Re: [Xen-devel] [PATCH V2 3/4] arm: allocate per-PCPU domheap pagetable pages

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Tue, 2013-04-23 at 11:55 +0100, Stefano Stabellini wrote:

> > +    flush_xen_dcache_va_range(root, PAGE_SIZE);
> > +    flush_xen_dcache_va_range(domheap, DOMHEAP_SECOND_PAGES*PAGE_SIZE);
> 
> Don't we need to flush first too (on ARMv8)?

Yes, I think so.

> 
> 
> > +    per_cpu(xen_pgtable, cpu) = root;
> > +    per_cpu(xen_dommap, cpu) = domheap;
> 
> I think we should flush the two per_cpu variables here

These are just normal per-cpu variables, they aren't passed to the MMU
hardware or anything like that, so I don't think we do need to flush.

If we need to flush per_cpu writes in the general case then we have a
big problem, but I don't think this is the case.

Ian.


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