Re: [PATCH] x86/speculation/l1tf: fix off-by-one error when warning that system has too much RAM

[Andi Kleen]

On Fri, Aug 24, 2018 at 04:22:57AM +0200, Andre Tomt wrote:
> On 23. aug. 2018 17:44, Andi Kleen wrote:
> > On Thu, Aug 23, 2018 at 03:44:18PM +0200, Vlastimil Babka wrote:
> > > Two users have reported [1] that they have an "extremely unlikely" system
> > > with more than MAX_PA/2 memory and L1TF mitigation is not effective. In fact
> > > it's a CPU with 36bits phys limit (64GB) and 32GB memory, but due to holes
> > > in the e820 map, the main region is almost 500MB over the 32GB limit:
> > 
> > Ah I see it's a client part with very large DIMMs and someone being
> > very brave and using that much memory without ECC.
> 
> FYI; It is also happening on Xeon E3v2 (Ivy Bridge generation) w/ 32GB of
> ECC RAM here, a low-end server part that officially supports up to 32GB.

Good point.

-andi