Messages in this thread | | | Subject | Re: [RFC][PATCH] linux-2.6.0-test2_mtrr-race-fix_A0 | From | john stultz <> | Date | 06 Aug 2003 10:15:05 -0700 |
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On Wed, 2003-08-06 at 01:52, Mathias Fröhlich wrote: > Hi, > > You should not remove the barrier past mtrr change. If you do that, it is > possible that cpu's run with inconsistent mtrrs. This can have bad > sideeffects since at least the cache snooping protocol used by intel uses > assumptions about the cachability of memory regions. Those information about > the cachability is also taken from the mtrrs as far as I remember. > This intel cpu developer manual, which documented the early PII and PPro > chips, recommended this algorithm. Since actual intel cpus use the same old > cpu to chipset bus protocol, this old documentation most propably still > applies.
Hmm. I should dig up that doc. Its a little hazy in my mind, but I think I understand your description. I'm glad you caught this, as I can't imagine the subtle bugs that might have popped up.
Well, let me look at it again and see if I can come up with a proper fix.
Thanks for the knowledgeable feedback and sanity checking! -john
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