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From: Andy Lutomirski <luto@amacapital.net>
Date: Tue, 10 Mar 2015 06:19:14 -0700
Message-ID: <CALCETrXQEOiPxXvx86-T2qKmpNvBJC9OaSPn30heem_PanbSog@mail.gmail.com>
Subject: Re: [PATCH 3/3] e820: Add the unknown-12 Memory type (DDR3-NvDIMM)
To: joeyli <jlee@suse.com>
Cc: Matthew Wilcox <willy@linux.intel.com>, Boaz Harrosh <boaz@plexistor.com>,
        Ross Zwisler <ross.zwisler@linux.intel.com>,
        Thomas Gleixner <tglx@linutronix.de>, X86 ML <x86@kernel.org>,
        Dan Williams <dan.j.williams@intel.com>,
        "Roger C. Pao" <rcpao.enmotus@gmail.com>,
        Ingo Molnar <mingo@redhat.com>,
        linux-nvdimm <linux-nvdimm@ml01.01.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Christoph Hellwig <hch@infradead.org>
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On Mar 10, 2015 1:12 AM, "joeyli" <jlee@suse.com> wrote:
>
> Hi,
>
> 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.

Nothing useful.  You can't detect the NvDIMM in EFI mode on my board
as far as I know.

Rumor has it that we'll learn more about the EFI case very soon.

--Andy

>
> > >
> > > --Andy
> > >
> >
> > Thanks
> > Boaz
> >
>
> Thanks a lot!
> Joey Lee