence of an MP table in favor or an APIC table is what happens on real computers too. I therefore doubt the bochs developers would consider it a bug if you can still find out about multiple processors in a correct way.

Edit: with ACPI disabled the MP tables don't appear either :(

Re: bochs & mp tables

Posted: Sat Sep 20, 2008 1:03 pm
by geppy
In bochs 2.3.7 precompiled for windows MP signature "_MP_" is at 0xFB850 with the config file that doesn't touch any MP settings(if thats possible at all). ACPI present as well somewhere.