Re: [Qemu-devel] QEMU NVDIMM as type 7 in e820 table

[Dan Williams]

On Fri, Jul 28, 2017 at 12:45 PM, Ross Zwisler
<address@hidden> wrote:
> On Fri, Jul 28, 2017 at 11:11:10AM -0700, Dan Williams wrote:
>> On Fri, Jul 28, 2017 at 11:04 AM, Ross Zwisler
[..]
> [ Adding Linda & Toshi to see if they have an opinion. ]
>
> I guess maybe we don't need it.  Yep, /proc/iomem looks good:
>
>   # cat /proc/iomem
>   00000000-00000fff : Reserved
>   00001000-0009fbff : System RAM
>   ...
>   100000000-23fffffff : System RAM
>   240000000-a3fffffff : Persistent Memory
>     240000000-a3fffffff : namespace0.0
>
> I was just worried that this was an inconsistency between the way that virtual
> NVDIMMs are presented vs the way that they will be presented on bare metal.  I
> at least look at the e820 table to get my bearings of how memory is laid out -
> maybe I just need to look at /proc/iomem instead?

I don't think e820 matters as long as /proc/iomem ends up correct, and
the effective type is "reserved" . There's nothing in the
specification that requires the OS to validate e820 ranges vs NFIT.