[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH=v3 1/8] xen: arm: map memory as inner shareable.
Hi Ian, On 03/17/2014 02:53 PM, Ian Campbell wrote: > The inner shareable domain contains all SMP processors, including different > clusters (e.g. big.LITTLE). Therefore this is the correct thing to use for Xen > memory mappings. The outer shareable domain is for devices on busses which are > coherent and barrier-aware (e.g. AMBA4 AXI with ACE). While the system domain > is for things behind bridges which are not. > > One wrinkle is that Normal memory with attributes Inner Non-cacheable, Outer > Non-cacheable (which we call BUFFERABLE) must be mapped Outer Shareable on ARM > v7. Therefore change the prototype of mfn_to_xen_entry to take the attribute > index so we can DTRT. On ARMv8 the sharability is ignored and considered to > always be Outer Shareable. > > Don't adjust the barriers, flushes etc, those remain as they were (which is > more than is now required). I'll change those in a later patch. > > Many thanks to Leif for explaining the difference between Inner- and > Outer-Shareable in words of two or less syllables, I hope I've replicated that > explanation properly above! Is there any reason to not modify VTCR_EL2? Regards, -- Julien Grall _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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