[Xen-devel] [PATCH] Re: SMP dom0 with 8 cpus of i386

["Nakajima, Jun" <jun.nakajima@xxxxxxxxx>]

The patch attached fixes this problem. Now SMP dom0 booted using >=8
CPUs with MMCONFIG (par of PCI Express) enabled. Basically it adds a
spurious page fault handler in the  guest. See the comments in the
patch. Tested it both on none-PAE and PAE. Thanks for Nitin and Xin for
testing this patch.

Signed-off-by: Jun Nakajima <jun.nakajima@xxxxxxxxx>

Ian Pratt wrote:
>> I tried changing set_pte_mfs_ma to set_pte_at, and it also
>> let dom0 boot few times. I didn't have not observed the issue with
>> it. 
>> 
>> As it is a racing case kind of issue, I am not totally sure
>> that it is totally curing the issue. It can be possible we
>> are just reducing the chances of the race condition.
>> Especially with emulation, the slowness changes timing.
> 
> Yes, using set_pte_at won't cure the race (which we *definitely* need
> to investigate), but is actually a better choice than set_pte anyway
> -- it will go x10 faster.
> 
> If only we had a 16 way machine on which we could try and reproduce
> this problem :-)
> 
> The race is a big worry, but the code looks correct. Please can you
> tell us more about the failure you observe. You mentioned that the
> shared info page appears to be unmapped. Please provide more details.
> 
> Thanks,
> Ian
> 

Jun
---
Intel Open Source Technology Center

Attachment: pmd_present.patch
Description: pmd_present.patch

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