Re: [Patch v2] Make PCI extended config space (MMCONFIG) a driver opt-in



On Fri, 11 Jan 2008, Matthew Wilcox wrote:

Ivan's patch doesn't start enabling MMCONFIG in more places than we
currently do. It makes us use conf1 accesses for all accesses below
256 bytes. That fixes all known problems to date.

.. and I agree with that patch. But there will be people who try to access
extended space by mistake, and they'll have a hard-locked machine or
something.

Tell me what *other* armor plating you could have that actually works?

The armour plating that already exists -- pci=nommconf.

No. It needs to be automatic, OR THE OTHER WAY AROUND.

Ie we disable the unsafe feature on purpose, and then force people who
access it to do so *consciously*.

Extended config space is different, for chissake! It's not even like it's
just a bigger normal config space where normal config accesses just
overflow into it. It really does have different rules etc.

Linus
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