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SubjectRe: [PATCH 03/11] x86 topology: Add CPUID.1F multi-die/package support
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On 2019/2/19 11:40, Len Brown wrote:
> From: Len Brown <len.brown@intel.com>
>
> Some new systems have multiple software-visible die within each package.
> The new CPUID.1F leaf can enumerate this multi-die/package topology.
>
> CPUID.1F a super-set of the CPUID.B "Extended Toplogy Leaf",
> and a common updated routine can parse either leaf.
>
> Legacy systems without CPUID.1F, and systems without multi-die/package
> hardware, will see no functional change from this patch series.
>
> Multi-die/package systems will use CPUID.B before this patch,
> and CPUID.1F after this patch. In the CPUID.B case, all die appear
> (incorrectly) to software as individual packages. In the CPUID.1F case,
> the package id's reflect reality, and die_id's become meaningful.
>
> Subsequent patches in this series update the kernel to be multi-die aware.
> In particular, some software needs to know the difference between
> a die-scope MSR and a package-scope MSR.
>
> Signed-off-by: Len Brown <len.brown@intel.com>
> Cc: linux-doc@vger.kernel.org
> Signed-off-by: Len Brown <len.brown@intel.com>
> ---
> Documentation/x86/topology.txt | 4 ++
> arch/x86/include/asm/processor.h | 4 +-
> arch/x86/kernel/cpu/topology.c | 82 ++++++++++++++++++++++++--------
> arch/x86/kernel/smpboot.c | 4 +-
> 4 files changed, 73 insertions(+), 21 deletions(-)
>
> diff --git a/Documentation/x86/topology.txt b/Documentation/x86/topology.txt
> index 06b3cdbc4048..8107b6cfc9ea 100644
> --- a/Documentation/x86/topology.txt
> +++ b/Documentation/x86/topology.txt
> @@ -46,6 +46,10 @@ The topology of a system is described in the units of:
>
> The number of cores in a package. This information is retrieved via CPUID.
>
> + - cpuinfo_x86.x86_max_dies:
> +
> + The number of dies in a package. This information is retrieved via CPUID.
> +
> - cpuinfo_x86.phys_proc_id:
>
> The physical ID of the package. This information is retrieved via CPUID
> diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
> index 33051436c864..f2856fe03715 100644
> --- a/arch/x86/include/asm/processor.h
> +++ b/arch/x86/include/asm/processor.h
> @@ -105,7 +105,8 @@ struct cpuinfo_x86 {
> int x86_power;
> unsigned long loops_per_jiffy;
> /* cpuid returned max cores value: */
> - u16 x86_max_cores;
> + u16 x86_max_cores;
> + u16 x86_max_dies;
> u16 apicid;
> u16 initial_apicid;
> u16 x86_clflush_size;
> @@ -117,6 +118,7 @@ struct cpuinfo_x86 {
> u16 logical_proc_id;
> /* Core id: */
> u16 cpu_core_id;
> + u16 cpu_die_id;
> /* Index into per_cpu list: */
> u16 cpu_index;
> u32 microcode;
> diff --git a/arch/x86/kernel/cpu/topology.c b/arch/x86/kernel/cpu/topology.c
> index 8f6c784141d1..6dce6ee77849 100644
> --- a/arch/x86/kernel/cpu/topology.c
> +++ b/arch/x86/kernel/cpu/topology.c
> @@ -15,33 +15,61 @@
> /* leaf 0xb SMT level */
> #define SMT_LEVEL 0
>
> -/* leaf 0xb sub-leaf types */
> +/* extended topology sub-leaf types */
> #define INVALID_TYPE 0
> #define SMT_TYPE 1
> #define CORE_TYPE 2
> +#define DIE_TYPE 5

This patch set is going to export die topology via sysfs
while the extended topology sub-leaf type could be one of followings:
SMT/Core/Module/Tile/Die according to CPUID.1F from SDM.

Why not choose to export module/tile topology as well?

>
> #define LEAFB_SUBTYPE(ecx) (((ecx) >> 8) & 0xff)
> #define BITS_SHIFT_NEXT_LEVEL(eax) ((eax) & 0x1f)
> #define LEVEL_MAX_SIBLINGS(ebx) ((ebx) & 0xffff)
>
> -int detect_extended_topology_early(struct cpuinfo_x86 *c)
> -{
> #ifdef CONFIG_SMP
> +/*
> + * Check if given CPUID extended toplogy "leaf" is implemented
> + */
> +static int check_extended_topology_leaf(int leaf)
> +{
> unsigned int eax, ebx, ecx, edx;
>
> - if (c->cpuid_level < 0xb)
> + cpuid_count(leaf, SMT_LEVEL, &eax, &ebx, &ecx, &edx);
> +
> + if (ebx == 0 || (LEAFB_SUBTYPE(ecx) != SMT_TYPE))
> return -1;
>
> - cpuid_count(0xb, SMT_LEVEL, &eax, &ebx, &ecx, &edx);
> + return 0;
> +}
> +/*
> + * Return best CPUID Extended Toplogy Leaf supported
> + */
> +static int detect_extended_topology_leaf(struct cpuinfo_x86 *c)
> +{
> + if (c->cpuid_level >= 0x1f)
> + if (check_extended_topology_leaf(0x1f) == 0)
> + return 0x1f;
>
> - /*
> - * check if the cpuid leaf 0xb is actually implemented.
> - */
> - if (ebx == 0 || (LEAFB_SUBTYPE(ecx) != SMT_TYPE))
> + if (c->cpuid_level >= 0xb)
> + if (check_extended_topology_leaf(0xb) == 0)
> + return 0xb;
> +
> + return -1;
> +}
> +#endif
> +
> +int detect_extended_topology_early(struct cpuinfo_x86 *c)
> +{
> +#ifdef CONFIG_SMP
> + unsigned int eax, ebx, ecx, edx;
> + int leaf;
> +
> + leaf = detect_extended_topology_leaf(c);
> + if (leaf < 0)
> return -1;
>
> set_cpu_cap(c, X86_FEATURE_XTOPOLOGY);
>
> + cpuid_count(leaf, SMT_LEVEL, &eax, &ebx, &ecx, &edx);
> /*
> * initial apic id, which also represents 32-bit extended x2apic id.
> */
> @@ -52,7 +80,7 @@ int detect_extended_topology_early(struct cpuinfo_x86 *c)
> }
>
> /*
> - * Check for extended topology enumeration cpuid leaf 0xb and if it
> + * Check for extended topology enumeration cpuid leaf, and if it
> * exists, use it for populating initial_apicid and cpu topology
> * detection.
> */
> @@ -60,46 +88,62 @@ int detect_extended_topology(struct cpuinfo_x86 *c)
> {
> #ifdef CONFIG_SMP
> unsigned int eax, ebx, ecx, edx, sub_index;
> - unsigned int ht_mask_width, core_plus_mask_width;
> + unsigned int ht_mask_width, core_plus_mask_width, die_plus_mask_width;
> unsigned int core_select_mask, core_level_siblings;
> + unsigned int die_select_mask, die_level_siblings;
> + int leaf;
>
> - if (detect_extended_topology_early(c) < 0)
> + leaf = detect_extended_topology_leaf(c);
> + if (leaf < 0)
> return -1;
>
> /*
> * Populate HT related information from sub-leaf level 0.
> */
> - cpuid_count(0xb, SMT_LEVEL, &eax, &ebx, &ecx, &edx);
> + cpuid_count(leaf, SMT_LEVEL, &eax, &ebx, &ecx, &edx);
> + c->initial_apicid = edx;
> core_level_siblings = smp_num_siblings = LEVEL_MAX_SIBLINGS(ebx);
> core_plus_mask_width = ht_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);
> + die_level_siblings = LEVEL_MAX_SIBLINGS(ebx);
> + die_plus_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);
>
> sub_index = 1;
> do {
> - cpuid_count(0xb, sub_index, &eax, &ebx, &ecx, &edx);
> + cpuid_count(leaf, sub_index, &eax, &ebx, &ecx, &edx);
>
> /*
> * Check for the Core type in the implemented sub leaves.
> */
> if (LEAFB_SUBTYPE(ecx) == CORE_TYPE) {
> core_level_siblings = LEVEL_MAX_SIBLINGS(ebx);
> + die_level_siblings = core_level_siblings;
> core_plus_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);
> - break;
> + }
> + if (LEAFB_SUBTYPE(ecx) == DIE_TYPE) {
> + die_level_siblings = LEVEL_MAX_SIBLINGS(ebx);
> + die_plus_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);
> }
>
> sub_index++;
> } while (LEAFB_SUBTYPE(ecx) != INVALID_TYPE);
>
> core_select_mask = (~(-1 << core_plus_mask_width)) >> ht_mask_width;
> -
> - c->cpu_core_id = apic->phys_pkg_id(c->initial_apicid, ht_mask_width)
> - & core_select_mask;
> - c->phys_proc_id = apic->phys_pkg_id(c->initial_apicid, core_plus_mask_width);
> + die_select_mask = (~(-1 << die_plus_mask_width)) >>
> + core_plus_mask_width;
> +
> + c->cpu_core_id = apic->phys_pkg_id(c->initial_apicid,
> + ht_mask_width) & core_select_mask;
> + c->cpu_die_id = apic->phys_pkg_id(c->initial_apicid,
> + core_plus_mask_width) & die_select_mask;
> + c->phys_proc_id = apic->phys_pkg_id(c->initial_apicid,
> + die_plus_mask_width);
> /*
> * Reinit the apicid, now that we have extended initial_apicid.
> */
> c->apicid = apic->phys_pkg_id(c->initial_apicid, 0);
>
> c->x86_max_cores = (core_level_siblings / smp_num_siblings);
> + c->x86_max_dies = (die_level_siblings / core_level_siblings);
> #endif
> return 0;
> }
> diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
> index ccd1f2a8e557..4250a87f57db 100644
> --- a/arch/x86/kernel/smpboot.c
> +++ b/arch/x86/kernel/smpboot.c
> @@ -393,6 +393,7 @@ static bool match_smt(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
> int cpu1 = c->cpu_index, cpu2 = o->cpu_index;
>
> if (c->phys_proc_id == o->phys_proc_id &&
> + c->cpu_die_id == o->cpu_die_id &&
> per_cpu(cpu_llc_id, cpu1) == per_cpu(cpu_llc_id, cpu2)) {
> if (c->cpu_core_id == o->cpu_core_id)
> return topology_sane(c, o, "smt");
> @@ -404,6 +405,7 @@ static bool match_smt(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
> }
>
> } else if (c->phys_proc_id == o->phys_proc_id &&
> + c->cpu_die_id == o->cpu_die_id &&
> c->cpu_core_id == o->cpu_core_id) {
> return topology_sane(c, o, "smt");
> }
> @@ -461,7 +463,7 @@ static bool match_llc(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
> */
> static bool match_die(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
> {
> - if (c->phys_proc_id == o->phys_proc_id)
> + if (c->cpu_die_id == o->cpu_die_id)
> return true;
> return false;
> }
>

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