Re: [PATCH 3/3] e820: Add the unknown-12 Memory type (DDR3-NvDIMM)

From: joeyli
Date: Tue Mar 10 2015 - 01:12:21 EST


On Mon, Mar 09, 2015 at 02:10:37PM +0200, Boaz Harrosh wrote:
> On 03/06/2015 01:09 AM, Andy Lutomirski wrote:
> <>
> >
> > I will be shocked if a standard of this form ever appears. Modern
> > systems *don't have e820*. The BIOSes that are using this type 12
> > hack are awful throwbacks.
> So far the systems we have, with DDR4 NvDIMM(s) (Actual chips arriving soon)
> still have BIOS (On by default). The BIOS was yelled "Wolfe" for so long NOW ;-)
> Again these are working system in the field, who will switch them all to UEFI?
> How will the UEFI present them to the system? can you point me to the relevant
> code? (Or did you mean BIOS but with a different communication path than e820?)

Per my understand...

With EFI Boot Stub, there have setup_e820() codes in arch/x86/boot/compressed/eboot.c
that used to transfer EFI memmap to e820 entries. Currently doesn't have any
EFI_MEMORY_TYPE reflects to NvDIMM that will map to e820_type.

I wonder what kind of EFI_MEMORY_TYPE reported by UEFI BIOS on those "shipped
NvDIMMs motherboards", like supermicro X9DRH-iF-NV. Then we may need add code
to setup_e820() for mapping the efi memory type to e820 type 12 region.

> >
> > --Andy
> >
> Thanks
> Boaz

Thanks a lot!
Joey Lee
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