Re: [PATCH 1/5] x86: validate against acpi motherboard resources
From: Robert Hancock
Date: Mon Feb 18 2008 - 15:26:26 EST
Andi Kleen wrote:
With just this patch you will have this problem. You need either the
patch to disable decode during BAR sizing,
Isn't that one already merged?
I remember the BAR decoding patch did help with at least one
of the original failures (there were multiple ones iirc0)
I believe that one's been dropped as it's not needed if we don't use
MMCONFIG for non-extended accesses (like we use during BAR sizing).
(Though, there may still be a case where it's needed, see below.)
If someone points me to all the patches needed or a tree who
has them all applied I can give it a quick spin on the boxes I have here.
One of the systems where it originally failed I don't have anymore
though.
or the patch to use MMCONFIG
for extended config space only, if you don't have them already.
That would mean it would boot, but anything that uses extended config
space would fail. While not as catastrophic as before I'm not sure
it's that great either. At least there would be still breakage,
but much more subtle ones.
The only issue on those boards is that since certain device BARs will
overlap the MMCONFIG area during BAR sizing, if you use MMCONFIG to do
the accesses used during BAR sizing itself, it'll fail. If you use conf1
to do the BAR sizing then that problem doesn't happen.
However, I suppose there could be an issue if you hotplugged a device
(causing BAR sizing) once you'd booted, while extended config space was
in use on another device. The BAR sizing wouldn't fail, but the guy
using extended config space would since he's actually reading
from/writing into the BAR of the device being sized instead of the
MMCONFIG area. That wouldn't be good. The disable-decode-during-sizing
patch would avoid that problem.
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