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Re: [PATCH v5 8/8] i386: Simplify CPUID_8000_001E for AMD
From: |
Igor Mammedov |
Subject: |
Re: [PATCH v5 8/8] i386: Simplify CPUID_8000_001E for AMD |
Date: |
Wed, 26 Aug 2020 14:19:05 +0200 |
On Fri, 21 Aug 2020 17:13:09 -0500
Babu Moger <babu.moger@amd.com> wrote:
> apic_id contains all the information required to build
> CPUID_8000_001E. core_id and node_id is already part of
> apic_id generated by x86_topo_ids_from_apicid_epyc.
> Also remove the restriction on number bits on core_id and
> node_id.
>
> Remove all the hardcoded values and replace with generalized
> fields.
>
> Refer the Processor Programming Reference (PPR) documentation
> available from the bugzilla Link below.
>
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=206537
> Signed-off-by: Babu Moger <babu.moger@amd.com>
> ---
> target/i386/cpu.c | 81
> ++++++++++++++++++++++++-----------------------------
> 1 file changed, 37 insertions(+), 44 deletions(-)
>
> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> index b29686220e..bea2822923 100644
> --- a/target/i386/cpu.c
> +++ b/target/i386/cpu.c
> @@ -385,58 +385,51 @@ static void encode_topo_cpuid8000001e(X86CPUTopoInfo
> *topo_info, X86CPU *cpu,
> uint32_t *ecx, uint32_t *edx)
> {
> X86CPUTopoIDs topo_ids = {0};
> - unsigned long dies = topo_info->dies_per_pkg;
> - int shift;
>
> x86_topo_ids_from_apicid(cpu->apic_id, topo_info, &topo_ids);
>
> *eax = cpu->apic_id;
> +
> /*
> - * CPUID_Fn8000001E_EBX
> - * 31:16 Reserved
> - * 15:8 Threads per core (The number of threads per core is
> - * Threads per core + 1)
> - * 7:0 Core id (see bit decoding below)
> - * SMT:
> - * 4:3 node id
> - * 2 Core complex id
> - * 1:0 Core id
> - * Non SMT:
> - * 5:4 node id
> - * 3 Core complex id
> - * 1:0 Core id
> + * CPUID_Fn8000001E_EBX [Core Identifiers] (CoreId)
> + * Read-only. Reset: 0000_XXXXh.
> + * See Core::X86::Cpuid::ExtApicId.
> + * Core::X86::Cpuid::CoreId_lthree[1:0]_core[3:0]_thread[1:0];
> + * Bits Description
> + * 31:16 Reserved.
> + * 15:8 ThreadsPerCore: threads per core. Read-only. Reset: XXh.
> + * The number of threads per core is ThreadsPerCore+1.
> + * 7:0 CoreId: core ID. Read-only. Reset: XXh.
> + *
> + * NOTE: CoreId is already part of apic_id. Just use it. We can
> + * use all the 8 bits to represent the core_id here.
> */
> - *ebx = ((topo_info->threads_per_core - 1) << 8) | (topo_ids.die_id << 3)
> |
> - (topo_ids.core_id);
> + *ebx = ((topo_info->threads_per_core - 1) << 8) | (topo_ids.core_id &
> 0xFF);
> +
> /*
> - * CPUID_Fn8000001E_ECX
> - * 31:11 Reserved
> - * 10:8 Nodes per processor (Nodes per processor is number of nodes + 1)
> - * 7:0 Node id (see bit decoding below)
> - * 2 Socket id
> - * 1:0 Node id
> + * CPUID_Fn8000001E_ECX [Node Identifiers] (NodeId)
> + * Read-only. Reset: 0000_0XXXh.
> + * Core::X86::Cpuid::NodeId_lthree[1:0]_core[3:0]_thread[1:0];
> + * Bits Description
> + * 31:11 Reserved.
> + * 10:8 NodesPerProcessor: Node per processor. Read-only. Reset: XXXb.
> + * ValidValues:
> + * Value Description
> + * 000b 1 node per processor.
> + * 001b 2 nodes per processor.
> + * 010b Reserved.
> + * 011b 4 nodes per processor.
> + * 111b-100b Reserved.
> + * 7:0 NodeId: Node ID. Read-only. Reset: XXh.
> + *
> + * NOTE: Hardware reserves 3 bits for number of nodes per processor.
> + * But users can create more nodes than the actual hardware can
> + * support. To genaralize we can use all the upper 8 bits for nodes.
> + * NodeId is combination of node and socket_id which is already decoded
> + * in apic_id. Just use it by shifting.
> */
> - if (dies <= 4) {
> - *ecx = ((dies - 1) << 8) | (topo_ids.pkg_id << 2) | topo_ids.die_id;
> - } else {
> - /*
> - * Node id fix up. Actual hardware supports up to 4 nodes. But with
> - * more than 32 cores, we may end up with more than 4 nodes.
> - * Node id is a combination of socket id and node id. Only
> requirement
> - * here is that this number should be unique accross the system.
> - * Shift the socket id to accommodate more nodes. We dont expect both
> - * socket id and node id to be big number at the same time. This is
> not
> - * an ideal config but we need to to support it. Max nodes we can
> have
> - * is 32 (255/8) with 8 cores per node and 255 max cores. We only
> need
> - * 5 bits for nodes. Find the left most set bit to represent the
> total
> - * number of nodes. find_last_bit returns last set bit(0 based). Left
> - * shift(+1) the socket id to represent all the nodes.
> - */
> - dies -= 1;
> - shift = find_last_bit(&dies, 8);
> - *ecx = (dies << 8) | (topo_ids.pkg_id << (shift + 1)) |
> - topo_ids.die_id;
> - }
> + *ecx = ((topo_info->dies_per_pkg - 1) << 8) |
> + ((cpu->apic_id >> apicid_die_offset(topo_info)) & 0xFF);
I'd prefer approach used in "[PATCH v4 1/3] i386: Simplify CPUID_8000_001E for
AMD"
that way numa node id in this leaf will aways be consistent with -numa CLI.
> *edx = 0;
> }
>
>
>
- [PATCH v5 4/8] Revert "hw/i386: Move arch_id decode inside x86_cpus_init", (continued)
- [PATCH v5 4/8] Revert "hw/i386: Move arch_id decode inside x86_cpus_init", Babu Moger, 2020/08/21
- [PATCH v5 5/8] Revert "i386: Introduce use_epyc_apic_id_encoding in X86CPUDefinition", Babu Moger, 2020/08/21
- [PATCH v5 6/8] Revert "hw/i386: Introduce apicid functions inside X86MachineState", Babu Moger, 2020/08/21
- [PATCH v5 1/8] hw/i386: Remove node_id, nr_nodes and nodes_per_pkg from topology, Babu Moger, 2020/08/21
- [PATCH v5 2/8] Revert "i386: Fix pkg_id offset for EPYC cpu models", Babu Moger, 2020/08/21
- [PATCH v5 3/8] Revert "target/i386: Enable new apic id encoding for EPYC based cpus models", Babu Moger, 2020/08/21
- [PATCH v5 7/8] Revert "hw/386: Add EPYC mode topology decoding functions", Babu Moger, 2020/08/21
- [PATCH v5 8/8] i386: Simplify CPUID_8000_001E for AMD, Babu Moger, 2020/08/21
- Re: [PATCH v5 8/8] i386: Simplify CPUID_8000_001E for AMD,
Igor Mammedov <=
- Re: [PATCH v5 0/8] Remove EPYC mode apicid decode and use generic decode, Dr. David Alan Gilbert, 2020/08/24
- Re: [PATCH v5 0/8] Remove EPYC mode apicid decode and use generic decode, Babu Moger, 2020/08/24
- Re: [PATCH v5 0/8] Remove EPYC mode apicid decode and use generic decode, Dr. David Alan Gilbert, 2020/08/25
- Re: [PATCH v5 0/8] Remove EPYC mode apicid decode and use generic decode, Igor Mammedov, 2020/08/25
- Re: [PATCH v5 0/8] Remove EPYC mode apicid decode and use generic decode, Dr. David Alan Gilbert, 2020/08/25
- Re: [PATCH v5 0/8] Remove EPYC mode apicid decode and use generic decode, Igor Mammedov, 2020/08/26
- Re: [PATCH v5 0/8] Remove EPYC mode apicid decode and use generic decode, Dr. David Alan Gilbert, 2020/08/26
- Re: [PATCH v5 0/8] Remove EPYC mode apicid decode and use generic decode, Igor Mammedov, 2020/08/27
- RE: [PATCH v5 0/8] Remove EPYC mode apicid decode and use generic decode, Babu Moger, 2020/08/27
- Re: [PATCH v5 0/8] Remove EPYC mode apicid decode and use generic decode, Igor Mammedov, 2020/08/28