This series fixes APIC ID encoding problem reported on AMD EPYC cpu models. https://bugzilla.redhat.com/show_bug.cgi?id=1728166
Currently, the APIC ID is decoded based on the sequence sockets->dies->cores->threads. This works for most standard AMD and other vendors' configurations, but this decoding sequence does not follow that of AMD's APIC ID enumeration strictly. In some cases this can cause CPU topology inconsistency. When booting a guest VM, the kernel tries to validate the topology, and finds it inconsistent with the enumeration of EPYC cpu 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. The documentation is available from the bugzilla Link below. Link: https://bugzilla.kernel.org/show_bug.cgi?id=206537 Here is the text from the PPR. Operating systems are expected to use Core::X86::Cpuid::SizeId[ApicIdSize], 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[ApicIdSize] 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]} v6: Generated the patches on top of git://github.com/ehabkost/qemu.git (x86-next). Changes from v5. 1. Eduardo has already queued couple of patches, submitting the rest here. 2. Major change is how the EPYC mode apic id encoding handlers are loaded. Added a boolean variable use_epyc_apic_id_encoding in X86CPUDefinition. The variable is will be used to tell if we need to use EPYC mode encoding. 3. Eduardo reported bysectability problem with x86 unit test code. Quashed the patches in 1 and 2 to resolve it. Problem was change in calling conventions of topology related functions. 4. Also set the use_epyc_apic_id_encoding for EPYC-Rome. This model is added recently to the cpu table. v5: https://lore.kernel.org/qemu-devel/158326531474.40452.11433722850425537745.st...@naples-babu.amd.com/ Generated the patches on top of git://github.com/ehabkost/qemu.git (x86-next). Changes from v4. 1. Re-arranged the patches 2 and 4 as suggested by Igor. 2. Kept the apicid handler functions inside X86MachineState as discussed. These handlers are loaded from X86CPUDefinitions. 3. Removed unnecessary X86CPUstate initialization from x86_cpu_new. Suggested by Igor. 4. And other minor changes related to patch format. v4: https://lore.kernel.org/qemu-devel/158161767653.48948.10578064482878399556.st...@naples-babu.amd.com/ Changes from v3. 1. Moved the arch_id calculation inside the function x86_cpus_init. With this change, we dont need to change common numa code.(suggested by Igor) 2. Introduced the model specific handlers inside X86CPUDefinitions. These handlers are loaded into X86MachineState during the init. 3. Removed llc_id from x86CPU. 4. Removed init_apicid_fn hanlder from MachineClass. Kept all the code changes inside the x86. 5. Added new handler function apicid_pkg_offset for pkg_offset calculation. 6. And some Other minor changes. v3: https://lore.kernel.org/qemu-devel/157541968844.46157.17994918142533791313.st...@naples-babu.amd.com/ 1. Consolidated the topology information in structure X86CPUTopoInfo. 2. Changed the ccx_id to llc_id as commented by upstream. 3. Generalized the apic id decoding. It is mostly similar to current apic id except that it adds new field llc_id when numa configured. Removes all the hardcoded values. 4. Removed the earlier parse_numa split. And moved the numa node initialization inside the numa_complete_configuration. This is bit cleaner as commented by Eduardo. 5. Added new function init_apicid_fn inside machine_class structure. This will be used to update the apic id handler specific to cpu model. 6. Updated the cpuid unit tests. 7. TODO : Need to figure out how to dynamically update the handlers using cpu models. I might some guidance on that. v2: https://lore.kernel.org/qemu-devel/156779689013.21957.1631551572950676212.stgit@localhost.localdomain/ 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://lore.kernel.org/qemu-devel/20190731232032.51786-1-babu.mo...@amd.com/ --- Babu Moger (13): hw/i386: Introduce X86CPUTopoInfo to contain topology info hw/i386: Consolidate topology functions machine: Add SMP Sockets in CpuTopology hw/i386: Remove unnecessary initialization in x86_cpu_new hw/i386: Update structures to save the number of nodes per package hw/i386: Rename apicid_from_topo_ids to x86_apicid_from_topo_ids hw/386: Add EPYC mode topology decoding functions target/i386: Cleanup and use the EPYC mode topology functions hw/i386: Introduce apicid functions inside X86MachineState i386: Check for apic id encoding target/i386: Enable new apic id encoding for EPYC based cpus models hw/i386: Move arch_id decode inside x86_cpus_init i386: Fix pkg_id offset for EPYC cpu models hw/core/machine.c | 1 hw/i386/pc.c | 15 ++- hw/i386/x86.c | 78 ++++++++++++++--- include/hw/boards.h | 2 include/hw/i386/topology.h | 195 +++++++++++++++++++++++++++++++------------ include/hw/i386/x86.h | 14 +++ softmmu/vl.c | 1 target/i386/cpu.c | 199 +++++++++++++------------------------------- target/i386/cpu.h | 3 + tests/test-x86-cpuid.c | 116 +++++++++++++++----------- 10 files changed, 361 insertions(+), 263 deletions(-) -- Signature