Hi,
On 10/27/2017 10:09 PM, Udit Kumar wrote:
(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.
You mean, have a driver in el3 or el2 and UEFI or OS is doing smc call to get
things done.
On this line, some sort of permission manager could reside in el3 or el2.
Either UEFI or OS driver needs to make a call, if they are allowed to access
this
specific controller or other driver is accessing it.
With this performance issue could be ironed out .
That isn't really what I meant, what I was thinking about was creating
an emulated (AHCI for example) controller where accesses to the
"register" space would trap to synchronous data/external aborts. That
way the firmware and OS could use existing drivers without knowledge
that the device was in any way special. If you create a driver and do
SMC/whatever calls, then your basically doing #5..
Regards
Udit
-----Original Message-----
From: Jeremy Linton [mailto:jeremy.lin...@arm.com]
Sent: Friday, October 27, 2017 11:16 PM
To: Ard Biesheuvel <ard.biesheu...@linaro.org>; Udit Kumar
<udit.ku...@nxp.com>
Cc: edk2-devel@lists.01.org; Andrew Fish <af...@apple.com>;
olivier.mar...@arm.com; Vladimir Olovyannikov
<vladimir.olovyanni...@broadcom.com>
Subject: Re: [edk2] Storing Non volatile variables on SD/NAND
On 09/20/2017 12:39 PM, Ard Biesheuvel wrote:
On 20 September 2017 at 10:34, Udit Kumar <udit.ku...@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://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.01
.org%2Fmailman%2Flistinfo%2Fedk2-
devel&data=02%7C01%7Cudit.kumar%40nxp.com%7Cfe11f07ea67a4efa7d1b08
d51d629deb%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C63644723
1755528994&sdata=FYnH3ItGhXmqxNr%2BnaJBFMcKKduf%2FcS06JEA6dT6ZQA
%3D&reserved=0
_______________________________________________
edk2-devel mailing list
edk2-devel@lists.01.org
https://lists.01.org/mailman/listinfo/edk2-devel
