On Tue, 2020-04-21 at 04:45 +0000, Anup Patel wrote: For riscv-sbi-doc, we have not finalized mailing list based review OR
Github PR based review so most of usl are sending riscv-sbi-doc
changes as patches to mailing list and Github PR.
Regards,
Anup
From: tech-unixplatformspec@... <
tech-unixplatformspec@...> On Behalf Of Abner Chang
Sent: 21 April 2020 08:26
To: Anup Patel <Anup.Patel@...>; Jonathan Behrens <
behrensj@...>
Cc: Atish Patra <Atish.Patra@...>; Schaefer, Daniel (DualStudy) <
daniel.schaefer@...>; tech-unixplatformspec@...
Subject: Re: [RISC-V] [tech-unixplatformspec] [RISC-V] [software] Add
SBI extension space for firmware code base implementation
We would like to have firmware code base SBI based on OpenSBI
implementation ID, because edk2 is not one of the implementations of
SBI. I saw the patches of overriding SBI implementation ID was also
committed. EDK2 still has chance to override the ID to avoid any
conflicts if it is a case.
BTW, the changes made on riscv-sbi-doc should go through the mail
list for review or PR is good?
From: Anup Patel [mailto:Anup.Patel@...]
Sent: Tuesday, April 14, 2020 1:25 PM
To: Jonathan Behrens <behrensj@...>
Cc: Chang, Abner (HPS SW/FW Technologist) <abner.chang@...>;
Atish Patra <Atish.Patra@...>; Schaefer, Daniel (DualStudy) <
daniel.schaefer@...>; tech-unixplatformspec@...
Subject: RE: [RISC-V] [tech-unixplatformspec] [RISC-V] [software] Add
SBI extension space for firmware code base implementation
As-per my understanding, U-Boot and Coreboot don’t need this SBI
firmware code base extension. Other SBI extensions are sufficient for
these bootloaders.
In my opinion, use of SBI firmware code base extension should be last
resort (when we have no other way) because this extension adds SBI
implementation specific code in S-mode software. The EDK2 developers
want to use SBI firmware code base extension in their own S-mode
booting stage so we are fine in-context of EDK2.
Also, we are certainly fine if EDK2 want their own SBI implementation
ID and to facilitate OpenSBI can provide API to override SBI
implementation ID which EDK2 can use. Finally, it’s EDK2 developer’s
choice.
Regards,
Anup
From: tech-unixplatformspec@... <
tech-unixplatformspec@...> On Behalf Of Jonathan Behrens
Sent: 14 April 2020 09:50
To: Anup Patel <Anup.Patel@...>
Cc: Abner Chang <abner.chang@...>; Atish Patra <
Atish.Patra@...>; Schaefer, Daniel (DualStudy) <
daniel.schaefer@...>; tech-unixplatformspec@...
Subject: Re: [RISC-V] [tech-unixplatformspec] [RISC-V] [software] Add
SBI extension space for firmware code base implementation
Anup wrote:
With EDK2 + OpenSBI running in background, the S-mode software will
see SBI implementation ID of OpenSBI because EDK2 uses unmodified
OpenSBI as library. This means from S-mode perspective the
underlying SBI implementation is still OpenSBI.
But EDK2 can and will register extensions with OpenSBI, meaning that
even identical OpenSBI versions might behave differently with regards
to such extension. So far I think you are right that S-mode won't
actually care about the difference. But I fear that this could end up
like User Agent Strings in web browsers where everybody lies and
claims they're basically the same as OpenSBI so they report the same
implementation ID.
The OpenSBI itself does not need the SBI firmware code base
extension hence I suggested that EDK2 can use ext_id = 0xA000000 +
opensbi_imp_id.
Most of the other bootloaders (U-Boot and Coreboot) use OpenSBI
FW_DYNAMIC firmware. For such bootloaders, the SBI firmware code
extension won’t be available because OpenSBI firmwares will not
implement it.
Are you saying that you are or aren't OK with U-Boot or Coreboot
hypothetically using ext_id = 0xA000000 + opensbi_imp_id to design
their own incompatible extensions? As Abner points out below, it
would probably be fine even if there were incompatible extensions
with the same ID, but I'm trying to understand if that's what you
intend. (My own opinion is that with 2^32 possible IDs it would be
preferable to try to keep them distinct)
Apart from bootloaders, the SBI firmware code base extension space
can be used hypervisors to provide hypervisor specific SBI calls.
Agreed. I think this reservation will prove to be very useful going
forward.
Jonathan
Regards,
Anup
From: Jonathan Behrens <behrensj@...>
Sent: 14 April 2020 08:42
To: Anup Patel <Anup.Patel@...>
Cc: Abner Chang <abner.chang@...>; Atish Patra <
Atish.Patra@...>; Schaefer, Daniel (DualStudy) <
daniel.schaefer@...>; tech-unixplatformspec@...
Subject: Re: [RISC-V] [tech-unixplatformspec] [RISC-V] [software]
Add SBI extension space for firmware code base implementation
Anup, are you saying that EDK2's extension would be the only use of
ext_id = 0xA000000 + opensbi_imp_id or that any firmware that uses
OpenSBI is free to make a (potentially incompatible) extension
using that ID?
Jonathan
On Mon, Apr 13, 2020 at 2:26 AM Anup Patel <Anup.Patel@...>
wrote:
Hi Abner,
Yes, your understanding is correct.
The 0xA000000 + opensbi_imp_id is the SBI Firmware code base
extension meant to be used by OpenSBI.
Now EDK2 uses unmodified OpenSBI as library/submodule so
underlying SBI implementation in-case of EDK2 is indeed OpenSBI
itself.
From OpenSBI perspective, we don’t see any OpenSBI specific SBI
calls being implemented in-future because previous and next
booting stages are totally black-box for OpenSBI. This means SBI
Firmware code base extension will be never used by OpenSBI hence
EDK2 can certainly register custom SBI extension for ext_id =
0xA000000 + opensbi_imp_id (Note: EDK2 can use
sbi_ecall_register_extension() API for this from platform
final_init() callback).
Apart from above, I do see SBI firmware code base extension
useful to some of the hypervisors (such as Xvisor, Xen, etc) but
this is in totally different context.
Regards,
Anup
From: tech-unixplatformspec@... <
tech-unixplatformspec@...> On Behalf Of Abner Chang
Sent: 13 April 2020 08:45
To: Jonathan Behrens <behrensj@...>
Cc: Anup Patel <Anup.Patel@...>; Atish Patra <
Atish.Patra@...>; Schaefer, Daniel (DualStudy) <
daniel.schaefer@...>; tech-unixplatformspec@...
Subject: Re: [RISC-V] [tech-unixplatformspec] [RISC-V] [software]
Add SBI extension space for firmware code base implementation
From: Jonathan Behrens [mailto:behrensj@...]
Sent: Monday, April 13, 2020 10:49 AM
To: Chang, Abner (HPS SW/FW Technologist) <abner.chang@...>
Cc: Anup Patel <Anup.Patel@...>; Atish Patra <
Atish.Patra@...>; Schaefer, Daniel (DualStudy) <
daniel.schaefer@...>; tech-unixplatformspec@...
Subject: Re: [RISC-V] [tech-unixplatformspec] [RISC-V] [software]
Add SBI extension space for firmware code base implementation
Also respond to Anup’s reply, 0xA000000+opensbi_imp_id is the
best and simple solution for now.
That is fine, just realize that if you are using OpenSBI's
implementation ID then you need to get approval from them before
defining the extension.
[Abner] I suppose the intention of reserving 0xa000000 is to let
firmware defines its own SBI functions. SBI spec won’t touch or
specify anything in this range as it doesn’t touch vendor
extension. To have 0xa000000 + opensbi_imp_id means the firmware
code base extension is defined base on OpenSBI SBI
implementation.
Anup, is my understanding correct?
Abner
Jonathan
On Sun, Apr 12, 2020 at 8:57 PM Abner Chang via lists.riscv.org <
abner.chang=hpe.com@...> wrote:
Basically OpenSBI is a git submodule of edk2 and we don’t make
any modification on it, we just build OpenSBI on edk2 build
environment.
Yes, edk2 will have its own control of extensions for those
firmware code base specific functions. One think we concern
about is the conflict of extension ID with vendor extension.
Also respond to Anup’s reply, 0xA000000+opensbi_imp_id is the
best and simple solution for now. We don’t have to add edk2 as
one of SBI implementation and this can also prevent from
extension ID conflict with vendor’s ones.
We can just take #1 opinion.
Any other comments?
Will let you know if we miss something later. Thanks to all for
supporting ekd2.
Abner
From: Jonathan Behrens [mailto:behrensj@...]
Sent: Sunday, April 12, 2020 10:19 PM
To: Anup Patel <Anup.Patel@...>
Cc: Chang, Abner (HPS SW/FW Technologist) <abner.chang@...>
; Atish Patra <Atish.Patra@...>; Schaefer, Daniel
(DualStudy) <daniel.schaefer@...>;
tech-unixplatformspec@...
Subject: Re: [RISC-V] [tech-unixplatformspec] [RISC-V]
[software] Add SBI extension space for firmware code base
implementation
Is the code for the extension you want to add going to live in
the OpenSBI repository or in the EDK2 repository? If I
understand correctly, it would live in the EDK2 repository,
meaning that your implementation would actually be downstream
from OpenSBI and should have its own implementation ID. If you
did this then it seems like everything else would fall out
nicely: you could decide on version numbers independently of
OpenSBI, there'd be no need for a separate set of firmware IDs,
and you'd have full control over all the details of your
extension.
Jonathan
On Sun, Apr 12, 2020 at 8:18 AM Anup Patel <Anup.Patel@...>
wrote:
Hi Abner,
We have two options here:
EDK2 can use 0xA000000 + <opensbi_imp_id> as SBI Extension
OpenSBI provides a way to EDK2 for overriding SBI
implementation ID (preferably using some API)
If we go with Option1 above then we don’t need separate SBI
implementation ID for EDK2.
Let us know what you guys think in this context.
Regards,
Anup
From: Chang, Abner (HPS SW/FW Technologist) <
abner.chang@...>
Sent: 12 April 2020 14:50
To: Chang, Abner (HPS SW/FW Technologist) <
abner.chang@...>; Anup Patel <Anup.Patel@...>;
Jonathan Behrens <behrensj@...>
Cc: Atish Patra <Atish.Patra@...>; Schaefer, Daniel
(DualStudy) <daniel.schaefer@...>;
tech-unixplatformspec@...
Subject: RE: [RISC-V] [tech-unixplatformspec] [RISC-V]
[software] Add SBI extension space for firmware code base
implementation
This is the PR according to the discussion we had in mail
thread. However you may see some confusions from this change.
https://github.com/riscv/riscv-sbi-doc/pull/43/commits/e208f23c64f7a6a4be47d6d0ca852433107f6cf4
EDK2 is a SBI implementation? Actually edk2 is not one of
the SBI implementations, edk2 fully compliant with OpenSBI
and additionally provides the firmware code base SBI
extension.
We can explain this in the external Firmware code base SBI
extension spec (edk2 RISC-V OpenSBI spec), says edk2 SBI
implementation actually goes alone with SBI OpenSBI
implementation.
What is the SBI implementation version associated with EDK2
SBI implementation? This is another confusion because the
major SBI implementation is OpenSBI.
We also can explain this in the external Firmware code base
SBI extension spec, says edk2 SBI implementation version is
the version of SBI OpenSBI implementation.
Apart from the above proposal, can we have more clear
definitions for Firmware code base SBI extension in SBI spec
instead of fixing those confusions in the extern spec? The
below proposal makes more sense?
Define another table for firmware code base, e.g. SBI
Firmware Code Base ID. In the table we can have edk2, uboot,
Coreboot and etc..
Create a new SBI Base function,
sbi_get_firmware_code_base_id() which returns the SBI
Firmware Code Base ID.
Create a new SBI Base function,
sbi_get_firmware_code_base_version() for the version control
of firmware code base SBI extension
Firmware code base SBI extension is from 0xA000000 to
0xAffffff with Firmware Code Base ID in low bits.
I feel the later one makes more sense and clear, how do you
think?
Abner
From: tech-unixplatformspec@... [mailto:
tech-unixplatformspec@...] On Behalf Of Abner
Chang
Sent: Saturday, April 11, 2020 12:08 AM
To: Anup Patel <Anup.Patel@...>; Jonathan Behrens <
behrensj@...>
Cc: Atish Patra <Atish.Patra@...>; Schaefer, Daniel
(DualStudy) <daniel.schaefer@...>;
tech-unixplatformspec@...
Subject: Re: [RISC-V] [tech-unixplatformspec] [RISC-V]
[software] Add SBI extension space for firmware code base
implementation
Cool. This works for edk2. I will have another PR for this.
For edk2, we will request a new SBI implementation ID (4) and
register firmware code base extension SBI in edk2 SEC phase.
From: Anup Patel [mailto:Anup.Patel@...]
Sent: Friday, April 10, 2020 11:14 PM
To: Chang, Abner (HPS SW/FW Technologist) <
abner.chang@...>; Jonathan Behrens <behrensj@...>
Cc: Atish Patra <Atish.Patra@...>; Schaefer, Daniel
(DualStudy) <daniel.schaefer@...>;
tech-unixplatformspec@...
Subject: Re: [RISC-V] [tech-unixplatformspec] [RISC-V]
[software] Add SBI extension space for firmware code base
implementation
I agree with Jonathan's proposal. Let's have SBI FW extension
ID depend on SBI implementation ID.
We can target this for SBI v0.3 spec along with System Reboot
extension.
Regards,
Anup
Sent from Outlook Mobile
From: tech-unixplatformspec@... <
tech-unixplatformspec@...> on behalf of Jonathan
Behrens <behrensj@...>
Sent: Friday, April 10, 2020 7:14:45 PM
To: Chang, Abner (HPS SW/FW Technologist) <
abner.chang@...>
Cc: Atish Patra <Atish.Patra@...>; Schaefer, Daniel
(DualStudy) <daniel.schaefer@...>;
tech-unixplatformspec@... <
tech-unixplatformspec@...>; Anup Patel <
Anup.Patel@...>
Subject: Re: [RISC-V] [tech-unixplatformspec] [RISC-V]
[software] Add SBI extension space for firmware code base
implementation
What I was suggesting is something like:
Implementation specific SBI extension Space, Extension IDs 0x0A000000 through 0x0AFFFFFF. Low bits from SBI
Implementation ID.
In this scheme, each SBI implementation would have one
extension reserved for it: BBL gets 0x0A000000, OpenSBI gets
0x0A000001, Xvisor gets 0x0A000002, KVM gets 0x0A000003, etc.
That might not seem like a lot of space, but each extension
can have up to 2^32 different functions (including ones for
version number discovery, etc.) so it shouldn't actually be
limiting.
As a side note, I don't think edk2 has an SBI Implementation
ID assigned yet. You should just be able to ask for one and
get it.
Jonathan
On Fri, Apr 10, 2020 at 2:23 AM Chang, Abner (HPS SW/FW
Technologist) <abner.chang@...> wrote:
-----Original Message-----
From: tech-unixplatformspec@... [mailto:tech-
unixplatformspec@...] On Behalf Of Atish Patra
Sent: Friday, April 10, 2020 11:32 AM
To: Chang, Abner (HPS SW/FW Technologist) < abner.chang@...>;
behrensj@...
Cc: Schaefer, Daniel (DualStudy) <daniel.schaefer@...
; tech-
unixplatformspec@...; Anup Patel < Anup.Patel@...>
Subject: Re: [RISC-V] [tech-unixplatformspec] [RISC-V] [software] Add SBI
extension space for firmware code base implementation
On Fri, 2020-04-10 at 01:08 +0000, Chang, Abner (HPS SW/FW
Technologist) wrote:
Got it, Software ML removed.
Johnathan, do you mean to define it as below?
Firmware Base Extension, Extension ID: 0xxxxxxxxx (FWBE) , and the
SBI functions definition is firmware code base
implementation-
specific.
I prefer this one as well. But you should pick any value
within experimental
range. Not quite follow this, why pick up one from experimental
range? The extension ID must be in the range of 0x0800000-
0x08ffffff?
I am not sure about the purpose of the extension but if it
has the
potential to be a generic SBI extension for firmwares, you should propose it
to the Unix Platform working group. We can add it to the official spec.
For those SBI extension which is generic to all firmware
code bases, then we should just propose it to the official
SBI spec and don’t not have to go with Firmware Base
Extension.
Firmware Base Extension is classified to those firmware
code base specific SBI, for example to load an edk2 driver
into M-mode managed memory and executed in M-mode which is
behaved as secured system manage mode driver. So the detail
Firmware Base Extension would be defined in the separate
spec and not part of official sbi spec. Occupied an SBI
extension ID is to avoid conflicts.
This also works for me and better than to reserve a
range of IDs.
Thanks
Abner
From: software@... [mailto:
software@...] On
Behalf Of Jonathan Behrens
Sent: Friday, April 10, 2020 12:39 AM
To: Chang, Abner (HPS SW/FW Technologist) <
abner.chang@...>
Cc: Atish Patra <Atish.Patra@...>; Anup Patel <anup.patel@...
; Schaefer, Daniel (DualStudy) <
daniel.schaefer@...>;
software@...;
tech-unixplatformspec@...
Subject: Re: [RISC-V] [software] Add SBI extension
space for firmware
code base implementation
I think tech-unixplatformspec@... might be
the right list?
To address the PR itself, I'd personally prefer to have
this space
allocated based on SBI implementation IDs analogously
to how the
vendor space is allocated. It also probably makes sense
to pick a
different address range so experimental extension space
doesn't have
to move.
Jonathan
On Thu, Apr 9, 2020 at 4:39 AM Abner Chang via
lists.riscv.org <
abner.chang=hpe.com@...> wrote:
Seems opensbi ML is no longer exist? Use
software@...
insrtead.
From: Chang, Abner (HPS SW/FW Technologist)
Sent: Thursday, April 9, 2020 4:23 PM
To: Atish Patra <Atish.Patra@...>; Anup Patel <
anup.patel@...>
Cc: opensbi@...; Schaefer, Daniel
(DualStudy) <
daniel.schaefer@...>
Subject: Add SBI extension space for firmware code
base
implementation
Hi Atish and Anup,
We are working on some edk2-specific SBI extension
which intends to
be used by upper layer edk2 drivers. We originally
consider to use
Vendor Extension space however vendor may have its
own proprietary
SBI extension as well. In order to prevent from the
conflicts of SBI
extension space, we propose to have a range for
firmware code base.
The changes look like the PR below,
https://github.com/riscv/riscv-sbi-doc/pull/43
How do you think?
Thanks
Abner
--
Regards,
Atish
Kindly send the proposal to the mailing list. We have enough topics now that we can schedule a meeting to finalize things. -- Regards, Atish
|
