You are referring to a 2000 line patch so it is not 100% clear where to look tbh. On Tue, 21 Nov 2023 at 19:37, Chiu, Chasel <chasel.chiu@xxxxxxxxx> wrote: > > > In PR, UefiPayloadPkg/Library/FdtParserLib/FdtParserLib.c, line 268 is for related example code. > That refers to a 'memory-allocation' node, right? How does that relate to the 'reserved-memory' node? And crucially, how does this clarify in which way "runtime-code" and "runtime-data" reservations are being used? Since the very beginning of this discussion, I have been asking repeatedly for examples that describe the wider context in which these reservations are used. The "runtime" into runtime-code and runtime-data means that these regions have a special significance to the operating system, not just to the next bootloader stage. So I want to understand exactly why it is necessary to describe these regions in a way where the operating system might be expected to interpret this information and act upon it. > > > -----Original Message----- > > From: Chiu, Chasel > > Sent: Tuesday, November 21, 2023 10:34 AM > > To: Ard Biesheuvel <ardb@xxxxxxxxxx>; Simon Glass <sjg@xxxxxxxxxxxx> > > Cc: devicetree@xxxxxxxxxxxxxxx; Mark Rutland <mark.rutland@xxxxxxx>; Rob > > Herring <robh@xxxxxxxxxx>; Tan, Lean Sheng <sheng.tan@xxxxxxxxxxxxx>; lkml > > <linux-kernel@xxxxxxxxxxxxxxx>; Dhaval Sharma <dhaval@xxxxxxxxxxxx>; Brune, > > Maximilian <maximilian.brune@xxxxxxxxxxxxx>; Yunhui Cui > > <cuiyunhui@xxxxxxxxxxxxx>; Dong, Guo <guo.dong@xxxxxxxxx>; Tom Rini > > <trini@xxxxxxxxxxxx>; ron minnich <rminnich@xxxxxxxxx>; Guo, Gua > > <gua.guo@xxxxxxxxx>; linux-acpi@xxxxxxxxxxxxxxx; U-Boot Mailing List <u- > > boot@xxxxxxxxxxxxx>; Chiu, Chasel <chasel.chiu@xxxxxxxxx> > > Subject: RE: [PATCH v7 2/2] schemas: Add some common reserved-memory > > usages > > > > > > Hi Ard, > > > > Here is the POC PR for your reference: > > https://github.com/tianocore/edk2/pull/4969/files#diff- > > ccebabae5274b21634723a2111ee0de11bed6cfe8cb206ef9e263d9c5f926a9cR26 > > 8 > > Please note that this PR is still in early phase and expected to have significant > > changes. > > > > The idea is that payload entry will create gEfiMemoryTypeInformationGuid HOB > > with payload default memory types and allow FDT to override if correspond node > > present. > > Please let me know if you have questions or suggestions. > > > > Thanks, > > Chasel > > > > > > > -----Original Message----- > > > From: Ard Biesheuvel <ardb@xxxxxxxxxx> > > > Sent: Tuesday, November 21, 2023 8:42 AM > > > To: Simon Glass <sjg@xxxxxxxxxxxx> > > > Cc: Chiu, Chasel <chasel.chiu@xxxxxxxxx>; devicetree@xxxxxxxxxxxxxxx; > > > Mark Rutland <mark.rutland@xxxxxxx>; Rob Herring <robh@xxxxxxxxxx>; > > > Tan, Lean Sheng <sheng.tan@xxxxxxxxxxxxx>; lkml > > > <linux-kernel@xxxxxxxxxxxxxxx>; Dhaval Sharma <dhaval@xxxxxxxxxxxx>; > > > Brune, Maximilian <maximilian.brune@xxxxxxxxxxxxx>; Yunhui Cui > > > <cuiyunhui@xxxxxxxxxxxxx>; Dong, Guo <guo.dong@xxxxxxxxx>; Tom Rini > > > <trini@xxxxxxxxxxxx>; ron minnich <rminnich@xxxxxxxxx>; Guo, Gua > > > <gua.guo@xxxxxxxxx>; linux- acpi@xxxxxxxxxxxxxxx; U-Boot Mailing List > > > <u-boot@xxxxxxxxxxxxx> > > > Subject: Re: [PATCH v7 2/2] schemas: Add some common reserved-memory > > > usages > > > > > > On Mon, 20 Nov 2023 at 21:12, Simon Glass <sjg@xxxxxxxxxxxx> wrote: > > > > > > > > Hi, > > > > > > > > On Mon, 13 Nov 2023 at 11:09, Chiu, Chasel <chasel.chiu@xxxxxxxxx> wrote: > > > > > > > > > > > > > > > Hi Ard, > > > > > > > > > > Please see my reply below inline. > > > > > > > > > > Thanks, > > > > > Chasel > > > > > > > > > > > > > > > > -----Original Message----- > > > > > > From: Ard Biesheuvel <ardb@xxxxxxxxxx> > > > > > > Sent: Saturday, November 11, 2023 3:04 AM > > > > > > To: Chiu, Chasel <chasel.chiu@xxxxxxxxx> > > > > > > Cc: Simon Glass <sjg@xxxxxxxxxxxx>; devicetree@xxxxxxxxxxxxxxx; > > > > > > Mark Rutland <mark.rutland@xxxxxxx>; Rob Herring > > > > > > <robh@xxxxxxxxxx>; Tan, Lean Sheng <sheng.tan@xxxxxxxxxxxxx>; > > > > > > lkml <linux-kernel@xxxxxxxxxxxxxxx>; Dhaval Sharma > > > > > > <dhaval@xxxxxxxxxxxx>; Brune, Maximilian > > > > > > <maximilian.brune@xxxxxxxxxxxxx>; Yunhui Cui > > > > > > <cuiyunhui@xxxxxxxxxxxxx>; Dong, Guo <guo.dong@xxxxxxxxx>; Tom > > > > > > Rini <trini@xxxxxxxxxxxx>; ron minnich <rminnich@xxxxxxxxx>; > > > > > > Guo, Gua <gua.guo@xxxxxxxxx>; linux- acpi@xxxxxxxxxxxxxxx; > > > > > > U-Boot Mailing List <u-boot@xxxxxxxxxxxxx> > > > > > > Subject: Re: [PATCH v7 2/2] schemas: Add some common > > > > > > reserved-memory usages > > > > > > > > > > > > On Sat, 11 Nov 2023 at 04:20, Chiu, Chasel <chasel.chiu@xxxxxxxxx> > > wrote: > > > > > > > > > > > > > > > > > > > > > Just sharing some usage examples from UEFI/EDK2 scenario. > > > > > > > To support ACPI S4/Hibernation, memory map must be consistent > > > > > > > before entering and after resuming from S4, in this case > > > > > > > payload may need to know previous memory map from bootloader > > > > > > > (currently generic payload cannot access platform/bootloader > > > > > > > specific non-volatile data, thus could not save/restore memory > > > > > > > map > > > > > > > information) > > > > > > > > > > > > So how would EDK2 reconstruct the entire EFI memory map from > > > > > > just these unannotated /reserved-memory nodes? The EFI memory > > > > > > map contains much more information than that, and all of it has > > > > > > to match the pre-hibernate situation, right? Can you given an example? > > > > > > > > > > > > > > > Here we listed only typically memory types that may change cross > > > > > different > > > platforms. > > > > > Reserved memory type already can be handled by reserved-memory > > > > > node, > > > and rest of the types usually no need to change cross platforms thus > > > currently we could rely on default in generic payload. > > > > > In the future if we see a need to add new memory types we will > > > > > discuss and > > > add it to FDT schema. > > > > > > > > > > > > > > > > > > > > > > > > > > > > Another usage is to support binary model which generic payload > > > > > > > is a prebuilt > > > > > > binary compatible for all platforms/configurations, however the > > > > > > payload default memory map might not always work for all the > > > > > > configurations and we want to allow bootloader to override > > > > > > payload default > > > memory map without recompiling. > > > > > > > > > > > > > > > > > > > Agreed. But can you explain how a EDK2 payload might make > > > > > > meaningful use of 'runtime-code' regions provided via DT by the > > > > > > non-EDK2 platform init? Can you give an example? > > > > > > > > > > > > > > > Runtime-code/data is used by UEFI payload for booting UEFI OS > > > > > which > > > required UEFI runtime services. > > > > > Platform Init will select some regions from the usable memory and > > > > > assign it to > > > runtime-code/data for UPL to consume. Or assign same runtime-code/data > > > from previous boot. > > > > > If UEFI OS is not supported, PlatformInit may not need to provide > > > > > runtime-code/data regions to payload. (always providing > > > > > runtime-code/data should be supported too) > > > > > > > > > > > > > > > > > > > > > > > Under below assumption: > > > > > > > FDT OS impact has been evaluated and taken care by > > > > > > > relevant > > > > > > experts/stakeholders. > > > > > > > Reviewed-by: Chasel Chiu <chasel.chiu@xxxxxxxxx> > > > > > > > > > > > > > > > > > > > I am sorry but I don't know what 'FDT OS impact' means. We are > > > > > > talking about a firmware-to-firmware abstraction that has the > > > > > > potential to leak into the OS visible interface. > > > > > > > > > > > > I am a maintainer in the Tianocore project myself, so it would > > > > > > help if you could explain who these relevant experts and > > > > > > stakeholders are. Was this discussed on the edk2-devel mailing > > > > > > list? If so, apologies for missing it but I may not have been cc'ed perhaps? > > > > > > > > > > > > > > > > > > > > > > > > > I'm not familiar with FDT OS, also I do not know if who from > > > > > edk2-devel were > > > supporting FDT OS, I think Simon might be able to connect FDT OS > > > experts/stakeholders. > > > > > We are mostly focusing on payload firmware phase implementation in > > > > > edk2 (and other payloads too), however, since we have aligned the > > > > > payload FDT and OS FDT months ago, I'm assuming FDT OS impact must > > > > > be there and we need (or already done?) FDT OS experts to support > > > > > it. (again, maybe Simon could share more information about FDT OS) > > > > > > > > > > In edk2 such FDT schema is UefiPayloadPkg internal usage only and > > > > > payload > > > entry will convert FDT into HOB thus we expected the most of the edk2 > > > generic code are no-touch/no impact, that's why we only had small > > > group > > > (UefiPayloadPkg) discussion. > > > > > Ard, if you are aware of any edk2 code that's for supporting FDT > > > > > OS, please let > > > us know and we can discuss if those code were impacted or not. > > > > > > > > We discussed this and just to clarify, 'FDT OS' is not a special OS, > > > > it is just Linux. > > > > > > > > So, with the above, are we all on the same page? Can the patch be > > > > applied, perhaps? If not, what other discussion is needed? > > > > > > > > > > An example of how a platform-init/payload combination would make > > > meaningful use of such runtime-code/data regions.
