This is a note to let you know that I've just added the patch titled
x86/topology: Fix multiple packages shown on a single-package system
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
x86-topology-fix-multiple-packages-shown-on-a-single.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit aaeb3fa9575615e7b38d511c254f474efdfbca2f
Author: Zhang Rui <rui.zhang@xxxxxxxxx>
Date: Fri Oct 14 17:01:46 2022 +0800
x86/topology: Fix multiple packages shown on a single-package system
[ Upstream commit 2b12a7a126d62bdbd81f4923c21bf6e9a7fbd069 ]
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@xxxxxxxxx>
Signed-off-by: Zhang Rui <rui.zhang@xxxxxxxxx>
Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Reviewed-by: Len Brown <len.brown@xxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Link: https://lkml.kernel.org/r/20221014090147.1836-4-rui.zhang@xxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/arch/x86/kernel/cpu/topology.c b/arch/x86/kernel/cpu/topology.c
index 8678864ce712..696309749d62 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.
*/
