On Mon, 31 Oct 2016 19:09:07 +0800 Xiao Guangrong <guangrong.x...@linux.intel.com> wrote:
> On 10/31/2016 06:56 PM, Igor Mammedov wrote: > > On Mon, 31 Oct 2016 17:23:31 +0800 > > Xiao Guangrong <guangrong.x...@linux.intel.com> wrote: > > > >> On 10/31/2016 05:20 PM, Igor Mammedov wrote: > >>> On Sun, 30 Oct 2016 23:24:46 +0200 > >>> "Michael S. Tsirkin" <m...@redhat.com> wrote: > >>> > >>>> From: Xiao Guangrong <guangrong.x...@linux.intel.com> > >>>> > >>>> According to ACPI 6.0 spec, "Memory Device Physical Address > >>>> Region Base" in memdev is defined as "This field provides the > >>>> Device Physical Address base of the region". This field should > >>>> be zero in our case > >>> I'm not sure that it should be a zero, > >>> care to point source which tells that it should be zero? > >> > >> The spec says that this is the Device Physical Address, so that > >> it is the device internal address, it should be zero as we do not > >> reserve any thing in device internal and we do not have no memory > >> interleave. > > spec says (ACPI 6.1: 5.2.25.3 NVDIMM Region Mapping Structure): > > "NVDIMM Physical Address Region Base": > > "The base physical address within the NVDIMM of the NVDIMM region." > > > > and nothing more than that so it's hard to come to conclusion that > > it's internal address nor it is offset as you treat it here > > (structure has 'Region Offset' for that). > > I think it is clear as the spec says "_within_ the NVDIMM", it is > even more clear than ACPI 6.0 (5.2.25.2 Memory Device to System Physical > Address Range Mapping Structure), in that, it says: > "In bytes. This field provides the Device Physical Address > base of the region." It would be less confusing if spec would say "starting offset of NVDIMM region within the NVDIMM" (at least that's how I read it now after looking at 6.0 and NVDIMM_Namespace_Spec.pdf) as "base physical address" is not defined/described in ACPI spec. > In the namespace spec (http://pmem.io/documents/NVDIMM_Namespace_Spec.pdf), > the explanation to DPA in page 9: > "DIMM Physical Address: A memory address from a DIMM’s perspective, > that is, the offset into the DIMM’s memory, starting > with DPA zero > as the lowest addressable byte of the DIMM.
