The following commit has been merged into the x86/urgent branch of tip:

Commit-ID: 2b12a7a126d62bdbd81f4923c21bf6e9a7fbd069 Gitweb: https://git.kernel.org/tip/2b12a7a126d62bdbd81f4923c21bf6e9a7fbd069 Author: Zhang Rui rui.zhang@intel.com AuthorDate: Fri, 14 Oct 2022 17:01:46 +08:00 Committer: Dave Hansen dave.hansen@linux.intel.com CommitterDate: Mon, 17 Oct 2022 11:58:52 -07:00

x86/topology: Fix multiple packages shown on a single-package system

CPUID.1F/B does not enumerate Package level explicitly, instead, all the APIC-ID bits above the enumerated levels are assumed to be package ID bits.

Current code gets package ID by shifting out all the APIC-ID bits that Linux supports, rather than shifting out all the APIC-ID bits that CPUID.1F enumerates. This introduces problems when CPUID.1F enumerates a level that Linux does not support.

For example, on a single package AlderLake-N, there are 2 Ecore Modules with 4 atom cores in each module. Linux does not support the Module level and interprets the Module ID bits as package ID and erroneously reports a multi module system as a multi-package system.

Fix this by using APIC-ID bits above all the CPUID.1F enumerated levels as package ID.

[ dhansen: spelling fix ]

Fixes: 7745f03eb395 ("x86/topology: Add CPUID.1F multi-die/package support") Suggested-by: Len Brown len.brown@intel.com Signed-off-by: Zhang Rui rui.zhang@intel.com Signed-off-by: Dave Hansen dave.hansen@linux.intel.com Reviewed-by: Len Brown len.brown@intel.com Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20221014090147.1836-4-rui.zhang@intel.com --- arch/x86/kernel/cpu/topology.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kernel/cpu/topology.c b/arch/x86/kernel/cpu/topology.c index 132a2de..f759281 100644 --- a/arch/x86/kernel/cpu/topology.c +++ b/arch/x86/kernel/cpu/topology.c @@ -96,6 +96,7 @@ int detect_extended_topology(struct cpuinfo_x86 *c) 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; + unsigned int pkg_mask_width; bool die_level_present = false; int leaf;

@@ -111,10 +112,10 @@ int detect_extended_topology(struct cpuinfo_x86 *c) 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); + pkg_mask_width = die_plus_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);

sub_index = 1; - do { + while (true) { cpuid_count(leaf, sub_index, &eax, &ebx, &ecx, &edx);

/* @@ -132,8 +133,13 @@ int detect_extended_topology(struct cpuinfo_x86 *c) die_plus_mask_width = BITS_SHIFT_NEXT_LEVEL(eax); }

+ if (LEAFB_SUBTYPE(ecx) != INVALID_TYPE) + pkg_mask_width = BITS_SHIFT_NEXT_LEVEL(eax); + else + break; + sub_index++; - } while (LEAFB_SUBTYPE(ecx) != INVALID_TYPE); + }

core_select_mask = (~(-1 << core_plus_mask_width)) >> ht_mask_width; die_select_mask = (~(-1 << die_plus_mask_width)) >> @@ -148,7 +154,7 @@ int detect_extended_topology(struct cpuinfo_x86 *c) }

c->phys_proc_id = apic->phys_pkg_id(c->initial_apicid, - die_plus_mask_width); + pkg_mask_width); /* * Reinit the apicid, now that we have extended initial_apicid. */