Re: [RFC 2 PATCH 00/16] APIC ID fixes for AMD EPYC CPU models

[Moger, Babu]

Eduardo and all,
 Waiting for the feedback on this to move forward. Appreciate your time.
Thanks Babu

On 9/6/19 2:11 PM, Moger, Babu wrote:
> These series fixes the problems encoding APIC ID for AMD EPYC cpu models.
> https://bugzilla.redhat.com/show_bug.cgi?id=1728166
> 
> This is the second pass to give an idea of the changes required to address
> the issue. First pass is availabe at 
> https://patchwork.kernel.org/cover/11069785/
> 
> Currently, apic id is decoded based on sockets/dies/cores/threads. This 
> appears
> to work for most standard configurations for AMD and other vendors. But this
> decoding does not follow AMD's APIC ID enumeration. In some cases this
> causes CPU topology inconstancy. While booting guest Kernel is trying to
> validate topology. It finds the topology not aligning to EPYC models.
> 
> To fix the problem we need to build the topology as per the
> Processor Programming Reference (PPR) for AMD Family 17h Model 01h, Revision 
> B1
> Processors. It is available at https://www.amd.com/en/support/tech-docs
> 
> Here is the text from the PPR.
> 2.1.10.2.1.3
> ApicId Enumeration Requirements
> Operating systems are expected to use
> Core::X86::Cpuid::SizeId[ApicIdCoreIdSize], the number of least
> significant bits in the Initial APIC ID that indicate core ID within a
> processor, in constructing per-core CPUID
> masks. Core::X86::Cpuid::SizeId[ApicIdCoreIdSize] determines the maximum 
> number
> of cores (MNC) that the
> processor could theoretically support, not the actual number of cores that are
> actually implemented or enabled on
> the processor, as indicated by Core::X86::Cpuid::SizeId[NC].
> Each Core::X86::Apic::ApicId[ApicId] register is preset as follows:
> • ApicId[6] = Socket ID.
> • ApicId[5:4] = Node ID.
> • ApicId[3] = Logical CCX L3 complex ID
> • ApicId[2:0]= (SMT) ? {LogicalCoreID[1:0],ThreadId} :
> {1'b0,LogicalCoreID[1:0]}.
> """
> 
> v2:
>   1. Introduced the new property epyc to enable new epyc mode.
>   2. Separated the epyc mode and non epyc mode function.
>   3. Introduced function pointers in PCMachineState to handle the
>      differences.
>   4. Mildly tested different combinations to make things are working as 
> expected.
>   5. TODO : Setting the epyc feature bit needs to be worked out. This feature 
> is
>      supported only on AMD EPYC models. I may need some guidance on that.
> 
> v1:
>   https://patchwork.kernel.org/cover/11069785/
> 
> ---
> 
> Babu Moger (16):
>       numa: Split the numa functionality
>       hw/i386: Rename X86CPUTopoInfo structure to X86CPUTopoIDs
>       hw/i386: Introduce X86CPUTopoInfo to contain topology info
>       machine: Add SMP Sockets in CpuTopology
>       hw/i386: Simplify topology Offset/width Calculation
>       hw/core: Add core complex id in X86CPU topology
>       hw/386: Add new epyc mode topology decoding functions
>       i386: Cleanup and use the new epyc mode topology functions
>       hw/i386: Introduce initialize_topo_info function
>       hw/i386: Introduce apicid_from_cpu_idx in PCMachineState
>       Introduce-topo_ids_from_apicid-handler
>       hw/i386: Introduce apic_id_from_topo_ids handler in PCMachineState
>       machine: Add new epyc property in PCMachineState
>       hw/i386: Introduce epyc mode function handlers
>       i386: Fix pkg_id offset for epyc mode
>       hw/core: Fix up the machine_set_cpu_numa_node for epyc
> 
> 
>  hw/core/machine-hmp-cmds.c |    3 
>  hw/core/machine.c          |   38 ++++++
>  hw/core/numa.c             |  110 ++++++++++++----
>  hw/i386/pc.c               |  143 +++++++++++++++------
>  include/hw/boards.h        |    8 +
>  include/hw/i386/pc.h       |    9 +
>  include/hw/i386/topology.h |  294 
> +++++++++++++++++++++++++++++++++++---------
>  include/sysemu/numa.h      |    2 
>  qapi/machine.json          |    4 -
>  target/i386/cpu.c          |  209 +++++++++++--------------------
>  target/i386/cpu.h          |    1 
>  vl.c                       |    3 
>  12 files changed, 560 insertions(+), 264 deletions(-)
> 
> --
> Signature
>