From: Jeremy Linton <jeremy.linton@arm.com>
To: Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Udit Kumar <udit.kumar@nxp.com>
Cc: "edk2-devel@lists.01.org" <edk2-devel@lists.01.org>,
Andrew Fish <afish@apple.com>,
"Olivier.Martin@arm.com" <Olivier.Martin@arm.com>,
Vladimir Olovyannikov <vladimir.olovyannikov@broadcom.com>
Subject: Re: Storing Non volatile variables on SD/NAND
Date: Fri, 27 Oct 2017 12:46:10 -0500 [thread overview]
Message-ID: <c5cf597d-f978-bf5f-1fc3-17b5509598ac@arm.com> (raw)
In-Reply-To: <CAKv+Gu8-hC9+rCwUw-j+CATfiAA+zO=s=LRH_zD5cZfU9M-aLw@mail.gmail.com>
On 09/20/2017 12:39 PM, Ard Biesheuvel wrote:
> On 20 September 2017 at 10:34, Udit Kumar <udit.kumar@nxp.com> wrote:
>>
>> When we want to have UEFI and OS accessing same media ,
>> Possibilities I see
>>
>> 1- Patch OS For status check of media (diversion from generic OS), Good case will be modify low level driver.
>> But we may end up some surprises on synchronization.
>>
>> 2- no runtime service for OS . I guess this will not be possible
>>
>> 3- Way the Vladimir implemented for eMMC, This has risk of losing data in case of AC power off.
>>
>> 4- update hardware with dual view (Ard suggestion)
>>
>
> 5 - abstract direct block device access into a firmware service that
> is exposed via a DXE_RUNTIME_DRIVER.
(along those lines)
6 - Build an emulated disk controller as well as NV region in el3 (or
el2) and export them to UEFI & the OS as real devices. Then trap/forward
requests to the actual storage device, which is "hidden". This AFAIK was
the basic idea behind the PS/2 emulation in x86/SMM. Again, probably not
a high performance option.
>
> The UEFI spec allows you to expose entry points into a
> DXE_RUNTIME_DRIVER module via a UEFI configuration table, and the OS
> can use a driver that uses the abstracted device rather than the real
> device. Performance is going to be terrible, probably, and lots of
> things that are specific to SD/MMC will no longer work, but it is a
> possibility nonetheless.
> _______________________________________________
> edk2-devel mailing list
> edk2-devel@lists.01.org
> https://lists.01.org/mailman/listinfo/edk2-devel
>
next prev parent reply other threads:[~2017-10-27 17:42 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-18 13:52 Storing Non volatile variables on SD/NAND Udit Kumar
2017-09-18 15:43 ` Ard Biesheuvel
2017-09-18 16:52 ` Vladimir Olovyannikov
2017-09-19 5:28 ` Udit Kumar
2017-09-19 16:38 ` Ard Biesheuvel
2017-09-20 4:27 ` Udit Kumar
2017-09-20 4:47 ` Andrew Fish
2017-09-20 5:09 ` Udit Kumar
2017-09-20 5:17 ` Andrew Fish
2017-09-20 14:51 ` Pankaj Bansal
2017-09-20 17:34 ` Udit Kumar
2017-09-20 17:39 ` Ard Biesheuvel
2017-09-20 17:39 ` Ard Biesheuvel
2017-09-20 17:46 ` Andrew Fish
2017-10-27 9:35 ` Udit Kumar
2017-10-27 9:37 ` Udit Kumar
2017-10-27 13:20 ` Ard Biesheuvel
2017-10-27 17:46 ` Jeremy Linton [this message]
2017-10-28 3:09 ` Udit Kumar
2017-10-30 23:10 ` Jeremy Linton
2017-10-31 4:25 ` Udit Kumar
2017-09-20 17:34 ` Andrew Fish
2017-09-18 20:47 ` Jeremy Linton
2017-09-18 20:53 ` Ard Biesheuvel
2017-09-19 5:27 ` Udit Kumar
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