On Fri, 2017-07-28 at 13:45 -0600, Ross Zwisler 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
> <ross.zwisler(a)linux.intel.com> wrote:
> Do you need that informationin e820? Linux effectively ignores
> type-7. As long as the range is treated as reserved it's not clear
> that you need the e820 entry. We also infect the persistent type
> back into the memory map when the NFIT driver loads. /proc/iomem
> should show the right data.
[ 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
FW should present a persistent memory range in e820 or UEFI memory
descriptor table. So, it's a good practice for QEMU to do it as well.
That said, the NFIT driver inserts a persistent memory range to the
kernel IO resource table from NFIT, so we are OK without this info.
Yes, /proc/iomem shows how the resources are managed by the kernel.