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 > > <[email protected]> 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 > /proc/iomem instead?
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. Thanks, -Toshi
