Messages in this thread | | | Date | Mon, 7 Aug 2023 16:44:08 -0400 | Subject | Re: [PATCH 1/2] platform/x86/amd: Introduce AMD Address Translation Library | From | Yazen Ghannam <> |
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On 8/2/2023 2:55 PM, Yazen Ghannam wrote: > AMD Zen-based systems report memory errors through Machine Check banks > representing Unified Memory Controllers (UMCs). The address value > reported for DRAM ECC errors is a "normalized address" that is relative > to the UMC. This normalized address must be converted to a system > physical address to be usable by the OS. > > Support for this address translation was introduced to the MCA subsystem > with Zen1 systems. The code was later moved to the AMD64 EDAC module, > since this was the only user of the code at the time. > > However, there are uses for this translation outside of EDAC. The system > physical address can be used in MCA for preemptive page offlining as done > in some MCA notifier functions. Also, this translation is needed as the > basis of similar functionality needed for some CXL configurations on AMD > systems. > > Introduce a common address translation library that can be used for > multiple subsystems including MCA, EDAC, and CXL. > > Include support for UMC normalized to system physical address > translation for current CPU systems. > > Future development to include: > - DF4.5 Non-power-of-2 interleaving modes. > - Heterogeneous CPU+GPU system support. > - CXL translation support. > - Caching of common intermediate values and results. > - Leverage UEFI PRM methods as alternate backends to existing native > code. > > Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com> > --- > MAINTAINERS | 7 + > drivers/platform/x86/amd/Kconfig | 1 + > drivers/platform/x86/amd/Makefile | 1 + > drivers/platform/x86/amd/atl/Kconfig | 20 + > drivers/platform/x86/amd/atl/Makefile | 18 + > drivers/platform/x86/amd/atl/access.c | 107 ++++ > drivers/platform/x86/amd/atl/core.c | 212 +++++++ > drivers/platform/x86/amd/atl/dehash.c | 459 ++++++++++++++ > drivers/platform/x86/amd/atl/denormalize.c | 644 ++++++++++++++++++++ > drivers/platform/x86/amd/atl/internal.h | 307 ++++++++++ > drivers/platform/x86/amd/atl/map.c | 659 +++++++++++++++++++++ > drivers/platform/x86/amd/atl/reg_fields.h | 603 +++++++++++++++++++ > drivers/platform/x86/amd/atl/system.c | 282 +++++++++ > drivers/platform/x86/amd/atl/umc.c | 53 ++ > include/linux/amd-atl.h | 18 + >
Hi all,
I'd like to get feedback on the most appropriate place for this code.
I want to move this out of EDAC, since it's not really an EDAC feature. And it needs to be used by subsystems other than EDAC.
I thought x86 Platform Drivers, because the code is very platform-specific. And there are already some AMD platform drivers. But there isn't any platform control or management for this translation. It's just reading registers and calculating values. So it's not really a "platform driver" in the sense that it manages platform-specific behavior.
Another option is for this code to be in arch/x86/ras/. But I would like the option for this code to be built as a module, at least for debug and development. And I don't know that modules, nor platform-specific code, should be in arch/.
Currently, I think this could go in drivers/ras/. This address translation is needed for RAS use cases, so making it a part of "RAS Infrastructure" may make the most sense.
Boris, Tony, (and others) what do you think?
Thanks, Yazen
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