> -----Original Message----- > From: Ard Biesheuvel <ardb@xxxxxxxxxx> > Sent: Tuesday, November 28, 2023 10:08 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 > > 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. > I think runtime code and data today are mainly for supporting UEFI runtime services - some BIOS functions for OS to utilize, OS may follow below ACPI spec to treat them as reserved range: https://uefi.org/specs/ACPI/6.5/15_System_Address_Map_Interfaces.html#uefi-memory-types-and-mapping-to-acpi-address-range-types Like I mentioned earlier, that PR is still in early phase and has not reflected all the required changes yet, but the idea is to build gEfiMemoryTypeInformationGuid HOB from FDT reserved-memory nodes. UEFI generic Payload has DxeMain integrated, however Memory Types are platform-specific, for example, some platforms may need bigger runtime memory for their implementation, that's why we want such FDT reserved-memory node to tell DxeMain. The Payload flow will be like this: Payload creates built-in default MemoryTypes table -> FDT reserved-memory node to override if required (this also ensures the same memory map cross boots so ACPI S4 works) -> Build gEfiMemoryTypeInformationGuid HOB by "platfom specific" MemoryTypes Table -> DxeMain/GCD to consume this MemoryTypes table and setup memory service -> Install memory types table to UEFI system table.Configuration table... Note: if Payload built-in default MemoryTypes table works fine for the platform, then FDT reserved-memory node does not need to provide such 'usage' compatible strings. (optional) This FDT node could allow flexibility/compatibility without rebuilding Payload binary. Not sure if I answered all your questions, please highlight which area you need more information. Thanks, Chasel > > > > > > -----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.
